Program booklet (PDF)

Programme and Abstracts

8th Biennial Canadian Optometry Schools Research Conference Waterloo, Ontario December 6 - 8, 2013

Table of Contents

Welcome……………………………………………………………………………………………….. 3 Program…………………………………………………………………………………………………. 4 List of posters…………………………………………………………………………………………. 7 Paper abstracts………………………………………………………………………………………. 9 Poster abstracts……………………………………………………………………………………… 30

Thank you to our sponsors

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8th Canadian Optometry Schools Research Conference

School of Optometry & Vision Science, University of Waterloo École d’optométrie, Université de Montréal

Co-Chairs: Vivian Choh

Susan J. Leat

Organizing committee: Jenniffer Fleet

Vasudevan Lakshminarayanan Daphne McCulloch

Chris Mathers

Elizabeth Reidt

Also thanks to: Andrea Carthew

B. Ralph Chou

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Jeff Hovis

Marilyn Smith

Welcome to COSRC 2013

Paul Murphy, Director, School of Optometry & Vision Science, Waterloo Canada has a strong reputation internationally for the quality of optometry education and research that is carried out in our two institutions. As a new arrival, it is pleasure to become part of this family of researchers, and to attend my first Canadian Optometry Schools Research Conference. Along with all of you, I look forward to discovering more about research happenings in our two Schools. I hope that these two days of presentations, networking and eating (!) will help in promoting our shared desire to find new ways of working together in education and research, to the benefit of optometry in Canada. On behalf of all of my colleagues, I welcome our friends and colleagues from Montreal to Waterloo. I hope that you enjoy your time here – we are delighted that you have come!

Christian Casanova, Directeur, École d’optométrie, Université de Montréal La tradition se poursuit ! Pour une huitième fois, les étudiants et professeurs des deux Écoles d’optométrie du Canada auront l’occasion de se retrouver dans une ambiance chaleureuse afin de présenter leurs plus récents travaux de recherche. Nos deux Écoles se distinguent non seulement par le fait qu’elles sont uniques au Canada, mais aussi par le fait qu’elles ont acquis une notoriété internationale en recherche. Cette conférence est importante. Ce sera en effet l’occasion, pour les uns, de se revoir et pour les autres, de tisser de nouveaux liens; des liens qui, je l’espère, continueront de se développer pour le bénéfice de la recherche en optométrie et en Sciences de la vision. Je remercie le comité organisateur de l’École de Waterloo, et en particulier les Drs Susan Leat et Vivian Choh, pour la préparation de ce bel évènement. Je remercie aussi le Dr Claude Giasson de l’École de Montréal qui a eu la gentillesse de bien vouloir agir comme « agent de liaison » entre nos deux institutions. Bonne conférence à tous ! Have a fruitful conference!

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Program Friday, December 6, 2013 McCabe’s Irish Pub & Grill

6:30-9:30pm Cocktail reception

Saturday, December 7, 2013 School of Optometry & Vision Science - Student Commons & Room 1129 8:30am

Registration

9:00am

Welcome: Paul Murphy

SESSION ONE Moderator:

Susan J. Leat

9:20am

Keynote Speaker

Sponsored by

Training the use of the peripheral retina in low vision patients: From inference to evidence in three decades Olga Overbury, Associate Professor, École d’optométrie, Université de Montréal 10:00am

Break

Sponsored by

SESSION TWO Moderators:

Claude Giasson/Elizabeth L. Irving

10:15am

Lagrange: A three-dimensional analytic lens design method for spectacles application Yang Lu, University of Waterloo

10:30am

Optical changes during emmetropization, lens induced myopia and recovery in early chick eye development Zheng Shao, University of Waterloo

10:45am

Functional imaging of the retina by optical imaging of retinal intrinsic signals Azadeh Naderian, Université de Montréal

11:00am

Blood and lymph vessel size and depth location across the limbal region Emmanuel Alabi, University of Waterloo

11:15am

The potential of optical imaging of the eye to provide a window on the brain in Alzheimer’s disease Melanie C.W. Campbell, University of Waterloo

POSTER SESSION 11:30am

Posters

12:30pm

Lunch

Sponsored by

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SESSION THREE Moderators:

Vivian Choh/Elvire Vaucher

1:30pm

The integrating sphere: A curse or a blessing in the measurement of contact lens transmittance? Claude J. Giasson, Université de Montréal

1:45pm

Effect of LATISSE on the ocular surface Etty Bitton, Université de Montréal

2:00pm

Vasculature of the reptilian spectacle Kevin van Doorn, University of Waterloo

2:15pm

Expression and function of endocannabinoids in the retina Bruno Cecyre, Université de Montréal

2:30pm

GPR55, a new actor in RGC axon guidance during the development Hosni Cherif, Université de Montréal

2:45pm

Break

Sponsored by

SESSION FOUR Moderator:

Jake Sivak

3:10pm

Keynote Speaker

Sponsored by

Blood flow demands and regulation in the human eye John Lovasik, Professor, École d’optométrie, Université de Montréal 4:00pm

Group photo and adjourn

Dinner and Dance Kitchener Waterloo Hotel & Conference Centre - Grand Ballroom 6:00pm

Cocktails (cash bar)

7:00pm

Dinner

8:30pm

Dance (featuring music from The Lost Faculties)

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Sunday, December 8, 2013 School of Optometry & Vision Science - Student Commons & Room 1129 8:30am

Registration

SESSION FIVE Moderator:

Jacques Gresset

9:00am

Keynote Speaker

Sponsored by

Ocular surface sensory processing in humans Trefford Simpson, Professor, School of Optometry and Vision Science, University of Waterloo 9:40am

Break

Sponsored by

SESSION SIX Moderators:

Vasile Diaconu/Patty Hrynchak

10:00am

Fabry disease: updates on a longitudinal study of its related ocular manifestations Langis Michaud, Université de Montréal

10:15am

A novel finding in the outflow pathway of eyes with primary open-angle glaucoma Thomas Freddo, University of Waterloo

10:30am

The perceived needs and availability of eye care services for older residents in Quebec long-term care facilities Hélѐne Kergoat, Université de Montréal

10:45am

A new treatment regimen for amblyopia using an iPod based game platform: A preliminary report Raiju J. Babu, University of Waterloo

11:00am

Protans are not always slower Jeff Hovis, University of Waterloo

11:15am

Presentation of The Murchison Callender Young Investigator Award

11:30am

Adjourn Boxed Lunch

Sponsored by

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POSTER SESSION 1

A new concept, LED-based, electronic anomaloscope Marc-Antoine Marchand-Thibeault, École d’optométrie de l'Université de Montréal

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Sparsity-based image denoising using a new nonlinear dictionary Damber Thapa, School of Optometry and Vision Science, University of Waterloo

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Perception of ophthalmic lens failure based on the Canadian Standards Association. Maureen Oyaide-ofenor, School of Optometry and Vision Science, University of Waterloo

4

Impact resistance of ophthalmic lenses at low temperatures B. Ralph Chou, School of Optometry and Vision Science, University of Waterloo

5

Ocular hazard of a thermal lance B. Ralph Chou, School of Optometry and Vision Science, University of Waterloo

6

The sub-foveal choroidal blood flow remains unchanged in senescence John V. Lovasik, École d’optométrie de l'Université de Montréal

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Imaging the corneal epithelium in two cases of advanced Keratoconus using ultra-high resolution OCT Luigina Sorbara, School of Optometry and Vision Science, University of Waterloo

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Effects of magnification on tear meniscus parameters using optical coherence tomography (OCT) images Marc Schulze, School of Optometry and Vision Science, University of Waterloo

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Comparative study of visual and optical performances between different soft contact lenses for high order aberrations. Anne-Josée Gauthier, École d’optométrie de l'Université de Montréal

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Inter- and intra-observer agreement using infrared meibography systems William Ngo, School of Optometry and Vision Science, University of Waterloo

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Acceptance of a silicone hydrogel multifocal lens in emmetropic presbyopes Jill Woods, School of Optometry and Vision Science, University of Waterloo

14

Management of post-LASIK keratoectasia with a piggyback contact lens system Lacey Haines, School of Optometry and Vision Science, University of Waterloo

15

Estimating in-vivo contact lens wettability through tear film hydrodynamics Jalaiah Varikooty, School of Optometry and Vision Science, University of Waterloo

16

Contact lens solution efficacy at removing in vitro tear film constituents from silicone hydrogel contact lenses: An atomic force microscopy study Steven Cheung, School of Optometry and Vision Science, University of Waterloo

17

The impact of hand washing time and soap on the surface of silicone hydrogel contact lenses: A pilot study Etty Bitton, École d’optométrie de l'Université de Montréal

18

In vitro uptake and release of natamycin Dex-b-PLA nanoparticles from silicone hydrogel contact lens materials Chau-Minh Phan, School of Optometry and Vision Science, University of Waterloo

19

Method optimization to quantify oxidative stress in tear film lipids Hendrik Walther, School of Optometry and Vision Science, University of Waterloo

