ALK (Automated lamellar keratoplasty) is a surgical procedure used to correct high degrees of nearsightedness, or myopia, and low to moderate amounts of farsightedness, or hyperopia. The surgery is performed with an instrument called an automated keratome, and affects the shape of the cornea, or window of the eye, to achieve the correction.

This surgery is a more streamlined and effective version of a surgery called keratomileusis, which was first performed in the United States in 1964. ALK can correct from about -5.00 dioptres up to -30.00 dioptres of myopia and about +1.00 dioptres to about +4.00 dioptres of hyperopia. The surgery for hyperopia is performed much less often than the surgery for myopia, because high myopes have a greater improvement in both amount and quality of vision, and the results for myopia are more predictable.

During the surgery, a special instrument is used to isolate the central part of the cornea. A thin layer is sliced off of the center of the cornea. This layer, called the lenticule, should remain attached or "hinged" to the cornea to allow reattachment in the same position. In the surgery for myopia, the settings on the instruments are changed at this point, and a second thin button of tissue is removed from the cornea and is discarded. The hinged lenticule is then replaced in a way that makes it stick without the use of stitches. The removal of the piece of tissue can flatten the front of the cornea significantly, which allows for correction of large amounts of nearsightedness.

The thickness of the layer shaved off is of critical importance, because these calculated amounts are what predict the amount of prescription correction. Surgery calculations with a skilled eye surgeon, or ophthalmologist, should also be based upon corneal thickness, amount of glasses prescription, and predictions from mathematical tables, or nomograms, specifically designed for ALK.

Unlike other keratorefractive surgical procedures, age does not currently appear to be a factor in the results achieved with ALK. As with other surgical procedures, you should seek out an ophthalmologist with the most current technology and information and an excellent success rate, i.e., patients who are pleased with their results. This will give you the most predictable results for your ALK surgery.

The goal of automated lamellar keratoplasty is to significantly decrease a large prescription so that thinner glasses or no glasses need to be worn. The procedure can make you much more functional without glasses. However, if the full correction is not achieved with ALK alone, more correction is still possible. Three to six months after the ALK, further correction can be obtained with a secondary radial keratotomy (RK) and/or astigmatic keratotomy (AK) procedure.

Automated lamellar keratectomy is a safe and effective procedure to reduce large amounts of myopia, but it is a surgery and thus has risks involved. These risks include undercorrection, overcorrection, inflammation, infection, loss of tissue which would have to be replaced with donor tissue, and even loss of vision. Be sure that you are fully informed of all the benefits and risks of ALK before you have the procedure performed by a well qualified surgeon. The surgery is performed under local anesthesia (you are awake), and it is done on an outpatient basis (you go home the same day).