Acute idiopathic blind spot enlargement syndrome: prolonged retinal dysfunction revealed by multifocal electroretinogram technique.

Objective: To report the multifocal electroretinographic findings of a patient with acute idiopathic blind spot enlargement syndrome recorded at 2 weeks and 4 months after the onset.

Methods: A 35-year-old patient underwent static visual field (Humphrey, 30-2) and multifocal electroretinogram testing at 2 weeks and 4 months after the onset of acute idiopathic blind spot enlargement. The stimulus array for the multifocal electroretinogram consisted of 61 hexagons, and the total recording time was about 4 minutes.

Results: At 2 weeks, the patient had a large, well-demarcated scotoma centered on the blind spot, and its margin extended to within 5 degrees of fixation. The multifocal electroretinograms were depressed in the areas corresponding to the scotoma. At 4 months, her visual symptoms disappeared and static visual fields showed normal sensitivities at almost all locations. However, the multifocal electroretinograms still revealed reduced focal responses in a broad area around the blind spot.

Conclusions: These results suggest that multifocal electroretinograms may be used to detect subclinical retinal dysfunction in patients with acute idiopathic blind spot enlargement.