In pseudophakia, the eye is unable accommodate so proximal objects can be properly focused. Achieving functional vision levels relies on individual anatomical features, notably, the pupil size. This study measured the range of pupil sizes found in a population of pseudophakes, for an object placed at different distances, and modeled the optical quality associated to pupil variation. The pupil size of 58 pseudophakic eyes (age mean ± standard deviation: 70.5 ± 11.3 years) was measured using a binocular eye-tracker. The participants observed on a monitor a circular white patch subtending 5° with a cross on its center. The object was placed at 3.0, 1.0, 0.66, 0.5, 0.4, 0.33 m. The pupil size variation as a function of object distance was modelled using a linear mixed effects model. The mean and 95% confidence interval (CI) were calculated for a far object and the slope of the function, indicative of the proximal myosis. The effect of object distance on the image quality was modeled using a pseudophakic model eye for the pupil size data. The mean distance pupil sizes were 4.45 (95%CI: 2.74, 6.17) mm and the mean proximal myosis was -0.23 (95%CI: -0.53, -0.08) mm/D. The VA estimation for a distance object ranged from -0.1 logMAR for the smallest pupil to 0.08 logMAR and the near VA when mean myosis was considered ranged from 0.28 logMAR to 0.65 logMAR. These results support the importance of distance pupil size measurement for the prediction of visual performance in pseudophakia, while suggesting that myosis has a negligible impact in VA variability.

Date Published: 3 October 2019
PDF: 6 pages
Proc. SPIE 11207, Fourth International Conference on Applications of Optics and Photonics, 112071N (3 October 2019); doi: 10.1117/12.2527412

Published in SPIE Proceedings Vol. 11207:
Fourth International Conference on Applications of Optics and Photonics
Manuel Filipe P. C. M. Martins Costa, Editor(s)