20

Efficacy of contact lens solutions against achromobacter xylosoxidans biofilms using confocal microscopy David J. McCanna, School of Optometry and Vision Science, University of Waterloo

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Membrane permeability of staphylococcus aureus aggregates exposed to contact lens care solutions David J. McCanna, School of Optometry and Vision Science, University of Waterloo Tear film cytokine analyses using a novel electrochemiluminescent array technique Lakshman N. Subbaraman, School of Optometry and Vision Science, University of Waterloo Quantification of Lipocalin-1 in tears and contact lens deposits using a sandwich ELISA technique Rajan Mistry, School of Optometry and Vision Science, University of Waterloo Extraction versus in situ techniques for measuring surface-adsorbed lysozyme Brad Hall, School of Optometry and Vision Science, University of Waterloo In vitro cell models for drug release studies from contact lenses Saman Mohammadi, Systems Design Engineering, University of Waterloo Release of ciprofloxacin and dexamethasone from commercial contact lens materials Alex Hui, School of Optometry and Vision Science, University of Waterloo Untangling the mysteries of the tear film neutrophil Cameron Postnikoff, Systems Design Engineering, University of Waterloo

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Impact of environmental changes on in vitro corneal epithelial wound healing Emma Dare, School of Optometry and Vision Science, University of Waterloo Comparison of Prestoblue, LamarBlue and MTT in evaluation cell viability of human corneal epithelial cells Manlong Xu, School of Optometry and Vision Science, University of Waterloo The influence of the energy drinks on the blood oxygenation of the optic nerve’s capillaries Liliane Linh Lan Le-Ngoc, École d’optométrie de l'Université de Montréal

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31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61/62

Suppression of pro-inflammatory gene expression by PPARγ activation and B1 receptor antagonism in the retina of type 2 diabetic Menakshi Bhat, École d’optométrie de l'Université de Montréal Microvascular alterations in the retina of type 2 diabetic rats Soumaya Hachana, École d’optométrie de l'Université de Montréal Stimulation of proliferation in the chick retina following optic nerve section and growth factor treatment Stacey Chong, School of Optometry and Vision Science, University of Waterloo The cannabinoid receptors CB1 and CB2 are differentially expressed in the retina of vervet monkeys Joseph Bouskila, École d’optométrie de l'Université de Montréal Distribution pattern of the endocannabinoid system throughout the dorsal lateral geniculate nucleus of non-human primates Pasha Javadi, École d’optométrie de l'Université de Montréal Repetitive Donepezil administration combined with visual exposure increases visual acuity in rats Chamoun Mira, École d’optométrie de l'Université de Montréal Functional properties of primary visual cortex in dopamine D2-receptor deficient mice Bruno Oliveira Ferreira de Souza, École d’optométrie de l'Université de Montréal Activation of the primary visual cortex but not the basal forebrain following prefrontal electrical stimulation Hoang Nam Nguyen, École d’optométrie de l'Université de Montréal Muscarinic receptors knock-out mice present an impaired functional organization of their visual cortex Marianne Groleau, École d’optométrie de l'Université de Montréal Impact of pulvinar on cortical processing in primary visual cortex Jimmy Lai, École d’optométrie de l'Université de Montréal Biochemical composition and spectral transmittance of the reptilian spectacle Kevin van Doorn, School of Optometry and Vision Science, University of Waterloo Supernumerary Puncta: An unusual case of seeing double Zoé Lacroix, École d’optométrie de l'Université de Montréal A novel method for removing inter-observer bias in optical pachometry Amir Moezzi, School of Optometry and Vision Science, University of Waterloo Self vs. examiner-guided administration of ocular surface disease index (OSDI) Sruthi Srinivasan, School of Optometry and Vision Science, University of Waterloo Meibography and lipid layer evaluation in Sjogren’s Syndrome Sruthi Srinivasan, School of Optometry and Vision Science, University of Waterloo Test-retest characteristics of standard automated perimetry in glaucoma as a function of eccentricity Sarah L. Bishop, School of Optometry and Vision Science, University of Waterloo Correction of meridional aniseikonia: A case report Leslie Suzanne McNeill, School of Optometry and Vision Science, University of Waterloo Can vergence adaptation explain convergence insufficiency and its remediation? William R. Bobier, School of Optometry and Vision Science, University of Waterloo Symptomatology of convergence insufficiency in Parkinson's disease Stéphanie Chriqui, École d’optométrie de l'Université de Montréal Can the legibility of prescription medication labels for older adults and adults with visual impairment be improved? Antonio Carbonara, School of Optometry and Vision Science, University of Waterloo Visual correlates of balance, mobility and fear of falling in older adults Mohammed M. Althomali, School of Optometry and Vision Science, University of Waterloo Evaluation of a pre-season vision screening program in varsity athletes Kristine Dalton, School of Optometry and Vision Science, University of Waterloo Can suppression explain reduced fixational instability in amblyopia Rajkumar Nallour Raveendran, School of Optometry and Vision Science, University of Waterloo Evaluation of central and peripheral visual-motor reaction times in varsity athletes Amy Willms, School of Optometry and Vision Science, University of Waterloo Summary of Waterloo eye study findings: Age and visual function Elizabeth Irving, School of Optometry and Vision Science, University of Waterloo The role of normal binocular vision in the development of fine motor skills Lisa W. Christian, School of Optometry and Vision Science, University of Waterloo Evaluation of interprofessional collaboration and education in optometry Lisa W. Christian, School of Optometry and Vision Science, University of Waterloo Best practices in history-taking: a qualitative study Caroline Faucher, École d’optométrie de l'Université de Montréal Clinical reasoning education using team-based learning: Optometry student perceptions Patricia Hrynchak, School of Optometry and Vision Science, University of Waterloo Student satisfaction with experiential learning in external clinics Tammy Labreche, School of Optometry and Vision Science, University of Waterloo The Macular Assessment Program Mira Acs, Toronto

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Saturday, December 7

9:20am

Keynote Address

Olga Overbury, Associate Professor, École d’optométrie de l'Université de Montréal Adjunct Professor, Department of Ophthalmology, McGill University Dr. Olga Overbury received her doctorate in Experimental Psychology from Concordia University. After her graduate studies, she held a postdoctoral fellowship at the Western Blind Rehabilitation Center of the Veterans Affairs Department in Palo Alto, California. Her research program encompasses the sensory, perceptual, and psychosocial aspects of visual impairment. She is interested in visual pathologies that affect older people and her research involves the comprehensive assessment of vision before and after medical and surgical intervention. Additionally, Dr. Overbury’s research examines the possibility of improving the use of remaining vision and the development of appropriate outcome measures to assess the effectiveness of various training techniques. Finally, given that visual impairment can have a significant psychological effect on people experiencing the loss, as well as on their family members and social circle, her research program also encompasses the psychosocial aspects of visual loss in later life. Training the use of the peripheral retina in low vision patients: From inference to evidence in three decades It is well known that the majority of older people who are visually impaired no longer have a functioning fovea due to age-related macular degeneration. Since the 1970s low vision research and rehabilitation programs have focused on the use of the peripheral retina to accomplish tasks such as reading, face recognition, and visual search. Only recently, however, has emerging technology allowed researchers and clinicians to better understand the underlying processes of this behavioural change. This talk will briefly review the history of eccentric viewing training and describe, in more detail, current studies examining techniques that aim to improve the use of the peripheral retina. One such ongoing investigation is comparing the effectiveness of fixation-stability training with the improvement of eye movements, using a scanning laser ophthalmoscope and a binocular eye tracker. The results of this and similar studies will be discussed from the perspective of what evidence we have concerning the effectiveness of the training techniques that have been implemented over the last three decades.

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10:15am

Lagrange: A three-dimensional analytic lens design method for spectacles application Presenting Author: Yang Lu, School of Optometry and Vision Science, University of Waterloo Co-Author: V. Lakshminarayanan, School of Optometry and Vision Science, University of Waterloo Purpose Traditional optical design is a numerical process based on ray tracing theory. The traditional method has the limitation of the application of the spectacle lens because of the necessity of initial configurations and the evaluations of the aberrations of the lens. This study is an initial attempt to investigate an analytic lens design method, Lagrange, which has a potential application in modern spectacle lens for eliminating the limitation of the traditional method. Methods The Lagrange method can derive the differential equations of an optical system in term of its output and input. The generalized Snell’s law in three-dimensional space and the normal of a refracting surface in fundamental differential geometry are applied to complete the derivation. Based on the Lagrange method, the solution of a refracting surface to perfectly image a point at infinity is obtained. Results A Plano-convex lens and a Bi-convex lens from this solution were designed. In spherical coordinates, the differential equations of the single surface system and its solution were obtained. The optical design software, ZEMAX, was used to simulate the lenses and evaluate their image qualities. The results illustrated that both of the two lenses were aberration free. Conclusions The Lagrange solves unknown lens surface based on definable inputs and outputs according to customer requirements. The method has the potential applicants of the modern customized lens design. Moreover, the definable outputs make the simultaneous elimination of several aberrations possible.

