Change in monochromatic aberrations with accommodation in a large adult population.

Background: During accommodation, the eye undergoes significant structural changes, altering wavefront aberrations. So, this study aimed to evaluate changes in Zernike coefficients up to the 6th order with different accommodation demands and ages in a large cohort of young adults, considering the decrease in pupil size with the accommodation.

Methods: Aberrometric measurements for 210 healthy subjects aged 18-40 were performed with the irx3 (Imagine Eyes, Orsay, France), stimulating accommodation with the Badal system of the instrument, from 0 to 5 D. Each wavefront was rescaled to a standardized pupil size for each accommodative vergence. Variations of Zernike coefficients were analyzed for each accommodative demand, and the change of Zernike coefficients with age.

Results: The most notable changes observed during accommodation was the increase in C(2,0). Both C(2,±2) astigmatism showed a reduction in magnitude during accommodation. C(4,0) became less positive, or more negative, as accommodation increased. C(3,-1) remained constant as the accommodation demand increased, while C(3,1) showed an increase. Changes were observed with accommodation and age, where C(2,0) had a negative linear relationship. The C(4,0) changed gradually with age only for accommodative demands below 3 D. C(3,±1) decreased with age.

Conclusions: Wavefront aberration coefficients presented changes during accommodation in people aged 20-40 years. C(2,0) underwent the most pronounced changes and C(4,0) changed more with accommodation than other higher-order aberrations. Zernike coefficients C(2,0), C(4,0) and C(3,±1) decreased with age, and C(2,±2) astigmatisms showed an increase in magnitude with age. These findings were made considering the decrease in pupil size with accommodation, highlighting the importance of accounting for pupil diameter variations when evaluating wavefront aberrations.