Multimodal imaging of chorioretinal folds induced by orbital vascular malformation in two cases

Purpose: To investigate the alterations in the retinal pigment epithelium (RPE) in the crest and trough portions of chorioretinal folds (CRFs) induced by an orbital vascular tumor. Methods: Review of multimodal imaging in two eyes of two patients with globe compression and CRFs from an orbital vascular tumor. Results: Fundus photography demonstrated obliquely extending CRFs with alternating hyperpigmented and hypopigmented linear alterations in both eyes. Fundus autofluorescence (AF) imaging showed obliquely oriented hypoAF lines, incompletely alternating with hyperAF lines. In Case 1, the hyperAF lines had interspersed hypoAF segments and Case 2 had peripapillary mottling of AF. Fluorescein angiography (FA) showed alternating hyper and hypofluorescent lines in the late phase in Case 1. Optical coherence tomography (OCT) documented relative thinning of RPE at the folded crests in Case 1 and preservation of RPE in Case 2. Swept-source OCT angiography (SS-OCTA) demonstrated oblique hyporeflective lines in the outer retina and choriocapillaris layers in Case 2. These findings suggest that the crest of a CRF represents thinned or rarified RPE with hypoAF, transmission hyperfluorescence (FA), partially attenuated RPE layer (OCT), and isoreflectivity (SS-OCTA) while the trough represents compressed RPE with irregular hyperAF, transmission hypofluorescence (FA), thickened RPE layer (OCT), and hyporeflectivity (SS-OCTA). Conclusion: The anatomic and functional status of the RPE in CRFs based on multimodal imaging reveals normal to attenuated RPE with hypofunctionality at the fold crest and compacted, thickened RPE at the trough with segmental functional impairment on AF imaging. Anatomic information regarding CRFs is evident on OCT, FA, and SS-OCTA while the functional status is depicted on AF.