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10:30am

constant in the previously goggled eye while power initially decreases, contributing to emmetropization. In summary, optical power changes are important in normal growth and during recovery from LIM. More accurate measurements are needed to determine the changes between normal and goggled eyes.

Optical changes during emmetropization, lens induced myopia and recovery in early chick eye development Presenting Author: Zheng Shao, School of Optometry and Vision Science, University of Waterloo

Acknowledgement(s): Our appreciation is extended to O Stanley and K Tuck for their assistance. This research was supported by NSERC Canada, CRC Program & CFI. Disclosure(s): Authors have no commercial relationships relevant to this work.

Co-Authors: K. Bunghardt, Physics and Astronomy, University of Waterloo; M.L. Kisilak, School of Optometry and Vision Science, Department of Physics and Astronomy, University of Waterloo; E.L. Irving, School of Optometry and Vision Science, University of Waterloo; M.C.W. Campbell, School of Optometry and Vision Science, Department of Physics and Astronomy, University of Waterloo, Guelph Waterloo Physics Institute Purpose The prevalence of myopia is increasing worldwide. Normal eyes emmetropize in childhood. Changes in mean ocular refraction (MOR) in normal growth and development of myopia can be due to changes in either dioptric length or optical power. We analyzed the contributions of eye power and optical length to emmetropization, lens induced myopia (LIM), and recovery in the early developing chick eye. With this knowledge, we hope to better understand the causes of myopia. Methods Literature values of chicken schematic eye parameters were used to study emmetropization by plotting the rate of change of MOR, eye power and optical length as a function of age up to day 15. For LIM and recovery, two of our experimental data sets (20 chicks) with eye length (ultrasound) and MOR (retinoscopy or Hartmann-Shack) were considered. A -15D goggle was unilaterally placed on the chicks’ eye from the day of hatching to day 7 then removed; measurements continued up to day 15. Calculations of dioptric length and eye power were made as a function of age and treatment. The assumption that the power in the goggled eye was the same as in the control eye was tested. Results During normal emmetropization, MOR showed an exponential decrease with age. MOR varies linearly with the amount of retinal blur present. The variation of eye power with age was similar when calculated from age dependent schematic eye models and when inferred from optical length and MOR. Changes in optical length and eye power are biphasic. Eye power changes more rapidly from hatching until about day 4 dependent on strain; and it is approximately proportional to the retinal blur. The change in dioptric length is larger than the change in eye power until day 6. Then both eye power and dioptric length decrease linearly with time but nonlinearly with retinal blur. For LIM and its recovery, MOR of the goggled eye showed a rapid, almost complete emmetropization to the -15 D goggle by day 7 primarily due to eye length changes. The dioptric length for the previously goggled eye was not significantly different between days 7 and 8 and days 8 and 9, but power decreased until day 8. Beginning between days 7 and 8, the difference in power between the goggled and control eyes began to decrease significantly. After goggle removal, recovery from myopia was complete by day 9.After day 9, the goggled eye emmetropized similarly to the control eye. Conclusions Changes in both dioptric length and eye power contribute to the reduction of MOR during normal emmetropization but length changes dominate. Emmetropization to the goggle is mainly due to an increase in eye length. Emmetropization, following goggle removal, is more rapid than to the goggle. Optical length remains relatively

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10:45am

Functional imaging of the retina by optical imaging of retinal intrinsic signals Presenting Author: Azadeh Naderian, École d’optométrie de l'Université de Montréal Co-Author(s): L. Bussières, École d’optométrie de l'Université de Montréal; S. Thomas, École d’optométrie de l'Université de Montréal; F. Lesage, École d’optométrie de l'Université de Montréal; C. Casanova, École d’optométrie de l'Université de Montréal Purpose Functional imaging of the retina can be useful for studying retinal physiology and for accurate diagnosis of retinal diseases. Optical imaging of retinal intrinsic signals (RIS) is a relatively new method that measures light reflectance changes of the retina that occur following visual stimulation. Interestingly, the exact physiological mechanisms behind RIS remain to be determined. Thus, the aim of this study is to examine the relation between stimulation conditions and RIS characteristics and to determine the cellular activity of which retinal cell-types is at the origin of RIS. Methods Experiments were performed on anesthetized and paralyzed rabbits in scotopic conditions. Optical imaging of retinal intrinsic signals was performed using a fundus camera capturing the reflected light from the retina, illuminated by near infrared light (750 nm). The activitydependency of RIS was evaluated by observing the effects of stimulus intensity and duration on intrinsic responses amplitude. Retinal stimulation consisted of a diffuse flash of green light (546 nm). The cellular origin of RIS was studied by dissecting the outer retina from the inner retina through intra-vitreal injection of aspartate (final vitreous concentration of 25 mM). Electroretinograms were also recorded to monitor retinal physiology and confirm the effects of drug injections. Results A non-linear proportional relationship was observed between intrinsic responses amplitude and both the intensity and duration of the stimuli. When increasing stimulus intensity from 1.5 log cd.s.m‐2 to 2.5 log cd.s.m‐2, RIS increased by 27 % (n= 7). Regarding the experiments designed to determine the origin of RIS, RIS were completely abolished after injection of aspartate. Conclusions Our results indicate that: 1) The RIS are dynamic signals that can reflect the level of retinal activity. 2) In rabbits, the inner retina cellular activity is at the origin of RIS whereas the influence of photoreceptors’ activity per se is negligible.

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11:00am

Blood and lymph vessel size and depth location across the limbal region Presenting Author: Emmanuel Alabi, School of Optometry and Vision Science, University of Waterloo Co-Authors: N. Hutchings, School of Optometry and Vision Science, University of Waterloo; K. Bizheva, Department of Physics and Astronomy, University of Waterloo; T.L. Simpson, School of Optometry and Vision Science, University of Waterloo Purpose To compare the morphometric characteristics of blood and lymph vessels such as size and depth location, and investigate their relationship within the superior and inferior limbal regions. Methods Cross-sectional images of the human corneo-scleral limbus were acquired with a research-grade ultra-high resolution optical coherence tomographer (UHR-OCT) from 14 healthy subjects after manual retraction of the upper and lower eyelid. The UHR-OCT provides axial and lateral resolution in biological tissue of ~3μm and ~18μm, respectively. 3D stacks of OCT images (1000 x 1024 x 256) were acquired of the transition from cornea to bulbar conjunctiva at the superior and inferior limbal region. All visible vessels within this region were measured using an Image J (NIH Image) circle or ellipse tool. Quantitative differences in vessel size and depth in the limbal region were analyzed using repeated measured ANOVA. The relationship between superior and inferior limbal vessel size and depth was computed using the Pearson correlation coefficient. R (R Foundation) and SPSS (IBM) were used for all data analyses. Results The average vessel sizes for superior and inferior limbus were 29.28µm ± 17.649 µm (SD) and 23.68µm ± 18.118µm (SD) respectively. The average vessel depths for superior and inferior limbus were 176.76µm ± 108.698µm (SD) and 205.62µm ± 131.991µm (SD) respectively. The vessels within the superior limbus were on average larger than the vessels found in the inferior limbus (RM-ANOVA POS p = 0.004), and the vessels within the inferior limbus were on average deeper than the vessels found within the superior limbus (RM-ANOVA POS p = 0.042). There was a positive linear relationship between limbal vessel depth and size within the superior and inferior limbus with a Pearson correlation coefficient of 0.803 and 0.754, respectively. There were on average 9 vessels per subject within the superior limbal region as compared to 13 vessels per subject with the inferior limbal region. Conclusions This study provided evidence that the UHR-OCT is capable of imaging (and therefore measuring) morphometric characteristics such as the size and depth of vessels within the limbus. A positive linear association between vessel depth and size was identified in the superior and inferior limbal regions. The results of this study suggest a difference in the size and depth of vessels across different positions of the limbus and this may be indicative of adaptations to chronic hypoxia caused by the constant covering of the superior limbus by the upper eyelid. Acknowledgement(s): Natural Sciences and Engineering Research Council of Canada; Canadian Institute of Health Research. Disclosure(s): None

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11:15am

details of the fluorescent structures found near the retinal surface and of the Optic Nerve Fibre Layer (ONFL) at nanoscale resolution. In other ex vivo retinas, we measured the interaction of the amyloid beta deposits with polarized light. The polarization properties of the deposits differed from those of bare glass and from the surrounding retinal tissue.

The potential of optical imaging of the eye to provide a window on the brain in Alzheimer’s disease Presenting Author: Melanie C. W. Campbell, School of Optometry and Vision Science, Department of Physics and Astronomy, University of Waterloo

Conclusions The size, position and optical properties of the structures have influenced our design of in vivo imaging methods. Ours are the first measurements of the polarization properties of unstained amyloid beta. We believe that the imaging methods that we are developing could become a more accessible, less invasive and less expensive technique than others under development for the diagnosis of Alzheimer’s disease.

