Outer retinal abnormalities in acute macular neuroretinopathy

Abstract

Purpose: To investigate the spectral-domain optical coherence tomography findings in four cases of acute macular neuroretinopathy and identify features that may differentiate acute macular neuroretinopathy from similar conditions in the acute zonal occult outer retinopathy complex.

Methods: Patients with acute macular neuroretinopathy underwent complete periodic examinations, including ophthalmoscopy, color photography and autofluorescence photography, visual field testing, and spectral-domain optical coherence tomography. Abnormalities as seen by multimodal imaging were documented and evaluated during follow-up.

Results: The average age of the 4 patients was 32 years (range, 28-34 years), and 2 had bilateral involvement. The follow-up ranged from 1 month to 5 months. In each patient, dark lobular areas seen by ophthalmoscopy corresponded to the measured visual field defect and what appeared to be a regional loss of outer segments of the photoreceptors. The outer segment defect resolved in two patients and improved in the other two during follow-up. All patients showed a colocalizing regional thinning of the outer nuclear layer, which did not change during the follow-up period. There were no associated abnormalities in the fundus appearance.

Conclusion: Acute macular neuroretinopathy causes reddish brown patches that are because of outer retinal damage as documented by spectral-domain optical coherence tomography. Unlike other entities in the acute zonal occult outer retinopathy complex, acute macular neuroretinopathy has no other synchronic ophthalmoscopically visible fundus abnormalities. These lesions may resolve over time, with restoration of the outermost retinal architecture, but persistent thinning of the overlying outer nuclear layer remained.