Occult Acute Macular Neuroretinopathy

Area of Science:

• Ophthalmology
• Retinal Diseases
• Neuro-ophthalmology

Background:

• Acute macular neuroretinopathy (AMN) is a rare condition affecting vision.
• Phenylephrine, a common decongestant, has been anecdotally linked to retinal vascular events.
• Diagnostic challenges exist for atypical presentations of AMN.

Purpose of the Study:

• To report a rare case of acute macular neuroretinopathy (AMN).
• To highlight the diagnostic utility of spectral-domain optical coherence tomography (SD-OCT) in identifying an unusual variant of AMN.
• To describe a case potentially linked to phenylephrine use.

Main Methods:

• Case report of a 19-year-old woman with visual disturbances.
• Clinical examination including fundoscopy, visual fields, and electrophysiological testing.
• Advanced imaging with spectral-domain optical coherence tomography (SD-OCT).

Main Results:

• The patient developed visual symptoms after ingesting phenylephrine for an upper respiratory infection.
• Standard ophthalmological examinations were unremarkable, failing to detect any retinal abnormalities.
• SD-OCT revealed a focal lesion confined to the fovea, characteristic of a variant of AMN.
• This variant was termed "occult AMN" due to its subclinical nature on conventional testing.

Conclusions:

• This case underscores the importance of SD-OCT in diagnosing subtle retinal pathologies.
• Phenylephrine may be a potential trigger for rare neuroretinopathic events.
• The identification of "occult AMN" expands the spectrum of AMN presentations and diagnostic considerations.