Forty percent of North Americans are affected by myopia, a number that doubled between 1972 and 2004 and continues to grow at a rate that qualifies the phenomenon as an epidemic.
In Europe, myopia is prevalent among 42.2 percent of adults aged 25 to 29 years, almost twice that of adults aged 55 to 59 years.
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Many cases of myopia significantly increase the risk of major ocular health disorders such as retinal tearing (21 times greater), glaucoma (40 times) or cataracts (six times).
An eye that becomes short-sighted becomes longer. The stretching is proportional to the increase in myopia. The more the eye stretches, the more the retina, which lines the inside of the eye, becomes thinner. Symptoms such as cracks, abnormal development of subretinal blood vessels, and bleeding may appear.
Ultimately, the very nearsighted patient has a more than 50 percent risk of spending the rest of his or her life legally blind, which is when vision is reduced by 60 percent or more. This means that the length of their eye exceeds 28 mm (the normal length is 23 mm) or that the myopia levels exceeds six diopters. Diopter is a unit of measurement used to calculate eyesight—the further away from zero indicates a worsening in vision. It is important to intervene before these levels of myopia are reached.
What’s Behind the Epidemic?
There are many causes of myopia. Genetics plays an important role but epigenetics—the environment in which the child evolves—is a more important factor.And what has changed in our environment to explain the recent skyrocketing rates myopia? The impact of technology, which has seen a boom in recent years, is being closely examined.
A rapid increase in visual problems has been noted since the introduction of the smartphone in 2007. The device requires the user to read its screen at a distance of 20 cm rather than the normal distance of 45 cm to 50 cm. It has been suggested that this close distance boosts the risk of developing myopia by eight times, especially if both parents are myopic.
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Ambient lighting also plays a role because the use of fluorescent lights in places like classrooms also promotes myopia. When a tablet is used in such an environment, the effect is multiplied tenfold.
Unlike books printed on paper, tablet and computer screens are optically associated with so-called chromatic aberrations. The shortest wavelengths (blue light) reach the eye faster than other colors, which generates a myopia stimulus. There is a dose and response effect here, suggesting that prolonged use leads to more negative effects.
Today’s young people don’t play outside nearly as much as previous generations and are heavy users of electronics. Exposure to daylight has a protective effect against myopia.
Possible Solutions
The purpose of myopia treatment is to slow down the elongation of the eye. To avoid this problem, it is imperative to influence epigenetics—the environment in which the child grows.The American Academy of Pediatrics says parents should keep their children away from electronic media before the age of two, due to wide-ranging health issues. A limit of one hour per day should be the rule for those between two and five years, and the emphasis should be put on educational sites or applications that promote interactions between the parent and child, the Academy recommends.
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While school requests should be taken into consideration, the use of electronic media should continue to be limited as the child gets older. A maximum of one hour, besides school work, must be observed for good eye health. A two-minute break after every 30 minutes of device use will also lessen harmful effects. Children should also be kept from using devices for at least one hour before sleep to avoid sleep issues.
Children need a minimum of 45 minutes of daylight per day. They can get this by walking to school or participating in outdoor activities like sports.
Regular optometrist checkups are also important to ensure the health and coordination of both eyes. An optometrist will need to correct, by exercise or optical means, any anomaly that may be detected.
Finally, optical correction must be chosen with the goal of slowing down the progression of myopia. In rare cases, glasses with anti-myopia lenses may be prescribed. They can decelerate progression by about 30 percent. Specialized contact lenses are often preferred and offer control ranging from 50 percent to 80 percent. The contact lens treatment is available from the age of seven, and will be periodically reassessed according to the child’s changing needs.
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In short, myopia is not just a commonplace vision defect. It is a significant risk factor for serious eye disease. We must therefore do everything possible to slow its progress and protect our children’s vision—especially reviewing their use of electronic devices.
Langis Michaud is a tenured professor at the school of optometry at the University of Montreal in Canada. Michaud is an expert in eye health and the use of specialized contact lenses. This article was first published on The Conversation under a Creative Commons license.
