ASA (Advanced Surface Ablation) is a form of Laser Vision Correction (LVC) that is really a variation of the original PRK (Photorefractive Keratectomy) procedure. If you haven't done so already, please read the LVC page as an introduction to ASA. In PRK the outer covering of the cornea, the epithelium, is removed and discarded. An excimer laser is used to reshape the stroma of the cornea to correct astigmatism, nearsightedness, or farsightedness. The epithelium is then allowed to re-grow. Thus, after PRK one is left with a large corneal abrasion which causes blurred vision and pain. The abrasion can take anywhere from 4-7 days to heal.
In ASA, the epithelium is more carefully removed and saved. After treatment, the epithelium is replaced and then held in place with a contact lens. The contact lens is then removed after four to five days. Given the similarity in spelling between LASIK and LASEK, Dr. Price prefers the term ASA (advanced surface ablation).
Using new oral and topical medicines post operatively keeps a person who has had ASA very comfortable. Most ASA patients will describe minimal discomfort and a scratchy feeling or an "eyelash in the eye" feeling for a few days after surgery. Visual recovery after ASA is not quite as fast as after LASIK but most patients having ASA will see 20/40 - 20/50 within one week after surgery.
What are the advantages of ASA? First the long term vision results are similar between ASA and LASIK. The majority of patients having ASA are going to see 20/40 or better without glasses. Second there is no flap to worry about. If an infection occurs (which is unlikely) then it is much easier to treat in the absence of a flap. Also, if an individual is involved in activity that may involve getting hit in the face (i.e. Martial Arts) the structural integrity of the cornea is greater and there is no flap to slip. In fact, when the epithelium heals it is more tightly adherent to the stroma than before surgery. Finally, not making a stromal flap saves approximately 100 microns of cornea that can be used in the correction of nearsightedness. In other words, ASA allows a greater range of treatment for a given patient than LASIK.
|A flap of surface epithelium is loosened with a diluted alcohol solution and moved aside.
||The surface under the epithelium is treated with the laser, and the epithelial flap is returned to its original position, as with LASIK.
||A protective, soft contact lens is then placed over the cornea to make the eye more comfortable while it heals.
Learn more about LASIK >>
Which should I choose? ASA or LASIK? >>