Not Just in Your Genes: The Quest for the True Causes of Myopia


You thought it was genetic. But, you’re wrong.

Myopia is on the rise, and researchers are discovering that it’s not all in your genes. It may, in fact, be in your eyes. Here’s what you need to know.

Some researchers believe they’ve come up with a formula that can accurately predict if a person will become nearsighted. And, it’s one of the most unusual formulas that you’ve ever heard of. After studying more than 4,500 children, measuring vision from around age 6, they found that they could predict who would become nearsighted by age 13.

The findings are published in the Journal Of the American Medical Association’s JAMA Ophthalmology. The researchers of the study found that light plays a major role in the development of myopia.

For years, researchers believed that near work may be a contributing factor. And, for many more years, it was thought that myopia was genetic.

But, new research seems to show that exposure to bright light causes a chemical called “retinal dopamine” to be released. This chemical blocks axial lengthening of the eye, at least partially. Not all researchers agree, however, and some still believe that part of the equation lies in a combination of factors.

It is known that muscles in the eye must contract and lengthen the eye for humans to see up close. This temporary lengthening is usually not a problem because the normal shape of the eye is such that when we look far off into the distance, our naturally emmetropic vision returns.

In other words, temporary flexing of ocular muscles does not appear to cause dramatic or permanent changes in the shape of the eye or negatively affect its structural integrity.

But, when we’re young, and still developing, a combination of near work and a lack of retinal dopamine, may cause our eyes to grow haphazardly and irregularly – leading to a natural state of myopia, in which we’re able to see close up but not off into the distance.

The research provides a more clear and focused window into potential causes, and allows researchers to suggest that certain activities may increase the risk for a child developing myopia. Another thing that researchers find, again and again, is that children tend to be slightly farsighted in first grade. The children who are less farsighted tend to become nearsighted later on.

In this sense, researchers believe they have a reliable way to detect potential future myopes: pre-refractive error in first grade. If a child is less farsighted than the norm, this signals that the child is at an increased risk for myopia.

From there, the child’s parents may be able to consult with an eye doctor about any number of preventative therapies which may help the child, which includes orthokeratology – a therapy that is known to arrest myopia by temporarily reshaping the cornea.

Another therapy that can help older children, after myopia has set in, is LASIK. This therapy uses a laser to reshape the cornea. A laser cuts open the cornea, and creates a flap, while another laser reshapes the cornea. The flap is replaced and the eye is allowed to heal.

Once it’s healed, normal 20/20 vision is restored. If you want more help in determining whether this procedure is appropriate for your child, contact your eye doctor. Not all children are good candidates – especially if they have refractive instability.

Regardless of the causes or treatments, researchers and doctors agree: Myopia is a serious condition and a significant issue, with more than 90 percent of east Asian teens and young adults afflicted with it.

In the U.S., and UK, it’s also a serious problem, and the trend is that it’s only getting worse.

Louise Woods is studying to become a ophthalmologist. Strange she knows, but she is fascinated by eyes, and loves to tell her friends and family all about what she is learning. She has now taken this a step further by sharing her knowledge with an online audience.


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