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Vista Alliance Eye Care Associates The New York LASIK doctors

At Vista Alliance Eye Care Associates, we want you to understand the different reasons that you might need vision correction, either with glasses, contact lenses, or with laser vision correction.  There are four common reasons why you might need vision correction.

They are: (just click on the word to link to the definition)

• Myopia                                 Surgery: LASIK LASEK INtacs
• Astigmatism                                       Surgery for Astigmatism
• Hyperopia                                          Surgery for Hyperopia
• Presbyopia                                         Surgery for Presbyopia

Myopia

Myopia is the medical term for nearsightedness.  More than 70 million people in North America are nearsighted. The myopic eye is too long for the cornea's curvature. Light rays enter and focus in front of the retina and produce a blurred image instead of coming to a sharp focus on the retina at the back of the eye.

The term 'nearsighted' means that you can see 'near' objects clearly without your glasses, but objects further in the distance are blurry. There are varying degrees of myopia (nearsightedness).  The more myopic you are, the more blurred objects appear in the distance, the higher your eyeglass prescription and the thicker your glasses. Of all myopic people, about 90% have corrections less than 6.00 diopters. The table below shows the categories of severity for myopia:

Almost everyone feels that their myopia is severe, because of how dramatically dependent they are on glasses and contact lenses. However, only one in ten myopic people are actually in the severe and extreme categories.

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Astigmatism

Many patients with myopia have some degree of astigmatism, or ovalness in their cornea. It is the most common refractive condition, and occurs to some extent in most eyes. Astigmatism occurs when the cornea is shaped more like an egg than a marble. As a result, patients with astigmatism experience distortion or tilting of images because of unequal bending of light rays entering the eye. Patients with high degrees of astigmatism have blurred vision not only for distant objects, as with myopia, but for near objects as well. Astigmatism is also measured in diopters. Of all myopic people, 50% or more have astigmatism as well. Most of these people have corrections of less than 1 diopter. The table below shows the categories of severity for astigmatism:

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Hyperopia

Hyperopia is the medical term for `farsightedness.' It occurs when an eye is too short for the cornea's curvature. Light rays entering the eye focus behind the retina, and as a result a blurred image is produced. Farsighted individuals, however, can use their focusing muscles to 'pull' the image forward onto the retina. In a young person with severe hyperopia, or once presbyopia sets in around age 45, distant objects are seen more clearly than near objects. Certain laser technologies, such as holmium lasers and hyperopic LASIK may correct this condition.

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Presbyopia

Presbyopia is the normal process of aging, where the natural lens of the eye loses some of the flexibility that characterizes a younger eye. This usually occurs between the ages of 40 to 50. Everyone experiences presbyopia, some sooner, some later. Because of this normal process, nearsighted people begin to wear bifocals in their forties, and those who never needed glasses before may require reading glasses. The one advantage to mild myopia is the ability to remove your glasses after age 40 and continue to read (your myopia effectively counteracts your presbyopia). After having the excimer laser procedure, you will lose this ability. You will typically be normally sighted after the procedure, and you will need reading glasses for small print, like every other normally sighted person at age 40 to 50. The excimer laser has no effect on your focusing muscles. Patients who are experiencing the effects of presbyopia cannot be helped by the excimer laser. However, there are new techniques being developed for this condition. Ask your doctor if you are a candidate for these new procedures.

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