Objectives: This study examined the effect of antiglaucomatous drops with different preservatives on corneal biomechanics using the ocular response analyzer (ORA) (Reichert Technologies, Inc., Depew, NY, USA).Methods: Patients using antiglaucomatous medical treatment containing a single agent combined with a preservative for at least 1 year who underwent a control examination between January and December 2017 at a glaucoma unit were included in this retrospective study. The patients were divided into 5 groups according to the antiglaucomatous agent and preservative ingredients. Measurements were taken with the ORA and compared with a control group.Results: A total of 83 eyes treated eyes were included and analyzed. Thirty-three eyes of 33 patients were treated with latanoprost+benzalkonium chloride (BAC), 17 eyes of 17 patients were treated with travoprost+polyquad, 7 eyes of 7 patients were treated with bimatoprost+BAC, 18 eyes of 18 patients were treated with brimonidine+purite, 8 eyes of 8 patients were treated with brimonidine+BAC. A control group of 23 eyes of 23 healthy patients was also assessed for comparison. A significant decrease in corneal hysteresis (CH) and corneal resistance factor (CRF) was seen in the patients using bimatoprost+BAC and brimonidine+BAC when compared with the control group. Evaluation of the bimatoprost+BAC group and the latanoprost+BAC group revealed that the CH and the CRF was significantly lower in the group using bimatoprost+BAC (p<0.01).Conclusion: It has been reported that CH is a more important prognostic marker than central corneal thickness in glaucoma patients. Loss of visual field progresses faster in eyes with a low CH. Both preservatives and the active antiglaucomatousagents in medications can affect CH. Variation in CH in patients using antiglaucomatous drops over a long period is important in both the progression and follow-up of the disease.