Macular Function and Morphologic Features in Juvenile Stargardt Disease: Longitudinal Study

Abstract

To evaluate disease progression in a cohort of patients with a clinical and genetic diagnosis of Stargardt disease. Longitudinal cohort study. A total of 56 selected patients with a clinical and molecular diagnosis of Stargardt disease, an early age of onset, and a median follow-up length of 2 years. Patients underwent routine examination, including full-field electroretinography, microperimetry, and optical coherence tomography. Best-corrected visual acuity (BCVA), mean retinal sensitivity, fixation stability, preferred retinal locus, inner segment/outer segment (IS/OS) junction loss, and atrophic lesion area. A total of 56 patients with a mean age at disease onset of 15.3 years (range, 3-28 years), a mean disease duration of 12.1 years, and a mean age at baseline of 27.4 years were analyzed. The median BCVA was 20/200 in both eyes. Optical coherence tomography parameters (IS/OS alteration and retinal pigment epithelium lesion area) were obtained in only 49 patients because the signal quality was poor in the remaining 7 patients. Optical coherence tomography revealed a mean retinal pigment epithelium lesion area of 2.6 mm(2), preserved foveal IS/OS in 4.1% of patients, loss of foveal IS/OS in 59.2% of patients, and extensive loss of macular IS/OS in 36.7% of patients. Microperimetric findings showed a reduced macular sensitivity (mean, 10 decibels [dB]) and an unstable fixation in half of the patient cohort. The longitudinal analysis showed a significant progressive reduction of BCVA and macular sensitivity (at an estimated rate of 0.04 decimals and 1.19 dB/year, respectively) associated with a significant enlargement of retinal pigment epithelium lesion area (0.282 mm(2)/year). No significant changes in ophthalmoscopic findings and electroretinographic responses were detected. This study highlights the importance of microperimetry and optical coherence tomography in monitoring patients with Stargardt disease. Quantifying the decline of visual functionality and detecting morphologic macular changes prove useful in evaluating disease progression over a short-term follow-up and should be taken into account for the design of future clinical trials of gene therapy to treat retinal dystrophy.