Are the benefits of overnight contacts worth the risks?
Myopia, also known as “nearsightedness” is increasing worldwide. Without effective prevention measures, it’s estimated that by the year 2050, 50% of the world will have some form of myopia. Therefore, ophthalmologists and researchers worldwide have slowly become more interested in methods that can slow myopia’s progression. More specifically, overnight “hard” (orthokeratology) lenses have recently become a popular method to slow myopia. However, as with all treatments, these methods come with risks. In this article, we will explore various methods to treat myopia, and whether they are worth the risk.
Firstly, we must understand why we seek to manage myopia rather than correct it with glasses. Myopia can lead to vision loss through sight-threatening ocular pathology later in life. Therefore, when comparing risks of myopia-slowing treatments, we have to keep in mind that these methods could prevent blindness down the road.
Overnight “hard” contacts essentially work to slow myopia progression by “shaping” the cornea to the “normal” shape, so that in the morning, when the user removes them, they can see clearly. In the long term, these contacts work to slow the progression of myopia as they don’t allow the cornea to become increasingly misshapen; in fact, it is more effective and can cause the corneal curvature to return closer to normal in children.
However, the major risk factor associated with these types of contacts is an infection called microbial keratitis, which often stems from human error (e.g. lack of cleanliness) when wearing these contacts, with an overall incidence of 7.7 per 10,000 patient years. Therefore, the risk associated with these contacts is negligible.
Orthokeratology lenses are a novel and cutting edge method to slow the progression of myopia, especially in children. With negligible risks, it’s surprising that it isn’t more popular. However, the medical literature fails to note the cost of these overnight lenses; most families cannot afford to pay the thousands of dollars that consultation appointments cost, nor the hundreds of dollars that follow up exams, replacement lenses, and lens solutions also can cost. Until we adapt our healthcare system to be more accommodating of those with lower socioeconomic status, we won’t achieve our goal of slowing myopia progression worldwide.