Quantitative analysis of photoreceptor recovery in acute zonal occult outer retinopathy (AZOOR) using adaptive optics scanning laser ophthalmoscope

Abstract

Purpose: To assess the photoreceptor abnormalities quantitatively in eyes with acute zonal occult outer retinopathy (AZOOR) in the recovery phase by adaptive optics scanning laser ophthalmoscope (AO-SLO).

Methods: Four consecutive patients with unilateral AZOOR were examined at the Osaka University Hospital (4 women; ages ranged from 23 to 32 years). A custom built wide-field AO-SLO (Topcon) was used to evaluate the cone density of the affected retinal area before and after treatment by oral corticosteroids. Four hundred retinal images were photographed sequentially at 30 frames/sec. The wavefront aberrations were continuously corrected. The field of view of the retinal images was 0.920 ×1.250 for counting the cone density and 6.90 ×8.30 for evaluating the affected area. The cone density was measured at 30 and 50 nasal and temporal to the fovea. The size of lesion area was determined by a prototype software.

Results: The lesion was located on the nasal side in 3 patients and on the temporal side in one patient. The visual fields improved in all four patients after the treatment. The cone density in lesion area was 11069 ± 2287 cones/mm² at 30 and 7286 ± 937 cones/mm² at 50. After the treatment, the cone density in lesion area increased to 15931 ± 3611 cones/mm² at 30 (P=0.097), and to 14021 ± 2055 cones/mm² at 50 (P=0.010). The size of the lesion was reduced from 20069 ± 4871 to 7933 ± 3370 pixels (60%) after the treatment (P=0.013).

Conclusions: Our results demonstrated that AO-SLO can detect the decrease in the lesion area and the increase in cone density quantitatively after corticosteroid therapy in eyes with AZOOR. We recommend the use of AO-SO to evaluate the retinal structure of eyes with AZOOR during the recovery phase.