Browse A-Z
More <
bookmarks-menu

Nearsightedness

Show Alternative Names
Myopia
Shortsightedness
Refractive error - nearsightedness

Nearsightedness is when light entering the eye is focused incorrectly. This makes distant objects appear blurred. Nearsightedness is a type of refractive error of the eye.

If you are nearsighted, you have trouble seeing things that are far away.

Causes

People are able to see because the front part of the eye bends (refracts) light and focuses it on the retina. This is the inside of the back surface of the eye.

Nearsightedness occurs when there is a mismatch between the focusing power of the eye and the length of the eye. Light rays are focused in front of the retina, rather than directly on it. As a result, what you see is blurry. Most of the eye's focusing power comes from the cornea.

Seeing - Animation

This animation illustrates the various structures of the eye and how the shape of the eye affects vision(nearsightedness and farsightedness).

Nearsightedness affects males and females equally. People who have a family history of nearsightedness are more likely to develop it. Most eyes with nearsightedness are healthy. However, a small number of people with severe nearsightedness develop a form of retinal degeneration.

The predominant wavelength of light in your environment may affect the development of myopia. Recent research suggests that more time outdoors may lead to less myopia.

Symptoms

A nearsighted person sees close-up objects clearly, but objects in the distance are blurred. Squinting will tend to make far away objects seem clearer.

Nearsightedness is often first noticed in school-aged children or teenagers. Children often cannot read the blackboard, but they can easily read a book.

Nearsightedness gets worse during the growth years. People who are nearsighted may need to change glasses or contact lenses often. Nearsightedness most often stops progressing as a person stops growing in his or her early twenties.

Other symptoms may include:

  • Eyestrain
  • Headaches (uncommon)

Exams and Tests

A nearsighted person can easily read the Jaeger eye chart (the chart for near reading), but has trouble reading the Snellen eye chart (the chart for distance).

A general eye exam, or standard ophthalmic exam may include:

Treatment

Wearing eyeglasses or contact lenses can help shift the focus of the light image directly onto the retina. This will produce a clearer image.

The most common surgery to correct myopia is LASIK. An excimer laser is used to reshape (flatten) the cornea, shifting the focus. A newer type of laser refractive surgery called SMILE (Small Incision Lenticule Extraction) is also approved for use in the United States.

Outlook (Prognosis)

Early diagnosis of nearsightedness is important. A child can suffer socially and educationally by not being able to see well at a distance.

Possible Complications

Complications may include:

  • Corneal ulcers and infections may occur in people who use contact lenses.
  • Rarely, complications of laser vision correction may occur. These can be serious.
  • People with myopia, in rare cases, develop retinal detachments or retinal degeneration.

When to Contact a Medical Professional

Contact your health care provider if your child shows these signs, which may indicate a vision problem:

  • Having difficulty reading the blackboard in school or signs on a wall
  • Holding books very close when reading
  • Sitting close to the television

Contact your eye doctor if you or your child is nearsighted and experiences signs of a possible retinal tear or detachment, including:

  • Flashing lights
  • Floating spots
  • Sudden loss of any part of the field of vision

Prevention

It has been generally believed that there is no way to prevent nearsightedness. Reading and watching television do not cause nearsightedness.

During the Covid-19 pandemic of 2020, when most school-aged children were learning from home, there was an increase in the development of nearsightedness over what had been seen before. In the past, dilating eye drops were proposed as a treatment to slow the development of nearsightedness in children, but those early studies were inconclusive. However, there is recent information that certain dilating eyedrops used in certain children at just the right time, may decrease the total amount of nearsightedness that they will develop.

The use of glasses or contact lenses does not affect the normal progression of myopia -- they simply focus the light so the nearsighted person can see distant objects clearly. However, it is important to not prescribe glasses or contact lenses that are too strong. Hard contact lenses will sometimes hide the progression of nearsightedness, but vision will still get worse "under" the contact lens.

