Analysis of retinal nerve fibre layer changes in anisometropic amblyopia by Heidelberg retina tomograph.

OBJECTIVE To identify if anisometropic amblyopia is associated with changes in optic disk morphology. METHODS The study comprised a total of 80 eyes recruited from Shifa Foundation Community Health Centre and the Pakistan Institute of Medical Sciences, Islamabad between May and October 2012. Anisometropic amblyopia was the only cause of disability (visual acuity > or = 6/12) in amblyopic eyes whereas normal eyes had a best corrected visual acuity of 6/6 and no morbidities. Patients with other causes of amblyopia, co-morbid ocular diseases, and in whom a good-quality image could not be obtained were excluded. Mean retinal nerve fiber layer thickness was analysed using Heidelberg retina tomograph. Analysis of frequency distribution, probability and regression were run on the data collected during the study using SPSS version 15.0. RESULTS The mean age of the patients was 23.85 +/- 5.85 years. The retinal nerve fibre layer thickness ranged between 0.09 mm and 0.35 mm (mean: 0.23 mm +/- 0.07) in amblyopic eyes, and between 0.18 mm and 0.36 mm (mean: 0.25 mm +/- 0.05) in normal eyes. The difference was not statistically significant (p = 0.087). No association was found between the retinal nerve fiber layer thickness or the age and refractive error of patients. CONCLUSION The optic disk does not appear to be the site of morphological changes in amblyopia.