Simple OCT Rule Helps Distinguish Glaucoma From Myopia

Glaucoma can be difficult to diagnose in myopic patients because the two conditions come with many similar features, such as retinal nerve fiber layer bundle shifts, scleral thinning and axial elongation. This study developed a formalized method of assessing dips in TSNIT curves that may one day help reduce false positives (image from an unrelated patient). Photo: James L. Fanelli, OD. Click image to enlarge. An OCT signal based on the shape of the temporal-superior-inferior-nasal-temporal (TSNIT) retinal nerve fiber layer (RNFL) curve accurately distinguished glaucomatous optic neuropathy (GON) from nonpathologic myopia in a JAMA Ophthalmology study. The approach was reported to have the potential to help reduce false-positive glaucoma diagnoses, which commonly occur in myopic eyes.Diagnosing glaucoma in patients with moderate or high myopia remained challenging because structural changes such as optic disc tilt, peripapillary atrophy and RNFL bundle displacement often resembled glaucomatous damage. The authors noted in their paper that commercial OCT reference databases, which are largely based on nonmyopic eyes, have produced false-positive findings in as many as 43% of healthy myopic eyes.The study included 943 adults (1,525 eyes) with nonpathologic moderate or high myopia. The mean participant age was 45.9 years, and 43.6% of eyes were from female participants. The external validation cohort included participants identifying as Chinese, Indian, white, Black and other ethnicities. Eyes with pathologic myopia, including posterior staphyloma or advanced myopic maculopathy, were excluded to avoid confounding structural changes.The researchers first used a modified Delphi process involving 31 glaucoma and ocular imaging experts to establish five prespecified OCT diagnostic rules before validating them against masked clinical diagnoses. The top-performing rule relied on identifying a focal dip or broad depression in the TSNIT curve, while another combined inferior peripapillary RNFL thinning with inferotemporal macular ganglion cell-inner plexiform layer thinning. The paper defines dips as “focal, steep downward deflections (notches) within the superior or inferior peak zones” and depressions as “a broad flattening or loss of the physiological double-hump architecture in the superior or inferior quadrants.” The TSNIT rule achieved 96% sensitivity and 95% specificity in the internal validation cohort. In the external cohort, it maintained 93% sensitivity and 93% specificity. The combined structural rule also performed well, achieving 90% sensitivity and 93% specificity in the external cohort. Performance remained strong in highly myopic eyes and in eyes with mild glaucoma, supporting the rules' usefulness in difficult cases.The authors wrote that “results indicate these prespecified OCT rules may serve as effective decision-support tools to help clinicians distinguish early glaucoma from physiological myopic variations,” but they cautioned that the rules should complement, rather than replace, comprehensive glaucoma evaluation, because OCT findings must still be interpreted alongside clinical examination and functional testing.Click here for the journal source. Li F, Kong K, Jiang J, at al. Diagnostic Performance of Prespecified OCT Rules for Glaucomatous Optic Neuropathy in Nonpathologic Myopia. JAMA Ophthalmol. Jul 2, 2026. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.