Efficient predictors of Maximum Reading Speed

Wet vs. Dry Age-Related Macular Degeneration in Patients With Central Field Loss : Different Effects on Maximum Reading Speed Aurélie Calabrèse (1), Jean-Baptiste Bernard (1), Louis Hoffart (1,2), Géraldine Faure (2), Fatiha Barouch (2), John Conrath (1,2), Eric Castet (1)

1. Université Aix-Marseille II, CNRS - Institut de neurosciences cognitives de la Méditerranée INCM – UMR 6193 ; 2. Department of Ophthalmology, La Timone hospital, France

Program No: 724

Introduction

Retinal

Functional

Results: Efficient predictors of Maximum Reading Speed

Patients with Age-related Macular Degeneration (AMD) have an impairment of the central retina which leads to the presence of a scotoma in their visual field. Because of the absence of central vision, patients mostly complain about reading difficulty. Causes of these low performances remain unclear but wet AMD is commonly assumed to be more deleterious than dry AMD. We propose here to investigate the relation between reading speed and type of AMD while controlling for other factors. We used a set of French sentences following the MNRead principles (Legge 1989) to determine three measures of monocular Maximum Reading Speed (MRS) in each eye. Anatomic impairment and Preferred Retinal Location used to fixate (fPRL) were assessed with a MP1 microperimeter. Finally, a linear mixed-effects model was adjusted to estimate implication of each factor on MRS when adjusting for all the others.

Our first major result is a higher MRS for the Wet group compared to the Dry group. To assess whether this Wet-Dry difference in MRS could be induced by covariates, we performed a mixed-effects analysis including the following factors: - scotoma size (in deg²) - scotoma shape - fPRL-fovea distance (in deg) - island of vision within the scotoma - fixation stability - fPRL position along the scotoma - ETDRS acuity - phakic vs. pseudophakic - time since diagnosis - lens opacity - number of rehabilitation sessions - better eye vs. worse eye within a patient - age

Wet AMD vs. Dry AMD

Methods We analyzed a dataset initially collected to assess the effect of interline spacing on reading speed in AMD patients (Calabrese 2009).

- 90 eyes (64 dry + 26 wet) from 61 patients with AMD (aged 55-94 years) - Only eyes with an absolute macular scotoma - Patients followed at the low vision clinic of La Timone Hospital, France

Kinetic

Scotoma size (deg²)

Le chien aboyait en entendant passer le facteur à bicyclette

1x

2x

Ce matin j’ai vu en me levant deux jolis oiseaux verts et gris

0,79 x

1x

L’oiseau s’est posé sur la branche avant de partir vers le sud 2x

Reading speed (words/min)

Papa et maman sont Ma mère prend une allés se balader près tasse de thé tous les un homme qui aime du lac vendredi soir matins en se levant la pêche et la nature

160

1

1.2 1.3

1.4

1.5

1.6

1.7

= 30.67 words/min

120 100 80 60 40 20 0

0

0.5

1

1.5

2

2.5

3

3.5

x-height (degrees)

4

4.5

5

Interline 1X

Statistical analysis

p-value 0.0000 0.0002 0.0048 0.0033 0.0000 0.0026

Maximum Reading Speed (words/min)

Slope for wet & dry = - exp(0.035)

Slope for phakic & pseudophakic = - exp(0.002)

References

ma porte

A linear mixed-effects analysis was performed on the dataset using the lme program (Pinheiro 2000) in the statistical software R (R Development Core Team, 2008). We transformed MRS on log scale and centered continuous factors on their respective means.

- Calabrese 2009 - Mutlu 2009 - Rubin 2009 - Sunness 1999 - Ergun 2003 - Pinheiro 2000 -R - Akutsu 1992

Mean distance

fPRL-fovea distance (deg²)

Scotoma size (deg²)

(Curves represent the effect predicted by our model)

Scatterplot of MRS as a function of the fPRL-fovea distance for wet and dry AMD groups

Scatterplot of MRS as a function of scotoma size for phakic and pseudophakic groups

Significant effect of scotoma area on MRS (p=0.005) Increase scotoma area by 1deg² decreases MRS by a factor of 1.002 (exp(0.002)) in wet and dry AMD

Significant effect of fPRL-fovea distance (p=0.003) Moving away the fPRL from 1deg decreases MRS by a factor of 1.03 (=exp(0.035)) in wet and dry AMD.

Significant effect of the presence of an intra-ocular implant on MRS (p=0.003) MRS for phakic group is 42% (exp(0.352)) higher than for pseudo-phakic group

Significant difference in MRS from wet to dry AMD (p