Refractive Errors

Your eye operates in much the same way as a camera. Just as the lens of a camera focuses entering light on a piece of film to produce a sharp image, the lens of your eye focuses light on the retina to form a picture that is then sent to the brain. When a refractive error is present, it means that your eye cannot focus light correctly on the retina. A refractive error is a common eye disorder that can occur for a number of reasons. It may be due to an irregularly shaped cornea (the clear front surface of the eye), the length of the eyeball itself or can develop as the lens of your eye ages.

The four common types of refractive errors are:

• Myopia (nearsightedness)- Myopia is the most common refractive error. Most cases of myopia occur because the eyeball is too long and light is focused before it reaches the retina. It can also be the result of the cornea or the lens being too curved relative to the length of the eyeball.
• Hyperopia (farsightedness)- Hyperopia is a refractive error that is due to the eyeball being too short and/or a cornea that is flatter than normal. In cases of hyperopia, it is more difficult to see up-close objects clearly.
• Astigmatism – Astigmatism is due to an irregularly shaped cornea or lens. In cases of astigmatism, the eye is unable to evenly focus light on the retina to produce a clear image.  Astigmatism may occur in conjunction with myopia or hyperopia.
• Presbyopia- Presbyopia is a refractive error that affects the majority of individuals over the age of 40. It occurs with advancing age as the lens of the eye loses its elasticity and its ability to focus. With presbyopia, it is more difficult to see up close.

As part of a routine eye exam, you will be evaluated for the presence a refractive error. While wearing a pair of eyeglasses to this day remains an excellent way to enjoy clear, crisp vision; getting a prescription for contact lenses or having a refractive surgery such as LASIK to permanently change the shape of the cornea are also effective methods of vision correction.