Visual Cortex Training Using Gabor Patches Improves Vision And Contrast Sensitivity In Crosslinked Stable Keratoconus: Randomized Control Study

Subjects with keratoconus, despite stabilisation, exhibit sub-optimal vision and contrast post-crosslinking.

This study evaluates patient-specific, computer-based visual perceptual learning (VPL) therapy using Gabor Patches to improve best-corrected vision (BCVA) and contrast sensitivity function (CSF) in cross-linked stable keratoconus (KC).

A tertiary eye hospital. A prospective, controlled-randomized, open-label study.

A prospective, controlled-randomized, open-label study. KC, stable over 1 year with a BCVA worse than 20/40, was randomized in a 2:1 ratio into the treatment arm (G1), in which computer-based perceptual learning therapy using Gabor Patches amidst co-linear flankers was employed, and the control arm (G2).

This study consisted of two phases: screening and VPL. Mid-training (post 20 sessions), 40 training sessions, and post-therapy follow-up at 6 months were evaluated for improvements in BCVA (ETDRS character counts) and CSF at spatial frequencies of 3, 6, 12, and 18 cycles per degree (cpd) using ANOVA and Friedman tests for repeated measures.

A total of 45 cases were randomized. Baseline BCVA was 68.20+/-8.11 and 67.40+/-7.09 in G1 and G2, respectively. The BCVA of the perceptual therapy (PL) arm (G1) improved to 73.30+/-7.47 and 79.10+/-8.46 post 20 and 40 sessions, and remained stable after 6 months. No improvements were observed among controls (G2).

Friedman tests for repeated measures showed no statistical differences between study visits, with p-values of 0.097, 0.135, 0.05, and 0.097 for 3, 6, 12, and 18 cpd, respectively, in the Control Arm. In the treatment arm, there were significant improvements in CSF between study visits (all p < .0001).

The improved vision and contrast function in the VPL group remained stable during the 6-month post-therapy period.

Sequential, patient-specific, perceptual therapy improved vision & contrast (CSF) in crosslinked keratoconus with visual deficiencies & acts as proof of concept of improving neural connections at cortical levels.
Keratorefractive surgeons could consider it as a post-crosslinking therapeutic adjuvant.
Visual Perceptual Therapy trains the brain to see better without additional surgery, enhancements, drugs, or side effects in cases of stable Keratoconus.