Presented at the 49th AAPOS annual meeting, April 2024
Background: There are limited treatment options to improve vision in patients with congenital nystagmus. We examined the use of repeated visual stimulation with Gabor Patches to achieve that goal.
Methods: In a prospective randomized (3:1) controlled open label study, patients aged 9-55 years with congenital nystagmus and best corrected visual acuity (BCVA) between 20/40–20/200 were included. The treatment group underwent visual stimulation for four months, controls were treated with sham stimuli. BCVA, contrast sensitivity, and stereoacuity were assessed.
Results: 26 patients were treated and 10 served as control. Mean age was 22.47±12 years. 6/26 (23%) of treatment subjects achieved driving license BCVA (20/40) vs 1/10 (10%) of controls. Distance treated BCVA improved by 0.10±0.07 logMAR (one ETDRS line) compared with 0.015±0.09 logMAR in controls (p=0.006). Near BCVA improved by 0.16±0.14 logMAR (1.6 ETDRS lines) compared with 0.05±0.13 logMAR in controls (p=0.040). 88% (8/9) of study patients who had no binocularity prior to treatment achieved binocularity (mean 630’) as opposed to 25% (1/4) of controls (p=0.10). Mean stereoacuity and contrast sensitivity improved by 801±730’ and 292±391% in the study group as opposed to 246±376’ and 152±67% in controls respectively (p=0.031; p=0.157).
Conclusions: Visual perceptual learning using Gabor Patches resulted in a significant improvement in near and distance visual acuity, which allowed 23% of patients to achieve a driving license BCVA. A corresponding improvement in stereopsis was noted, and 88% of patients with no binocularity gained it. Further studies will identify which patients will benefit most from this treatment.
Lional Raj Daniel Raj Ponniah, MD
Dr. Agarwal’s Eye Hospital, India
Presented at the ASCRS annual meeting, April 2024 – https://ascrs.confex.com/ascrs/24am/meetingapp.cgi/Paper/99713
Purpose
To evaluate computer based perceptual visual therapy regime using Gabor patches for improving visual acuity and contrast sensitivity function (CSF) in crosslinked stable keratoconic eyes
Methods
A Prospective, controlled randomized, open label study. Post CXL Keratoconus, stable for over one year, by serial clinical and topographic evaluations, BCVA worse than 20/40 were recruited and randomized in 2:1 ratio into treatment (G1) and control (G2) arms. The study consists of 2 phases, screening period and therapy period. The post therapy effectiveness were evaluated for improvement in Monocular Best Corrected Visual Acuity (BCVA) distance & near (ETDRS VA chart) and CSF in Cycles per Degree (CPD), say CPD -3, CPD-6, CPD-12, CPD-18 on the CSV-1000 E chart one.
Results
30 cases randomised into 2:1. Baseline BCVA was 68.20 (SD-8.11) & 67.40 (SD-7.09) ETDRS characters in G1, and G2 respectively (p=0.793). The mean BCVA of perceptual learning group (G2) improved to 73.30 (SD-7.477) & 79.10 (SD-8.466) post 20 & 40 treatment sessions respectively, improved by over 2.5 equivalent Snellen’s lines, (repeated measure ANOVA p<0.0001). The change in CSF at various spatial frequencies say, 3,6,12 & 18 CPD analysed using Friedman tests showed significant improvements in contrast sensitivity at all spatial frequencies of 3,6,12,18 cpd, of the perceptual learning group (G1), & no improvement in control group (G2)
Conclusion
Sequential, patient specific, perceptual learning program based on visual stimulation improved vision and contrast sensitivity in crosslinked keratoconus with visual deficiencies & acts as a proof of concept of improving neural connections at cortical level. Keratorefractive surgeons could consider this as a post operative therapeutic adjuvant.