Angle configuration changes after phacoemulsification measured with anterior segment optical coherence tomography (AS OCT)

Purpose To assess the changes of the irio corneal angle configuration and anterior chamber depth with anterior segment optical coherence tomography (AS OCT) after phacoemulsification. Methods Prospective study including consecutive patients operated on age related cataract with phacoemulsification and intraocular lens implantation. An AS OCT was performed before and one month after cataract surgery on the horizontal meridian. The primary objective was to assess the changes of AC depth, iridocorneal angle, angle opening distance at 500 and 750 µm and trabeculum iris space area at 500 and 750 µm. The secondary objective was to evaluate intra ocular pressure (IOP) changes. Results Thirty five eyes of 35 patients were included. Mean age was 72 ± 9 years. Anterior chamber depth increased from 2.62 ± 0.39 µm to 3.66 ± 0.21 µm after cataract removal Nasal AOD 500 and 750 increased by 75 and 73%, nasal TISA 500 and 750 by 69 and 65%, and nasal angle by 52%, respectively, p<0.01. Temporal AOD 500 and 750 increased by 70 and 71%, temporal TISA 500 and 750 by 55 and 64% , and temporal angle by 42%, respectively, p<0.01. A statistically significant but weak correlation was found for AC depth change and axial length, p=0.004, r2=0.22, but not for AC depth change and age and preoperative spherical equivalent, p= 0.52 and p=0.38, respectively. The pre and post operative IOPs were 16.7 ± 3.7 mm Hg and 14.0 ± 2.7 mm, respectively, p=0.0015. Conclusion Cataract extraction leads to important changes of anterior segment configuration evaluated with AS OCT. In our series, all measured parameters showed an opening of the IC angle with wide variation among patients.