Glaucoma and High Myopia: Mid-2026 Clinical Insights

This audio article is from VisualFieldTest.com.Read the full article here: https://visualfieldtest.com/en/glaucoma-and-high-myopia-mid-2026-clinical-insightsTest your visual field online: https://visualfieldtest.comSupport the show so new episodes keep coming: https://www.buzzsprout.com/2563091/supportExcerpt:Glaucoma and High Myopia: Mid-2026 Clinical Insights Evidence reviewed through July 26, 2026. Introduction High myopia and glaucoma often overlap, but they are not the same condition. High myopia changes the shape of the eye, optic nerve, retina, and supporting tissues. These changes can imitate glaucoma on an eye examination, optical coherence tomography, or visual field test. At the same time, high myopia appears to increase the eye’s susceptibility to true glaucomatous damage. High myopia is commonly defined as a spherical equivalent refractive error of −6 diopters or more negative or an axial length of approximately 26 millimeters or longer, although definitions vary between studies. The distinction matters because a highly myopic eye may have an abnormal-looking optic disc and visual field without progressive glaucoma, while another eye may develop glaucoma despite apparently normal eye pressure. Evaluating glaucoma in myopic eyes Interpreting the structure–function relationship in high myopia-associated glaucoma () The most reliable principle through mid-2026 is: > Do not diagnose or exclude glaucoma from one “red” optical coherence tomography result, one tilted disc, one unusual visual field, or one eye-pressure reading. Look for reproducible, anatomically coherent change over time. Why the Glaucoma–Myopia Interface Is Difficult Axial elongation stretches and remodels the back of the eye. The optic disc may become tilted, rotated, enlarged, or obliquely inserted. The surrounding tissue may show a large temporal crescent, peripapillary atrophy, a gamma zone, posterior staphyloma, or other myopic changes. These findings can: Make the optic cup appear larger than it truly is. Shift the normal location of retinal nerve fiber layer bundles. Cause false-positive color warnings on optical coherence tomography. Create visual field defects that resemble nasal steps or arcuate defects. Make the same retinal location appear different on serial scans if the scan is not centered consistently. Hide early central or paracentral glaucoma damage when only a standard 24-2 visual field is used. The 2026 European Glaucoma Society research-priority survey found that the most common questions from glaucoma specialists concerned how to distinguish myopic structural change from glaucomatous damage and progression, followed by the reliability of optical coherence tomography and visual field testing. This indicates that the problem remains clinically unresolved even among specialists. Research priorities for diagnostics, progression monitoring, and treatment of glaucoma in myopic eyes () Optical Coherence Tomography: Recognizing Myopia-Related Artifacts Why a normal optical coherence tomography report may be misleading Most commercial optical coherence tomography devices compare a patient’s measurements with a normative database. These databases may contain relatively few highly myopic eyes. As a result, a healthy myopic eye may be incorrectly labeled as having abnormally thin retinal nerve fiber tissue. Long axial length also creates ocular magnification. A scan circle designed to be a fixed size may actually be placed farther from the optic disc than intended. Retinal nerve fiber tissue is naturally thinner farther from the disc, which can produce an artificially low measurement. In addition, myopic retinal anatomy can cause the scan to cross: Peripapillary atrophy. Posterior staphyloma. Peripapillary intrachoroidal cavitation. Retinoschisis or epiretinal membrane. Areas where the automated software cannot correctly identify the retinal boundaries. How common are artifacts? In one study, optical coherence tomography artifacts were found in approximately 51.9% of scans from highly myopic eyes, compared with 18.6% in eyes without high myopia. Peripapillary atrophy was a leading cause of artifact in highly myopic eyes. The frequency was even higher when high myopia and glaucoma were both present. The prevalence of optical coherence tomography artifacts in high myopia and its influence on glaucoma diagnosis () This does not mean optical coherence tomography is useless. It means the individual scan must be inspected rather than relying only on the summary page. A practical optical coherence tomography quality check Before interpreting a thickness map, the clinician should review: The raw cross-sectional images rather than only the color-coded report. The automated segmentation lines to confirm that they follow the correct