Visual Functions in Amblyopia: Effect of Treatment and Prognostic Significance

Vinita Singh

Purpose – To study the various visual functions and their prognostic significance for treatment outcome in amblyopia. The visual functions studied were visual acuity, accommodation, contrast sensitivity, colour vision, mesopic vision and stereopsis.

Study design- prospective interventional study

Patient profile, inclusion and exclusion criteria- 69 patients of unilateral & bilateral amblyopia (total 114 amblyopic eyes) in the age group 3 to 15 yrs, mean age was 8.80 +/- 2.9 were included in this study. There was a slight male preponderance (57.97%). Mild (33.33%), moderate (37.72%) and severe (28.95%) grades of amblyopia were nearly equally distributed.

Method –Clinical evaluation included visual acuity, cycloplegic correction, ocular alignment, ocular motility, colour vision, contrast sensitivity, accommodation, stereopsis and mesopic vision. All patients were treated by conventional occlusion given 6hrs/day for mild to moderate amblyopia ( Vision 6/24 or better ) and full time full time for severe amblyopia (Vision 6/36 or less) . During occlusion, activities requiring hand-eye coordination were advised. 3 and 6 monthly follow up was done with all variables being measured. Analysis was done using Wilcoxon signed rank test.

Result – Stereopsis was was found to be absent in 50.72%, accommodative dysfunction was present in 22.8%, eccentric fixation was found in 18.42% and mesopic visual acuity was found to be better in 57.01% eyes. There was a statistically significant association of poor contrast sensitivity with depth of amblyopia (p<0.001)
The response to treatment was found to continue till 6 months there was a statistically significant difference in the mean visual acuity at 3months and 6months.
We found that good accommodative function, good stereopsis and better mesopic function have a good prognostic significance. Fixation pattern has been found to have insignificant effect on the response to treatment. Better contrast sensitivity was associated with better therapeutic response, we strongly feel that this interesting finding needs to be explored further.