Influence of pupil size on vision performance and visual satisfaction with two multifocal contact lenses

Authors
Percy Lazon de la Jara¹, Anna Sulley², Rachel Marullo¹, Michel Guillon³
1 Coopervision, Inc., USA
2 CooperVision International Ltd, UK
3 Optical Technology Group International, UK
 

Purpose 
The aim of the analysis was to determine whether the visual performance of two multifocal contact lenses was pupil size independent over a representative luminance range. 
 

Methods 
A 1-week cross-over, double masked, dispensing study was conducted involving  45 presbyopes (15 from Low, Med, High add groups) who wore two multifocal contact lenses (stenfilcon A and comfilcon A, CooperVision, Inc.) in random order. Pupil sizes were measured under 250, 50 and 2.5cd/m² luminance. Distance monocular and binocular LogMAR visual acuities (VA) were measured at 250 cd/m² at >90% and 10% contrasts and at 2.5 cd/m² at >90% contrast. Near monocular and binocular LogMAR VAs were measured at 50 cd/m² at >90% and 10% contrast. To obtain an overall measure of correlations between VAs and pupil sizes, a combined VA score was calculated using principal component analysis, a dimensionality reduction method to simplify large variable sets while maintaining significant patterns and trends; linear regression was applied to the combined values to test for correlations.
 

Results
Participants were 68.9% female; mean age 54 years; mean spherical equivalent refraction -2.28D ±2.4D; mean add power +1.59D±0.4D. Pupil sizes ranged from 2.3 mm (250cd/m²) to 6.6 mm (2.5cd/m²), right and left pupil sizes were very highly correlated (r: 0.843 to 0.931; p<0.001).  For stenfilcon A and comfilcon A respectively mean monocular VAs were 0.26±0.08logMAR and 0.24±0.09logMAR and mean binocular VAs were 0.17±0.08logMAR and 0.15±0.08logMAR. The regression results demonstrated the absence of significant correlation between VA and pupil both for the monocular (stenfilcon A r²=0.017; p=0.427; comfilcon A r²=0.021 p=0.198) and binocular (stenfilcon A r²=0.017; p=0.427; comfilcon A r²=0.021 p=0.198) measurements.
 

Conclusions
Visual performance of both multifocal contact lenses was not correlated with pupil size, highlighting that the performance of both designs is pupil size independent. 
 

Disclosures
Study was supported by CooperVision, Inc.
Anna Sulley, Rachel Marullo and Percy Lazon de la Jara are employees of CooperVision.