Progression of Electroretinogram Responses in Stargardt‐Fundus Flavimaculatus: A longitudinal study

Abstract

AbstractPurpose To investigate the progression in Stargardt‐fundus flavimaculatus (S‐FFM) by repeated clinical and electrophysiological examination.Methods A longitudinal study of 59 patients with S‐FFM was undertaken. The mean age at the initial examination was 31.6 years; mean follow‐up interval was 10.5 years. Electrophysiological tests included pattern and full‐field electroretinogram (ffERG); clinical ophthalmic examinations were performed. Patients were classified into 3 groups as previously published (Lois et al, 1999); Group 1 had dysfunction confined to the macula; Group 2 had macular and generalized cone dysfunction; Group 3 had macular, generalized cone and generalized rod dysfunction. Initially, there were 27 patients in Group 1, 16 patients in Group 2, and 16 patients in Group 3. The data obtained at follow‐up were compared with those originally obtained. An amplitude reduction of > 50% or a peak time shift of >3 ms for the 30Hz flicker ERG or bright flash a‐wave were considered clinically significant. Molecular analysis of the ABCA4 gene showed likely disease causing variants in 30/40 patients.Results During follow‐up, 3/27 patients from Group 1 progressed to Group 2, and 2/27 patients to Group 3. Eight of 16 patients of Group 2 progressed to Group 3. Significant deterioration in ERG was observed 13/59 patients. Electrophysiological progression occurred in 22% of Group 1, 50% of Group 2, and 100% of Group 3.Conclusion All patients with initial rod involvement demonstrated clinically significant electrophysiological deterioration; only 20% of the patients initially having normal ffERGs showed significant deterioration. These data confirm and elucidate the role of ffERG in the prognosis of patients with S‐FFM.