Basic Information on Different Laser Eye Surgery Procedures
There are basically two different types of laser eye surgery that are performed, PhotoRefractive Keratectomy (PRK) and Laser Assisted in Situ Keratomileusis (LASIK). Each of these types has, however, several modifications. All laser eye surgeries are performed with drops used to numb the eyes and when the patient is awake.
In any laser eye surgery, the process of removing the epithelium, the outermost layer of the cornea, is the first and foremost step. However, the method in which it is done may differ. The eye surgeries that fall under PRK involve surface ablation techniques to remove the epithelium. LASIK procedures differ from these in the fact that a corneal flap with a hinge is created using a specialised cutting technique to remove the epithelium.
After this, the cornea is reshaped using an excimer laser. The mapping or guidance systems vary according to the type of the excimer laser model. The results after a laser eye surgery are up to expectations when the mapping and guidance systems of the excimer laser are more accurate.
In PRK, the epithelium is manually scraped off and the tissues that lie under the surface of the cornea are reshaped with the excimer laser. This method is employed for those who have thin corneas and the cutting of the flap is not desirable. The advantage of PRK is that it is less risky as there is no flap cutting involved. PRK surgeries have the disadvantage that they take a longer time to heal and the patient suffers more discomfort during the period. Some advanced versions of PRK use a specialised excimer laser to vaporise the corneal layer instead of scraping it off manually.
Laser Assisted Sub-Epithelial Keratomileusis (LASEK) is an advanced form of PRK. In this procedure, a solution of alcohol is used to soften the epithelium, which is then removed. The stromal tissues are reshaped with the excimer laser and thereafter the epithelium is replaced. This action facilitates fast healing after the surgery. Epi-LASEK is yet another modification of the LASEK procedure that uses a separator to preserve a living layer of the epithelium that has removed. Once the epithelium is replaced the recovery time is even less compared to the LASEK procedure.
In LASIK eye surgery, a microkeratome metal blade cuts a hinged flap of the cornea, and after reshaping the tissues with an excimer laser, the flap is replaced in position at the end of the surgery. The procedure is painless and correction of vision is immediate. However, the vision may be blurred for the initial 24 hours after the surgery. The vision improves over a period of a few weeks.
The only difference between the conventional LASIK surgery and Custom Vue Lasik is that the excimer laser is guided by an advanced software package called Wavefront. This helps to map the optical system of the patient very accurately and the surgery is conducted accordingly. This method is used to correct imperfections left behind by other laser surgeries.
Conventional IntraLasik uses a femtosecond Intralase laser to cut the cut the corneal flap instead of a blade. The flap that is cut is thinner and the imperfections that come along with using a blade can be avoided. It takes slightly longer to cut the flap and the procedure is more expensive.
Custom Vue Intralasik combines the best of both the procedures. While a laser is used to create a flap in the cornea, the Wavefront software guides the excimer laser for reshaping the tissues with minimum imperfections. It is the most expensive type of laser surgery.
Laser eye surgery is conducted on a patient only after due consideration by the consulting ophthalmologist.