Co-Authors: F. J. Avila, Department of Physics and Astronomy, School of Optometry and Vision Science, University of Waterloo and Laboratorio de Óptica, Universidad de Murcia, Campus de Espinardo, 30071 Murcia, Spain; L. Emptage, Department of Physics and Astronomy, University of Waterloo; M.L. Kisilak, Department of Physics and Astronomy, School of Optometry and Vision Science, University of Waterloo; Y. Choi, Department of Biology, University of Waterloo; Z. Leonenko, Department of Physics and Astronomy, Department of Biology, University of Waterloo; J.M. Bueno, Laboratorio de Óptica, Universidad de Murcia, Campus de Espinardo, 30071 Murcia, Spain

Acknowledgement(s): This research was supported by CIHR and NSERC Canada. Disclosure(s): Campbell and Bueno hold patents in polarization imaging of the retina. Campbell has a patent pending in the diagnosis of Alzheimer's disease through imaging the retina.

Purpose As well as measuring the optical quality of the eye more precisely, we can correct optical blur with adaptive optics and produce high resolution in vivo images of individual retinal cells, including cones in retinal dystrophies. Imaging the retina may provide a “window on the brain”, potentially enabling diagnosis of neural conditions. Alzheimer’s disease is a neurodegenerative disease, characterized by the formation of insoluble fibrils (plaques) composed of amyloid beta proteins. There is currently no definitive diagnosis available prior to death. Neurotoxic effects of amyloid beta have been demonstrated in the retinas of animal models and human retinal function is affected by Alzheimer’s Disease. However, amyloid beta had not been found reliably in the retinas of those diagnosed with Alzheimer’s Disease. In the past, amyloid beta has been imaged with the dye, Congo Red demonstrates birefringence when illuminated under cross polarization. However, the polarization properties of unstained amyloid beta deposits are unknown. Methods Whole mounts were prepared of post-mortem retinas of 12 subjects with Alzheimer’s Disease (AD) and 12 age matched subjects without Alzheimer’s Disease or dementia. Retinas were stained with thioflavin S and examined using a combined AFM/fluorescence microscope. In some retinas, positive for AD or dementia, fluorescently labeled structures near the retinal surface and nearby structures were compared to phase and morphological images obtained by Atomic Force Microscopy (AFM). Simultaneous imaging in fluorescence and AFM, allowed direct image overlay. The polarization properties of the amyloid beta deposits deposited on glass and those found in the ex vivo retinas were imaged under crossed polarisers along with the surrounding retina. In addition spatially defined Mueller matrices were found by imaging in a microscope modified with an adjustable polarization generator and an analyzer. Results We have confirmed the presence of amyloid beta in the ex vivo neural retina of those with the disease and not in age matched normal donors without the disease with sensitivity and specificity each at 75%. Thioflavin S fluorescence, indicative of amyloid-beta was observed preferentially in anterior retinal layers. Globular, fibrillar and donut-like structures were observed. Co-located AFM images confirmed that some fluorescent structures were located close to the surface of the retina. Phase and morphological differences, indicating a differing material, were observed between these structures and surrounding tissue. AFM gave three dimensional

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1:30pm

The integrating sphere: A curse or a blessing in the measurement of contact lens transmittance? Presenting Author: Claude J. Giasson, École d’optométrie de l'Université de Montréal Co-Author(s): Montréal

V. Diaconu, École d’optométrie de l'Université de

Purpose The ANSI (American National Standards Institute) standard dictates that contact lens percent transmittance (%T) be measured with an integrating sphere (IS) to include the scatter (total T). However, ISs are not ideal devices and their use is based on assumptions that may not be met when contact lens T is measured. This study compared 1) contact lens transmittance obtained with and without an IS and 2) the signal/noise ratio (S/N) obtained with and without an IS. Method After a baseline %T measurement of a quartz chamber filled with saline, the total and direct %T of the chamber with a contact lens (Encore 100) were measured 4 times with and without an integrating sphere using a scanning spectrophotometer (Cary 5000, Varian) in the range of 200 to 800 nm. Differences between total and direct T were tested for significance at 550 nm with an independent t test. In other measurements performed under similar conditions, the raw signal intensity was measured with the unobstructed beam and, then, with the measuring cell in the chamber of the spectrophotometer. Results There was no significant difference at 550 nm between the total (100.8 ± 8.5%) and direct transmittance (98.3 ± 0.2%) of the Encore 100 contact lens when analyzed with an independent t test. Upon the addition of the wet cell and saline, the signal was at 500 nm 92.2 ± 1.4 and 45.8 ± 0.2 % of the value of the unobstructed beam with and without the IS, respectively. At 250 nm, corresponding values were 61.6 ± 0.9 and 36.8 ± 0.5 % of the original signal. Conclusions The difference between the total and direct %T of the contact lens was small. The signal was drastically decreased and the noise increased by the addition of a wet cell with the IS in place. Considering these results and the fact that the contact lens cannot be positioned tangentially to the inner wall of the IS (an assumption required by IS), it is necessary to reconsider the use of IS in the standard of contact lens transmittance. Acknowledgement(s): Canada Foundation for Innovation Disclosure(s): None

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1:45pm

Effect of LATISSE on the ocular surface Presenting Author: Etty Bitton, École d’optométrie de l'Université de Montréal Co-Author(s): C. Courey, École d’optométrie de l'Université de Montréal; P. Giancola, École d’optométrie de l'Université de Montréal; V. Diaconu, École d’optométrie de l'Université de Montréal; J. Wise, École d’optométrie de l'Université de Montréal Purpose LATISSE® is used for the treatment of hypotrichosis (insufficient lashes). The active ingredient is bimatoprost, similar to LUMIGAN® (for the treatment of glaucoma) with benzalkonium chloride (BAK) as the preservative. Instead of being instilled in the eye (as is the case for LUMIGAN®), LATISSE® is applied on the upper lid margin. It is well established that chronic use of products having BAK, as in glaucoma users, has found to be irritating to the ocular surface. The aim of this study was to evaluate if LATISSE®, even though it is applied to the lid margin, has a similar effect on the ocular surface. Methods Non-dry eye (DE) volunteers had subjective symptoms (comfort, drying, burning, grittiness, vision), tear film stability, osmolarity, length of lashes, conjunctival redness (saturation and tint using a photochromometer), and intraocular pressure (IOP) evaluated prior to the use of LATISSE® and 1 and 2 months following the recommended use of the product. Results Twenty-eight women (n=28, ages 18-29, avg 23.8 ± 3.5yrs) enrolled in the study. Eleven dropped out of the study with 5 due to discomfort and 6, which were lost to follow-up. Average lash length increased from 6.52 to 8.96mm at the end of the 2 months (p=0.001). All symptoms changed negatively throughout, however comfort (p=0.07) and dryness (p=0.04) were the symptoms that changed the most in the first month. Osmolarity, tear stability, OSDI scores, conjunctival saturation/tint and IOP did not change significantly (p>0.05) with the use of LATISSE® during the 2 month utilisation. Conclusion LATISSE® effectively treats hypotrichosis and lengthens eyelashes, as quickly as 2 months. Of those that use the product for cosmetic reasons alone, they will most probably use it long term, hence potentially increasing the likelihood of irritation to the ocular surface. Even though Canadian optometrists cannot prescribe LATISSE® at this time, it is important that they discuss potential symptoms and look for irritation of the ocular surface with prolonged use. Further studies are needed to determine if the cause of dryness and discomfort are linked to the preservative, BAK. Acknowledgement(s): Support from COETF and Allergan Canada Disclosure(s): This poster was presented at the 2012 AAO

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2:00pm

Vasculature of the reptilian spectacle Presenting Author: Kevin van Doorn, School of Optometry and Vision Science, University of Waterloo Purpose The ""reptilian spectacle"" is a layer of transparent skin that overlays the eyes of snakes, most geckos, and a disparate array of other lizards. An ocular protective structure par excellence, the spectacle allows animals to remain vigilant during activities that would otherwise require the eyelids to close, such as slithering through brush, striking prey, or in arid environments where blowing grit and evaporative water loss present threats respectively to the eyes and to the whole organism. This remarkable adaptation comes with a significant drawback however: the spectacle's vascularity, a characteristic that is expected to have a deleterious impact on vision, due to scatter and the potential to resolve the spectacle vessels as entoptic phenomena. Because the walls of the spectacle blood vessels are transparent, any visual impact would be attributable almost exclusively to the blood cells flowing through them. The research presented here was based on the hypothesis that spectacle blood flow can be dynamically adjusted, for example by constricting the vessels to empty them of blood cells, to minimize their effect on vision when the animal is visually engaged. Methods Blood flow through the spectacles of coachwhip snakes (Masticophis flagellum; Colubridae) was imaged under near-infrared illumination while the animals were at rest and while visually engaged. The animals were held in transparent containers to constrain them without physically restraining them, thus minimizing stress and sympathetic responses. Specifically, the presence or absence of blood flow through the spectacle vasculature was recorded to 1 second accuracy. Three snakes were each subjected to 7 trials during which their baseline spectacle blood flow was observed for 30 minutes before being presented with a visual stimulus in the form of a whitecoated human performing routing lab activities within 2 meters of the animal. This stimulus was twice presented for 8 minutes each time, separated by a span of 16 minutes. Analyses were done on the proportion of blood flow before, during, and after the stimuli to determine if visual engagement alters the blood flow characteristics of the spectacle. Results Baseline (i.e. resting) spectacle blood flow was found to follow a cyclical pattern of vessel dilation and full constriction. The mean durations of these periods with and without flow were 57 s (SD = 49 s) and 115 s (SD = 80 s) respectively. This difference was statistically significant (P = 0.000). When the visual stimulus was presented, the total proportion of blood flow was reduced from baseline (P = 0.011), resulting in shorter periods of flow (M = 33.5 s, SD = 17.6 s). Flow patterns immediately returned to baseline during the 8 minutes following the removal of the stimulus. Conclusions Spectacle blood flow is discontinuous at rest, which at specific ambient temperatures results in a greater proportion of time without blood flow. When a snake is visually engaged, the proportion of spectacle blood flow is significantly reduced. As a result, any negative visual effects owing to the spectacle vasculature are nullified in times of visual need.

