Schlemm's Canal Expansion After Uncomplicated Phacoemulsification Surgery: An Optical Coherence Tomography Study

Purpose: To evaluate the effects of phacoemulsification cataract surgery on Schlemm's canal (SC) using swept-source optical coherence tomography (OCT). Methods: Patients with a senile cataract were included. The SC area and diameter were checked by OCT at the baseline and 1 day, 1 week, 1 month, and 6 months after the cataract surgery. Multivariate linear regression analysis was performed for predictors of change in the mean SC area and diameter. Results: Twenty-five eyes (25 patients) were included in the final analysis. After the cataract surgery, there was a significant increase in the SC area and diameter, and a decrease in the intraocular pressure (IOP) (repeated-measures analysis of variance; all P < 0.05), which extended to the end of the follow-up period. After multivariate analysis, the changes in the SC area and diameter 6 months after surgery were correlated with the change in the IOP (SC area, β = -0.575, P < 0.0001; SC diameter, β = -0.576, P < 0.0001) and the change in the anterior vault (AV) (SC area, β = 0.359, P = 0.007; SC diameter, β = 0.413, P = 0.003). Conclusions: Expansion of the SC was observed after cataract surgery. The degree of expansion was related to the extent of the decrease in the IOP. Further studies are needed to determine whether these changes will last over a long period of time.