TEAR FILM CHANGES ASSOCIATED WITH NORMAL AGING

We examined a group of normal subjects to evaluate the tear film funct ion by measuring reflex tear capacity using the Schirmer test without anesthetic, steady state tear now using fluorophotometry, meibomian gl and function based on gland drop-out, expressible lipid volume and vis cosity, tear loss from evaporation, and tear osmolarity. We found the average tear flow to be 0.19 +/- 0.19 mu l/min, lower than previously measured. The average tear volume was also correspondingly less, 2.74 +/- 2.0 mu l. We found there was a decline associated with advancing a ge for all parameters except the decay constant and lipid volume. The highest correlations with aging were tear volume (-0.64), Schirmer tes t (-0.63), and tear osmolarity (0.59). Our results indicate that there is a decline in tear film function throughout life and that tear now is considerably less than previously estimated.