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2:15pm

Expression and function of endocannabinoids in the retina Presenting Author: Bruno Cecyre, École d’optométrie de l'Université de Montréal Co-Author(s): S. Thomas, École d’optométrie de l'Université de Montréal; C. Casanova, École d’optométrie de l'Université de Montréal; J.-F. Bouchard, École d'optométrie de Université de Montréal Purpose In the last decades, there has been an increased interest in the physiological roles of the endocannabinoid (eCB) system and its main receptors, cannabinoid receptor types 1 (CB1R) and 2 (CB2R). There is great interest in eCBs for their role in neuroplasticity as well as for therapeutic use in numerous conditions, including pain, neurodegenerative diseases, glaucoma and inflammatory diseases, among others. However, there has been relatively far less research in the eye and retina compared with the brain and other systems. Some constituents of the eCB system, i.e., ligands, synthesizing and catabolic enzymes, and receptors, were found in different retinal cell types in several species. The activation of cannabinoid receptors modulates neurotransmitter release from photoreceptors and could also affect bipolar cell synaptic release. However, the impact of cannabinoid receptors on the retinal function as a whole is currently unknown. Methods We investigated the expression pattern of several components of the eCB system, such as the CB1R and CB2R as well as synthesizing and catabolic enzymes. The rodent retina represents an interesting and valuable model for studying CNS, as it contains well-identified cell types with clearly established and distinct development timelines. We also investigated the function of cannabinoid receptors in the retina by recording electroretinographic responses (ERG) from mice lacking either CB1R or CB2R. Results Our results indicate that the eCB system is expressed in the rodent retina, from birth to adulthood. Both CB1R and CB2R are largely expressed in the retina, as synthesizing enzyme DAGLα and degradative enzymes FAAH and MGL. In electroretinography, our results show that, under scotopic conditions, the amplitudes of the awave of the ERG were increased in CB2R KO mice, while they remained unchanged in CB1R KO mice. No differences were observed in the retinal function of CB1R KO mice compared to WT animals. Conclusion Overall, these results suggest that the eCB system plays a key role in the development and function of the retina and that CB1R and CB2R have different roles in visual processing.

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2:30pm

GPR55 signaling affects retinal projection growth and axonal navigation.

GPR55, a new actor in RGC axon guidance during the development

Conclusions Overall, these findings establish for the first time the role played by GPR55 and the mechanism by which it influences axon guidance during the development of the visual system. These results suggest that GPR55 modulates the navigation of retinal projections and plays an important role in the development of the neurovisual system.

Presenting Author: Hosni Cherif, École d’optométrie de l'Université de Montréal Co-Author(s): A. Argaw, École d’optométrie de l'Université de Montréal; B. Cécyre, École d’optométrie de l'Université de Montréal; J. Gagnon, École d’optométrie de l'Université de Montréal; A. Bouchard, École d’optométrie de l'Université de Montréal; S. Desgent, École d’optométrie de l'Université de Montréal; K. Mackie, École d’optométrie de l'Université de Montréal; J.-F. Bouchard, École d’optométrie de l'Université de Montréal Purpose The Deorphanized G Protein-Coupled Receptor, GPR55, is a new receptor that is involved in a wide variety of processes such as breast cancer, bone metabolism, gastrointestinal functions, pain, and obesity. In the present study, we demonstrate the presence of GPR55 in the developing visual system and its implication during axon growth and retinothalamic development. Methods Primary cultures of cortical neurons and retinal explants from embryonic mice (E14-15) were used to study the signaling pathway through which GPR55 induces its effects. Quantification and visualisation of the neurons and RGCs to elucidate GPR55 expression and effects were performed by western blot analysis and immunocytochemistry. The growth cone (GC) morphology and the axonal length of retinal ganglion cells (RGCs) were measured using Image-Pro software. Axonal guidance was performed using a growth cone turning assay in which we create a micro gradient of LPI, O1602, cannabidiol or vehicle at 100µm and 45° from the GC and we tape his behaviour in the presence of different ligands. In vivo, we used hamster, as their immature visual system at birth allows us to better understand the localization and effects of GPR55 and its ligands. The evaluation of the role of GPR55 during RGC projection growth during development was conducted using intravitreous injection of the B fragment of the cholera toxin, an anterograde tracer. GPR55 agonist or antagonists were injected at the same time. Four days later, the brains were fixed, cryosectioned, mounted onto slides, and image collected microscope. Results We demonstrate that GPR55 is expressed by the retinothalamic system during development and it regulates GC morphology and axon growth via the ERK1/2 pathway. Pharmacological treatment of retinal explants and primary cortical neuron cultures with LPI, an endogenous GPR55 agonist, and O1602, a synthetic GPR55 agonist, increases the GC’s surface area. Furthermore, the application of Cannabidiol, a GPR55 antagonist, to the neuron cultures induces the collapse of the GCs. When these agents were added to neuronal cultures obtained from GPR55 knockout (GPR55-/-) mouse embryos, no effects on growth cone morphology or on axon growth were observed. Most importantly, we report that GPR55 is required for the reorganization of the growth cone and axon growth. Also, turning in real time shows that micro-gradient created with LPI and O-1602 attract growth cone of the RGC and cannabidiol repelled it. In vivo, GPR55 is expressed in the RGCs of hamsters from day 1 to 5. In fact, LPI and cannabidiol induce miss-segregation in RGCs axons’ projections at the superior colliculus. In the dorsal terminus nuclei (DTN), LPI increase the projection’s growth and branching whereas cannabidiol decrease them compare to their littermates injected with the vehicle. Pharmacological interference with the intrinsic ocular

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3:10pm

Keynote Address

John Lovasik, Professor, École d’optométrie de l'Université de Montréal John V. Lovasik graduated from McGill University with a BSc in 1969. He then went to the University of Waterloo to study optometry and earned his OD in 1974. During his undergraduate studies he became interested in research under the tutelage of Professor Murcheson G. Callender, and later obtained an MSc in Physiological optics 1977 and a PhD in neurophysiology in 1980 under Professor Ross D Beauchamp. After he joined the faculty at Waterloo in 1979 he quickly developed an NSERC funded research program in visual physiology and developed the Clinical Electrodiagnostic Services for pediatric patients and adults with abnormal vision. Within ten years John Lovasik earned a full professor status in July 1989. Later that year Professor Lovasik was recruited by the Université de Montréal to develop a vision research program at the Ecole d’optométrie Université de Montréal (EOUM) and bring its clinical education to North American standards. While serving as Director from 1989 to 1995, Professor Lovasik recruited key vision researchers and clinicians, secured major research funds from the former Medical Research Council of Canada, and headed a major Research and Development project that allowed the EOUM to work towards its full potential. Today the EOUM’s optometry program enjoys full accreditation by the American Council on Optometric Education (ACOE) and is a major force in basic and applied vision sciences. Professor Lovasik maintains an active NSERC funded research program in ocular blood flow. Blood flow demands and regulation in the human eye The human retina is a delicate three-dimensional neural structure with vascular input from the choroid for the outer third of the retina and the retinal vasculature that perfuses the inner two thirds of the retina. For neural structure and visual function to remain normal, blood flow in the choroid and retinal vasculature must remain constant despite changes in systemic blood pressure associated with postural changes and strenuous physical activities. In his presentation, Professor Lovasik will discuss how blood flow in the choroid and retina can be measured non-invasively in humans. He will also present some of his findings on the effect of visual stimuli on ocular blood flow (neurovascular coupling, NVC) and factors involved in keeping vascular perfusion constant (auto-regulation, AR) during systemic changes in blood pressure. Abnormalities in NVC and AR are thought to underlie sight-threatening diseases of the eye such as Age Related Macular Degeneration and glaucoma.

