The Relationship Between the Positioning of Multifocal Contact Lens Optics and Satisfaction with Vision Marc-Matthias Schulze, Doerte Luensmann, Alison Ng, Farah Panjwani, Sruthi Srinivasan, Lyndon Jones Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
Results cont’d
Introduction •
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Eye care practitioners (ECPs) are hesitant to prescribe contact lenses (CLs) for presbyopia,1,2 often due to concerns related to
Decentration Direction
increased chair time.3,4 As a result, only 16% of all CL fittings worldwide relate to the correction of presbyopia, with 84% of patients using single vision corrections.4
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Good visual performance at all distances is the major criterion for patients with respect to eventual success or failure with multifocal (MF) CLs.2,3 Adequate visual performance with MF CLs depends on a number of factors, including the age of the patient, distance ametropia, required reading addition and pupil size.2, 5, 6
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In 96% of eyes, lens optics were decentered temporally relative to the LoS (171/178 eyes; Figure 3). For the dominant eye, lens optics were decentered temporally relative to the LoS in 83/89 cases, with the majority of these temporal decentrations being superior (61%); lens optics were decentered nasally for only 6 lenses (Figure 4).
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While the 6 nasally decentered lenses were all considered successful fits (100%), the success of temporally decentered lenses was less predictable (44/83; 53%) (Figure 4).
Recently, Lampa et al.6, 7 have used a corneal topographer to acquire tangential power maps of eyes with and without different MF CL designs in place. By displaying the tangential power difference of these two maps, they were able to visualize the power distribution of the MF CL on-eye relative to reference points such as the pupil center or line of sight (LoS).
Purpose • •
LoS
To examine the relationship between the positioning of multifocal contact lens (MF CL) optics and satisfaction with vision. To investigate whether it is possible to “predict” eventual lens fit success based on the positioning of the MF CL optics.
Methods •
visit and three lens assessment visits, with a washout of at least 1 day between assessment visits.
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Eligibility criteria required the participants to have previous experience with MF CL wear, be at least 42 years of age, and to have a vertex-corrected distance prescription of +6.00 to -8.00D, with astigmatism of ≤0.75D and a minimum required reading addition of ≥+1.00D.
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Figure 3: Direction of lens decentration relative to the LoS; data are shown for both eyes combined (total of 178 eyes).
This was a prospective, double-masked, non-dispensing, randomized pilot study with four study visits, including a screening
Decentration Magnitude
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Figure 4: Distribution of lens optics decentration relative to the LoS, by quadrant (data are shown for the dominant eye); the center of the chart corresponds to the LoS. The blue numbers in each quadrant are the total number (and %) of lenses that decentered in that general direction. The green numbers (and %) identify the number of participants willing to wear this lens type based on its visual performance, irrespective of cost. The red numbers (and %) identify the participants who were not willing to wear these lenses.
Satisfaction with vision ratings were not correlated with decentration magnitude (Figure 5; Spearman’s r = -0.02; p>0.05). The magnitude of decentration did not impact the willingness to wear the studied MF CLs (Figure 6; Chi-square test p=0.33).
30 presbyopic volunteers (15 previously unsuccessful and 15 current MF CL wearers) wore one of three silicone hydrogel (SiHy) MF CL types (ACUVUE OASYS® for Presbyopia; PureVision®2 for Presbyopia; Biofinity® Multifocal) at a single visit (randomized order; double-masked). Each lens type was fit according to the manufacturers’ guidelines.
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The Medmont E300 corneal topographer was used to acquire topography maps with and without MF CLs in place; difference maps of these topography maps (‘CL-on-eye’ minus corneal) were derived to visualize the positioning of the optical center of the MF CL relative to the placido disc center (representative of the line of sight (LoS); Figure 1).
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After at least 30 minutes of settling time, each participant completed a series of routine “real-life” tasks, such as walking (including stairs), reading a magazine or using a computer.
Outcome variables
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Figure 5: Distribution of satisfaction with vision ratings (0-100 scale) vs decentration magnitude.
Decentration direction and magnitude (mm; see Figure 1). Subjective ratings of satisfaction with vision (0-100 scale)
Discussion and Conclusions
while performing the real-life tasks and an overall satisfaction score.
