PRK / LASEK

PRK (Photo-Refractive Keratectomy)

PRK was the first laser refractive surgery approved by the FDA, receiving final approval in 1995. Surgeons at the UCLA Laser Refractive Center participated in this pioneering FDA trial. Unlike LASIK, no flap is created in PRK. The flap in LASIK is what allows for the very fast, overnight recovery. PRK is similar to LASIK in terms of its success and outstanding, predictable visual outcomes but differs significantly in recovery time. The procedure begins with the surgeon applying a solution to the cornea which loosens the surface layer of cells. These cells, much like skin cells, are then removed and discarded. The excimer laser is then applied, precisely as in LASIK, to reshape the permanent tissue of the cornea. A cool solution is then applied to the cornea and a bandage contact lens is placed. This bandage contact lens facilitates healing of the “skin” cells of the cornea, a process that takes approximately 4 days. During this healing phase, the eye will be intermittently uncomfortable: scratchy, sandy, gritty, itchy and light sensitive. There may be some swelling of the eyelids. This discomfort usually peaks on post-operative day 2 or 3 and then subsides. When your surgeon removes the bandage contact lenses around post-operative day 5, the discomfort is typically gone but the vision will take several weeks to stabilize. Patients typically need to take 4 days off from work, refrain from driving in unfamiliar areas for about a week and will require 1 month to achieve excellent, stable vision.

Alcohol solution loosens surface layer of cells	Surface layer of cells is moved aside	Laser energy reshapes the cornea	Cool fluid is applied to the cornea	Bandage contact lens aids in healing and comfort

Variations of PRK (LASEK, epi-LASIK, ASA)

There are several alternative terms used that are essentially synonymous with PRK. LASEK (laser sub-epithelial keratomileusis), epi-LASIK (epithelial LASIK) and ASA (Advanced Surface Ablation) are variations of PRK. LASEK involves removing the surface (epithelial) layer of cells using the same solution used in PRK. Instead of discarding the cells, the sheet of cells are replaced after the excimer laser treatment. Epi-LASIK uses an epikeratome, a system similar to the microkeratome used for LASIK, to separate the surface sheet of cells from the permanent corneal tissue. This epikeratome uses a blunt separator rather than a sharp blade used in a microkeratome. ASA is a general term used for any surface procedure which removes the epithelium rather than creating a LASIK flap. It is important to recognize that all of these procedures offer outstanding visual outcomes, just like LASIK, but prolonged healing as compared to LASIK. Wavefront optimized and wavefront guided technology is routinely used with PRK procedures as well as LASIK.

Who might consider PRK?

• If you are patient with thin corneas, PRK might be your only option. Because the LASIK flap is typically about 20% of the corneal thickness, this leaves 80% of the corneal tissue to work with. In PRK, only the surface layer of cells are removed, prior to the laser tissue removal. This surface layer of cells is <10% of the corneal thickness, leaving more tissue to work with as compared to LASIK.
• If you have a history of severe dry eye syndrome and would like vision correction doctors might be more inclined to suggest this procedure. Please consult our UCLA Laser Refractive Center ophthalmologists before making a decision or opinion on this matter. Each patient has unique visual circumstances that could affect a vision correction suggestion
• Patients with high levels of myopia might consider this because the treatment range can often be higher with PRK than LASIK eye surgery. UCLA also offers the Visian ICL commonly known as the implantable contact lens. Before a UCLA Laser Refractive Center surgeon can make a suggestion a pre-operative evaluation will be required.

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