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Sunday, December 7

9:00am

Keynote Address

Trefford Simpson, Professor, School of Optometry and Vision Science, University of Waterloo Dr. Simpson completed his optometric training in South Africa and has an MS and PhD from the University of Houston. His post-doctoral fellowship was at the University of Toronto in Canada. He is a Professor of Optometry & Vision Science at the University of Waterloo. He teaches clinical techniques and visual neurophysiology in the professional programme, psychophysics, research methods and data analysis in the graduate programme and works in the Electrodiagnostic Clinic. He was a founding member of the Waterloo Institute for Health Informatics Research and is a Fellow of ARVO. His research includes ocular soft metrology, sensory, structural and physiological properties of the ocular surface, ophthalmic imaging, binocular vision (particularly inhibitory interactions), and applying technology in teaching, clinical and research settings. Ocular surface sensory processing in humans There is a strong scientific history of work in done in Montreal & Waterloo examining ocular surface sensitivity using esthesiometry. We have continued this research using a pneumatic esthesiometer that delivers mechanical, chemical and cooling stimuli to explore the characteristics of ocular surface processing of pain and thermal stimulation. I will review this work, particularly in the context of ocular surface sensory channels, how processes vary across the ocular surface and how these stimuli affect the physiological functions of lacrimation and pupil and conjunctival blood vessel control. In addition to better understanding ocular surface detection thresholds, we have also done work on sensory discrimination, using signal detection theory and suprathreshold processing that will be presented. Finally the linking hypotheses will be discussed, particularly in light of our relatively poor understanding of the physiological processes and subsequent processing of sensory stimuli across the whole ocular surface.

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Sunday, December 8

10:00am

Fabry disease: updates on a longitudinal study of its related ocular manifestations Presenting Author: Langis Michaud, École d’optométrie de l'Université de Montréal Purpose To provide information and updated results on a longitudinal study made on patients with Fabry diseases. To present also a new clinical finding related to Fabry disease. To explain the unique role of optometrists in the screening of this life-threatening disease. Methods Reports of the results collected over the last 3 years on a cohort of 38 Fabry patients compared to a control group. Emphasis is made on ocular manifestations (cornea verticilata, Fabry's cataracts, vessels tortuosities of the conjunctiva and the retina). Visual field abnormal findings are explored. Results In general, over 90% of the Fabry patients are showing the classic cornea verticillata, while 75% are showing conjunctival vessels tortuosities. Retinal vessels tortuosities affect only 35% of the patients. There are significant differences between hétérozygotes and homozygotes patients. Also, systemic symptoms differ between those 2 populations. A new clinical finding was identified on Fabry patients: tortuosities of blood vessels of the upper eyelid. This new entity is presented (photos) with a grading system based on the severity of the clinical sign. Finally, data from a screening program established across Canada are presented. To this date, more than 30 new Fabry patients were found based on optometrist's examination. This is important considering that this disease is very often misdiagnosed and if not treated, is life threatening. Conclusions Optometrists are key players as primary care providers to screen for Fabry disease patients. They can make a difference for these patients affected by a life threatening disease. Ocular manifestations are among the first clinical signs present on Fabry patients. A slit lamp exam can save a life. This lecture is highlighting the ocular manifestations with emphasis on a new clinical finding helping optometrists to suspect for Fabry disease. Acknowledgement(s): Canada

This research is funded by Genzyme

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Sunday, December 8

10:15am

additional source of resistance, distal to the trabecular meshwork in POAG.

A novel finding in the outflow pathway of eyes with primary open-angle glaucoma

Acknowledgement(s): This work was supported in part by BrightFocus Foundation Grant G2007-013 and The Massachusetts Lions Eye Research Fund. The technical assistance of Rozanne Richman, M.S. is gratefully acknowledged. Disclosure(s): None

Presenting Author: Thomas Freddo, School of Optometry and Vision Science, University of Waterloo Co-Author(s): H. Gong, Department of Ophthalmology, Boston University School of Medicine, Boston, USA Purpose The source of the additional outflow resistance that raises IOP in POAG remains unknown. Several morphological changes have been documented but when compared to age-matched normal human eyes, none of these have been able to account for the added resistance in POAG. In recent studies on bovine eyes we demonstrated that progressive pressure elevation induces proportionally greater herniations of meshwork into collector channel (CC) ostia and that these herniations are reversible when IOP is reduced. The purpose of these studies was to determine if herniations might also be present in human eyes, and most especially whether permanent herniations, obstructing CC ostia, are found in eyes with POAG. Methods Age-matched normal and POAG eyes (N=12) were obtained from NDRI (Philadelphia, PA), within 24 hrs post-mortem. Eyes were immersion-fixed (0 mmHg) with buffered aldehydes. Eyes were cut equatorially and the vitreous and lens removed. Anterior segments were divided into 4 quadrants. Frontal sections (1.5 μm thick) were post-fixed in osmium, dehydrated in a graded series of ethanols, and embedded in Epon-Araldite. Serial frontal semi-thin sections (3 µm) were cut and stained with 1% Toluidine Blue to identify the trabecular meshwork, the inner wall of SC and CC ostia regions. Light micrographs were taken at magnifications of 10X, 20X and 40X at areas in which SC and /or CC were widest to evaluate differences between normal and POAG eyes. For each eye, all four quadrants were examined and at least 4 pictures taken per quadrant, for a total of at least 16 pictures per eye. A total of 257 images were examined at magnifications of 10X and 20X. Parameters measured included the width of Schlemm’s canal in each quadrant, width of CC ostia and number of ostia containing herniations. Statistical analysis: Two-tailed Student’s t-test was used with a required significance level of 0.05. Results SC Width SC became significantly narrower in POAG eyes compared to normal eyes (11.89 ± 7.29 μm vs. 21.00 ± 7.87 μm, p< 0.0001). In normal eyes, SC was significantly wider at CC ostia regions than elsewhere (23.07 ± 7.24 μm vs. 18.94 ± 7.80 μm, p= 0.0034), a difference not found in eyes with POAG (11.12 ± 7.57 μm vs. 11.02 ± 7.15 μm, p= 0.95). CC Width CC ostia became significantly narrower in POAG eyes compared to normal eyes (31.55 ± 18.89 μm vs. 42.15 ± 14.48 μm, p= 0.0017). Herniations Significantly more herniations of the TM into CC ostia were found in POAG eyes (33 of 54) than in normal eyes (7 of 51) (61% vs. 14%, p2/3 total area dropout) was used to grade meibomian gland dropout in the images. The first set of images served to train two observers, O1 and O2; the second and third sets were presented to both observers (24 hours apart) on a 50” high definition monitor in a darkened room. All images in each set were presented in a random order. Results For both devices combined, the mean difference in ratings between O1 and O2 (mean±sd) was 0.08±0.55 on day 1 (D1), and 0.13±0.50 on day 2 (D2); the concordance correlation coefficient (CCC) between O1 and O2 was CCC=0.79 on D1 and CCC=0.81 on D2. When looking at both devices individually, the inter-observer mean differences in ratings when using the K4 was -0.01±0.58 on D1 and 0.08±0.52 on D2; while the mean differences when using the K5M was -0.16±0.51 on D1, and 0.18±0.47 on D2. Interobserver CCCs when using the K5M (D1=0.79, D2=0.81) were slightly higher than with the K4 (D1=0.78, D2=0.80). When comparing ratings between sessions for each observer, the intraobserver mean difference in ratings for O1 was -0.08±0.49 and 0.01±0.58 for the K5M and K4, respectively; mean difference for O2 was -0.09±0.51 and -0.10±0.68 for the K5M and K4, respectively. The intra-observer CCC for the K5M (O1=0.82, O2=0.80) was higher than for K4 (O1=0.76, O2=0.68). Conclusions The repeatability of the K5M was slightly better than the K4 when using a 4-point grading scale. In all cases, both observers graded within -1 to +1 grades of each other and against themselves. Acknowledgements: We would like to thank OCULUS for providing the instruments for this study.

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11 Acceptance of a silicone hydrogel multifocal lens in emmetropic presbyopes Jill Woods, School of Optometry and Vision Science, University of Waterloo; C. Woods, Deakin Optometry, Deakin University, Melbourne AUSTRALIA; D. Fonn, School of Optometry and Vision Science, University of Waterloo; L.W. Jones, School of Optometry and Vision Science, University of Waterloo Purpose The purpose of this pilot study was to investigate the success of the AIR OPTIX AQUA MULTIFOCAL contact lens (Alcon) (AOAMF) in a group of emmetropes with low or moderate levels of presbyopia and to determine the most accepted wear schedule of this silicone hydrogel, multifocal contact lens design. Methods The study was conducted over two 1-week phases and involved 16 emmetropic participants with a mean near addition of 1.45D, who were naïve to contact lens wear. During phase one, participants paid close attention to their habitual reading spectacle wear and recorded positive and negative experiences using a subjective questionnaire. During phase two, they wore a pair of AOAMF lenses and completed the same questionnaire. Results Subjective vision ratings for computer use, shopping and tasks involving changes in focus for distance tasks were statistically better (p 0.05) and vascular permeability (Evans blue, µg/g of fresh tissue: 22.8 ± 4.3 vs. 22.0 ±2.3, P > 0.05) were not changed in 30and 36-GK rats compared to controls. Conclusions Data suggest the presence of alterations in the vascular bed of GK rats. Lipid accumulation in the retina and choroid associated with VEGF production may contribute to these vascular alterations in spontaneous type 2 diabetic retina. Acknowledgement: Supported by FRQS Vision network.

