Evaluation of Intrascleral Lakes after Phaco-Viscocanalostomy using Anterior Segment Optical Coherence Tomography

Purpose: This study aimed to investigate the results of combined phacoemulsification and viscocanalostomy (phaco-VC) in a six-month follow-up and its relationship with intrascleral lake (IL) using anterior segment optical coherence tomography (AS-OCT) in patients with primary open-angle glaucoma (POAG).

Methods: In total, 36 eyes with POAG eligible for phaco-VC were enrolled in this prospective observational study. All patients underwent AS-OCT evaluation and ophthalmologic examination including Goldman tonometry, cup-disc ratio assessment, best corrected visual acuity (BCVA) measurement, and antiglaucoma medication(s) prior to surgery and one, three, and six months after the surgery. The width, length, area, and circumference of the ILs were evaluated using AS-OCT at each follow-up.

Results: A total of 36 eyes of 34 patients with POAG were investigated in this study. According to the results, the mean age of the patients was 70.09 $\pm$ 8.73 years, and the majority of the cases were male (n = 23; 63.9%). The mean preoperative intraocular pressure (IOP) was 20.11 $\pm$ 7.22 mmHg on 2.47 $\pm$ 1.1 medications, and the mean postoperative IOP reduced to 11.11 $\pm$ 2.58 mmHg on 0.11 medications, which was statistically significant (P $<$ 0.001). ILs were detectable in all cases which resulted in a 100% qualified success rate. The reduction in the width, area, and circumference of the IL was significant during the six-month follow-up. The relationship between IOP changes and IL parameters on AS-OCT was not significant.

Conclusion: This study evaluated the associations between IL changes and IOP reduction after phaco-VC. A six-month follow-up showed a notable reduction in the IL, but unexpectedly, IOP control did not decline. A reduction in IL diameter, when there is sufficient IOP control, indicates that there may be various IOP lowering mechanisms through VC other than the IL diameters. Further evaluation of VC focusing on long-term changes in IL and Schlemm's canal diameter is necessary to explain the precise mechanisms of lowering the IOP.