Abstract
Purpose :
To describe the progression of flecks temporal to the fovea in young patients with ABCA4-related Stargardt disease.
Methods :
From a total of 44 patients, aged 4.7–19 (median 11. 9) years at first visit, having confirmed biallelic pathogenic variants in ABCA4 and serial autofluorescent (AF) Optos imaging, we selected green laser (532 nm) optomap images of 10 eyes from 5 patients to demonstrate the progression of ABCA4-related Stargardt’s (STDG1) by genotype. We selected these patients because their genotypes could be sorted according to the putative residual functionality of the combined alleles based on biochemical characterizations available in the literature. We analyzed the AF images using ImageJ. In the analyses, we set the distance between the center of the fovea and the center of the optic nerve, in each respective image, to unity. We then produced a rectangular region of interest (ROI) of size 1×1.5, with the long sides parallel to the fovea-ONH segment and the nasal short side centered on the fovea (such that the ROI extended into temporal macula). We then used the thresholding tool to identify and quantify (%) bright flecks within the ROI for each image. (Fig. 1A.)
Results :
We observed the rise and fall in %AF within the ROI with the age of patient, consistent with the disease progression model described in Cideciyan, et al. (2004). Furthermore, severe genotypes, such as double null, peaked earlier in life than did the milder genotypes (e.g., two semi-functional alleles).
Conclusions :
The %AF in the temporal macula is a strong indicator of the stage of STDG1 disease progression in young patients. Both the timing and the peak values of %AF within the ROI are indicative of the severity of the genotype; more severe genotypes produce higher %AF at earlier ages.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.