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eyes and there were more ganglion cells, likely a result of the enhanced proliferation these eyes.

Stimulation of proliferation in the chick retina following optic nerve section and growth factor treatment

Acknowledgements: Grants: NSERC, COETF, CNIB (E.A. Baker), CFI; Scholarships: NSERC, OGS; Conflicts: None

Stacey Chong, School of Optometry and Vision Science, University of Waterloo, A. Kumar, School of Optometry and Vision Science, University of Waterloo; V. Choh, School of Optometry and Vision Science, University of Waterloo Purpose Optic nerve section (ONS) is an experimental model for mechanically damaging retinal ganglion cells (RGCs) and typically results in cell loss that is not replaced. It has been shown that the chick retina can be stimulated to proliferate following acute chemotoxin-induced damage (Fischer & Reh, 2003: Glia, 43: 70-76) and that proliferation can be enhanced with exogenous growth factors (Fischer & Reh, 2002: Dev Biol, 251: 367-79). This study was undertaken to determine if mechanically-damaged retinas have the ability to proliferate and whether growth factors can enhance proliferation. Methods ONS was carried out on one eye of day old post-hatch chicks while the other eye underwent sham surgery. One group of birds received no growth factors (n = 32; –GF group) while another received intravitreal injections of insulin and fibroblast growth factor 2 in both eyes immediately following ONS and every 3 days thereafter (n = 28; +GF group). All eyes were injected with a thymidine analogue, 5-bromo-2-deoxyuridine (BrdU) prior to sacrifice. Proliferative activity and the number of cells remaining in the ganglion cell layer (GCL) were assessed as a function of time and growth factor treatment. Results The total number of cells in the GCL decreased in the ONS-eyes for both the –GF and +GF groups, with no differences over the first 3 days (p = 1.0000 for all time points), followed by a significant decrease in cell numbers starting at day 5 post-ONS (relative to day 3: p ≤ 0.0070). At overlapping time points, no difference in cell numbers between the two groups of birds was found (p = 0.6218). Cell numbers in the sham-treated eyes for both groups did not change over time (p ≥ 0.4961). For the –GF birds, proliferation was only detected in ONS-eyes starting at 3 days post-ONS (3.58 ± 2.63 cells/mm; p=0.8846), with a significant peak at 5 days post-ONS (13.77 ± 7.39 cells/mm; p = 0.0453), and no detectible activity thereafter (p = 1.0000). Proliferation was never observed in sham ONS-eyes. Growth factor injection resulted in enhanced proliferation; in ONS-eyes, proliferating cells were now observed at every time point, and a lower, but unchanging level of proliferative activity (p = 0.6645) was also found in the sham ONSeyes. Ganglion cell (GC) numbers in ONS-treated eyes decreased in both groups, with the –GF group showing earlier significant decreases (at days 2 and 4 through 8; p ≤ 0.0078) than the +GF group (at day 5; p ≤ 0.0001). Overall, the number of GCs in the +GF group was greater than in the –GF group (383.02 ± 29.90 cells/mm vs 316.93 ± 32.93 cells/mm, respectively; p = 0.0031) but no growth factor-related changes over time were detected (p = 0.8252). Conclusions Proliferation was induced in ONS-eyes, but peak activity was not reflected in the total number of cells in the GCL, indicating that proliferation was not sufficient to counter ONS-associated cell loss. Growth factors enhanced proliferation in both ONS- and sham-

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34 The cannabinoid receptors CB1 and CB2 are differentially expressed in the retina of vervet monkeys Joseph Bouskila, École d’optométrie de l'Université de Montréal; P. Javadi, École d’optométrie de l'Université de Montréal; C. Casanova, École d’optométrie de l'Université de Montréal; M. Ptito, École d’optométrie de l'Université de Montréal; BRAINlab, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark; J.F. Bouchard, École d’optométrie de l'Université de Montréal Purpose The presence of the cannabinoid receptor 1 (CB1R) has been largely documented in the rodent and primate retinas in recent years. There is however some controversy concerning the presence of cannabinoid receptor 2 (CB2R; first considered to be the peripheral cannabinoid receptor) within the central nervous system. Only recently, CB2R has been found in the rodent retina. Certainly, the involvement of both cannabinoid receptors in cannabis-like effects seems to support the presence of CB2R in the retina. The aim of this study was twofold: 1) to characterize the distribution patterns of CB2R in the monkey retina and compare this distribution to that previously reported for CB1R and 2) to solve the controversy on the presence of CB2R in the neural component of the retina. Methods We therefore thoroughly examined the cellular localization of CB2R in the vervet monkey (Chlorocebus sabeus) retina, using confocal microscopy. Results Our results demonstrate that CB2R, as CB1R, is present throughout the retinal layers with however striking dissimilarities. Double labelling of CB2R and glutamine synthetase shows that CB2R is restricted to Müller cell processes, extending from the internal limiting membrane with very low staining, to the external limiting membrane with heavy labelling. Furthermore, double labeling of CB2R and retinal markers allowed us to exclude possible CB2R expression in retinal neurons. Conclusion We conclude that CB2R is indeed present in the retina exclusively in the retinal glia whereas CB1R is expressed mainly in the neuroretina. These results extend our knowledge on the expression and distribution of cannabinoid receptors in the monkey retina, although further experiments are still needed in order to clarify their role in retinal functions. CB2R may represent an interesting therapeutic target for the treatment of retinal diseases.

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Council of Canada (NSERC) and Groupe de Recherche en Sciences de la Vision (GRSV).

Distribution pattern of the endocannabinoid system throughout the dorsal lateral geniculate nucleus of non-human primates Pasha Javadi, École d’optométrie de l'Université de Montréal; J. Bouskila, Biomedical Sciences, Faculty of Medicine, University of Montreal; J.F. Bouchard, École d’optométrie de l'Université de Montréal; M. Ptito, École d’optométrie de l'Université de Montréal, BRAINlab, Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark Purpose The endocannabinoid system mainly consists of cannabinoid receptors 1 (CB1R) and 2 (CB2R), their endogenous ligands, endocannabinoids (eCBs), and enzymes responsible for the synthesis and degradation of these ligands. ECBs are synthesized “on demand” by catalyzing the release of N-acylethanolamine (NAE) from N-acyl-phosphatidylethanolamine (NAPE) by specific enzymes, such as N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD). The eCBs are not accumulated into synaptic vesicles and are rather degraded rapidly by specific enzymes, particularly fatty acid amide hydrolase (FAAH). The localization and function of the molecular components of the eCB system in the CNS has been the subject of recent research. The CB1R is found primarily in the hippocampus, the associative cortex, cerebellum and basal ganglia. eCB system also appears to be involved in CNS development by modulating axon growth and guidance. Despite recent progress in the field of cannabinoids and vision, the specific role of this system is not totally understood. Some studies dating from 1970 indicate that cannabis could affect several visual functions, such as photosensitivity, intraocular pressure, visual acuity, tracking of moving objects, color vision, and stereoscopic vision. These visual manifestations have been linked to the presence of CB1R and CB2R in the adult visual system. The distribution of CB1R and enzyme of degradation FAAH of the ligand of these receptors in rat and monkey retina has been well characterized. Methods The main objective of this study is to investigate the expression and localization of the eCB system beyond the retina in the dorsal lateral geniculate nucleus (dLGN) using classic immunohistochemistry (3, 3'-diaminobenzidine (DAB) and fluorescent (double labeling) methods on the vervet monkey brain. Results Our results show that CB1R is expressed throughout the dLGN with higher abundance in the magnocellular layers. The same pattern is observed for the degradation enzyme, FAAH. However, NAPE-PLD, synthesis enzyme, is expressed homogenously throughout the LGN with no preferences for any of the layers. Moreover, the eCB system is absent in the koniocellular layers. Conclusion The abundance of the CB1R, FAAH and NAPE-PLD in the dLGN and their pattern of expression in different layers raise the hypothesis of their role in visual function especially the sensitivity in movement perception. These findings open novel doors to understand the effect of cannabinoid on vision that can lead us towards novel therapeutic or toxic outcomes of the cannabinoids. Acknowledgements: We are grateful to Dr. Frank Ervin and Dr. Roberta Palmour of the Behavioral Sciences Foundation Laboratories of St.-Kitts, West Indies, for supplying the vervet monkey tissues. This project is funded by Canadian Institutes of Health Research (CIHR), Natural Sciences and Engineering Research

