• Normal eye

The eye functions like a camera, bending light waves so that they focus on a certain point. The front surface of the eye is called the cornea and is responsible for about 75% of the eye's focusing power. The remaining focusing power is done by the lens, which refines the images received from the cornea. These images are then projected onto the retina, which acts like the "film" of the camera and records the image so that is can be sent to the brain. Due to the significant role of the cornea, many common refractive conditions are the result of a misshaped cornea, and can be corrected by laser surgery.

• Myopia/Nearsightedness

Occurs when the eye is too long in relation to the curvature of the cornea, and light rays focus in front of the retina. With myopia, near objects are seen more clearly than distant objects. Myopia occurs in 25% of the population, and usually stabilizes in the early twenties. LASIK can correct myopia by flattening the cornea.

• Hyperopia/Farsightedness

Occurs when the eye is too short in relation to the curvature of the cornea, and light rays focus behind the retina. A farsighted person has difficulty viewing close objects, although distance vision can be affected as well. LASIK can correct hyperopia by steepening the cornea.

• Astigmatism

Occurs when the cornea exhibits an uneven curvature. As a result, light rays that enter the eye are focused at different points causing distorted vision. Astigmatism frequently occurs in conjunction with myopia and hyperopia. LASIK can correct astigmatism by smoothing out the cornea's irregular curvature.

• Presbyopia

Occurs naturally as the flexibility of the lens of the eye decreases predictably in the 40's and 50's, and makes viewing near objects more difficult. Bifocals and/or reading glasses often become necessary. LASIK cannot correct presbyopia, as this is just the normal aging process of the eye. However, LASIK can create "monovision" which allows certain individuals to read without glasses after LASIK. Dr. Tyson can discuss the pros and cons of monovision with you