The authors designed a device to measure the depth of the inferior conjunctival fornix at the slit lamp using topical anesthesia. The fornices of 179 glaucoma patients receiving topical medications for glaucoma and 420 control subjects who had no history of ocular disease were measured. These measurements were age-stratified by decade. A significant foreshortening of the inferior conjunctival fornix was found with aging (P less than 0.01). Patients in their sixth through ninth decades using miotics for 3 years or longer and patients using nonmiotic agents for 3 years or longer exhibited significant foreshortening of the inferior fornix when compared with age-stratified (by decade) control subjects (P less than 0.01). These observations suggest that increasing age and topical medications for glaucoma, or the preservatives, used for 3 years or longer, are independently associated with conjunctival shrinkage.