Purpose: To evaluate the short- and long-term effects of selective serotonin reuptake inhibitors (SSRIs) on intraocular pressure (IOP) and anterior segment parameters in open angle eyes.Materials and methods: This cross-sectional study included 325 eyes of 166 subjects. Subjects were divided into three groups: Group 1 included 116 eyes of 58 patients receiving SSRIs for 1week-6months, Group 2 included 102 eyes of 53 patients receiving SSRIs for longer than 6months and Group 3 included 107 eyes of 55 healthy subjects not receiving any drugs. All of the patients receiving SSRIs were diagnosed as major depressive disorder. All groups were chosen to be similar in terms of age and gender. All patients underwent a detailed ophthalmologic examination including IOP measurement by Goldmann applanation tonometer and gonioscopy. Anterior segment parameters including pupil diameter (PD), central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) were assessed by a Scheimpflug system.Results: Pupil diameter was significantly larger in patients receiving SSRIs for <6months and 6months than the control subjects (3.530.71mm, 3.48 +/- 0.60mm versus 3.11 +/- 0.72mm, p<0.05) but this effect was independent from the duration of SSRI treatment. IOP was significantly lower in patients receiving SSRIs for <6months and 6months than the control group (16.04 +/- 2.17mmHg, 16.11 +/- 2.13mmHg versus 17.34 +/- 2.15mmHg, p<0.05), but there were no statistically significant differences between the patients receiving SSRIs for <6months and 6months. There were no statistically significant differences between the patient and the control group in values of CCT, ACD, ACV and ACA. The ACAs were measured between 25 degrees and 55 degrees with Scheimpflug system and also classified as grade 3-4 (Shaffer system) by gonioscopy.Conclusions: Selective serotonin reuptake inhibitors cause mydriasis which is persistent during the treatment. In depression patients with open angle eyes, short- and long-term use of SSRIs leads to decrease in IOP.