retinal layers. The scan centration in relation to the optic disc, Bruch’s membrane opening, and fovea. Signal strength and motion artifacts. Whether the scan passes through peripapillary atrophy or a posterior staphyloma. Whether the same device, scan pattern, and positioning were used at each visit. Whether the apparent change is visible on the actual image or exists only in the software’s color classification. A new “red” sector is much less convincing when it is caused by segmentation failure, scan displacement, or a pre-existing tilted disc. Which optical coherence tomography measurements may help? Several approaches may improve confidence: Macular ganglion cell-inner plexiform layer or ganglion cell complex measurements. These may show better diagnostic performance than standard peripapillary retinal nerve fiber layer measurements in some highly myopic eyes. Bruch’s membrane opening minimum rim width. This measures the minimum rim tissue from the anatomic opening of Bruch’s membrane rather than relying only on the clinically visible disc margin. Anatomically corrected retinal nerve fiber layer scans. These attempt to account for axial length and the shifted position of nerve fiber bundles. Vertical, fovea-centered scans. These may improve structure–function matching when the usual peripapillary scan is distorted. Swept-source or wide-field imaging when posterior staphyloma, peripapillary cavitation, or a very large tilted disc makes conventional imaging difficult. A 2024 study found that macular ganglion cell-inner plexiform layer and peripapillary retinal nerve fiber layer parameters could still have good diagnostic accuracy in high axial myopia, but the results were population-specific and should not replace clinical examination or visual field testing. Diagnostic accuracy of optic nerve head and macula optical coherence tomography parameters Comparison of optical coherence tomography structural parameters for diagnosis of glaucoma in high myopia () Common optical coherence tomography traps For the full table, please open this article on visualfieldtest.com. Disc Tilt, Disc Rotation, and Peripapillary Anatomy What a tilted disc means A tilted disc is often associated with: An oval or vertically elongated disc. Oblique insertion of the optic nerve. Temporal peripapillary atrophy or a crescent. Rotation of the retinal nerve fiber layer pattern. Displacement of the central retinal vessels. A mismatch between the clinically visible disc margin and the true anatomic opening of Bruch’s membrane. A tilted disc does not prove glaucoma. However, it also does not protect the eye from glaucoma. The most concerning findings are not simply “tilt” or “cupping,” but focal, repeatable, progressive loss that corresponds to a visual field defect. Examples include: A focal inferior or superior rim notch. A wedge-shaped retinal nerve fiber layer defect. A disc hemorrhage. Corresponding loss in the macular ganglion cell-inner plexiform layer. A repeatable arcuate, nasal-step, or paracentral field defect. Why disc measurements can disagree In high myopia, the clinical disc margin, Bruch’s membrane opening, and anterior scleral canal opening may not line up. A 2025 prospective study found that highly myopic glaucoma eyes had larger Bruch’s membrane opening and anterior scleral canal opening areas, greater displacement between these structures, and a smaller neural canal minimum cross-sectional area than non-highly myopic glaucoma eyes. These anatomic features were associated with faster temporal visual field and retinal nerve fiber layer change over three years. High myopia-induced optic nerve head deformation and glaucoma progression () This supports a shift away from judging a myopic disc by cup-to-disc ratio alone. The important question is whether the nerve tissue is being lost in a pattern and at a rate consistent with glaucoma. Atypical Visual Field Patterns in High Myopia Visual field defects that may occur without glaucoma Highly myopic eyes can produce several unusual visual field patterns: Enlarged blind spot. Vertical step. Partial peripheral rim loss. Nonspecific or irregular depression. Mixed temporal and nasal loss. “Gourd-shaped” defects. Field loss associated with peripapillary atrophy, posterior staphyloma, or peripapillary intrachoroidal cavitation. A 2025 study found an enlarged blind spot in approximately 37% of eyes with nonpathologic high myopia. The enlarged blind spot was associated with a larger gamma zone, larger peripapillary hyperreflective ovoid mass-like structures, and other myopic anatomic findings. Enlarged blind spot linked to gamma zone and peripapillary hyperreflective ovoid mass-like structures () A standardized classification system separates high-myopia-related defects from glaucoma-like defects. Glaucoma-like patterns inSupport the show