Review Date: 8/22/2022

Reviewed By

Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

References

Chia A, Chua WH, Wen L, Fong A, Goon YY, Tan D. Atropine for the treatment of childhood myopia: changes after stopping atropine 0.01%, 0.1% and 0.5%. Am J Ophthalmol. 2014;157(2):451-457. PMID: 24315293 pubmed.ncbi.nlm.nih.gov/24315293/.

Kanellopoulos AJ. Topography-guided LASIK versus small incision lenticule extraction (SMILE) for myopia and myopic astigmatism: a randomized, prospective, contralateral eye study. J Refract Surg. 2017;33(5):306-312. PMID: 28486721 pubmed.ncbi.nlm.nih.gov/28486721/.

Nischal KK. Ophthalmology. In: Zitelli BJ, McIntire SC, Nowalk AJ, Garrison J, eds. Zitelli and Davis' Atlas of Pediatric Physical Diagnosis. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 20.

Olitsky SE, Marsh JD. Abnormalities of refraction and accommodation. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 638.

Torii H, Ohnuma K, Kurihara T, Tsubota K, Negishi K. Violet light transmission is related to myopia progression in adult high myopia. Sci Rep. 2017;7(1):14523. PMID: 29109514 pubmed.ncbi.nlm.nih.gov/29109514/.

Wang J, Li Y, Musch DC, et al. Progression of myopia in school-aged children after COVID-19 home confinement. JAMA Ophthalmol. 2021;139(3):293-300. PMID: 33443542 pubmed.ncbi.nlm.nih.gov/33443542/.

Disclaimer

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

All
Videos
Images
Seeing

Seeing

Animation

Visual acuity test - Illustration Thumbnail

Visual acuity test

Visual acuity tests may be performed in many different ways. It is a quick way to detect vision problems and is frequently used in schools or for mass screening. Driver license bureaus often use a small device that can test the eyes both together and individually.

Illustration

Normal, nearsightedness, and farsightedness - Illustration Thumbnail

Normal, nearsightedness, and farsightedness

Normal vision occurs when light is focused directly on the retina rather than in front or behind it. A person with normal vision can see objects clearly near and faraway.

Nearsightedness results in blurred vision when the visual image is focused in front of the retina, rather than directly on it. It occurs when the physical length of the eye is greater than the optical length. For this reason, nearsightedness often develops in the rapidly growing school-aged child or teenager, and progresses during the growth years, requiring frequent changes in glasses or contact lenses. A nearsighted person sees near objects clearly, while objects in the distance are blurred.

Farsightedness is the result of the visual image being focused behind the retina rather than directly on it. It may be caused by the eyeball being too small or the focusing power being too weak. Farsightedness is often present from birth, but children can often tolerate moderate amounts without difficulty and most outgrow the condition. A farsighted person sees faraway objects clearly, while objects that are near are blurred.

Illustration

Lasik eye surgery - series - Normal anatomy - Presentation Thumbnail

Lasik eye surgery - series

Presentation

 
 
Seeing

Seeing

Animation

 
Visual acuity test - Illustration Thumbnail

Visual acuity test

Visual acuity tests may be performed in many different ways. It is a quick way to detect vision problems and is frequently used in schools or for mass screening. Driver license bureaus often use a small device that can test the eyes both together and individually.

Illustration

Normal, nearsightedness, and farsightedness - Illustration Thumbnail

Normal, nearsightedness, and farsightedness

Normal vision occurs when light is focused directly on the retina rather than in front or behind it. A person with normal vision can see objects clearly near and faraway.

Nearsightedness results in blurred vision when the visual image is focused in front of the retina, rather than directly on it. It occurs when the physical length of the eye is greater than the optical length. For this reason, nearsightedness often develops in the rapidly growing school-aged child or teenager, and progresses during the growth years, requiring frequent changes in glasses or contact lenses. A nearsighted person sees near objects clearly, while objects in the distance are blurred.

Farsightedness is the result of the visual image being focused behind the retina rather than directly on it. It may be caused by the eyeball being too small or the focusing power being too weak. Farsightedness is often present from birth, but children can often tolerate moderate amounts without difficulty and most outgrow the condition. A farsighted person sees faraway objects clearly, while objects that are near are blurred.

