Correlation of Macular Thickness, Multifocal ERG with Visual Acuity in Oculocutaneous Albinism (OCA)

Abstract

Background and Aim: Ocular albinism is known to have nystagmus and foveal hypoplasia. A study was done to evaluate the correlation of visual acuity with macular thickness (MT) and mf ERG. Materials and Methods: A total of 20 eyes (10 patients) with OCA were selected. Macular thickness was evaluated with optical coherence tomography and mf ERG was done in all the patients. Results: Mean age was 16.1 ± 7.3 years. The patients were divided into three groups based on their visual acuity > 6/12 (group A), 6/18 - 6/24 (group B), 6/36 or less (group C). Mean MT in patients with visual acuity in group A, B and C was 194.8 ± 26.7, 220 ± 12.3 and 243.5 ± 17.3 microns respectively. The amplitudes of first positive wave (P1) and first negative wave (N1) for the central ring in mf ERG in patients of group A, B and C was 1.1 ± 0.5 (P1), 0.7 ± 0.2 (N1), 0.6 ± 0.5 (P1), 0.3 ± 0.2 (N1), 0.7 ± 0.2 (P1), 0.3 ± 0.1 (N1) microvolts respectively. The vision correlated well with the macular thickness. The mf ERG potentials (P1 and N1) do not correlate with the visual acuity. Conclusion: We believe that the visual acuity in albinotic patients is affected by the macular thickness but the electric potentials do not depend on the visual acuity.