Two cases of acute macular neuroretinopathy.

PURPOSE

To report chorioretinal vasoconstriction as a potential pathogenic mechanism in acute macular neuroretinopathy (AMNR). To describe a time lag between the onset of functional deficits and that of fundoscopically visible lesions and illustrate the superior value of infrared (IR) compared to red-free or white light imaging in AMNR.

METHODS

Two young female patients (30 and 19 years old) with AMNR are described. Both underwent detailed clinical examination with additional imaging using IR, blue, and red-free light. Functional evaluation with pattern and multifocal electroretinography, Goldmann manual, and automated Humphrey visual fields (VFs) was also performed.

RESULTS

The first patient was diagnosed with AMNR after a caesarian section during and after which she received treatment with vasoconstrictive drugs. She was followed up for 28 months, after which time she still suffered from bilateral U-shaped paracentral scotomata associated with macular lesions. The second patient complained of central scotomata prior to the onset of any visible fundoscopic lesions, following a bout of flu. VFs confirmed a central scotoma and pattern electroretinography was consistent with loss of macular function. Bilateral petaloid lesions became visible after 3 days when function began to improve. In both patients IR imaging was superior to standard red-free and white light in identifying macular lesions.

CONCLUSIONS

Vasoconstriction in the chorioretina may be pathogenic in AMNR. Functional complaints precede fundus lesions in AMNR. And, IR light is superior to red-free or white light imaging in detecting typical fundus lesions in AMNR both early and late in the course of the disease.