Effects of timolol maleate on tear flow in human eyes.

Lacrimal function was studied in 30 patients treated for glaucoma, with 0.25% timolol eye drops. Rose bengal and fluorescein staining disclosed punctate epithelial defects in 11 eyes after one week. During the following weeks there defects disappeared spontaneously in most eyes. Schirmer tests (I and II), tear lysozyme and pre-corneal film break-up time were significantly decreased by the treatment, while tear immunoglobulins were unimpaired. The authors conclude that topical timolol treatment decreases tear production. This effect is quantitatively limited and does not appear dangerous for normal eyes, although it may become so for eyes with an originally low lacrimal secretion.