Over 40% of children aged 5-19 years are nearsighted—a prevalence that has approximately doubled in the past 25 years.[1,2] Although the explanations surrounding this upward trend are varied and incomplete, widespread use of digital devices, increased time spent reading, and lack of time spent outdoors have all been hypothesized to be a factor. Still, a definitive cause remains unclear. Here are two facts about childhood myopia that you should know, along with three strategies to respond to its rising incidence.
Two Things To Know
1. Myopia is a silent epidemic.
Fully half of the world's population is projected to be nearsighted by 2050. This incidence far exceeds normal expected levels, making myopia the epidemic that most people have not heard about.
In urban east Asia, 80%-90% of students completing high school are nearsighted, a dramatic rise from the 10%-20% incidence of 50 years ago. The epidemic isn't limited to east Asia; the prevalence of myopia is also increasing in the United States. Within the next 30 years, the National Eye Institute projects that over 40 million Americans will be nearsighted (Figure).
Figure. Projections for myopia over the next 30 years.
The development of myopia, which slowly progresses over a period of years with no outwardly visible signs, is far from dramatic, but the impact is significant. The World Health Organization has estimated that 42% of vision impairment in the world is due to uncorrected refractive error, with uncorrected myopia being the leading cause. In addition, myopia has financial, psychosocial, and vocational impacts.
2. Myopia is not a harmless condition.
Despite effective, widely available methods of treating myopia (eg, glasses, contact lenses), its prevention is more beneficial because the treatment, and even the condition itself, have associated risks.
Although contact lens wear is generally considered to be low-risk, substantial complications, ranging from mild discomfort to vision-threatening corneal ulcers, can occur. In a survey of contact lens wearers, approximately one third developed a complication of contact lens wear that necessitated a medical visit.
Nearsightedness can be difficult to recognize in children younger than 3 years because many of its symptoms (eg, holding objects very close, sitting near the television) can be normal behaviors in this age group. Myopia could easily be missed in routine pediatric vision screenings owing to the child's lack of cooperation or the technician performing a test inaccurately.
Children who develop myopia at a younger age are more likely to progress to pathologic myopia, a severe form of myopia that can occur at high levels of refractive error, generally greater than 5-6 diopters. Pathologic myopia is a significant threat to vision because it is associated with retinal atrophy and choroidal neovascularization. The macula can be affected by this degeneration, resulting in irreversible vision loss. Pathologic myopia is also associated with an increased risk for glaucoma and retinal detachment. As more children become nearsighted, the risk of developing these complications related to high myopia will increase.
Medscape Ophthalmology © 2019 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Why Myopia Matters: 5 Things to Know - Medscape - Jul 11, 2019.