55 EyeWorld Asia-Pacific | March 2025 GLAUCOMA and gonioscopy for predicting patients with mild angle closure who would go on to develop more severe angle closure.2 They found patients with narrow angles on ASOCT had a higher risk of progression, whereas gonioscopy was not as predictive. He added they have yet to identify specific cutoffs at which a patient should be considered higher risk and receive treatment, but this research is underway. A couple of limitations for anterior segment OCT are that it’s expensive and bulky, compared to a gonio lens, which is cheaper and portable. At this point, UBM of the angle is feasible but has some limitations, according to Dr. Xu. Not only does it require a trained technician to perform, but he said there is generally no way to locate the previous location of imaging (no clear landmarks), making repeatability with measurements difficult. “It’s hard to know exactly where on the eye you’re imaging. From a reproducibility standpoint, if you image a patient and re-image 6 months later, you might not be in the same location and therefore you might get different measurements,” he said, adding that some companies, like ArcScan, are working on overcoming this limitation. “It’s not as convenient or as reproducible as AS-OCT,” Dr. Xu continued of UBM. “However, it allows you to look behind the iris, which AS-OCT does not. If you have a ciliary body tumor or a cause of angle closure that originates behind the iris, you can’t see that with AS-OCT.” As of right now, Dr. Xu said, “we’re primarily trying to implement OCT as a complement to gonioscopy to make clinicians’ lives a bit easier and angle evaluations more precise.” In the meantime, Dr. Xu and Dr. Shareef advocate for regular office-based gonioscopy on glaucoma patients. “Imaging typically provides a 2-D view of a representative angle with multiple measurements. Even in those technologies that offer 3-D viewing, there are certain deficiencies inherent with imaging wherein manual gonioscopy provides superior clinical information that imaging cannot,” Dr. Shareef said, including identifying subtle neovascularization of the angle in patients with retinal ischemia, reliable identification of Schwabe’s line and the trabecular meshwork to determine the angle’s status, differentiating between appositional angle closure vs. synechial angle closure, and confirming proper anatomic placement of microstents in Schlemm’s canal postoperatively. In The Pipeline Dr. Shareef said the ViaLux Laser System (ViaLase) combines femtosecond laser with gonioscopic imaging for non-invasive trabeculotomy procedures. “A high-resolution video of the iridocorneal angle allows the surgeon to inspect the angle and to select the desired area of treatment to deliver the laser with minimal collateral damage to adjacent tissue,” he said. About the Physicians Shakeel Shareef, MD | Director, The Center for Glaucoma & Cataract Care, Chief of the Ophthalmology Section, Department of Surgery, HCA Reston Hospital Center, Reston, Virginia | drshareef@glaucomacc.com Benjamin Y. Xu, MD, PhD | Associate Professor of Clinical Ophthalmology, Chief of the Glaucoma Service, Director of Data Science and Artificial Intelligence, USC Roski Eye Institute, Keck School of Medicine, Los Angeles, California | benjamin.xu@med.usc.edu Relevant Disclosures Shareef: None Xu: ArcScan, Heidelberg Engineering References 1. Lee JH, et al. Patterns and disparities in recorded gonioscopy during initial glaucoma evaluations in the United States. Am J Ophthalmol. 2024:264;90–98. 2. Xu BY, et al. Ocular biometric risk factors for progression of primary angle closure disease: the Zhongshan Angle Closure Prevention Trial. Ophthalmology. 2022;129:267– 275. This article originally appeared in the December 2024 issue of EyeWorld. It has been slightly modified and appears here with permission from the ASCRS Ophthalmic Services Corp.
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