Correlating Photoreceptor Abnormalities on Adaptive Optics Scanning Light Ophthalmoscopy to Conventional Clinical Findings in Patients with Stargardt Disease

Abstract

Purpose: To compare retinal structure assessed with optical coherence tomography (OCT), fundus auto fluorescence (FAF) and microperimetry to photoreceptor structure seen on adaptive optics scanning light ophthalmoscope (AOSLO) in patients with Stargardt disease.

Methods: Ten patients (mean age 43, range 16-77 yrs) clinically diagnosed with Stargardt disease were imaged using confocal and split detection AOSLO. OCT, FAF and microperimetry were compared qualitatively to AOSLO montages. Cone photoreceptors were manually identified on temporal strips (2-8 degrees from the foveal center) to generate density maps. These were then compared to a normative database (n = 9) along the same retinal eccentricities and the results displayed as deviation maps to facilitate interpretation.

Results: Visible ellipsoid zone (EZ) defects observed on OCT correlated with disruptions on AOSLO, FAF and microperimetry. However, in areas of intact EZ, cone density varied dramatically, ranging from near zero to normal density. In retinas with decreased cone density, the integrity of the EZ on OCT appeared to be sustained by the remaining contiguous rod mosaic. Further analysis showed that in areas of decreased cone density, the interdigitation zone was absent, consistent with this band representing the cone outer segment tips. Focal density changes were detected that correlated with areas of hyper-reflectance seen on FAF. The cone density differences were also consistent with functional differences seen on microperimetry.

Conclusions: The information derived from confocal and split detection AOSLO can play an important role in understanding the pathogenesis of hereditary eye conditions like Stargardt disease. In particular, the correlation between cone density deviation maps and other clinical data would be a powerful tool in characterization and monitoring of retinal diseases.