Risk Factors for Ocular Surface Disease in Tunisian Users of Preserved Antiglaucomatous Eye Drops

PURPOSE: To study the clinical and the functional findings in glaucomatous patients under preserved eye drops having ocular surface alterations and to analyze their risk factors. METHODS: A cross-sectional study of 155 glaucomatous patients was conducted. All of them answered the “Ocular Surface Disease Index” (OSDI) questionnaire and had a complete and precise evaluation of the ocular surface state including a Schirmer I test, a tear break-up time evaluation, eyelid, conjunctival, and corneal examination with a Fluorescein and a Lissamin green test. We studied factors that could influence the OSDI score and each type of ocular surface alteration (age, sex, glaucoma treatment duration, number and type of the active principle, and Benzalkonium Chloride [BAK] use). RESULTS: BAK was used in 80% of cases. The OSDI score was ≥13, in 61.3% of cases. The biomicroscopic signs of ocular surface disease were at least minimal in 87.1% of cases. The main predictors of OSDI score increase were the glaucoma treatment duration (P = 0.01, t = 2.618), the number of molecules used (P = 0.018, t = 2.391), and the use of BAK (P = 0.011, t = 2.58). The severity of the biomicroscopic signs correlated with these same risk factors. Fixed combination was statistically associated with a lower incidence of superficial punctate keratitis (SPK) and corneal and conjunctival staining in the Lissamine green test (P < 0.001). Beta-blockers were associated with a significantly higher risk of SPK and corneal or conjunctival staining in the Lissamine green test (P < 0.001). CONCLUSIONS: Preserved antiglaucomatous eye drops alter the patients’ ocular surface. The main risk factors were advanced age, duration of glaucoma treatment, multiple therapies, and the use of BAK.