Making Decisions About Home Care

Understanding What LASIK Can Correct

by Mae Ferguson

Most people end up needing some type of corrective lens for their eyesight at some point in their life. How well you see things depends on where the light rays that enter your eye land. As light rays pass through the cornea, they are refracted, or bent. If the cornea is too long, too short, or too flat, the light will not properly hit the retina and you will have vision problems. LASIK is a type of laser eye surgery that corrects the shape of the cornea so you can see better. Here are the types of problems this surgery can cure.


Myopia is commonly referred to as nearsightedness. You can see things up close clearly but have a hard time seeing things further away. It is caused by an eyeball that is a bit longer than it should be or when the cornea has a sharp curve to it. The light is refracted so that it lands in front of the retina. Laser surgery can be done to reduce the sharp curve of the cornea or to adjust the cornea to allow for a longer eye.


Hyperopia is the opposite of myopia. You can see things far away clearly but things up close are blurry. It is caused by a short eyeball or a flat cornea. The light focuses behind the retina instead of on it. In this case, the laser is used to shave off bits of the cornea so it is not flat and the light can focus directly on the retina.


Astigmatism is an uneven cornea. It has flat spots and sharp curves. You have trouble focusing on things both close and far away. Once you do have a good focus on something, if you need to adjust that focus it takes a bit of time. For example, if you are reading a book, your eyes are focused up close. If you then have to look up to see who came into the room, you need to adjust that focus. With astigmatism, adjusting to see who came in takes a few seconds. The extra time to adjust the focus can be dangerous if you are driving or doing something where you could fall or get hit by something. LASIK can fix the cornea so it is smooth and provides accurate refraction.

If your vision problem is a result of a refractive error, LASIK can help. If your vision problem is due to something else, like cataracts or glaucoma, it won't. Talk with your eye doctor to learn more about LASIK.