Abstract
Purpose :
Stargardt disease (SD) is characterized by changes in the retinal pigment epithelium (RPE) that can be identified by ophthalmoscopy. The causative ABCA4 gene encodes a protein localizing to photoreceptor outer segments. The disease sequence by which ABCA4 mutations lead to defects in the RPE remains unclear. In this study, we imaged photoreceptors and RPE cells in SD using FAOSLO.
Methods :
Three SD patients underwent a comprehensive ophthalmic examination and conventional imaging including fundus photography and fundus autofluorescence (HRA, Heidelberg). FAOSLO was used to image the photoreceptor and RPE layers at the single cell level, and compared to age-matched control subjects. Cone and rod photoreceptors were counted and RPE segmentation was performed.
Results :
Cone and rod spacing was increased in all patients at all locations where photoreceptors were visible; cones had a dark appearance. FAOSLO showed structures consistent with RPE cells in the periphery. In a transition zone in the peripheral macula outside areas of atrophy, the autofluorescent (AF) pattern was consistent with photoreceptors. No AF cellular patterns were identified within areas of atrophy at the foveal center.
Conclusions :
This study provides the first in vivo high resolution images of cones, rods and RPE cells in SD. The AF pattern imaged in the transition zone appears to arise from photoreceptors. This pattern may be due to the accumulation of lipofuscin or lipofuscin precursors within the photoreceptors, and may represent an important early stage in the pathophysiology of SD.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.