[Contribution of multimodal imaging in the various stages of Stargardt disease]

To describe the contribution of multimodal imaging in the various stages of Stargardt disease (STGD).

We retrospectively reviewed 46 eyes of 23 STGD patients with identified ABCA4 mutations. All patients underwent a complete ophthalmic examination, spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF), fluorescein angiography (FA) and Indocyanine green angiography (ICGA).

The mean age of patients was 25.5 years (range 8-56). Fundus examination was normal in 2 patients (subclinical stage), where SD-OCT showed localized retrofoveolar retinal pigment epithelium (RPE) thickening. FAF was normal in 1 eye and showed mild heterogeneous hyper-FAF in 3 eyes. Twelve eyes had mild salt and pepper changes in the macula (early stage) with diffuse retinal atrophy on SD-OCT and mixed hyper and hypoautofluorescence on FAF. Nine patients showed central atrophy with white-yellow flecks distributed in the posterior pole and mid-periphery. This phenotype showed total foveal atrophy on SD-OCT and normal peripapillary area on FAF. Twelve eyes had a large demarcated area of RPE atrophy, pigment clumping and migration extending to the peripheral retina associated with peripapillary atrophy. These eyes showed diffuse retinochoroidal atrophy on OCT with diffuse alterations reaching the peripapillary area on FAF. On FA, it was difficult to analyze the choroidal silence sign in patients with advanced stages of the disease. A hyperfluorescent window defect pattern was also found in patients with white-yellow flecks and did not correspond exactly to them, or to the areas of peripheral autofluorescent lesions. ICGA showed hypocyanescent areas seen at intermediate and late phases with multiple cyanescent points adjacent to them. On ICGA, hypocyanescent areas were more extensive than lesions observed on FAF.

Multimodal imaging is helpful for the diagnosis of early stages of STGD disease and to better understand its pathophysiology. FAF and mostly SD-OCT have supplanted FA in the early, especially subclinical, stages. Over all, ICGA shows more extensive damage, making this tool useful for better understanding STGD and suggesting possible direct damage to the choriocapillaris associated with RPE lesions. In advanced stages, only DNA testing can confirm the diagnosis of STGD.