In Canada, there are four different types of laser eye surgery: PRK, LASIK, LASEK and Epi-LASIK. While PRK and LASIK have been around since the 90s, the other two are more recent. These surgical procedures differ from one method to the next. However, the aim is always the same: to correct the inner part of the cornea and the stroma and to improve vision. Find out more about each of these procedures.
PRK eye surgery
Photorefractive keratectomy (PRK) is a laser-based surgical technique for vision correction. Like all laser techniques, it aims to correct the cornea's curvature to improve vision.
The cornea is the transparent layer on the surface of the eye. It acts as the eye's primary lens, and its curvature partly determines the quality of vision. Laser surgery can therefore treat refractive problems, such as myopia or astigmatism.
During PRK surgery, the central thickness of the cornea is reduced. This is the stroma, the rigid tissue that makes up the bulk of the corneal thickness. The cornea's extremely thin outer layer (the epithelium) is first removed to access the stroma.
In the second step, the stroma is reshaped using an excimer laser, also known as an exciplex laser, an ultraviolet laser. Only a tiny part of the tissue is modified to correct vision. Then, within a week of the operation, a new epithelial layer forms.
Photokeratomileusis, known as the LASIK technique, is currently the most widely used laser surgery. The procedure involves first lifting a thin layer of cornea, consisting of the epithelium and part of the stroma.
In the second step, an excimer laser corrects the shape of the stroma. The corneal layer is then repositioned in its place.
It acts as a bandage by adhering perfectly to the eye without suturing. And thanks to this natural bandage, the eye heals in 2-3 days.
There are two main differences between these two laser eye surgeries:
#1- Recovery time with LASIK surgery is faster than with PRK. On average, it takes 2 to 3 days for a person to reach their final vision. With PRK, it can take from 3 to 6 weeks. But after two months, the visual result is identical for both techniques.
#2- PRK corrects the cornea less deeply than LASIK. PRK is an excellent option for people with thinner or less resistant corneas.
LASEK laser eye surgery
This technique combines some of the methods of PRK and LASIK and is best suited to the correction of minor vision problems. During surgery, only an extremely thin layer of epithelium is cut from the cornea's surface.
This layer is thinner than the one cut during LASIK surgery, which means that visual correction will be less in-depth.
Once the stroma has been laser-treated, the epithelial layer is folded over the eye. The eyes are then bandaged with contact lenses. These protect them during the approximately two weeks of healing that follow the operation.
Note that LASEK surgery is sometimes considered for people who do not qualify for LASIK and PRK.
Epi-LASIK eye surgery
Epi-LASIK or e-LASIK eye surgery is similar to LASEK. But rather than using alcohol to loosen the epithelium, a surgical tool is used. This procedure avoids the possibility of an alcohol-induced reaction.
Remember, no one method is better than the others long-term. The quality of vision is similar for all four laser eye surgeries. After an eye examination, you will be advised on the type of surgery best suited to your eyes and needs.
Ask your optometrist if you are a good candidate for LASIK surgery.