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What is high myopia?

Half of a test glasses with three stacked lenses for very high myopia

High myopia is a relatively severe level of shortsightedness that can be associated with significant eye health complications.

Typically, people who develop high myopia become shortsighted early in childhood and their myopia gets progressively worse year after year during the school years up to and sometimes beyond age 18 to 20.

Shortsightedness (like all refractive errors) is measured in units called diopters (D). The term high myopia generally is used to describe shortsightedness of -5.00 to -6.00 D or higher, which produces uncorrected visual acuity of 20/400 or worse.

In almost all cases, heredity plays a role in the development of high myopia. If both parents are quite shortsighted, their child has a greater risk of developing high myopia, too.

High myopia itself does not generally lead to vision loss. However, people with the condition have a greater risk of developing several other vision-threatening conditions, including:

For this reason, it's essential that people with high myopia have routine eye exams so their optician can monitor the health of their eyes and look for signs of these and other complications of severe shortsightedness.

Also if your child's shortsightedness is worsening year after year, ask your eye doctor about myopia control procedures to slow or halt the progression of shortsightedness.

One option is orthokeratology, which involves fitting specially designed gas permeable contact lenses that are worn nightly during sleep. The lenses gently reshape the cornea of the eye overnight, resulting in clear vision without corrective lenses during the day.

Though the vision correction effect of "ortho-k" is temporary (the lenses must be worn nightly to keep daytime vision without the lenses clear), this process also has been shown to slow the progression of myopia.

For more information on preventing high myopia, schedule an eye exam for your child with an eye doctor near you. READ NEXT: Can myopia lead to blindness?

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