October 9, 2017
If you have children, it’s important to follow national guidelines to protect their precious gift of sight. Vision screenings and comprehensive eye examinations are recommended at regular intervals, even if there are no signs of trouble. Any child who appears to have difficulties seeing or exhibits potential symptoms, such as squinting and frequent eye rubbing, should receive a comprehensive eye exam by an optometrist or ophthalmologist.
Uncorrected myopia (nearsightedness) in children may negatively impact their development and increase refractive error progression over time.
Myopia (nearsightedness) is a type of refractive error in which close vision is sharp, but objects farther away appear blurred. Nearsightedness occurs when the eyeball is too long, the cornea is steeply curved, the lens stays focused on near vision, or a combination of all these factors. This causes light rays to focus at a point near the front of the retina rather than directly on its surface, resulting in distant objects being out of focus.
Myopia affects 4% of children ages 6 months to 72 months and 9% of children ages 5 to 17. In about 10% of people with myopia, the condition progresses in severity. Recent studies show the prevalence of myopia is rising at an alarming rate. It is one of the five eye conditions considered an immediate priority by the World Health Organization’s Global Initiative for the Elimination of Avoidable Blindness. In all age groups, an estimated one-third of the population has myopia, however, the incidence rate is as high as 90% in some parts of East Asia. According to the latest data, an estimated 80% to 90% of students in China, Taiwan, and South Korea who completed secondary school are myopic, while 20% are highly myopic.
If you have myopia, this increases the risk of your children developing it. A 2017 meta-analysis looked at 16 studies from four continents (seven from Asia, four from Europe, three from the U.S. and two from Australia) and 8,393 cases of myopia. Researchers confirmed parental myopia has a significant positive association with a child’s risk of developing myopia. If two parents have myopia, the risk is even greater. Genetic and environmental factors or gene-environment interactions are possible explanations for the connection.
A recent Dutch study on 5,711 children who had been followed from birth to age 6 revealed important findings. Children who spent less time outdoors, had lower levels of vitamin D, had a higher body mass index, and were less likely to play sports were more likely to be nearsighted. Being of non-European descent, having a mother with a low education level, and low family income were also associated with myopia, however, lifestyle factors presented the greatest risks. Most eye experts agree that the genetic predisposition for myopia is exacerbated by behavioral habits, including excessive screen time, close reading (e.g. tablets and smartphones), and eyestrain at a young age.
Uncorrected refractive errors in children can result in significant cognitive, neurological, social, behavioral, and economic effects. The consequences of being complacent about a child’s refractive errors can negatively impact their development, learning performance, self-esteem, social/emotional behavior, academic achievement, high school drop-out rates and juvenile delinquency. Children whose myopia progresses beyond -5 diopters may be at greater risk as adults for glaucoma, cataracts, macular degeneration, retinal holes and tears, as well as detachments of the vitreous and retina. In some cases, even properly treated myopia may progress and lead to sight-threatening complications.
A study on 76 people with myopia (ages 11-19: 61, ages 20-33: 15) analyzed the impact of myopia under-correction. A significant positive correlation was found between under-correction of refractive error and myopia progression. The degree of under-correction was associated with the degree of progression, however, gender and age did not appear to play a statistically important role. Full correction of refractive error did not result in myopia progression.
Studies on children have demonstrated the efficacy of orthokeratology (ortho-k) and bifocal contact lenses for stopping the progression of myopia to some degree. Ortho-k uses specially designed GP contact lenses to temporarily reshape the contour of the cornea to reduce myopia. This may be a viable option for children, adolescents, and young adults with low to mild nearsightedness (-4 diopters or less). Children ages 8 to 12 with progressive myopia may be the best candidates for this procedure. Four studies found atropine eye drops produced on average, an 81% reduction in myopia progression among nearsighted children. Unfortunately, this reduction did not appear to be long lasting based on subsequent studies.
In the majority of cases, prompt intervention and proper treatment for myopia can help prevent this common refractive error from impeding a child’s development and future success. And remember – it’s important to encourage children to spend time outdoors engaging in physical activities, away from computer screens and their smartphones!