Bell's Phenomenon and the Fallacy of the Occlusion Test

Abstract

A discussion of Bell's phenomenon and the inverse Bell's phenomenon is given with the underlying theories usually offered. Report is then made of a large number of cases of normal persons who exhibited the normal Bell's phenomenon on closing the eyes but who were caused to exhibit the inverse phenomenon by forcibly retracting the upper lid. These observations lead the author to conclude that both phenomena are merely protective reflexes. A further series of observations made after occluding one eye of a large number of patients is reported. In this group a majority exhibited a hyperphoria of the occluded eye. The author believes this is merely a manifestation of Bell's phenomenon and not of a latent hyperphoria. The occlusion test is considered misleading in examination for heterophoria. From the Department of Ophthalmology, University of Chicago. Presented before the Chicago Ophthalmological Society, December 15, 1930. A discussion of Bell's phenomenon and the inverse Bell's phenomenon is given with the underlying theories usually offered. Report is then made of a large number of cases of normal persons who exhibited the normal Bell's phenomenon on closing the eyes but who were caused to exhibit the inverse phenomenon by forcibly retracting the upper lid. These observations lead the author to conclude that both phenomena are merely protective reflexes. A further series of observations made after occluding one eye of a large number of patients is reported. In this group a majority exhibited a hyperphoria of the occluded eye. The author believes this is merely a manifestation of Bell's phenomenon and not of a latent hyperphoria. The occlusion test is considered misleading in examination for heterophoria. From the Department of Ophthalmology, University of Chicago. Presented before the Chicago Ophthalmological Society, December 15, 1930.