 Vision Problems
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Eye disorders that affect vision can be divided into two groups:
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- refractive errors: Refractive errors are eye disorders in which the eye does not focus the light that enters the eye, resulting in blurred vision.
- non-refractive errors: Non-refractive errors are eye disorders that are caused by eye diseases.
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Refractive errors are seen in almost 20 percent of children. The following are the most common refractive errors, all of which affect vision:
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- myopia or nearsightedness: Myopia is the most common refractive error seen in children. Myopia means that a child can see close up, but has problems with seeing things far away. It is usually not present at birth, but begins to develop as the child gets older. It is usually noted in children around the ages of 9 or 10. This might be noted in a child that cannot read the blackboard from the back of the room, but can see to write and read without a problem. Other signs and symptoms may include headaches, nausea after reading, holding books close to one's face, or writing with one's head very close to the table.
- hyperopia or farsightedness: Hyperopia is one type of refractive error in which the child cannot see things close to him/her, but he/she does not have a problem seeing things far away. This is usually uncommon in children. Most children normally have a small degree of this until they are 7 years of age.
- astigmatism: Astigmatism is one type of visual condition in which an abnormal curvature of the cornea occurs, resulting in decreased vision. This can start in childhood or as an adult and can be easily corrected if it is causing problems. Some signs and symptoms of astigmatism may include headache, eye strain, difficulty reading, and fatigue.
- amblyopia or lazy eye: Amblyopia is one type of visual condition characterized by decreased vision that occurs in one eye, usually as a result of another problem in which that eye is not receiving proper visual stimulation. This is usually preventable if the underlying cause is treated before the child is 6 years old.
- strabismus or crossed-eyes: Strabismus is one of the most common eye problems in children in which the eyes are misaligned. The eyes (one or both) may turn inward (crossed-eyes), outward (wall eyes), turn up, or turn down. At times, more than one of these conditions are present. Children younger than 6 months of age may have a common form of strabismus that comes and goes. This type of strabismus may be normal. Strabismus can be a result of poor muscle strength in the eye, or some children are born with crossed-eyes.
The signs and symptoms of strabismus may include a child squinting his/her eyes, a child that cannot properly judge distance to pick up objects, a child that closes one eye to see better, dizziness, or the child's eyes move inward or outward. Early diagnosis of the underlying problem is essential in order to prevent vision loss. Treatment of strabismus may include patching the stronger eye in order to increase the strength in the weaker eye, eyeglasses, surgery to straighten the eyes, or eye exercises.
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More about refractive errors
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The following are some causes of non-refractive errors:
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The majority of congenital cataracts (those present at birth) are present in children who also have other eye problems or other health problems. In approximately 25 percent of children born with congenital cataracts, the condition is due to a genetic cause such as a metabolic disorder (caused by an inherited enzyme deficiency) or a chromosome abnormality (i.e., Down syndrome).
Signs and symptoms of a cataract may include the following:
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- cloudy or blurry vision
- decreased vision
- lights appear too bright and/or present a glare or a surrounding halo
- white pupil upon flashlight examination
- double vision
- colors seem faded
- increased nearsightedness - increasing the need to change eyeglass prescriptions
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Treatment of cataracts usually involves surgery.
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- retinoblastoma: Retinoblastoma is a rare cancer of the retina. The retina is the innermost layer of the eye, located at the back of the eye, that receives light and images necessary for vision. About 250 children in the US are diagnosed with this type of cancer each year. It mostly occurs in children under the age of 5; the highest incidence of the disease occurs between infancy and age 2. Both males and females are affected equally. Retinoblastoma can occur in either eye, however, in about 25 to 30 percent of the cases, the tumor is present in both eyes.
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Signs and symptoms of retinoblastoma may include:
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- leukocoria - a white light reflex that occurs at certain angles when light is shown into the pupil
- strabismus (Also called "wandering eye" or "crossed-eyes.") - a misalignment of the eyes; when one or both eyes do not appear to be "looking" in the same direction
- pain or redness around the eye(s)
- poor vision or change in child's vision
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Treatment for retinoblastoma may include one, or more, of the following:
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- surgery
- enucleation (removal of part or all of the eye or eyes involved with the tumor)
- chemotherapy
- radiation therapy
- phototherapy (uses light to destroy the blood vessels that supply the tumor)
- cryotherapy (uses a freezing process to destroy the tumor )
- fitting and training for a prosthesis
- blind or decreased vision adaptation training
- supportive care (for the side effects of treatment )
- antibiotics (to prevent/treat infection)
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