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Slowing the Increase in Myopia

Posted by Ilena Di Toro | Posted on November 21, 2017

Myopia is the Rodney Dangerfield* of vision conditions. Unlike glaucoma or macular degeneration, myopia isn’t ‘given respect’ because the majority of treatments don’t involve surgery. Most of the time, either eyeglasses or contact lenses do the trick. If a person is fed up with glasses or contact lenses, there’s vision correction surgery (e.g., LASIK). The end result for each is that the patient has close to 20/20 vision.

Still, myopia isn’t as benign as it seems. Over 40 percent of Americans are myopic, that’s up from 25 percent in 1971. In East and Southeast Asia, between 80 to 90 percent of school children have myopia. In addition, high myopia is increasing. High myopia leads to an increased risk of retinal detachment, glaucoma, and early development of cataracts. 

The increase in children doing near work, such as school work and using computers, smart phones and tablet computers is a possible cause of increasing numbers of myopia cases. In the NEI-funded Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE), researchers found that children who spent more time outdoors had a lower chance of developing myopia.

There are several theories as to why myopia occurs. One theory is the structural theory. As a child’s eye grows, the lens stretches, becomes flat and self-focusing. When eye growth and lens stretching do not happen in coordination, that is when myopia occurs. Another theory is the defocus theory. This states that the eye can tell whether light is focused in front or behind the retina and grow in the correct direction to reduce blur.

So far, it looks like the best way to prevent myopia in children is for them to spend more time outdoors. This has been done in Taiwan, and children’s vision has improved. In addition to spending time outdoors, low concentration doses (0.01%) of atropine eye drops, used daily, have been shown to prevent myopia without side effects. Why this happens isn’t entirely clear. One theory is that atropine also stimulates the dopamine release in the eye.

Another study used bifocal contact lenses to see if that would slow the development of myopia. This study, the Bifocal Lenses in Nearsighted Kids (BLINK) Study, was made up of children ages 7 to 11 to see if focusing light in front of the retina is a stop signal for eye growth. Single vision glasses focus light in back of the retina, which may be signaling the eye to grow in such a way as to continue the progression of myopia.

Others studies have shown that the use of orthokeratology (ortho-k) contact lenses can also slow the progression of myopia. Ortho-k lenses are worn while a person is sleeping and the lenses reshape the wearer’s cornea to focus light in front of the retina, in the same way that bifocal lenses work in the BLINK study.

Both studies show that specialized lenses slow the progression of myopia in the first year of use. The BLINK study is evaluating to see if the benefit extends beyond the first year. So, it looks like myopia is getting a little respect in the among the research community after all. One day soon, there may be treatments that can completely reverse the condition.

*Note: For those of a certain age or who don’t live in the United States, Rodney Dangerfield (1921–2004) was a comedian who appeared on television and film in the 1980s. His tagline was “I get no respect.”

Source:

https://www.nei.nih.gov/content/myopia-close-look-efforts-turn-back-growing-problem

https://www.biography.com/people/rodney-dangerfield-9542630

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