CORTICAL STIMULATION THERAPY USING GABOR PATCHES IMPROVES VISION AND CONTRAST SENSITIVITY IN CROSSLINKED STABLE KERATOCONUS: RESULTS OF RCT

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. 

A prospective, controlled-randomized, open-label study. Cross-linked keratoconus(KC), stable over 1 year with BCVA worse than 20/40 were randomized in 2:1 into Treatment arm(G1) in which computer-based perceptual therapy using Gabor patches amidst co-linear flankers was employed, and 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 Perceptual therapy arm PL(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 after 40 completed sessions and after 6 months (G1,p<0.0001), & not in 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.