Introduction: Glaucoma diagnosis is based on consideration of several factors, such as increased intraocular pressure (IOP), damage to the optical disc, and associated visual field loss. Evaluation of the integrity of the corneal endothelium and monitoring of the corneal thickness is indispensable during the preoperative preparation for phacoemulsification. These data are of great importance for later treatment and monitoring of early and late postoperative complications.

Objective: The aim of this study was to determine the central corneal thickness immediately before and after cataract surgery in patients with primary glaucoma (open and closed angle), comparing them with patients who do not have diagnosed glaucoma. Materials and methods: A prospective study covered a total of 159 subjects who performed cataract surgery by the method of phacoemulsification with the implantation of the intraocular lens in the posterior chamber at the Clinic for Eye Diseases at the Clinical Center of Serbia in Belgrade in 2017 and 2018. Pre-operative patients are classified into two groups. The first group with a primary glaucoma consisted of 71 respondents, with an open angle 41 with glaucoma, and a closed angle glaucoma 30. The second group consisted of people who did not have a diagnosed glaucoma, 88 of them. The central corneal thickness was measured using an ultrasound pachymeter. The measurements were made before the operation, 24 hours, 10 and 30 days after the operation, trying to get all done at the same time of day.

Results: Between patients without glaucoma (BG), primary open-angle glaucoma (POAG) and primary glaucoma of closed angle (PACG), there is a statistically significant difference in median age (χ2 = 10.102; DF = 2; p = 0, 006). Among the observed groups there were statistically significant differences in the values measured preoperatively (χ2 = 10.265; DF = 2; p = 0.006). Among the observed groups, there was no statistically significant difference in the values measured in the first postoperative day (χ2 = 4.364; DF = 2; p = 0.099), nor in the 10th postoperative day (χ2 = 3.250; DF = 2; p = 0.197); 30 days after surgery (χ2 = 1.427; DF = 2; p = 0.490). In each of the groups individually, the appearance of oedema or a very statistically significant difference in the first and tenth postoperative day. Statistically significant difference was present 30 days after surgery, but far less compared to early postoperative period.

Conclusion: Based on the values obtained in this prospective study, we estimate that monitoring of corneal thickness has a mandatory place in the observation of patients after cataract surgery. We found that there is no difference in preoperative measurement only between groups without glaucoma and open angle glaucoma. Measurements performed in the first, tenth, thirtieth day do not differ in groups, but edema restitutin in the 30-th day was observed in all observed groups.