Ocular Surface Disease in Glaucoma Patients Randomized to Benzalkonium Chloride-Containing Latanoprost and Preservative-Free Bimatoprost.

To investigate the influence of benzalkonium chloride (BAK) on ocular surface disease (OSD) in glaucoma patients receiving ocular-hypotensive agent. Patients were randomized to receive BAK-containing latanoprost (Xalatan) or preservative-free bimatoprost (Lumigan PF). Intraocular pressure (IOP), basal Schirmer's test, noninvasive keratograph tear-breakup time (TBUT), conjunctival redness score (R score), OSD index (OSDI), and corneal Oxford staining were recorded and compared between the 2 groups at 1-month and 4-month visits. The influence of BAK was analyzed by a generalized estimating equation model. We enrolled 74 and 76 eyes treated with latanoprost and bimatoprost, respectively. The IOP decreased in both groups, although greater reduction was observed for latanoprost (13.95 vs. 15.42 mmHg,  = 0.0264). There was a significantly negative association between tear flow and latanoprost use (β = -0.763,  = 0.0243). The first and average TBUT did not show intergroup differences, but the area with unstable tear film increased with latanoprost use and showed marginal significance at 4-month visit (9.33% vs. 5.94%  = 0.055). In both groups, OSDI decreased, whereas Oxford stain increased over time, and R scores showed improvement after transient increase in the first month. The bimatoprost group had significantly worse conjunctival hyperemia, whereas a negative association with conjunctival hyperemia was revealed for latanoprost use (R score-bulbar nasal: β = -0.045,  = 0.0423). BAK-containing latanoprost was associated with decreased tear secretion and may be associated with tear-film instability, whereas bimatoprost was associated with worse conjunctival hyperemia. Ocular surface side effects should be considered when prescribing BAK-containing medication to glaucoma patients.