Choroidal hyperreflective foci in Stargardt disease shown by spectral-domain optical coherence tomography imaging: correlation with disease severity.

IMPORTANCE: The presence of choroidal hyperreflective foci in Stargardt disease is, to our knowledge, a potentially new finding. Evaluation of these foci may aid in better understanding of the disease process.
OBJECTIVES: To report the presence of choroidal hyperreflective foci in spectral-domain optical coherence tomography (SD-OCT) images from eyes with Stargardt disease and investigate the relationship between the number of hyperreflective foci and disease severity. DESIGN, SETTING, AND PARTICIPANTS: Twenty-six eyes of 13 patients with a clinical diagnosis of Stargardt disease were evaluated in a retrospective case series. Patient data were collected between January 1, 2009, and August 31, 2014. MAIN OUTCOMES AND MEASURES: The number of choroidal hyperreflective foci in Stargardt disease as well as correlation with visual acuity, central macular thickness (CMT), and disease duration were the main outcomes. A total of 707 macular SD-OCT scans of 13 patients with Stargardt disease were reviewed and evaluated for the presence and number of retinal/choroidal hyperreflective foci, central macular thickness, visual acuity, and disease duration. Enhanced depth imaging with OCT (EDI-OCT) scans available for 2 patients were compared with SD-OCT scans. A PubMed/Google search was performed to identify SD-OCT images in Stargardt disease; these findings were reviewed for the presence of choroidal hyperreflective foci.
RESULTS: The mean (SD) numbers of hyperreflective foci in each retinal/choroidal layer in decreasing frequency were as follows: Bruch membrane/retinal pigment epithelial (RPE) complex, 78.22 (24.39); choriocapillaris, 25.77 (17.57); Sattler layer, 18.59 (12.89); outer retina, 16.64 (6.96); inner retina, 0.95 (1.58); and Haller layer, 0.73 (0.87). The number of hyperreflective foci in the Bruch membrane/RPE complex increased exponentially with decreasing CMT (R2 = 0.99; P = .008). The number of hyperreflective foci in the Bruch membrane/RPE complex, choriocapillaris, and Sattler layer increased proportionally with decreasing visual acuity (R2 = 0.97, R2 = 0.95, and R2 = 0.99, respectively; and P = .007, P = .006, and P = .008, respectively). Direct correlation existed between the number of hyperreflective foci in the choriocapillaris and the Sattler layer and disease duration (R2 = 0.98 and R2 = 0.99, respectively; and P = .006 and P =.009, respectively). In the 10 studies on Stargardt disease, choroidal hyperreflective foci were present in 51 of 54 SD-OCT images (94%). CONCLUSIONS AND RELEVANCE: Based on the findings of the present study, choroidal hyperreflective foci in Stargardt disease, prominent at the Bruch membrane/RPE complex, choriocapillaris, and Sattler layer, correlate with disease severity in terms of retinal atrophy, decline in vision, and disease duration. Further studies are necessary to assess whether these findings are unique to Stargardt disease.