Refractive Surgery (LASIK/PRK)
Refractive surgery is a group of surgical procedures designed to help you reduce or even eliminate your need for glasses or contact lenses. Various procedures are available to help correct the various types of refractive errors: myopia, hyperopia, and astigmatism.
Refractive surgery improves your vision by changing the focus power of your eye. This is accomplished by altering either of the two focusing structures of the eye–the cornea and the lens. The cornea or lens can be altered by various surgical techniques.
What types of refractive procedures are available?
The most common refractive surgery procedure of the cornea is LASIK (laser-assisted in situ keratomileusis). In LASIK, laser energy is used to reshape your cornea, essentially sculpting your prescription into your eye. If the laser energy were applied directly to the surface of your eye, the treated area would be sore for several days during the healing process. To avoid this discomfort, a thin flap is cut on the surface of your cornea, then folded out of the way. Laser energy is then used to sculpt your exposed cornea to correct your nearsightedness, then the flap is put back into its normal position, covering the treated area. LASIK is nearly painless, highly successful, and you can see the improvement in your vision immediately after surgery.
LASIK: Corneal flap is created, and laser is used to shape cornea under flap
Another type of corneal refractive surgery is called PRK (photorefractive keratectomy), which differs from LASIK in that no flap is made--the laser directly sculpts the front surface of your cornea to flatten it. PRK is used in patients who have corneas that are too thin or irregular for LASIK. It is also preferred for patients who have very active lifestyles that make them prone to eye injury (boxers, fighter-pilots), who prefer no-flap surgery. Unlike LASIK, PRK does result in pain that is improved with a contact lens for the first 3 days after surgery.
PRK: Laser reshapes cornea directly
There are two common refractive surgery procedures of the lens. One is implantation of an ICL (intraocular contact lens). An ICL is essentially a contact lens, but instead of being placed on the surface of your eye, it is permanently placed inside your eye. The implant rests on the surface of your natural lens, behind your iris. The strength of the implant is specifically selected to work with your cornea and lens to correct your refractive error. The second procedure is called RLE (refractive lens exchange). Refractive lens exchange involves removing your lens and replacing it with a lens implant that works with your cornea to correct your refractive error.
Am I a candidate for refractive surgery?
Each of these procedures has different risks and benefits, and each is designed for a different group of people based on the type and severity of their refractive error. If you are considering having refractive surgery, talk with your doctor about which procedure is best for your eyes.
Is LASIK safe?
With bladeless LASIK, the complication rate has decreased dramatically. It is a significantly safer procedure today than it was 10 years ago. In a slew of recently published clinical papers, LASIK has been shown to be significantly safer than contact lens wear, from an infectious and visual stand-point, over the life-time of the patient.
Are patients happy with LASIK?
Most patients are satisfied with the results of their LASIK surgery and would elect to undergo the procedure again, if given the opportunity.
What are the risks of LASIK?
In a small percentage of people, dry eye conditions can worsen, the appearance of halos around lights at night may develop, and infections and inflammations may arise. All of these conditions can be treated, and are more likely to occur in susceptible patients. It is therefore very important to have a thorough LASIK evaluation by a conscientious surgeon before proceeding with the surgery.
PRK treatment for myopia and astigmatism – in this procedure only one laser is used to shape the cornea to custom treat your myopia or astigmatism. No flap is created, and visual recovery is longer than LASIK. If you are not a good candidate for LASIK, you may be a candidate for PRK.
What is the difference between PRK and LASIK?
In PRK, a flap is not created, and the laser that shapes the cornea is applied directly to the corneal surface.
Why might I have PRK over LASIK?
PRK is indicated over LASIK in patients with irregular corneas, or corneas that are too thin for LASIK (there is not enough corneal tissue to safely create a flap). It is also preferred in patients at high risk for flap dislocation (for example, boxers or patients who engage in extreme sports or contact sports). It is a very safe procedure, used by almost all corneal surgeons. There are some risks that should be considered (see below) before deciding on PRK.
What are the risks of PRK?
Visual recovery is slower after PRK than after LASIK. It usually takes about 1 month to achieve the goal visual acuity, while after LASIK, the goal is usually achieved after 1 week.
Immediately after PRK, there may be some ocular discomfort or pain, because the laser creates a corneal abrasion on the surface of the eye. Therefore, we prescribe a pain reliever and put a "bandage" contact lens on the eye while it heals for 5 days.
PRK can also rarely result in corneal haze (blurry vision for the patient) in those who have very high myopia (high near-sightedness). For this reason, we use a special drop during the procedure to minimize haze. We can also treat haze after the procedure with drops for 1 month.