Decreased Lacrimation and Amyotrophic Lateral Sclerosis

Abstract

To the Editor.— I have read with interest Dr. Reuben Copperman's presentation (230:536, 1974) of the proposed relationship of decreased lacrimation and amyotrophic lateral sclerosis (ALS). Several points should be established. The Schirmer test is not necessarily a crude test if performed accurately and correctly with proper interpretation. Classically, lacrimation consists of tear production by two methods; reflex tearing from the lacrimal gland and, more important, basal secretion through the accessory lacrimal glands of Krause and Wolfring located in the conjunctival fornix and the lid tarsus, respectively. Basal secretion, so important in keratoconjunctivitis sicca syndromes is measured by a Schirmer test with topical anesthesia to eliminate the afferent arc of the trigeminal nerve. Basal lacrimal secretion has no known efferent nerve supply and usually accounts for the first 8 to 15 mmof wetting in normal eyes. On the other hand, total lacrimal secretion (basal and reflex) is measured without topical