We are happy to provide you with some basic information on several common vision conditions. Select from the following list or scroll to learn more about the symptoms and treatments for:

Hyperopia	Myopia	Amblyopia
Presbyopia	Astigmatism	Computer Vision Syndrome

Emmetropia

When rays are focused correctly on the retina of a relaxed eye, the eye is said to be emmetropic. Emmetropia is the medical term for 20/20 vision, vision that needs no corrective lenses, contact lenses, or reading glasses. It occurs because the optical power of the eye can perfectly focus an image to the retina, giving it “perfect” vision.

The opposite of emmetropia is ametropia. With ametropia, the focal point of the eye is some distance in front of or behind the retina. The following vision conditions are types of ametropia.

Hyperopia

hyperopia vision Hyperopia is more commonly known as farsightedness. As the name suggests, people with farsightedness are most often able to focus on objects that are further away, but have more difficulty focusing on objects which are very close. This is because the eyeball is shorter than normal, which prevents the crystalline lens in the eye from focusing correctly on the retina. About a fourth of the population is farsighted.

Babies are most often born hyperopic but usually move toward emmetropia by the time they are 4 or 5 years old.

Hyperopia can be corrected with eyeglasses or contact lenses. There are also new surgical procedures that can correct hyperopia.

Myopia

myopia vision Myopia is the medical term for what most people call nearsightedness. It is a condition in which a person can see objects clearly only when they are close; when objects are farther away it is difficult to focus on them. Myopia usually develops in childhood, but may develop in early adulthood as well. In rare cases, there may be health risks, including retinal detachment, associated with severe myopia. Signifificant research is being conducted in hope of learning the exact cause of myopia. For years we have thought myopia to be related to family history of myopia or with the stress or strain of nearwork. Hopefully current research will provide the answers we seek.

Myopia is corrected with eyeglasses or contact lenses or refractive surgery, such as lasik. Sometimes myopia continues to gradually worsen throughout life, a condition known as progressive myopia.

American Optometric Association – Myopia
All About Vision - Myopia

Amblyopia

amblyopia vision Amblyopia, sometimes called “lazy eye,” occurs when one eye develops differently than the other eye does, causing one eye to be weaker than the other. Sometimes a difference in focusing ability causes one eye to be used more often and for more attention to be paid to that eye by the patient’s brain. Other times, the eyes are misaligned, causing one eye to “shut off” to avoid double vision. Regardless of the cause, the result is a weakened, or amblyopic, eye.

Symptoms
It’s hard to spot amblyopia. Sometimes a child will noticeably favor one eye over the other. Another possible symptom is the child frequently bumping into things on one side. The best way to tell if your child has lazy eye is through a comprehensive eye exam at about six months, three years, and before kindergarten. In many cases amblyopia is treatable and early diagnosis may prevent amblyopia from leading to more serious problems, such as loss of the ability to see three dimensions or functional blindness in the amblyopic eye.

Treatment
Even with treatment the amblyopic eye may always be a bit weaker than the other. However, with treatment, vision in the amblyopic eye can be improved to some extent. Treatment involves encouraging the weak eye to develop. This is done using eye patches, vision therapy, glasses, or a combination of the three. The strong eye may be patched to encourage the weak eye to develop. Vision therapy can help to correct improper use of the eyes. If a focusing error is at the root of the problem, then glasses may reduce the error. Most of the time the amblyopic eye will always require glasses.

Presbyopia

presbyopia vision As a people get older, usually between 38 and 48 years old, a condition called presbyopia sets in. Presbyopia is the inability to focus on objects near the eye, such as reading or computer. Progressive lenses or reading glasses are a way to remedy this condition.

Presbyopia is a natural consequence of the aging process. There is no cure, though researchers are constantly looking for one. Even if a someone has never had vision problems before, he can still develop presbyopia. It may seem to occur suddenly, but it actually occurs gradually over a long period of time. Symptoms include having to hold things at arm’s length to see them clearly, eye strain, fatigue, and headaches from near work.

Astigmatism

Sometimes the cornea is irregularly shaped, causing the eye to focus an object on two different areas of the retina. This is known as astigmatism. For the cornea to bend light correctly, it should be spherically-shaped, like a basketball. Astigmatic corneas are not spherical. This causes a distorted view when looking at objects which are close-up and far away.

The cause of astigmatism is unknown. Astigmatism is often associated with myopia or hyperopia, and it usually is present from birth. It may be hereditary, or it may be caused by factors such as pressure on the cornea, incorrect posture, or increased use of the eyes for “near work.”

Mild astigmatism sometimes does not need to be corrected. Eyeglasses, contact lenses, or refractive surgery can correct moderate to high degrees of astigmatism.

American Optometric Association: Astigmatism
All About Vision - Astimatism

Computer Vision Syndrome

Computer vision syndrome (CVS) affects a significant percentage of computer users. It is a series of symptoms related to extended periods of computer usage. Measures can be taken to relieve symptoms of CVS.

Symptoms
CVS can appear as a variety of symptoms. Headaches, eye strain, neck and back aches, sensitivity to light, blurred vision, double vision, and dry or irritated eyes are all possible problems related to CVS.

Risk Factors
Any computer user can develop CVS. Your vision, your computer, and the environment where you use your computer are all factors which can lead to CVS.