Abstract
Purpose :
Debate exists on the extent to which patients adapt to Multifocal lenses operating by Simultaneous Vision (SV). Using a SV simulator we investigated short-term adaptation aftereffects to generic and commercial SV lens designs, and their dependency on Multifocal Intraocular Lens and Contact Lens (MIOL & MCL) design parameters, including energy balance between foci and near addition (NA).
Methods :
A commercial binocular SV simulator (SimVis Gekko, 2EyesVision) simulated adapting conditions and blur test sequences, in 2 psychophysical experiments (Exp1 & 2), where patients adapted to and judged perceived quality of a face stimulus (4x4° on a monitor @2m). In Exp1 a QUEST paradigm (20 trials; 2AFC task; sharp or blurred image) determined the Shift in Perceived Degradation Threshold (SPDT, i.e. % far energy in a bifocal lens to perceive blur neutrality) after each adaptation. In Exp2, subjects provided perceptual scores (PS, 0-10; 5 trials). Adapting conditions were a monofocal lens (MF), 3 generic bifocal lenses with different energy % for Far(F)/Near(N): 75F/25N, 50F/50N & 25F/75N with 5 NA (0.5-3D; Exp1) and 4 commercial lenses: Trifocal diffractive IOL (FV), EDoF IOL (VV), and center near Low (MDL) and High NA (MDH) refractive MCLs (Exp1 & 2). Exp1 & 2 were conducted on 6 subjects (29.7±5.2yo). Initial adaptation period was 60s (3s re-adaptation during trials), and test image response time was 0.5s. Matlab & PsychToolbox synchronized sequences of SV lenses and stimulus.
Results :
All tested SV lenses produced adaptation aftereffects compared to MF in Exp1 & 2. In Exp1, the largest SPDT aftereffects were produced by 25F/75N (29.1±11.4%), MDH (27.7±13.1%) and 0.5D NA (31.1±13.9%). Energy % and NA significantly influenced aftereffects measured by SPDT (F=11.6, p<0.01 & F=11.4, p<0.01; mixed linear model analysis). Different energy % induced significant adaptation aftereffects for 0.75 and 1.5D NA (p<0.01). Exp2 revealed significant shifts for MDH (2.7±2.2PS) and FV (2.0±1.2PS) with 1.5 and 3D NA test images (averaged across F/N distributions).
Conclusions :
The largest short-term adaptation aftereffects result from lenses with highest % energy at near and lower NA and occurred also with commercial designs though the interaction between these parameters varied individually. Adaptation is most effective on test images with matching NA magnitudes, highlighting the impact of lens design on both visual function and adaptation to optimize outcomes.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.