Acute bilateral peripheral cone system dysfunction.

Purpose: To report electrophysiological and psychophysical findings in an unusual case with acute loss of the peripheral visual field bilaterally.

Methods: A 19-year-old woman underwent fundus photography, fluorescein angiography, visual field testing, determination of full-field electroretinograms (ERGs) and multifocal ERGs (mfERGs), and rod-cone perimetry in addition to routine ophthalmologic examinations.

Results: Findings of fundus examination and fluorescein angiography were completely normal, and best-corrected visual acuity was 1.0 in both eyes. However, static perimetry revealed a temporal field defect in the right eye and an arcuate scotoma in the left eye. Full-field ERG cone responses were significantly reduced, but rod responses were normal in both eyes. Psychophysical rod-cone perimetry demonstrated that the peripheral cone system was impaired whereas the rod sensitivity was completely normal. mfERGs showed that the local cone responses were well preserved in the central retina but were severely reduced in the peripheral retina in both eyes.

Conclusions: These results indicate that there is an unusual retinopathy showing acute dysfunction of the peripheral cone system bilaterally whereas the rod system is functioning normally.