LASIK Eyesight Insight

Myopia–Nearsightedness

In the normal eye, light bends through the cornea and lens to focus on the retina. With myopia (nearsightedness) the eye is longer or the cornea is steeper, causing light to focus in front of the retina. The image is therefore out of focus on the retina and vision is blurred. LASIK can be used to treat low to high levels of nearsightedness (myopia) with the goal of reducing or eliminating dependence on corrective lenses. LASIK uses the computer-controlled Excimer laser to precisely treat the inner tissue of the cornea.

The Treatment. A thin flap of cornea is created and folded back. Excimer laser is applied to reshape (flatten) the cornea. The corneal flap is replaced over the treated cornea. (No stitches required.) The “flatter” cornea now bends light to become focused on the retina. Vision is clear.

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Hyperopia–Farsightedness

In the normal eye, light bends through the cornea and lens to focus on the retina. With hyperopia (farsightedness) the eye is shorter or the cornea is flatter causing the focal point of light to be behind the retina. The image is therefore out of focus on the retina and vision is blurred.

The Treatment. A thin flap of cornea is created and folded back. Excimer laser is applied to reshape (steepen) the cornea. The corneal flap is replaced over the treated cornea. The “steeper” cornea now bends light to become focused on the retina. Vision is clear.

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Astigmatism

In the normal eye, light traveling through the cornea in both the horizontal plane and the vertical plane is refracted the same so that the image is properly focused on the retina in the back of the eye. Vision is clear. With astigmatism, an abnormal curvature of the cornea in one direction causes light traveling in one plane, the horizontal plane in this case to be focused in front of the retina. The light striking the retina through the horizontal plane is out of focus on the retina and vision is blurred.

The Treatment. The outer surface of the cornea will be treated in such a way with the Excimer laser as to effectively “flatten” the cornea in the steep axis. In the example, the steep horizontal axis is reshaped along this axis. A thin flap of cornea is created and folded back. Excimer laser reshapes the high axis of the cornea. The corneal flap is replaced over the treated cornea. The reshaped cornea now bends light to become focused on the retina. Vision is clear. Often conditions are a combination of the above described problems, and Dr. Allison will use a combination of the treatments listed to correct the vision.

Call 495-2645 to set up your free consultation today or email Angela Short, Refractive Coordinator at adshort@saintfrancis.com.