Effects of Polyquaternium- and Benzalkonium-Chloride-Preserved Travoprost on Ocular Surfaces: An Impression Cytology Study

Purpose: To compare the toxicity effect of polyquaternium (PQ) and benzalkonium chloride (BAK) preservation of travoprost on the ocular surface. Methods: This prospective study included 44 eyes of 44 patients with newly diagnosed glaucoma. Twenty-two patients used PQ-preserved travoprost (PQ group) and 22 patients used BAK-preserved travoprost (BAK group). To investigate the effect on the ocular surface, conjunctival impression cytology (IC) was performed at baseline and the 1- and 6-month follow-up visits. Additionally, the ocular surface disease index (OSDI) questionnaire, Schirmer I test, and tear break-up time (TBUT) measurement were administered at baseline, and at 1-, 3-, and 6-month follow-up visits. Results: While both groups showed statistically significant IC grade increases at 1 and 6 months when compared with baseline measurements, IC grades were significantly higher for patients using PQ-preserved travoprost compared with patients using BAK-preserved travoprost. The Schirmer I test and TBUT scores were not statistically significant between group 1 and BAK group at baseline and at 1-, 3-, and 6-month visits (P > 0.05). OSDI scores did not statistically differ at baseline and the 1-month measurements between the 2 groups (P > 0.05), but the 3- and 6-month OSDI scores were significantly higher for BAK group (P = 0.001). Differences in OSDI and Schirmer I test scores were statistically significant at 1, 3, and 6 months in both groups as compared with baseline values (P < 0.05). Statistically significant differences in the TBUT scores were seen for both groups at 3 and 6 months, while BAK group, but not PQ group, had insignificant score differences at 1 month as compared with baseline values of PQ group (P = 0.083). Conclusion: PQ-preserved travoprost was found to be safer and better-tolerated than BAK-preserved travoprost. PQ-preserved travoprost provided better ocular surface comfort, and therefore a better patient experience, which would likely result in higher treatment compliance.