PRK Refractive Surgery: Precursor to LASIK

Filed in archive Other Types of Refractive Surgery , PRK on March 28, 2010

PRK, photorefractive keratectomy, is a refractive surgery procedure perfected in the 1980's and practiced in many countries other than the U.S. before lasers to perform this surgery were finally approved for use in the U.S. by the FDA in 1995. The FDA does not approve the surgical procedure, but rather the excimer lasers to be used.

In PRK, the excimer laser is applied directly to the eye's surface. In this process the epithelium, the extremely thin outer layer of cells covering the cornea is removed completely using a diluted alcohol solution to weaken the cells, causing the layer to separate from the corneal layers below it, however because epithelial cells are the fastest growing cells in the body this layer begins to regenerate within days of PRK surgery.

As in LASIK, an excimer laser is used to ablate or remove tissue from the cornea, reshaping it so that it can more exactly focus light onto the retina, resulting in clearer vision.

PRK has its advantages and disadvantages over LASIK. Since there is no corneal flap, there is no risk of any complications associated with the flap. There is, however, a slightly increased risk of infection just after surgery, since the epithelium is completely removed. After PRK, they eye is treated with medication and a contact lens is placed over the area where the epithelium was removed, serving as a bandage as the epithelium regenerates. This can take about 2-3 days or more, and at that point the contact lens will be removed. Vision can remain blurry until proper healing of the epithelium, and this can continue for days or weeks as healing progresses.

Another downside of PRK is that there is more discomfort or pain associated with the procedure post-operatively. Before the procedure, the eye is treated with anesthetic drops to deaden any pain during the procedure, however afterward there is usually some pain or discomfort as the epithelium heals.

The good thing about PRK is there's no microkeratome, no cutting. Many people are afraid of this cutting aspect of LASIK surgery, and are more willing to cope with the pain or discomfort and longer healing time of PRK in favor of greater stability of the cornea.

In LASIK, the flap remains and never fully heals. As the USAEyes website states, "Once you have LASIK, you always have LASIK." People who engage in activities with increased chance of eye injury or getting hit in the eye may benefit from PRK, because once healed there is no possibility the flap complications possible with LASIK.

Another benefit of PRK is that it has been in practice longer than LASIK or LASEK, and therefore is a perfected procedure.