Morpho-functional analysis of Stargardt Disease for reading.

Objective: To analyze Stargardt disease (STGD) by morpho-functional examination and investigate the relationship between morpho-functional measures and reading performance.

Design: Observational case series study.

Participants: Fifteen patients with STGD.

Methods: Twenty-six eyes of 15 patients underwent complete ophthalmic evaluation. Spectral domain optical coherence tomography, fundus autofluorescence (FAF), best corrected visual acuity (BCVA), and microperimetric examinations were performed. FAF and optical coherence tomography (OCT) overlap on microperimetric images was obtained in order to evaluate both tomographic and FAF features passing through the eccentric fixation area. Both morphologic features and functional data were correlated with magnification of prescribed device and reading rate.

Results: Univariable analysis showed a significant correlation between magnification power and greatest linear dimension of both OCT and FAF (r = 0.69 and r = 0.67; p < 0.05). Magnification power was related to best corrected visual acuity (r = 0.56; p < 0.05). Retinal sensitivity map (r = 0.57; p < 0.05) was considered an indicator of reading rate. Magnification levels showed a positive correlation with eccentric preferred retinal location (p = 0.03) and the degree of FAF alteration (normal, dishomogeneous, ipoautofluorescence; p < 0.0001).

Conclusions: As a result of the overlapping of OCT/FAF imaging on microperimetric exam, residual activity of outer retinal layers passing through the eccentric fixation area seems to be related with required magnification and reading rate. Identification of morpho-functional parameters is helpful for designing a customized rehabilitative program.