JUL 06, 2023
Fundus autofluorescence (FAF) appears to provide a similar prognostic value to electroretinogram (ERG) for monitoring Stargardt disease but in a noninvasive and more easily interpreted package.
This was a retrospective case series of 234 patients with Stargardt disease who received both FAF and ERG imaging at Moorsfield Eye Hospital. The purpose was to evaluate the prognostic ability of FAF in comparison to ERG for Stargardt disease. Patients were classified into 3 ERG groups based on pattern and full-field ERG (ffERG) testing: Group 1, macular dysfunction but normal ffERG; Group 2, macular dysfunction and generalized cone dysfunction on ffERG; or Group 3, macular dysfunction and generalized cone and rod dysfunction on ffERG. The same patients were classified into 3 groups based on the extent of hypoautofluorescence and background appearance on FAF. The concordance of ERG and FAF was determined by comparing patient classification between these two methods. Associations between baseline visual acuity, age of presentation, and genetic variants were also explored.
Of the 243 patients in the cohort, 73% had similar ERF and FAF findings (classified into equivalent groups via both ERF and FAF methods); 14% had milder FAF than ERG findings, and 13% had more severe FAF than ERG findings. When the investigation was limited to isolated macula vs widespread retinal involvement, more than 80% of the patients had matching ERG and FAF patterns.
Limitations include the retrospective nature of this study and the fact that it was conducted at a single center. Also, some of the images were not appropriate for FAF quantification since the data were acquired in a larger clinical context.
Even though ERG is considered the gold standard for monitoring patients with Stargardt disease, this method is time-consuming and not accessible for every patient. The results of this study indicate that FAF imaging is effective in determining the extent of Stargardt disease and is able to provide an accurate prognosis for affected patients. This raises the possibility that FAF may be an appropriate alternative testing modality to ERG for patients with Stargardt disease and that it could provide value in the context of new therapeutics and clinical trials.
Financial Disclosures: Dr. Marianeli Rodriguez discloses no financial relationships.