What is the link between myopia and glaucoma?
As myopia becomes increasingly common and concerns about its long-term effects grow, many optometrists are focusing on myopia management for children to help slow its progression.
By 2050, it’s projected that around half of the global population will be myopic, with about 10%, or 938 million people, experiencing high myopia (Holden et al). Myopia, particularly high myopia, raises the risk of conditions such as retinal detachment, myopic macular degeneration, cataracts, and open-angle glaucoma (Haarman et al).
This heightened risk associated with high myopia is crucial for glaucoma management. Individuals with high myopia are more than seven times more likely to develop open-angle glaucoma than those with normal vision (Wang et al), and nearly twice as likely as low myopes (Marcus et al). Additionally, myopes may experience glaucoma at a younger age than their emmetropic counterparts (Shim et al).
The precise mechanisms linking glaucoma and high myopia are not entirely clear. The increased axial length in myopic eyes likely introduces various biomechanical stresses, such as stretching and thinning of the retinal nerve fiber layer (RNFL) and damage to the axons in the lamina cribrosa.
Differentiating between normal anatomical features of high myopia and glaucomatous damage can be challenging. Both conditions can lead to peripapillary atrophy. In high myopia, the optic nerve often doesn’t align straight into the orbit, resulting in a tilted disc that may resemble glaucoma. This tilt can affect the appearance of nerve tissue on OCT, differing from the typical figure-eight pattern seen in healthy optic nerves. It’s important to consider these factors when analyzing imaging and photographs.
I make it a point to have thorough discussions with each patient about their individual risk factors and eye health, covering everything from the tear film to the retina. For high myopes, I highlight the increased risk of conditions like glaucoma and recommend regular eye exams to monitor for these issues.
Patients with more than 5 D of myopia—especially those with 10 D or more—should undergo careful glaucoma screening (Haarman et al). While I typically dilate most patients, I pay particular attention to those with over 5 D of myopia. Optometrists should maintain a heightened awareness of glaucoma in high myopes, even in their 30s.
I document any unusual anatomical features and monitor for changes over time. According to the American Academy of Ophthalmology guidelines, a patient exhibiting RNFL thinning and cupping without visual field defects should be regarded as having pre-perimetric or stage 1 glaucoma. However, these signs could also be attributed to myopic anatomy. I regularly repeat visual field and RNFL assessments; if these measurements remain stable, I continue monitoring. If changes are noted or if there is a strong family history of glaucoma, I begin treatment for the condition.
