What Can LASIK Correct?
LASIK solves poor vision at the source, correcting these common vision problems:
Nearsighted individuals have problems seeing well at a distance although near objects appear clear. The nearsighted eye is usually longer than a normal eye and its cornea steeper, so when light passes through the cornea it is focused in front of the retina, not on the retina. This makes distant images appear blurred.
Myopia is a very common condition that affects nearly 30 percent of the U.S. population. It normally starts to appear between the ages of 8 and 12, and almost always before the age of 20. As the body grows, the condition often worsens until stabilizing, typically in adulthood.
LASIK solves myopia by correcting the shape of the cornea so that clear, properly focused vision is obtained.
Farsighted individuals have trouble seeing well at a distance and even more trouble reading up close or seeing objects near at hand. The farsighted eye is slightly shorter than a normal eye and has a flatter cornea, so distant objects focus behind the retina.
LASIK eliminates farsightedness by correcting the corneal irregularities that cause it.
Uneven steepening of the cornea means images are focused irregularly on the retina, causing blurred vision. Astigmatism is very common and can accompany any other form of refractive error, such as myopia or hyperopia.
LASIK effectively solves Astigmatism
Presbyopia is a condition that becomes noticeable for most people after the age of 45. In children and young adults, the lens inside the eye can easily focus on distant and near objects. With age, the lens stiffens and loses its ability to focus properly, especially up close, occasioning the need for reading glasses and bifocals.
A LASIK technique called Blended Vision can resolve presbyopia by correcting one eye better for near vision and the other eye better for far vision. Blended Vision, as performed by Dr. Lipstock, enables nearsighted, farsighted, and astigmatic LASIK patients over age 40 to see well both at near and at a distance without glasses.
Understanding Your Prescription
The four main vision focusing disorders of the eye are:
- myopia (nearsightedness)
- astigmatism (ovalness of the eye)
- hyperopia (farsightedness) and
- presbyopia (inability to change the focus from far to near)
The units used to represent the amount of correction needed in order to normalize vision for distance are called ‘diopters’. The more nearsighted or farsighted you are, the higher your prescription is in diopters.
Your prescription is usually written in three numbers and the following example represents a typical prescription:
|OD||-4.25 -1.75 X 180|
|OS||-5.50 -1.25 X 175|
|+2.25 Add OU|
Here is the way to decipher your prescription:
- OD stands for right eye and is the abbreviation for the Latin term “Ocular Dexter”. OS is for the left eye. It is derived from the Latin “Ocular Sinister”. The 1st number (-4.25 and -5.50 in this example) is the degree of spherical nearsightedness or farsightedness. The sign identifies whether you are nearsighted (- sign) or farsighted (+ sign).
- The second number (-1.75 and -1.25) is the degree of astigmatism. The number can be written either with a + sign or a – sign.
- The last and 3rd number (180 and 175) is the axis, or the direction of your astigmatism. An axis of 180 degrees, for example, means the astigmatism is horizontal.
- Therefore, this prescription means that the patient is moderately nearsighted, with a moderate degree of astigmatism in a horizontal direction.
The “add” at the bottom of the prescription is for the reading part of a bifocal glass. It might be unusual for anyone under the age of 40 to need this. (OU on this line stands is the abbreviation for the Latin term “Oculus Uterque” – both eyes).
Some people only have one number written for each eye. This is when there is no astigmatism.