Preventing Nearsightedness in Children
Myopia, or nearsightedness, is a condition that affects up to 90% of children in East Asian cities. Understandably, parents are interested in protecting their children’s eyes from increased myopia (i.e. myopic progression). Genetics plays a role in nearsightedness, but evidence shows that environmental factors also greatly affect this condition. Despite the constant research conducted on this topic, no single method has yet been discovered as the most effective way to stunt myopia. With both “nature and nurture” contributing to a child’s nearsightedness, it is nearly impossible to fully stop a child’s myopic progression. However, measures can be taken to try to avoid high myopia (requiring a glasses or contact lens prescription greater than -6.00 diopters).
Some parents are under the impression that wearing glasses that match their child’s prescription will cause the eyes to become more nearsighted by increasing the need to focus. However, research shows that there is no benefit to wearing glasses that under-correct the myopia. In some cases, the myopia worsened more quickly.
Other trials have looked into bifocals or progressive addition lenses (PALs) as a means of reducing the strain of focusing, and thereby slowing myopic progression. Results show a decreased rate of progression for the first year, but results after this period were not statistically significant.
People used to think that wearing contact lenses would affect myopic progression. However, current research shows no clinically relevant change in myopic progression when nearsighted children switch from glasses to contacts. There is also no significant difference between wearing either rigid or soft contact lenses.
Corneal reshaping (i.e. orthokeratology) uses specially designed rigid contact lenses (ortho-K or OK lenses) to correct your vision while you sleep. The lenses modify the shape of the cornea while you sleep, and your vision is clear during the day. It has been proven that OK lenses slow eye growth and decrease myopic progression when the lenses are worn on a consistent basis. After you stop wearing OK lenses, your myopia will worsen again. The overall benefit of orthokeratology is difficult to prove because it is impossible to know what level of myopia a child would have reached without this therapy. However, orthokeratology is still a treatment option for those who prefer not to wear glasses or contacts during the day.
Corrective eye drops
Atropine is an eye drop that can be prescribed to decrease myopia progression. Results are generally positive, but there are side effects to consider. Atropine dilates the eyes and halts focusing; children who use these eye drops will have large pupils; be sensitive to light; and require bifocals, PALs, or reading glasses in order to see close objects. Research also shows that children undergo a faster-than-normal increase in myopia after the atropine is discontinued. However, children who use atropine have a slower overall myopic progression after three years than children who have never used it. Due to the discomfort that atropine causes children and its side effects, atropine is still commonly avoided by Western practitioners.
Outdoors vs. indoors
Evidence shows that children who spend more time playing outdoors rather than indoors suffer less from myopia. Researchers are delving into lighting as a possible factor for decreasing the progression of myopia. Studies about myopia have been done on rhesus monkeys and tree shrews. Early results show that the development of myopia can be slowed as much as 40% by using high ambient or fluorescent lighting. Although more research needs to be done in this area, it is clear that maximizing a child’s time outdoors helps to slow myopic progression.
Depending on the parents’ comfort level, the best treatment methods currently available for a nearsighted child are glasses or contacts with accurate prescriptions, or OK lenses. Abundant ambient lighting may also help. The use of atropine should be discussed at length with the child, caretakers and an eye doctor before beginning therapy. Unfortunately, none of these methods are definitive, but with further research, more effective methods may eventually be discovered.
Guggenheim, JA, et al. “Time Outdoors and Physical Activity as Predictors of Incident Myopia in Childhood: A Prospective Cohort Study.” Investigative Ophthalmology & Visual Science. 53(6):2856-65.
Gwiazda J, et al. “Progressive-Addition Lenses Versus Single-Vision Lenses for Slowing Progression of Myopia in Children with High Accommodative Lag and Near Esophoria.” Investigative Ophthalmology & Visual Science. 52(5):2749-57.
Morgan, IG. “Myopia.” The Lancet. 379(9827):1739-48.
Walline, JJ, Jones, LA, Sinnott, LT. “Corneal Reshaping and Myopia Progression.” British Journal of Ophthalmology. 2009(93):1181-85.