BLOG: What’s the connection between myopia and glaucoma?
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With the growing prevalence of myopia and concern about its long-term complications, many optometrists are offering myopia management for pediatric patients, to hopefully limit the progression of their myopia.
It is estimated that by 2050, about half the world’s population will be myopic, and 10%, or 938 million people, will have high myopia (Holden et al). Myopia — and especially high myopia — increases the risk for retinal detachment, myopic macular degeneration, cataract and open-angle glaucoma (Haarman et al).
The increased risk in high myopes is something to seriously consider in our management of glaucoma. High myopes have more than a sevenfold increase in risk for developing open-angle glaucoma compared with emmetropes (Wang et al) and nearly double the risk of a low myope (Marcus et al). Moreover, myopes can develop glaucoma at a younger age than their emmetropic peers (Shim et al).
The mechanisms that contribute to an association between glaucoma and high myopia are not fully understood. The longer axial length of myopic eyes likely introduces several biomechanical and other stressors, including stretching and thinning of the retinal nerve fiber layer (RNFL) and damage to the axons in the lamina cribrosa.
It can be difficult to distinguish normal high myope anatomy from glaucomatous damage. For example, both myopia and glaucoma can produce peripapillary atrophy. In high myopia, the optic nerve doesn’t come straight into the orbit, leading to a tilted disc that can mimic glaucoma. With a tilted disc, the nerve tissue can present very differently on OCT compared with the typical figure-eight pattern we associate with a healthy optic nerve. It’s important to be mindful of these confounding factors when reviewing photos and imaging.
Here are three things to consider changing in your management of highly myopic patients:
- Educate patients about the risk: I have a methodical conversation with every patient about their personal risk factors and the health of their eyes from the tear film to the retina and everything in between. For high myopes, I talk about conditions like glaucoma that high myopia predisposes them to and encourage regular eye exams to monitor for these conditions.
- Screen high myopes earlier: Patients with greater than 5 D of myopia — and certainly those with 10 D or more of myopia — should be screened more carefully for glaucoma (Haarman et al). Although I already dilate most patients, I am especially careful to do so in those with greater than 5 D of myopia. Optometrists should have a higher suspicion of glaucoma with high myopes, even those in their 30s.
- Establish patterns and watch for change: I make a note in the chart of any unusual anatomy and watch carefully for changes over time. According to American Academy of Ophthalmology guidelines, a patient with RNFL thinning and cupping but no visual field defects should be considered to have pre-perimetric or stage 1 glaucoma. However, the thinning and cupping could also be simply myopic anatomy. Over time, I repeat visual field and RNFL testing; if these remain stable, I continue to observe and monitor. If these metrics are changing or the patient has a strong family history of glaucoma, I initiate treatment for glaucoma.
As myopia management becomes increasingly common in optometric practices, it opens new opportunities to educate patients about and screen for glaucoma.
References:
- Haarman AEG, et al. Invest Ophthalmol Vis Sci. 2020;doi:10.1167/iovs.61.4.49.
- Holden BA, et al. Ophthalmology. 2016;doi:10.1016/j.ophtha.2016.01.006.
- Marcus MW, et al. Ophthalmology. 2011;doi:10.1016/j.ophtha.2011.03.012.
- Shim SH, et al. Curr Eye Res. 2017;doi:10.3109/02713683.2016.1151053.
- Wang YX, et al. Br J Ophthalmol. 2022;doi:10.1136/bjophthalmol-2021-320644.
For more information:
Nicole Albright, OD, is clinic director at Moses Eyecare Center in Merrillville, Indiana, where she also serves as externship coordinator for optometry students at Indiana University and Chicago College of Optometry. She practices full-scope optometry, with a focus on specialty lenses, perioperative care and ocular disease management.
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