Assessment of anterior chamber configuration changes after phacoemulsification with swept-source optical coherence tomography

Abstract

Background: To assess the changes of anterior chamber angle in patients with shallow anterior chamber and normal anterior chamber after phacoemulsification and intraocular lens implantation (IOL) using anterior segment swept-source optical coherence tomography (AS-SS-OCT). Methods: This was a prospective case control study; 60 eyes of 60 patients who scheduled for cataract surgery with normal intraocular pressure (IOP). Based on anterior chamber depth (ACD) and gonioscopy findings, the eyes were classified into two groups: shallow anterior chamber group with narrow angle (SAC group, 30 eyes)；and normal anterior chamber group with wide angle (NAC group, 30 eyes). Measurements of ACD, anterior chamber volume (ACV), Iris volume (IV), lens vault (LV) , angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and trabecular iris angle (TIA) were conducted in each group before and 3 months after surgery. Differences between the two groups were compared. Results: There was no significant difference in age, axial length (AL), corneal curvature, corneal diameter, IOP and IV between the SAC group and the NAC group before operation, except for the LV (p = 0.000). All angle parameters including ACD, ACV, AOD, ARA, TISA and TIA in both groups at 3 months post-surgery were significantly different from the preoperative values (p<0.01). In addition, there were significant differences in all angle parameters between two groups before and after operation (All P< 0.05). Besides, the TISA750 in superior quadrant, ACD and ACV were significantly smaller in the group of SAC than those in the group of NAC 3 months after operation (P = 0.041, 0.001 and 0.002, respectively). Conclusions: Cataract surgery can deepen anterior chamber and increase the width of anterior chamber angle in Chinese subjects, but the ACD and ACV in patients with shallow anterior chamber and narrow angle have not reached the normal level, presumably because the iris root of SAC group inserted more anteriorly than that of NAC group. Phacoemulsification may not completely eliminate the risk of glaucoma in NAC group of people after surgery.