Do You Suffer From Nearsightedness, Farsightedness,
Or Even Astigmatism & Want to Get Rid Of Your
Eyeglasses & Contacts for Good?

Yanhee’s eye surgeons can quickly correct your vision using 100% bladeless laser technology!

What is LASIK?

LASIK, which stands for Laser in-Situ Keratomileusis, is an eye surgery that uses laser energy to reshape the curvature of the cornea to change the manner in which light rays enter the eye.

The Cornea

The cornea is the eye’s outermost layer. It is the clear, dome-shaped surface that covers the front of the eye. See figure below.

Parts of an Eye

The cornea functions as the eye’s outermost lens. It controls and focuses the entry of light into the eye. It adds between 65 – 75% of the eye’s overall focusing power.

When light hits the cornea, it bends (refracts) the incoming light onto the lens. The lens then refocuses that light onto the retina, a group of special light sensing cells at the back of the eye that initiates the translations of light into vision. See figure below.

For one to see clearly, light rays have to be focused by the cornea and lens to land precisely on the retina. See figure below.

Normal Eye

Refractive Errors

To understand how LASIK works, you first have to know a little about refractive errors.

In refractive errors, the shape of the eye does not allow light from focusing on the retina. The length of the eyeball (longer or shorter), changes in the cornea’s shape, or aging of the lens leads to refractive errors.

Having normal vision simply indicates that your eye is shaped in such a way that it allows incoming light to focus precisely or directly on your retina, providing you with a clear image. See letter A, figure below. This condition in which the eye does not need correction is called emmetropia.

If your eye is shaped too short or your cornea is too flat, incoming light will focus behind the retina causing near objects near objects to appear blurry. This condition is called hyperopia or farsightedness. See letter B, figure below.

If your eye is shaped too long or your cornea is too steep, incoming light will focus in front of the retina causing distant objects to appear blurry. This condition is called myopia or nearsightedness. See letter C, figure below.

Errors of Refraction

If you have an irregularly shaped cornea or lens, both far and near objects appear to be blurry and distorted. This condition is called astigmatism.

When the lens of your eyes age and become less elastic, focusing on near objects becomes difficult. This condition is called presbyopia.