Outer retinal abnormalities in acute macular neuroretinopathy

Area of Science:

• Ophthalmology
• Retinal Imaging
• Neuro-ophthalmology

Background:

• Acute macular neuroretinopathy (AMNR) is a condition affecting the outer retina.
• Distinguishing AMNR from other conditions within the acute zonal occult outer retinopathy complex is crucial for accurate diagnosis and management.

Observation:

• Multimodal imaging, including spectral-domain optical coherence tomography (SD-OCT), was used to examine four patients with AMNR.
• Ophthalmoscopy revealed dark lobular areas corresponding to visual field defects and outer photoreceptor segment loss.

Findings:

• SD-OCT documented regional loss of photoreceptor outer segments, which showed partial or complete resolution during follow-up.
• A consistent finding was regional thinning of the outer nuclear layer, which persisted throughout the follow-up period.
• AMNR lesions were characterized by reddish-brown patches due to outer retinal damage, with no other synchronic fundus abnormalities observed.

Implications:

• SD-OCT is valuable in identifying characteristic findings of AMNR, aiding in its differentiation from other outer retinal diseases.
• While outer retinal damage may resolve, persistent thinning of the outer nuclear layer suggests potential long-term structural changes.
• Understanding these specific imaging features improves diagnostic accuracy for AMNR within the broader spectrum of outer retinopathy conditions.