Glaucoma Awareness Week is currently underway, aiming to spread vital information about this serious eye condition. To raise awareness and promote early detection, the week serves as a platform to educate the public about glaucoma's prevalence, risk factors, and potential consequences if left untreated. But could having myopia increase your risk of developing glaucoma? The below blog post explores this question.
Myopia is one of the leading causes of correctable sight impairment across the globe, with, according to some predictions, half of the world’s population likely to be affected by 2050. But did you know that glaucoma is the second leading cause of blindness worldwide, with Moorfields Eye Hospital [1] commenting that it affects two per cent of over 40s in the United Kingdom?
So, are myopia and glaucoma completely separate eye conditions, and will the incidence of one affect the chances of developing the other? Well, yes, myopia and glaucoma are very different conditions. Myopia (commonly referred to as short-sightedness here in the UK) generally occurs when the eyeball grows too long, resulting in images being focused in front of the retina. In time, as the retina is stretched, this can lead to retinal tears and other damage in the eye, which can further affect sight. Primary open-angle glaucoma (POAG), the most common type of glaucoma, generally arises when the pressure inside the eye is too high, or where blood supply to the optic nerve is impaired, resulting in damage to the optic nerve. However, in some cases, glaucoma can arise when eye pressures are closer to normal or even low in some cases.
Glaucoma and myopia can arise completely independently of each other. However, studies have shown that the risk of developing glaucoma increases depending on the level of myopia.
One review reported in the British Journal of Ophthalmology [2] concluded that high myopia was a major risk factor for the development of POAG, with a 7.3-fold risk increase compared to non-myopic eyes.
Studies are still ongoing as to why high levels of myopia are more likely to lead to the development of glaucoma. But it is thought that the myopic elongation of the eye can lead to structural and physiological changes, which increase the susceptibility to other conditions. Studies have shown that as the eyeball stretches and the optic nerve structure is changed, the effect of the eyes pressure on the optic nerve also changes, often leaving the nerve more susceptible to damage from comparatively lower eye pressures.
However, there is another problem. A 2017 article in the Review of Ophthalmology [3] highlighted the difficulty faced by practitioners in that: “Highly myopic eyes often resemble glaucomatous eyes, so if pressure is normal, diagnosis can be challenging.” The article also comments that it can be difficult to isolate optic changes due to glaucoma in those individuals who have high myopia.
Being able to distinguish between the two conditions is vital if appropriate treatments and management plans are to be put in place. Quite simply, opticians can’t afford to wait and see if a patient’s sight deteriorates in a way which is more indicative of glaucoma because, by then, the sight loss may well be irreversible. That is where effective screening tools can come into their own, enabling an early and accurate diagnosis which might just help to save an individual’s sight.
Glaucoma Awareness Week serves as a crucial reminder for everyone to prioritise their eye health and get regular eye examinations. By staying vigilant and proactive, we can detect glaucoma in its early stages, ensuring timely intervention and preserving our vision.