Correct focusing of images in the eye is determined by the focusing power of the cornea and the lens of the eye in relation to the length of the eye. Either the cornea or the lens or both can be changed to correct errors of focusing (called refractive errors) such as nearsightedness, farsightedness, or astigmatism.

Treatment of nearsightedness: the steep cornea is made flatter by removing tissue from the center of the cornea. This moves the point of focus from in front of the retina to directly on the retina.

Treatment of farsightedness: the flat cornea is made steeper by removing tissue outside of the central optical zone of the cornea. This moves the point of focus from behind the retina to directly on the retina

Treatment of astigmatism: the cornea is made more spherical -- like a soccer ball instead of a rugby ball. This eliminates multiple focusing points within the eye and creates one point of focus on the retina. Astigmatism can be treated at the same time as nearsightedness and farsightedness.

A "cataract" is a clouding of the natural lens in the eye and modern treatment of cataract involves removing this clouded lens and replacing it with an artificial intra-ocular lens (IOL) implant. Exactly the same operation can be done when the lens is not clouded in order to change the power of the lens as a way to correct nearsightedness or farsightedness. This is called a Refractive Lensectomy.

For further information please contact your Ophthalmologist.