Abstract
Purpose :
There is an association between myopia progression and near work that has led to speculation that the larger accommodative lags reported in myopes may be a factor or an effect in progression. We evaluated the impact of contact lenses design and addition on the accommodative behavior in myopes
Methods :
A Hartmann-Shack wavefront sensor in an Adaptive Optics (AO) visual simulator was used to measure the wavefront aberrations in 5 myopic subjects (MS, 27±2yrs; spherical error: -2.25±0.3D) while viewing a stimulus changing between 0-6D (ramdomized,1D steps) through multifocal/bifocal corrections, under natural viewing conditions, measurements were repeated 5times for repeatability. The corrections were simulated with a Spatial Light Modulator or a deformable mirror and the accommodative response was calculated using the defocus term, spherical aberration Z (4,0) of the wavefront aberrations.7 conditions were tested: NoLens (NL) and when viewing through aspheric designs of high (2.50D, HA) and medium add (1.75D, MA), bifocal (4mm central zone, 2.5 D) - center distance (CD), center near (CN) and with inducing positive and negative 1µm spherical aberration (PSA, NSA) using deformable mirror were measured.
Results :
There was a systematic decrease in pupil diameter with accommodation, the average slope was -0.19/-0.25/-0.15/-0.11/-0.16/-0.11/-0.15mm/D for NL/PSA/NSA/HA/MA/CN/CD. The average slope of change of spherical aberration with accommodative demand (0-6D) shifted to more negative values for NL/PSA/CD -0.02/-0.07/-0.005µm/D whereas the slope of this change reduced for NSA/HA/MD/CN 0.04/0.01/0.02/0.01µm/D. The accommodative lag computed considering only defocus and 4th order spherical aberration showed higher amount of lag with PSA (0.04D) than NL (0.03D) and the least with MA (0.02D), some conditions caused a lead of accommodation NSA(-0.041D).
Conclusions :
AO simulators are useful tools to simulate multifocal contact lenses. The performance and interaction of these lenses are driven by individual presence or absence of high-order aberrations which alters the accommodative response. Near additions in some cases can reduce the accommodative lag and convert them to leads.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.