Home > Health A – Z > Myopia

Myopia (Nearsightedness)

The condition in which the individual does not see far distances clearly.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Myopia

Otherwise known as nearsightedness, 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.

Why does the eyeball grow too long?

Scientists are unsure why the eyeball sometimes grows too long....Read more about Myopia
NIH - National Eye Institute

What works? Research summarized

Evidence reviews

Laser photocoagulation for treating choroidal new vessels near the centre of the retina in people with high myopia

In people with high myopia (refractive error ‐6 diopters or worse) new blood vessels can grow under the retina of the eye (choroidal neovascularisation). For decades laser coagulation has been used to destroy lesions that are not central. This review found one small study, including 70 participants, which compared laser photocoagulation with no treatment for people with this disease. This study was inadequately reported and analysed, although it suggested a benefit with photocoagulation during the first two years of follow up. Another small study compared three laser wavelengths to achieve photocoagulation of the lesion, but actually had very little power to demonstrate a difference between them as only 27 participants were included. Therefore, despite its widespread use for many years, the amount of benefit achieved with photocoagulation and the possibility that it is maintained over the years remains unknown. Furthermore, these and other studies suggest that the enlargement of the laser scar could be a potentially vision‐threatening long‐term complication after two years, since it may cause the gradual occurrence of a blind spot in the centre of the visual field due to progressive atrophy of the retina.

Anti‐VEGF for treatment of choroidal neovascularisation (new blood vessels) in people with pathological (severe) myopia

The aim of this Cochrane Review was to find out if anti‐vascular endothelial growth factor (called anti‐VEGF) treatment of new blood vessels in people with severe myopia (also known as nearsightedness or shortsightedness) prevents vision loss. Cochrane researchers collected and analysed all relevant studies to answer this question and found six studies.

Ranibizumab (Lucentis): Visual Impairment due to Choroidal Neovascularization Secondary to Pathologic Myopia [Internet]

Pathologic myopia (PM) is caused by the progressive and excessive elongation of the axial length of the eyeball. Myopic choroidal neovascularization (CNV) is a complication of PM and is a serious threat to vision. CNV is observed as an abnormal growth of blood vessels located between the neurosensory retina and the retinal pigment epithelium. Symptoms include a decrease in vision, central scotoma, and/or metamorphopsia. PM has a prevalence of 0.084% among adult Canadians, and myopic CNV is a leading cause of visual disability among young adults.>

See all (61)

Summaries for consumers

Laser photocoagulation for treating choroidal new vessels near the centre of the retina in people with high myopia

In people with high myopia (refractive error ‐6 diopters or worse) new blood vessels can grow under the retina of the eye (choroidal neovascularisation). For decades laser coagulation has been used to destroy lesions that are not central. This review found one small study, including 70 participants, which compared laser photocoagulation with no treatment for people with this disease. This study was inadequately reported and analysed, although it suggested a benefit with photocoagulation during the first two years of follow up. Another small study compared three laser wavelengths to achieve photocoagulation of the lesion, but actually had very little power to demonstrate a difference between them as only 27 participants were included. Therefore, despite its widespread use for many years, the amount of benefit achieved with photocoagulation and the possibility that it is maintained over the years remains unknown. Furthermore, these and other studies suggest that the enlargement of the laser scar could be a potentially vision‐threatening long‐term complication after two years, since it may cause the gradual occurrence of a blind spot in the centre of the visual field due to progressive atrophy of the retina.

Anti‐VEGF for treatment of choroidal neovascularisation (new blood vessels) in people with pathological (severe) myopia

The aim of this Cochrane Review was to find out if anti‐vascular endothelial growth factor (called anti‐VEGF) treatment of new blood vessels in people with severe myopia (also known as nearsightedness or shortsightedness) prevents vision loss. Cochrane researchers collected and analysed all relevant studies to answer this question and found six studies.

Acupuncture for near‐sightedness in children

Myopia, also called near‐sightedness or short‐sightedness, is one of the most commonly occurring eye problems in children and adolescents. Early detection and treatment of initial myopia is associated with better outcomes of visual improvement and correction. Myopia is usually managed by wearing glasses and/or contact lenses. It is common practice for traditional Chinese medicine practitioners to use acupuncture for the treatment of myopia. Acupuncture is the stimulation of acupuncture points by needle insertion, acupressure, surface electrical and laser stimulation. This review aimed to assess the effectiveness and safety of acupuncture in slowing the progression of myopia in children and adolescents. We included two studies conducted in Taiwan with a total of 131 school children and did not combine the results as the two trials assessed different outcomes. One study found no significant difference in changes in the length of the eyes. Both studies found several children experienced mild pain while pressing and dropped out. The included studies in this review were unable to provide evidence of the effect of acupuncture for slowing the progression of myopia. More trials should be conducted where acupuncture is compared to placebo, other types of acupuncture are investigated, compliance with treatment for at least six months is explored and axial length elongation of the eye should be for at least one year.

See all (13)

Terms to know

Cornea
The transparent part of the eye that covers the iris and the pupil and allows light to enter the inside.
Lens in the Eye
A clear disk that focuses light, as in a camera or microscope. In the eye, the lens is a clear, curved structure at the front of the eye behind the pupil. It focuses light rays that enter the eye through the pupil, making an image on the retina (light-sensitive layers of nerve tissue at the back of the eye).
Refractive Error
A defect in the focusing of light on the retina.
Retina
The light-sensitive tissue lining at the back of the eye. The retina converts light into electrical impulses that are sent to the brain through the optic nerve.

More about Myopia

Photo of a young adult

Also called: Near-sighted, Near sighted, Myopic

Other terms to know: See all 4
Cornea, Lens in the Eye, Refractive Error

Keep up with systematic reviews on Myopia:

Create RSS

PubMed Health Blog...

read all...