Ishihara color plates as a lest for simultanagnosia

PURPOSE: To alert ophthalmologists to the use of Ishihara color plates in the detection of simultanagnosia, METHODS:We examined seven patients referred for impaired vision. Evaluation included color plate resting with Ishihara color plates. RESULTS: Al seven patients had simultanagnosia, with marked difficulty in identifying the numbers in Ishihara color plates despite adequate visual acuity and the ability to name all of the colors in the plates correctly. One of these patients was referred with the diagnosis of a cone dystrophy because of her poor performance on the Ishihara test. All of the patients had bilateral occipitoparietal damage or atrophy on magnetic resonance imaging. CONCLUSIONS: Ophthalmologists must be aware that a poor performance with Ishihara plates may not, be attributable to an impairment of color vision but rather to occipitoparietal brain damage associated with simultanagnosia. (Am J Ophthalmol 1998;126:850-851, (C) 1998 by Elsevier Science Inc. All rights reserved.).