In glaucoma clinics, the use of imaging has expanded rapidly, offering increasingly detailed views of anterior-segment anatomy. Yet one of the oldest examination techniques remains underused, even as it continues to guide diagnosis and management in ways newer technologies cannot fully replicate.
At the ASCRS 2026 Glaucoma Subspecialty Day in Washington, DC, Ramya N. Swamy, MD, ABO, a glaucoma specialist and associate clinical professor at the University of Maryland School of Medicine, made a case for renewed attention to gonioscopy. Her presentation, “Various Modalities of Gonioscopy Imaging,” examined both the persistence of the technique and the growing role of adjunctive imaging.
“Gonioscopy is the only way we can directly visualize the iridocorneal angle,” Dr. Swamy noted, explaining that although anterior-segment OCT and ultrasound biomicroscopy (UBM) have become widely available, they remain indirect tools. “Neither provides direct visualization of the iridocorneal angle itself,” she said.
Despite its diagnostic importance, gonioscopy is not performed or documented as often as recommended. Dr. Swamy noted that only about 49% of Medicare patients had documented gonioscopy prior to glaucoma surgery,1 while a recent survey indicates that even experienced ophthalmologists report difficulty examining all 4 quadrants and performing indentation gonioscopy, with greater challenges among trainees.2 Another analysis shows that more than 70% of patients lack documented gonioscopy within the first 6 months of evaluation.3 “If this information is critical for so much of what we do, and we are not consistently performing or documenting it, are there other technologies that can help us?” she said.
Imaging modalities can supplement clinical assessment, but they do not replace it. Anterior-segment OCT and UBM provide structural information that may not be apparent on examination and can be useful for documentation and patient education. However, they do not offer the same direct assessment of angle structures that gonioscopy provides. Dr. Swamy discussed 3 cases that showed how the tools are complementary rather than interchangeable.
Dr. Swamy mentioned several handheld imaging devices that can generate images of the angle, in some cases providing 360° views through stitched composites.4,5 These include the Goniopen, invented in Singapore, as well as the commercially available EyeCam (Clarity Medical Systems) and GS-1 gonioscope (Nidek). These technologies could help address some of the variability inherent in gonioscopy, particularly in busy clinics or settings with limited training. Still, limitations remain. “The main challenge is capturing consistent, high-quality images across all 4 quadrants,” Dr. Swamy said.
The persistence of gonioscopy in contemporary practice reflects not only its historical role but also its continued clinical utility. Despite advances in imaging, the ability to directly assess angle structures in real time remains central to glaucoma care, particularly for classification, procedural planning, and identification of secondary pathology. “I will conclude by emphasizing that gonioscopy still plays a critical role,” Dr. Swamy said. “Imaging technologies are improving, but we should all be doing a better job of examining the angle.” GP
References
1. Coleman AL, Yu F, Evans SJ. Use of gonioscopy in Medicare beneficiaries before glaucoma surgery. J Glaucoma. 2006;15(6):486-493. doi:10.1097/01.ijg.0000212287.62798.8f
2. Khan SA, Zhou S, Niyadurupola N. A survey of current gonioscopy practice in the United Kingdom. J Glaucoma. 2024;33(11):888-893. doi:10.1097/IJG.0000000000002468
3. Lee JH, Yoo K, Lung K, et al. Patterns and disparities in recorded gonioscopy during initial glaucoma evaluations in the United States. Am J Ophthalmol. 2024;264:90-98. doi:10.1016/j.ajo.2024.02.032
4. Barbour-Hastie C, Deol SS, Peroni A, Gillan S, Trucco E, Tatham AJ. Feasibility of automated gonioscopy imaging in clinical practice. J Glaucoma. 2023;32(3):159-164. doi:10.1097/IJG.0000000000002162
5. Akkara JD, Owaidhah OA, Kuriakose A. Gonioscopic angle imaging. American Academy of Ophthalmology EyeWiki. March 29, 2026. Accessed April 12, 2026. https://eyewiki.org/Gonioscopic_Angle_Imaging