The lacrimal system consists of the lacrimal glands, the tear film in contact with the conjunctiva and cornea, and the lacrimal drainage system through the nasolacrimal duct to the nose. In this review the age related changes in this system will be given, including tear chemistry of the tear film. Certain aspects of tear physiology change with age, such as reflex secretion by the lacrimal gland, tear volume, and tear film stability, whereas others remain more or less unchanged, such as basal tear production.

The reflex secretion of tears, as measured by Schirmer’s I method (without anaesthesia), decreases significantly with increasing age as already was observed by Schirmer1 in 1903 and by many others thereafter.2-20 The age groups investigated mostly cover the 20–80 age range and the reduction in Schirmer values from the youngest to the oldest age group is about 70%. In contrast with these findings Xu and Tsubota21 and Nava et al 22 failed to demonstrate the decline of the Schirmer I value with age although in both studies the numbers of subjects were large. This discrepancy is probably attributable to the acknowledged variability in the performance of the Schirmer test—that is, in the latter studies the patients were asked to blink normally after placing the Schirmer strip. It is conceivable that blinking causes an extra irritation, which in elderly people may increase reflex tearing compared with a closed eye condition, such as is employed mostly. Newborn babies secrete tears in the first 24 hours of life.23 Premature infants may fail to secrete tears at birth, depending on the degree of prematurity.24 A negligible number of tears are formed during sleep,12526 in the course of which the protein pattern is also altered dramatically.27 The basal tear production, as …