What is the goal of LASIK surgery

LASIK is the most commonly performed refractive laser surgery. In refractive laser surgeries, lasers change the shape of the clear outer layer of the eye, called the cornea.

Conditions called refractive errors affect how light passes through the cornea and lens. If an eye has no refractive errors, the cornea and lens bend light rays to meet at a single point on the back of the eye. This area, called the retina, translates the light into signals to the brain that allow a person to see a clear image.

A refractive error happens when the light bends in such a way that it doesn't meet on the retina. This can happen because of:

• The condition of the cornea.
• The condition or placement of the lens.
• The size or shape of the eye.

When light doesn't come to a single point on the retina, an object is not in focus and it appears blurry. Refractive errors can cause different types of blurry vision:

• Nearsightedness, called myopia, happens when an image is focused in front of the retina. Near objects are clear, but distant objects are blurry.
• Farsightedness, called hyperopia, happens when light reaches the retina before it meets at a single point. The point at which light rays would meet is behind the retina. Distant objects are clear, but near objects are blurry.
• Astigmatism happens when the shape of the cornea or lens is uneven. Light cannot be bent to meet at a single point. Vision is blurry at all distances.

When a person wears glasses or contacts, the artificial lens bends the light so that it meets at a single point on the retina. The principle with LASIK and other refractive laser surgeries is similar. By changing the shape of the cornea, the surgeon is able to change how light is focused.