Illustration

- Presentation Thumbnail

Lasik eye surgery - series

Presentation

 
 
##RemoveMe##
 

Seeing - Animation

Vision is the dominant sense for most people with sight.

The organ of sight is the eye. Think of it as a slightly irregular, hollow sphere that takes in light and translates it into images.If we enlarge the eye and look inside it, we can discover how that's done.

Inside the eye are various structures working together to create an image the brain can understand. Among these are the cornea, a clear dome-like structure covering the iris or colored part of the eye, the lens directly below it, and the retina, which lines the back of the eye. The retina consists of thin layers of light-sensitive tissue.

This candle can help us understand how the eye captures images and then sends them to the brain.First, the candlelight passes through the cornea. As it does, it's bent, or refracted, onto the lens. As the light passes through the lens, it's bent a second time. Finally, it arrives at the retina where an image is formed.

This double bending, though, has reversed the image and turned it upside down. If that was the end of the story, the world would always appear upside down. Fortunately, the image is turned right side up in the brain.

Before that can happen, the image needs to travel as impulses along the optic nerve and enter the brain's occipital lobe. When the image forms there, it regains its proper perspective.

Now let's consider two common conditions that cause blurry vision. The eye's shape is important for keeping things in focus. With normal vision, light focuses precisely on the retina at a location called the focal point.

But what happens if the eye is longer than normal? The longer the eye, the more distance there is between the lens and retina. But the cornea and lens still bend light the same way. That means the focal point will be somewhere in front of the retina rather than on it.

This makes it difficult to see things that are far away. A person with a long eye is said to be nearsighted. Glasses with concave lenses can correct nearsightedness.

The lens widens the plain of light coming through the cornea. That pushes the focal point back onto the retina.

Farsightedness is just the opposite. The eye's length is too short. When that happens, the focal point is behind the retina. So it's difficult to see things that are up close.

Glasses with convex lenses narrow the plain of light. Narrowing the light passing through the cornea moves the focal point back onto the retina and can correct farsightedness.

 

Seeing - Animation

Vision is the dominant sense for most people with sight.

The organ of sight is the eye. Think of it as a slightly irregular, hollow sphere that takes in light and translates it into images.If we enlarge the eye and look inside it, we can discover how that's done.

Inside the eye are various structures working together to create an image the brain can understand. Among these are the cornea, a clear dome-like structure covering the iris or colored part of the eye, the lens directly below it, and the retina, which lines the back of the eye. The retina consists of thin layers of light-sensitive tissue.

This candle can help us understand how the eye captures images and then sends them to the brain.First, the candlelight passes through the cornea. As it does, it's bent, or refracted, onto the lens. As the light passes through the lens, it's bent a second time. Finally, it arrives at the retina where an image is formed.

This double bending, though, has reversed the image and turned it upside down. If that was the end of the story, the world would always appear upside down. Fortunately, the image is turned right side up in the brain.

Before that can happen, the image needs to travel as impulses along the optic nerve and enter the brain's occipital lobe. When the image forms there, it regains its proper perspective.

Now let's consider two common conditions that cause blurry vision. The eye's shape is important for keeping things in focus. With normal vision, light focuses precisely on the retina at a location called the focal point.

But what happens if the eye is longer than normal? The longer the eye, the more distance there is between the lens and retina. But the cornea and lens still bend light the same way. That means the focal point will be somewhere in front of the retina rather than on it.

This makes it difficult to see things that are far away. A person with a long eye is said to be nearsighted. Glasses with concave lenses can correct nearsightedness.

The lens widens the plain of light coming through the cornea. That pushes the focal point back onto the retina.

Farsightedness is just the opposite. The eye's length is too short. When that happens, the focal point is behind the retina. So it's difficult to see things that are up close.

Glasses with convex lenses narrow the plain of light. Narrowing the light passing through the cornea moves the focal point back onto the retina and can correct farsightedness.

 
 
 
 

 

 
 
 
© 1997-ADAM Company Logo All rights reserved.