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Prediction of eventual lens fit success
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The relationship of decentration and predicted fit success was evaluated for the dominant eye.
Figure 1: Example of a MF CL difference map. Shown is an Acuvue Oasys for Presbyopia MF CL on a left eye. The optical center of the CL (white dot) is decentered relative to the LoS (Placido disc center) by 0.67 mm at an angle of 334° (i.e. temporally and inferiorly).
Results •
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Thirty-five participants were screened, with 30 participants eligible
Table 1: Participant demographics
to continue on to the assessment visits (Table 1). All eligible participants completed the study and wore each of the 3 study lens
Gender
22 F, 8 M
Age
58 ± 6 (Range 49 to 69)
Distance Rx
-0.59D ± 2.88D (Range -7.50D to +3.75D)
types.
Near Add
2.14D ± 0.27D (Range 1.50D to 2.50D)
Medmont difference maps could be analyzed for 89 of the 90 cases;
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Current wearers of MF CLs were found to have a slightly higher willingness to wear the MF CL types (58%) compared to previous failed MF CL wearers (53%; Figure 2).
Overall willingness to wear the MF CL types was 56%, suggesting that overall acceptance of the MF CLs studied was low. MF lens optics typically decentered temporally relative to the LoS (83/89 vs 6/89 nasally). While each of the 6 nasally decentered MF CLs were considered successful fits (100%), the success of temporally decentered lenses was less predictable (53%). A larger sample of nasally decentered MF CLs would be required to evaluate the true benefit of this decentration direction.
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The magnitude of decentration did not seem to impact potential MF CL success, with virtually no relationship between decentration magnitude and satisfaction with vision or overall acceptance (Figures 5 and 6).
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Predicting success or failure of MF CLs based on determining the positioning of their lens optics was not feasible for this generation of MF CLs studied; the overall low acceptance rate for these MF CL types implies that reasons other than centration, such as visual performance, may have contributed to this finding.
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Future studies, with newer generations of MF CL designs, may allow further evaluation as to whether quantifying the positioning of MF lens optics is beneficial for predicting success with these lenses.
1 Evans BJ. Monovision: a review. Ophthalmic and Physiological Optics 2007;27:417-439. 2 Veys J et al. Essential Contact Lens Practice - A practical guide. The Vision Care Institute of Johnson & Johnson Medical Ltd.; 2009:168. 3 Bennett ES. Contact lens correction of presbyopia. Clin Exp Optom 2008;91:265-278. 4 Morgan PB et al. An international survey of contact lens prescribing for presbyopia. Clin Exp Optom 2011;94:87-92. 5 Borish IM. Pupil dependency of bifocal contact lenses. Am J Optom Physiol Opt 1988;65:417-423. 6 Lampa M et al. Assessing multifocal contact lens centration with the aid of corneal topography. Global Specialty Lens Symposium. Las Vegas: Springer VisionCare; 2012. 7 Caroline P, André M. The multifocal dilemma. Contact Lens Spectrum 2012;27:64.
Willingness to wear In 56% of cases (50/90 MF CLs), participants were willing to wear the MF CL type based on visual performance (Figure 2).
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References
in one case, the reference points for decentration analysis could not be properly visualized on the Medmont difference map.
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In agreement with previous studies,6,7 the Medmont E300 was a suitable device to capture both corneal as well as ‘CL-on eye’ topography. Using the difference maps feature, the positioning of the lens optics of the three MF CL types relative to the LoS could be visualized (Figure 1).
Forced-choice question (YES/NO) after real-world tasks: “Irrespective of the cost, would you wear these contact lenses, based on their visual performance?”
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Figure 6: Willingness to wear MF CLs vs decentration magnitude. To allow for statistical analysis and graphical representation, decentration magnitudes were grouped (see Legend).
© This presentation and all components thereof are protected by copyright. All rights reserved. Unauthorized utilization, editing, reproduction or distribution of this poster or any part thereof is strictly prohibited. Figure 2: Ratio of participants willing to wear the study MF CLs based on visual satisfaction, irrespective of cost.
ACKNOWLEDGEMENT: INVESTIGATOR INITIATED STUDY FUNDED BY JOHNSON & JOHNSON VISION CARE, INC.
AUTHOR CONTACT EMAIL:
[email protected]
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