Purpose: To determine the effects of antiglaucomatous drops on the conjunctival thickness. Methods: Between March 2018 and May 2018, conjunctival thicknesses (epithelium + stroma) were measured with anterior segment OCT in 51 eyes of the control group and 49 eyes who had glaucoma diagnosis at the Van YYU Medical Faculty Ophthalmology Department and had been using antiglaucomatous drops for at least 6 months. At 12 o'clock direction, horizontal multisections were taken aiming at the conjunctiva 3-5 mm away from the limbus. Multiple sections were taken from limbus up to 10 mm. The average of conjunctival thicknesses was calculated. The mean conjunctival thickness between the two groups was compared. Results: The mean age of the patient group was 65.5 +/- 8.01 (49-81) years; 19 (61.3%) were male and 12 (38.7%) were female. The mean age of the control group was 62.70 +/- 10.03 (48-81) years; 20 (55.6%) of them were male and 16 (44.4%) were female (P = 0.2). The mean conjunctival thickness of the patient group was 182.76 +/- 26.77 (130-240) mu m and the mean conjunctival thickness of the control group was 235.02 +/- 26.26 (185-327) mu m. There was a statistically significant difference between the mean of the conjunctival thicknesses of the patient and the control group (P < 0.001). Conclusions: Antiglaucomatous drops may affect conjunctival thickness. Changes in conjunctival thickness may reduce surgical success by impairing the function and morphology of the blebs that cannot be controlled by the drip and require surgical intervention.