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36 Repetitive Donepezil administration combined with visual exposure increases visual acuity in rats Mira Chamoun, École d’optométrie de l'Université de Montréal; J.I. Kang, École d’optométrie de l'Université de Montréal; F. HuppéGourgues, École d’optométrie de l'Université de Montréal; E. Vaucher, École d’optométrie de l'Université de Montréal Purpose Memory and learning are associated with cortical release of acetylcholine (ACh). Rat’s visual acuity and cortical activity for a specific pattern can be improved when repeated visual exposure of a specific stimulus is paired with electrical stimulation of basal forebrain cholinergic neurons. The clinical approach to stimulate the cholinergic transmission in human consists in increasing extracellular ACh level by acetylcholinesterase inhibitor (AChEI), the degradation enzyme for ACh. Donepezil is a non-competitive and reversible AChEI which has been shown to cause significant increase of ACh concentration in humans as well as in rats. In addition, Donepezil induces beneficial effects on learning performance in rats. Methods In the present study we evaluated whether repeated visual exposure of a specific stimulus would also change the visual acuity of the rats for the trained stimulus when the exposure is paired with Donepezil administration. Visual evoked potentials (VEPs) to a sinusoidal phase converting grating pattern, shown in a pseudorandom manner for 30° and 120° orientations and different spatial frequencies (0.08 to 1 CPD), were recorded in rat’s primary visual cortex (V1) before and after the two weeks visual exposure. The two weeks visual exposure consisted in 10 min daily exposure to a 0.12 cycle per degree (CPD) 30° sinusoidal pattern, in rats injected with Donepezil or saline 20 min prior to visual exposure. An index of variation (amplitude post – amplitude pre) is then calculated to determine the variations of cortical response. Results Our results show that VEPs index of variation for the 30° orientation was significantly increased in Donepezil injected rats at high spatial frequencies (0.9 CPD: 0.5±.18, Mann-whitney p=0.027 and 1.0 CPD: 0.45± 0.2 Mann-whitney p=0.050) but not in control animals . The VEP amplitude for the 30° orientation showed an increasing tendency at the training frequency 0.12 CPD, (0,64±0.39, Mann-whitney p=0.64) but not in the control group (0.04±1.3). These results were selective for the 30° orientation. No significant difference was observed in the VEPs amplitude to any spatial frequency for the 120° orientation. Conclusions Our present results showed increased visual acuity in rats trained with Donepezil. This agrees with the previous study in which the cholinergic system stimulation was provided by electrical stimulation of the basal forebrain. Overall, we demonstrate the possibility to increase visual performance and cortical response by combination of cholinergic stimulation and visual exposure in rats. Acknowledgement: CIHR Canadian Institute of Health Research, MOP-111003.

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37 Functional properties of primary visual cortex in dopamine D2receptor deficient mice Bruno Oliveira Ferreira de Souza, École d’optométrie de l'Université de Montréal; S. Thomas, École d'Optométrie, Université de Montréal; J.-M. Beaulieu, Centre de Recherche de l'Institut Universitaire en Santé Mentale de Québec; C. Casanova, École d'Optométrie, Université de Montréal Purpose Dopamine (DA) is a neurotransmitter involved in a variety of functions in the central nervous system such as motor control, reward behavior and cognition. Disruption of the DAergic system is associated with debilitating diseases like the Parkinson syndrome. Interestingly, several visual deficiencies are reported from patients suffering of these diseases. In the retina, DA acts through a set of receptors (D1, D2, D3, D4 and D5) to modulate the integration of horizontal cells, the size of ganglion cells receptive fields and is also implicated in light adaptation and circadian rhythm regulation. DAergic receptors are also found in the primary visual cortex (V1), but the functional impact of these receptors on the structure and function of V1 remains poorly understood. The objective of the present study is to evaluate the impact of D2 receptor loss of expression on cortical organization and visual processing in V1. Methods Adult D2-receptor deficient mice (D2r-KO, n=12) and control wildtype littermates (D2r-WT, n=9) were used. The cortical activity of V1 was measured by optical imaging of intrinsic signals. Using a periodic stimulation paradigm, visuotopic maps were analyzed to measure structural parameters such as V1 shape, cortical magnification factor, scatter, binocularity and ocular dominance. Contrast sensitivity, spatial frequency selectivity and cortical acuity were evaluated using dynamic sinusoidal gratings of different contrasts (6, 12, 25, 50 and 100% of contrast at 0.02 cpd) or spatial frequencies (0.005 to 0.64 cpd at 100% contrast). Results Primary visual cortex from D2r-KO mice were optimally activated by stimuli of higher spatial frequencies when compared to their control group (avg ± S.E.M: D2r-KO = 0.031cpd ± 0.0025, D2r-WT= 0.023 ± 0.0023, p0.05). Clinical findings normalized after 5 weeks but symptoms were not ameliorated until 12 weeks. Conclusions That reduced VAdapt coupled with excessive VA is normalized through orthoptic treatment indicates that CI and its remediation can be explained by current models defining the links between accommodation and vergence(3). Symptomatic relief following orthoptic training was associated more with actual measures of vergence adaptation and CA reduction than the clinical criteria of Sheard. Thus clinical criteria based on “fusion limits” appear to be an indirect assessment of an individual’s capacity to invoke

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49 Symptomatology of convergence insufficiency in Parkinson's disease Stéphanie Chriqui, École d’optométrie de l'Université de Montréal; C. Law, École d’optométrie de l'Université de Montréal; E.L. Irving, School of Optometry and Vision Science, University of Waterloo; M.J. Kergoat, Institut universitaire de gériatrie de Montréal; B.S. Leclerc, Department of social and preventive medicine, University of Montreal; M. Panisset, Department of Neurology, Centre hospitalier de l'Université de Montréal; S. Chouinard, Department of Neurology, Centre hospitalier de l'Université de Montréal; R. Postuma, Department of Neurology, Montreal General Hospital, McGill University; H. Kergoat, École d’optométrie de l'Université de Montréal Purpose Diplopia is often cited as a non-motor symptom of Parkinson's disease (PD). Furthermore, clinically, patients with PD often report difficulty in reading. Convergence insufficiency (CI) is associated with both difficulty in reading and diplopia. The objective of our study was to determine if the prevalence of visual symptoms linked with CI was higher in individuals with or without PD. Methods Two study groups (n= 100 each) were recruited: 1) participants having PD (Avg. ± SD: 65.7 ± 8.5 yrs) recruited from the Movement Disorder Clinic of the CHUM and the MGH neurology department, and 2) age-matched participants not having PD (65.4 ± 8.7 yrs). Participants with cognitive deficits, other ocular disease/dysfunction and specific health problems (eg. diabetes) were excluded. The Convergence Insufficiency Symptom Survey (CISS-15) is a validated questionnaire and a score of ≥21 is considered positive for CI symptomatology. CISS-15 was administered to each participant, by a telephone interview, to evaluate visual symptoms linked with CI. Confidence intervals and t-tests were performed using SPSS. Results The participants did not differ for age (p = 0.81). The results indicated that 27% [95% Confidence Intervals: 22.5 - 31.5] of participants with vs 9% (7.4 - 10.8) of those without PD presented a score of ≥21 on the CISS-15 questionnaire (p < 0.05). Conclusions The prevalence of visual symptoms linked with CI is higher in individuals with vs without PD. Therefore, CI might be one explanation for the diplopia and/or reading difficulties in PD. These results underline the importance of providing regular eyecare to patients with PD, including a complete binocular vision assessment. Acknowledgements: CAREC-IUGM, CIHR

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50 Can the legibility of prescription medication labels for older adults and adults with visual impairment be improved? Antonio Carbonara, School of Optometry and Vision Science, University of Waterloo; A. Krishnamoorthy, School of Optometry and Vision Science, University of Waterloo; S.J. Leat, School of Optometry and Vision Science, University of Waterloo; C. RojasFernandez, School of Pharmacy, University of Waterloo; D. Gold, Canadian National Institute for the Blind, Toronto, Canada Purpose Currently, most prescription medication labels do not meet NGO or health organization recommendations for print size, spacing and use of capitals (Leat et al, Envision, 2012). We studied the legibility of patient critical information on current medication labels compared to prototypes (based on current guidelines for legibility). Methods Twenty-four sets of prescription medication information of equal readability were developed. Sample medication labels with 12 of these prescriptions were obtained from 12 pharmacies and 12 prototype medication labels were developed according to legibility guidelines from NGO and pharmacy organizations. The prototype labels were 11% taller than current labels when maximizing font size to 16pt but identical when using 14 and 12pt print. 71 people participated; 24 aged >65 with normal vision, 24 >65 with low vision (LV) and 23 aged 20-64 with LV. Reading speed and accuracy were determined for reading the patient name, drug name and instructions (with habitual spectacles or reading aids). Participants ranked the labels for legibility and completed a questionnaire regarding their experience with prescription medications labels. Results Accuracy in reading was high (75-100%) for almost all sample and prototype labels but reading speed was significantly faster for prototype versus sample labels (p

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