Pattern flash visual evoked potentials in patients with homonymous hemianopia.

Visual evoked potentials from seven horizontally spaced electrodes were recorded from normal subjects and subjects with homonymous hemianopia in response to hemifield pattern flash stimulation. Stimulation produced a large early peak that was positive on the scalp contralateral to the hemifield and negative on the ipsilateral scalp. From computer fitting of the amplitudes versus electrode position, the position of the equivalent source was found to be in the contralateral hemisphere.

The clinical utility of the foveal electroretinogram: a review.

The historical development of the foveal electroretinogram is reviewed. The factors required to obtain a local cone electroretinogram with a small focal source of illumination against a lighted background are discussed. From these considerations and various studies of macular degeneration, the optimal size of the foveal source is found to be 5 degrees diameter or less.

Blue cone monochromatism.

Blue cone monochromatism (BCM) is a subtype of achromatopsia in which the blue cone mechanism predominates. Each of the four patients in this study had BCM proven by their having peak spectral sensitivities in the blue region of the visible spectrum (near 440 nm). Clinically, the diagnosis was suspected because of x-linked inheritance, the presence of acuities better than 20/200 in two patients and myopia ranging from -1.

Visual sensory disorders in congenital nystagmus.

Congenital nystagmus (CN) is a common disorder indicative of a primary disturbance of the ocular motor or visual sensory systems. The authors prospectively evaluated 81 patients with CN, structurally normal eyes, and minimal or no abnormalities of the optic nerve, macula, and retinal pigment epithelium (RPE). Seventy-four (91%) patients were found to have a disorder of the visual sensory system.