Purpose: To report thirteen cases of idiopathic multifocal choroiditis with discrete chorioretinal lesions who were found to have zonal, multizonal, or diffuse outer retinal or chorioretinal atrophy.
Methods: A retrospective observational case series using multimodal imaging including high-definition optical coherence tomography, fundus autofluorescence imaging, and fluorescein and indocyanine green angiography.
Results: Twenty-one eyes in 13 patients with idiopathic multifocal choroiditis were found to have zonal, multizonal, or diffuse outer retinal or chorioretinal atrophy visualized using multimodal imaging. Thirteen eyes presented with diffuse disease, six eyes with multizonal, and two with zonal atrophy. Patterns of atrophy included zones surrounding the optic nerve, multiple geographic zones in the mid and far periphery, and a diffuse peripheral pattern with relative sparing of the central macula until later in the course of disease. Eleven of the 13 patients were treated with topical, periocular, or systemic corticosteroids, and 1 patient was also treated with systemic immunomodulatory treatment. The atrophic changes progressed over an average of 8 years of follow-up in 10 eyes despite therapy.
Conclusion: Idiopathic multifocal choroiditis can present with an uncommon pattern of zonal, multizonal, or diffuse outer retinal or chorioretinal atrophy as part of its clinical spectrum. The severity, extent, and progression of these atrophic changes are best appreciated using multimodal diagnostic imaging.