Laser vision correction is one of the most exciting technological advances in the history of eye care. It is performed with an excimer laser, which combines argon and fluoride gases to produce a “cool”, ultra-violet light. Your surgeon uses the computer-guided excimer laser to gently alter the shape of your cornea through a series of ultra precise pulses. It does not cut or burn. Each pulse removes a remarkable 39 millionths of an inch in 12 billionths of a second!
Available laser technologies.
PRK (Surface Ablation)
PRK (photorefractive keratectomy) is the same laser procedure as LASIK. It differs, however, in being performed on the surface of the cornea, after removing or lifting the corneal epithelium, instead of a corneal flap. Today, PRK is more commonly referred to as “surface ablation,” meaning a laser procedure that is applied to the surface of the cornea. There are two other surface ablation techniques available which differ in the way the corneal epithelium is managed, LASEK and epi-LASIK. These procedures have not as yet proven to be more beneficial than PRK.
When is PRK or surface ablation technique the treatment of choice instead of LASIK?
- When the cornea is too thin for LASIK.
- When a pre-existing problem is present on the cornea which can be eliminated with PRK and result in better vision than LASIK.
- When there is a structural abnormality in the cornea that makes LASIK unsafe.
LASIK is the most frequently used procedure for laser vision correction. LASIK stands for Laser Assisted In Situ Keratomileusis. A wide range of myopia, hyperopia, and astigmatism can be corrected by the LASIK procedure. It is a delicate surgical procedure that allows for a very predictable healing response. Your vision stabilizes rapidly, and you can expect to have little or no discomfort following LASIK. Most patients have driving vision within 24 hours of treatment.
- The corneal flap is created by the surgeon using a laser. The corneal flap stays attached to the rest of the cornea on one side.
- The laser treatment is applied below the flap.
- The flap is repositioned smoothly and easily. Pressure holds the flap in place as it heals.
CLE / Clear Lens Extraction
For patients with very high levels of nearsightedness or farsightedness, and for people who have early lens opacities. In addition, people in their middle years may appreciate the dual advantage of a refractive lens exchange: not only will it correct nearsightedness or farsightedness, but it also prevents any future need for cataract surgery.
Unlike laser vision correction, which alters the shape of the cornea, refractive lens exchange changes the focusing power of the lens within the eye. During refractive lens exchange, the eye’s natural lens is removed and replaced by a lens implant, which has been selected to compensate for the eye’s refractive problems. In effect, the lens implant acts like a permanent contact lens within the eye, with newer lens designs offering both distance and reading vision.
The refractive lens exchange is the same procedure as modern cataract surgery. At the beginning of the surgery, a small incision—an eighth of an inch, or 3.5 mm—is made either in the sclera or in the periphery of the cornea. A delicate instrument is inserted through the incision to create a circular opening in the front of the lens capsule. A suction tip is then inserted into the lens capsule, and the gel-like natural lens is removed. Once the natural lens has been suctioned out, a lens implant is inserted into the lens capsule. Antibiotic solutions are placed around the new lens to reduce any risk of infection, and the surgery is usually completed without stitches, since the incisions are designed to be self-sealing.
ICL (Implantable Contact Lens)
For patients who are at least 18 years of age, with high levels of myopia, hyperopia, or astigmatism that are too extreme for laser vision correction, and for whom laser vision correction on the cornea is not safe.
The ICL™ is a very thin intraocular lens designed to rest in front of the eye’s natural lens, just behind the iris. The ICL™ is inserted through a small, 3mm corneal incision. The eye is made numb using anesthetic eye drops, and there is very little discomfort associated with the procedure. The surgery typically takes 15 to 20 minutes to perform, with only one eye being treated at a time. The second eye is usually treated several days after the first eye. If either one of these procedures is more appropriate for you, it will be discussed with you in detail.
A related link to information on ICLs can be found at www.staar.com.
Non-Surgical Vision Correction
There are contact lenses that are available for continuous wear. Currently there are 2 types that are Health Canada and FDA (Food and Drug Administration, USA) approved for 30 day continuous wear. However, not everyone is a good candidate for this type of contact, your doctor will need to assess your eyes to make that recommendation.