Scleral Excavation at Oblique Muscle Insertions: Imaging Characteristics and Correlation with Scleral Plaques and Sclerochoroidal Calcification

PURPOSE: To compare the imaging features of lesions showing hyporeflective posterior scleral excavation found near the insertions of the oblique extraocular muscles to the features and the natural course of Cogan scleral plaques.

METHODS: Multimodal imaging with color fundus photography, spectral-domain optical coherence tomography (OCT), swept-source optical coherence tomography, and B-scan ultrasonography.

RESULTS: A 71-year-old man and an 89-year-old man presented with ring-shaped hypopigmented lesions measuring between 200 μm and 300 μm transversally, and located along the superior vascular arcade and temporal to the fovea. All lesions were identified near the insertion of oblique muscles, with one observed in the temporal macula, and two found along the superotemporal arcades. Enhanced depth imaging-optical coherence tomography showed hyporeflective boat-shaped areas of scleral excavation with reduced choroidal thickness along their margins. B-scan ultrasonography showed the lesions to be intensely reflective with varying degrees of posterior shadowing.

CONCLUSION: To our knowledge, this is the first report of excavated hyporeflective scleral lesions found near the oblique muscle insertions. Imaging and clinical data support the diagnosis of a posterior form of Cogan scleral plaque and are consistent with the natural course of this entity.