Automated lamellar keratoplasty is a procedure used to reduce high levels of myopia, usually above five to six diopters, and hyperopia. Done as an outpatient procedure under topical anesthesia, ALK usually takes less than one hour.

ALK for Myopia

In ALK for myopia, the surgeon creates a flap by slicing across the front of the cornea with an instrument called a microkeratome.

After folding the flap to the side, the surgeon uses the microkeratome to remove a thin disc of tissue from the exposed surface of the cornea. The front flap is then replaced without the need for sutures. By removing this layer of tissue, the central optical zone is flattened, reducing myopia.

ALK for Hyperopia

In ALK for hyperopia, the surgeon slices the cornea at a deeper level with the microkeratome. The internal pressure of the eye stretches the remaining thin corneal surface, causing it to bulge forward.

The surface flap is then replaced without removing any corneal tissue. Because the cornea is bulging slightly, it is steeper and provides extra optical power for hyperopic (farsighted) correction. As with ALK for myopia, no stitches are used in this procedure.

Complications and Side Effects

Complications and side effects can include:

Irregular astigmatism, resulting in a decrease in best corrected vision
Glare
Over-correction
Under-correction, requiring additional RK or AK to achieve desired results
Inability to wear contact lenses
Loss of the corneal cap, requiring a corneal graft
Corneal scarring, infection and loss of vision