EFFECT OF EARLY VERSUS LATE EYE PATCHING THERAPY ON VISUAL ACUITY AND CONTRAST SENSITIVITY AMONG ANISOMETROPIC AMBLYOPIC CHILDREN

Abstract

Background: Anisometropia is a common reason for amblyopia in children. When both eyes have different refractive error, the eye with higher error becomes amblyopic due to suppression. In these children not only visual acuity is reduced but contrast sensitivity is also affected. Patching of good eye is routinely done for amblyopia management, but age at which patching are started matters a lot because of visual system plasticity.

Objective: This study was done to see and compare the effect of early and late patching therapy on VA and contrast sensitivity in children having anisometropic amblyopia.

Methodology: This was a comparative study. Total 52 children with anisometropic amblyopia were included and divided equally into two groups, Early patching group (n=26) and Late patching group (n=26). Visual acuity, Best corrected visual acuity (BCVA) both in log MAR and Contrast Sensitivity (CS) in log units were taken at baseline, at first follow up and at second follow up. Normality of data was checked through Kolmogorov-Smirnov and Shapiro- Wilk tests. For within group comparison paired sample t-test was used and for between groups independent sample t-test was applied. P value <0.05 was taken as significant.

Results: The tests of normality showed data was normally distributed at baseline and at follow ups with p>0.05. On within group analysis, there was significant improvement in VA, BCVA and CS from baseline to follow up 1 and follow up 2 in both groups (p<0.001). Overall mean improvement in VA was 0.15 log MAR at first follow up and 0.24 log MAR at second follow up. Similarly BCVA improved by 0.14 and 0.23 log MAR and CS improved by 0.13 and 0.23 log units. On between group comparison, early group showed better improvement than late group and difference was statistically significant (p<0.001). At final follow up, VA in early group was 0.32±0.08 log MAR as compared to 0.44±0.09 in late group. BCVA was 0.28±0.09 vs. 0.40±0.09 and CS was 1.49±0.11 vs. 1.39±0.15 in early and late groups respectively.

Conclusion: Both early and late patching therapies are effective for anisometropic amblyopia, but early patching gives significantly better results. Children who received patching early showed more improvement in both visual acuity and contrast sensitivity .So early screening and early start of occlusion therapy should be encouraged to get maximum visual recovery.