Retinal videofluorescence-angiographic findings in Bell's palsy.

Abstract

Different theories about the etiology of Bell’s palsy are discussed. Impaired blood supply to the facial nerve is, by many authors, considered to be the primary cause of the paralysis. It causes nerve swelling and subsequent self-strangulation in its bony canal, leading to the well-known vicious circle first described by Hilger in 1949 [1]. Other diseases such as sudden hearing loss or vestibular neuropathy seem to have a very similar etiology. Indications for generalized microangiopathic alterations leading to impaired blood supply to the nerve were found by various investigators. However, these data are controversial. Methods for microinvasive, direct measurement of facial nerve blood supply might solve this diagnostic problem. Although accurate and standardized methods are in experimental use for animal studies, clinical application in humans seems impossible in the foreseeable future. On the other hand, one can easily observe the retinal vessels in vivo down to the diameter of precapillaries by fundoscopic examination. Retinal blood flow can be measured exactly by means of videofluorescence-angiography.