Objectives: This study aimed to assess the possible role of preoperative corneal endothelial cell density in postoperative corneal clouding. We also looked at the role of age and sex in postoperative corneal clouding and whether there was an association between age of subjects and corneal endothelial cell density. Subjects and methods: This is a retrospective cohort study of people who underwent phacoemulsification cataract surgery in University Hospital of Split from 2022 to 2023. We obtained data of sex, age, preoperative corneal endothelial cell density, preoperative and postoperative visual acuity and corneal appearance observed at the medical examinations. Results: Out of 375 surgeries, 67 cases of subsequent corneal clouding occurred, including 28 cases in men and 39 cases in women. No statistically significant difference in preoperative endothelial cell density was found between the group that developed postoperative corneal clouding and the group that did not (t = -1.312; P = 0.190). By analyzing the influence of age and sex on postoperative corneal clouding, we found that older age is a predictive factor in postoperative corneal changes (t = 3.599; P < 0.001). We also noticed a weak negative correlation between age and endothelial cell density (r (338) = -0.144; P = 0.008). After the phacoemulsification procedure, visual acuity in the operated patients increased on average by 0.486 ± 0.242. Conclusions: In the observed population, we found no effect of preoperative endothelial cell density on postoperative corneal clouding. Age is an important predictive factor in postoperative corneal clouding. Corneal endothelial cell density decreases with age. The phacoemulsification procedure significantly improves visual acuity.