Abstract
Purpose :
To study Schlemm’s canal (SC) modifications in vivo after canaloplasty using swept-source anterior segment optical coherence tomography (AS-OCT).
Methods :
Open-angle glaucoma (OAG) patients undergoing standard canaloplasty with 10.0 prolene suture by the same surgeon were recruited into this prospective pilot interventional study between November 2017 and September 2018. The SC was identified and the horizontal SC diameter at the 3 and 9 o’clock positions was measured by the same experienced examiner using swept-source AS-OCT (Topcon DRI OCT Triton). Only images of good quality (signal strength intensity >41) were accepted for analysis. Correlations for gender, age, refractive error and IOP were assessed.
Results :
26 eyes of 24 patients were evaluated. All patients were Caucasians. 15 (62.5%) were men. Mean patient age (±SD) was 72.5 ± 12.5 years (range: 35-90). Mean refractive error was -0.46 ± 1.75 D. All patients were examined 1 week before and a mean of 30.0 ± 25.6 weeks (range: 1-78) after surgery, with a respective IOP drop from 21.1 ± 5.7 to 11.2 ± 2.6 mmHg (p < 0.001). In 4 eyes (9%) the SC could not be identified before surgery. Mean horizontal SC diameter at the nasal position before and after surgery was 72.3 ± 60.3 μm and 197.6 ± 129.8 μm, respectively. Mean horizontal SC diameter at the temporal position before and after surgery was 68.5 ± 60.35 μm and 209.9 ± 111.2 μm, respectively. Statistically significant SC changes after surgery were found for all measurements (p < 0.001). There was no correlation between SC changes after surgery and gender, age or IOP changes, but there was a tendency for a negative correlation between SC changes after surgery and refractive error (Pearson’s correlation coefficient = -0.5 and -0.4, for nasal and temporal position respectively).
Conclusions :
Swept-source AS-OCT shows a significant increase in SC horizontal diameter after canaloplasty with 10.0 prolene suture in OAG patients, suggesting a mechanical stretching of the SC as a mechanism for the postoperative IOP lowering.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.