A type of error in which the eye does not focus light evenly on the retina

Refractive error means that the shape of your eye does not bend light correctly, resulting in a blurred image. The main types of refractive errors are myopia (nearsightedness), hyperopia (farsightedness), presbyopia (loss of near vision with age), and astigmatism.

Symptoms

• Blurred vision
• Difficulty reading or seeing up close
• Crossing of the eyes in children (esotropia)

Causes

Overuse of the eyes does not cause or worsen refractive error. The causes of the main types of refractive error are described below:

• Myopia (close objects are clear, and distant objects are blurry)
  Also known as nearsightedness, myopia is usually inherited and often discovered in childhood. Myopia often progresses throughout the teenage years when the body is growing rapidly. Watch a video explaining myopia.
• Hyperopia (close objects are more blurry than distant objects)
  Also known as farsightedness, hyperopia can also be inherited. Children often have hyperopia, which may lessen in adulthood. In mild hyperopia, distance vision is clear while near vision is blurry. In more advanced hyperopia, vision can be blurred at all distances. Watch a video explaining hyperopia.
• Presbyopia (aging of the lens in the eye)
  After age 40, the lens of the eye becomes more rigid and does not flex as easily. As a result, the eye loses its focusing ability and it becomes more difficult to read at close range. This normal aging process of the lens can also be combined with myopia, hyperopia or astigmatism. Watch a video explaining presbyopia.
• Astigmatism Astigmatism usually occurs when the front surface of the eye, the cornea, has an asymmetric curvature. Normally the cornea is smooth and equally curved in all directions, and light entering the cornea is focused equally on all planes, or in all directions. In astigmatism, the front surface of the cornea is curved more in one direction than in another. This abnormality may result in vision that is much like looking into a distorted, wavy mirror. Usually, astigmatism causes blurred vision at all distances. Watch a video explaining astigmatism.

Risk Factors

People with high degrees of myopia have a higher risk of retinal detachment which may require surgical repair.

Tests and Diagnosis

A refractive error can be diagnosed by an eye care professional during a routine eye examination.  Testing usually consists of asking the patient to read a vision chart while testing an assortment of lenses to maximize a patient’s vision. Special imaging or other testing is rarely necessary.

Treatment and Drugs

Refractive disorders are commonly treated using corrective lenses, such as eyeglasses or contact lenses. Refractive surgery (such as LASIK) can also be used to correct some refractive disorders.  Presbyopia, in the absence of any other refractive error, can sometimes be treated with over-the-counter reading glasses. There is no way to slow down or reverse presbyopia.

When the shape of the eye prevents the light rays from focusing directly on the retina, and rather focuses in the front or back of the retina, refractive error occurs. Factors such as length of the eyeball, aging of the lens and change in the shape of the cornea contribute to refractive errors.

What is Refraction

The phenomenon of bending of light when it passes from one object to another is called refraction. Light rays bend when they pass through cornea and lens, enabling one to see objects. Optical refractive index refers to the number that measures how much light gets refracted in the eye, which gives an idea if you are suffering from a refractive error or not.

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Astigmatism is a type of refractive error in which the eye does not focus light evenly on the retina. This results in...

Presbyopia is a refractive disorder that makes it difficult for people to see things up close. Presbyopia is a normal part of aging, typically affecting people in their early to mid-40s and older.

Presbyopia occurs when the clear lens inside the eye becomes more rigid. Typically this lens changes shape to focus light onto the retina, allowing you to focus on objects that are both close-up and far away. As people age, this lens becomes more rigid and cannot change shape as easily. This rigidity makes it difficult to see things clearly up close.

Symptoms of Presbyopia include:

• Difficulty focusing on objects up close
• Blurred vision at normal reading distance
• Eye strain
• Headache

Presbyopia gets worse over time, but typically plateaus after age 65. Presbyopia is not a disease and cannot be prevented, it is simply a natural part of aging. While there is no way to stop or reverse the normal aging process, it can be corrected with eyeglasses, contact lenses, or surgery. It may also be helpful to consider simple lifestyle changes including holding reading materials farther away, increasing digital font sizes, choosing large-print reading materials, and using brighter lights for close-up activities.

What is a type of refractive error in which the eye does not focus light evenly on the retina 1 this result in distorted or blurred vision at all distances?

What is refraction error in eyes?

What is the error of refraction called?

What is the name of the condition where the eye does not reflect light equally in all directions?