Loss of vision induced by the color white: a sign of carotid occlusive disease.

Stroke welcomes Letters to the Editor and will publish them, if suitable, as space permits. They should not exceed 1,000 words (excluding references) and may be subject to editing or abridgment. Please submit Letters to the Editor in duplicate, typed double-spaced. Include an appropriate title and a fax number for the corresponding author. The American Heart Association requires that all authors sign a Copyright Transfer Agreement before publication. Fora copy of this agreement, contact the Stroke Editorial Office. Loss of vision in one eye is a well-known manifestation of carotid occlusive disease. 1 Occasionally, the loss of vision occurs with exposure to sunlight, evidence of carotid disease as well. 2 " 4 The spells are postulated to be caused by impaired regeneration of retinal pigment in the ischemic eye. 3 We would like to report a new symptom of this pathogenic mechanism: spells of vision loss induced by the color white. It is important to recognize this symptom because it can be a sign of impending carotid stroke. A 52-year-old hypertensive man suddenly noticed loss of vision in his right eye when he looked at a white wall while at home. The episode lasted about 5 minutes. The patient also noticed blurring of vision if he looked at other bright white objects. He consulted a doctor who performed an ophthalmoscopic examination that was normal. During the following days, the patient had more episodes of right visual loss induced either by the color white or sunlight. Ten days after the first events, he experienced left hemiparesis. A cranial computed tomographic scan disclosed a recent infarction in the territory of the right carotid artery. Cerebral angiograms demonstrated a complete occlusion of the right internal carotid artery 1 cm distal to its origin. The following tests were performed with normal results: erythrocyte sedimentation rate, complete blood count, renal function, liver function, cholesterol, triglycer-ides, serum glucose, chest x-ray, electrocardiogram, and echocar-diogram. Luetic serology and tests for antiphospholipid antibodies were negative. In the absence of chorioretinitis or retinal pigmentary degener-ation, vision loss in bright light is related to severe carotid occlusive disease occurring on a hemodynamic rather than an embolic basis. 2 The color white represents a photostress test in the same way as sunlight. However, as the color white represents less intensity of light than sunlight, it may suggest more severe carotid artery disease than loss of vision in sunlight. It is important to …