Cortical Stimulation Using Gabor Patches Improves Vision & Contrast In Dissatisfied Patients With Mf-Iols: A Randomized Controlled Trial

Photic phenomena and neuro-adaptation failures are reasons for dissatisfaction after MF-IOLs.

This study evaluates a patient-specific, computer-based perceptual visual therapy (VPL) regime using Gabor patches (grey level gratings, specific for cortical neuron-specific receptive visual fields) for improving vision & contrast sensitivity function(CSF) in patients not satisfied after multifocal IOL (MF-IOL) implantations.

A tertiary hospital. A Prospective controlled-randomised study.

A prospective, controlled-randomized study. Adults (50-70 yrs) with uneventful MF-IOLs, over 24 weeks post-surgery, BCVA worse than 20/40 with sub-optimal Contrast (CSF), complaining about vision quality, were randomized in a 2:1 ratio into Treatment(G1), in which computer-based perceptual therapy using Gabor patches amidst co-linear flankers was employed & Control(G2) arms. The study had 2 phases (screening + therapy). Mid-training (Post 20 sessions), 40 training sessions, post-therapy follow-up by 6 months were evaluated for improvements in BCVA distance & near (ETDRS) & CSF at spatial frequencies of 3, 6,12,18 cycles per degree (CPD).

30 cases were randomized into a 2:1 ratio into treatment and control arms. 16 Trifocals(PanOptix), 14 Bifocals(Tecnis). The average improvement after VPL therapy is 2.5 lines in Log Mar in the Treatment arm (p<0.0001), whereas no significant improvements were observed among the controls.

83% of subjects who underwent perceptual training showed improvement in Contrast Sensitivity (CSF at 3,6,12 & 18 CPD), (G1, all p<0.0001), whereas no significant improvements were observed amongst the controls.

The improved functional vision and CSF remained stable 6 months post-training with perceptual therapy.

Sequential, post-operative, patient-specific, visual perceptual training employing Gabor patches improved vision & CSF in patients with dissatisfied MF-IOL subjects & acts as proof of concept of improving neural connections at cortical levels.
The key to optimizing vision following MF-IOLs lies in training the brain to improve neuroadaptation processes.