Cortical Stimulation Therapy Using Gabor Patches Improves Vision And Contrast Sensitivity In Crosslinked Stable Keratoconus: Randomized Control Study

To evaluate patient-specific, computer-based perceptual visual therapy (PL) regime using Gabor patches for improving best-corrected vision(BCVA) & contrast sensitivity function(CSF) in crosslinked stable keratoconus(KC)

A prospective, controlled-randomized, open-label study in a Tertiary eye hospital.

A prospective, controlled-randomized, open-label study. Cross-linked keratoconus(KC), stable over 1 year with BCVA worse than 20/40 was randomized in 2:1 into the Treatment arm(G1) in which computer-based perceptual therapy using Gabor patches amidst co-linear flankers was employed, and the Control arm(G2). The study consists of 2 phases (screening + therapy periods(PL). Mid-training (Post 20 sessions), 40 training sessions, and 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 CPD using Friedman tests for repeated measures

30 cases were randomized. Baseline BCVA was 68.20+/-8.11 & 67.40+/-7.09 in G1, G2 (p=0.793). BCVA of the Perceptual therapy(PL) arm (G1) improved to 73.30+/-7.47 & 79.10+/-8.46 post 20 & 40 sessions (over 2.5 Log MAR lines equivalent, p<0.0001) and remained stable after 6 months whereas not in controls(G2).

Contrast sensitivity functions (CSF) at 3,6,12,18 CPD analyzed using Friedman repeated measure tests showed significant improvements in the PL group (G1) after 40 completed sessions and after 6 months (G1,p<0.0001), & not in the control arm.

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 post-operative therapeutic adjuvant, in crosslinked stable KC with visual deficiencies.

Visual Perceptual Therapy trains the brain to see better without additional surgery, enhancements, drugs, or side effects in cases with Stable Keratoconus.