Myopia occurs when the eye grows too long from front to back. Instead of focusing images on the retina—the light-sensitive tissue in the back of the eye—the lens of the eye focuses the image in front of the retina. People with myopia have good near vision but poor distance vision.
People with myopia can typically see well enough to read a book or computer screen but struggle to see objects farther away. Sometimes people with undiagnosed myopia have headaches and eyestrain from struggling to clearly see things in the distance.
Myopia also can be the result of a cornea – the eye’s outermost layer – that is too curved for the length of the eyeball or a lens that is too thick.
What is high myopia?
Conventionally, an eye is considered to have high myopia if it requires -6.0 diopters or more of lens correction. High myopia increases the risk of retinal detachment. High myopia can also increase the risk of cataract and glaucoma. Each of these conditions can cause vision loss.
What is pathological myopia?
A condition called pathological myopia (also called degenerative or malignant myopia) sometimes occurs in eyes with high myopia when the excessive elongation of the eye causes changes in the retina, choroid, vitreous, sclera, and/or the optic nerve (see image).
Treatment cannot slow or stop elongation of the eye; however, complications such as retinal detachment, macular edema , choroidal neovascularization (abnormal blood vessel growth), and glaucoma usually can be treated.
How is myopia diagnosed?
An eye care professional can diagnose myopia during a comprehensive eye exam, which includes testing vision and examining the eye in detail. When possible, a comprehensive eye exam should include the use of dilating eyedrops to open the pupils wide for close examination of the optic nerve and retina.
How is myopia corrected?
The most common way to treat myopia is with corrective eyeglasses or contact lenses, which refocus light onto the retina.
Refractive surgery is an option once the optic error of the eye has stabilized
Phakic intraocular lenses (IOLs) are an option for people who are very nearsighted or whose corneas are too thin to allow the use of laser procedures such as LASIK and PRK.