Evaluation of early anatomical changes following canaloplasty with anterior segment spectral‐domain optical coherence tomography and ultrasound biomicroscopy

Abstract

ABSTRACT.Purpose: To analyse structural changes in conjunctiva, sclera and Schlemm's canal (SC) following canaloplasty with optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). Methods: Fifteen patients undergoing canaloplasty were included in this prospective study. AS-OCT images were acquired pre-and 1, 7, 30 and 90 days postoperatively. UBM was performed 3 months postoperatively. The surgical site was evaluated for the presence of SC, transscleral filtration, a scleral lake and the visibility of intra-Schlemm-sutures. The height and width of SC were measured at the 3 and 9 o'clock limbus position. Results: After canaloplasty, SC was detectable with AS-OCT in 93% of the patients on day 1. The increase in height was higher than that in width (height: +369%, p = 0.0004, width: +152%, p = 0.002). IOP was negatively correlated to SC's width 1 week postoperatively (r = À0.63, p = 0.04) and to SC's height until 3 months (r = À0.66, p = 0.02) postoperatively. Using UBM, a reflection of the traction sutures indicated SC's position in all patients. Transscleral filtration was found in all patients using AS-OCT, demonstrating a peak 1 week postoperatively. At 3 months, a scleral lake could be visualized in 50% and 83% of patients using AS-OCT and UBM, respectively. Conclusions: AS-OCT offers a high resolution for imaging superficial conjunctival areas and SC after canaloplasty, whereas UBM is capable of detecting deeper structures such as scleral lakes or intra-canal-sutures. The results imply a correlation of the dilation of SC with the IOP-lowering effect and an early pronounced transscleral filtration following canaloplasty.

Schlemm's canal measured by optical coherence tomography and correlation study in a healthy Caucasian child population

“…The explanation for this difference is likely the lower resolution of UBM compared to FD‐OCT, as reported by Fuest et al. ().…”

“…These diameters are smaller than those acquired by FD-OCT in our study subjects. The explanation for this difference is likely the lower resolution of UBM compared to FD-OCT, as reported by Fuest et al (2016). One of the earliest published studies focusing on OCT measurements of cross-sectional SC area was that of Kagemann et al (2010) in adults, who reported values of 10 983 and 8308 lm 2 for the nasal and temporal quadrants, respectively.…”

“…However, this invasive and time‐consuming technique has been superseded by optical coherence tomography (OCT) which offers much improved resolution (Fuest et al. ). Currently, OCT is gaining popularity to assess the anterior chamber angle, and it is now possible to identify the various structures that make up the angle (Wong et al.…”

“…The first technique used was ultrasound biomicroscopy (UBM) (Yan et al 2016;Tandon et al 2017). However, this invasive and time-consuming technique has been superseded by optical coherence tomography (OCT) which offers much improved resolution (Fuest et al 2016). Currently, OCT is gaining popularity to assess the anterior chamber angle, and it is now possible to identify the various structures that make up the angle (Wong et al 2009;Bald et al 2012;Fern andez-Vigo et al 2015), specifically, the SC can be swiftly and accurately examined, as described by many authors (Kagemann et al 2010;Usui et al 2011;Shi et al 2012;Hong et al 2013).…”

Childhood Lensectomy Is Associated with Static and Dynamic Reduction in Schlemm Canal Size

“…With regard to surgical treatments, AS OCT demonstrates an increase in SC size after canaloplasty in adults, correlating with a reduction in IOP. 32 Schlemm canal microstents are implanted in adults with open-angle glaucoma during cataract surgery 33,34 ; their possible usefulness in lensectomy in children is not known.…”