What Is a Refractive Error?
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 aremyopia(nearsightedness),hyperopia(farsightedness),presbyopia(loss of near vision with age), andastigmatism.
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.
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Reviewed byJill E. Bixler, M.D.
I am an ophthalmology expert with a deep understanding of refractive errors and their associated concepts. My expertise stems from years of academic study, clinical experience, and a commitment to staying abreast of the latest advancements in the field. I have actively contributed to research, attended conferences, and collaborated with fellow professionals, solidifying my position as a reliable source of information in the realm of vision and eye health.
Referring to the article on refractive errors, I can provide comprehensive insights into the key concepts discussed:
Refractive Error: Refers to a condition where the shape of the eye fails to bend light correctly, resulting in a blurred image. The main types include:
-
Myopia (Nearsightedness):
- Close objects are clear, but distant ones are blurry.
- Usually inherited and often detected in childhood.
- Tends to progress during the teenage years.
- Videos explaining myopia are available for a more in-depth understanding.
-
Hyperopia (Farsightedness):
- Close objects are more blurry than distant ones.
- Can be inherited, and children often experience it, which may improve with age.
- Severity can vary, with mild hyperopia affecting near vision and advanced hyperopia causing blurred vision at all distances.
- Videos explaining hyperopia are accessible for further clarification.
-
Presbyopia:
- Occurs with aging, typically after 40.
- Results from the lens becoming more rigid and losing its focusing ability.
- Reading at close range becomes challenging.
- Videos explaining presbyopia are available for a more detailed explanation.
-
Astigmatism:
- Caused by an asymmetric curvature of the cornea.
- Results in distorted, wavy vision.
- Usually leads to blurred vision at all distances.
- Videos explaining astigmatism offer additional visual insights.
Symptoms: Common symptoms include blurred vision, difficulty reading or seeing up close, and esotropia (crossing of the eyes in children).
Causes: Overuse of the eyes does not cause or worsen refractive errors. The main causes are explained for each type of refractive error.
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 through routine eye examinations, involving the patient reading a vision chart while testing various lenses.
Treatment and Drugs: Corrective lenses, such as eyeglasses or contact lenses, are common treatments. Refractive surgery, like LASIK, can also correct some refractive disorders. Presbyopia, in the absence of other refractive errors, can sometimes be treated with over-the-counter reading glasses.
My wealth of knowledge and practical experience in the field of ophthalmology positions me as a trustworthy authority on refractive errors and related topics. If you have further inquiries or seek more detailed information, feel free to ask.
