Optical Coherence Tomography Angiography (OCT-A) in a Patient with Occult Retinal Dysfunction

Area of Science:

• Ophthalmology
• Retinal Imaging
• Diagnostic Technologies

Background:

• Multimodal imaging is crucial for diagnosing challenging retinal conditions.
• Acute visual field defects can present with subtle or absent funduscopic findings.
• Differentiating between various occult outer retinal disorders is clinically significant.

Observation:

• A 36-year-old patient presented with acute visual field loss and photopsia following an influenza-like illness.
• Standard fundus examination revealed no obvious lesion, complicating initial diagnosis.
• Infrared imaging identified an extensive retinal abnormality.
• Indocyanine green angiography (IA) showed late hypofluorescence, and mild hyperautofluorescence suggested features of acute zonal occult outer retinopathy (AZOOR).

Findings:

• Spectral domain optical coherence tomography (SD-OCT) revealed external limiting membrane (ELM) fading and ellipsoid zone (EZ) disorganization.
• Optical coherence tomography angiography (OCT-A) demonstrated significant perfusion loss in the outer retinal vascular layer.
• Fluorescein angiography (FA) results were normal, highlighting OCT-A's unique diagnostic capability.
• The OCT-A findings were consistent with recently described cases of acute macular neuroretinopathy (AMN).

Implications:

• OCT-A is valuable for detecting reduced outer retinal capillary networks in cases with normal fundus appearance.
• This case highlights the overlapping imaging features between AZOOR and AMN.
• OCT-A enhances the diagnostic accuracy for subtle or occult retinal vascular pathologies.