At UW Medicine Eye Institute, we spend time with each patient to develop an individualized treatment plan. It is very important to understand the different refractive procedures, so you and your doctor can decide which treatment is the best for you.
Laser-Assisted Subepithelial Keratectomy (LASEK)
LASEK is a vision correction procedure in which the epithelial layer of the cornea is gently removed and laser treatment is applied to Bowman’s layer and the upper layer of the stroma to reshape the cornea.
When the cornea is reshaped by the laser, the epithelial flap is returned to its original position. The corneal epithelial cells are the fastest reproducing cells in the human body and quickly regenerate. Visual recovery after LASEK is generally faster than in PRK.
The potential advantages of LASEK over PRK are a reduction of postoperative discomfort, a decreased risk of infection, and decreased incidence of corneal haze. Advantages of LASEK include elimination of the possibility of any stromal flap complications during surgery or throughout the patient’s lifetime, including flap folds, inflammation, a decreased risk of temporary induced dry eyes and an increase in the overall thickness of the untouched area of the cornea.
The use of the excimer laser for LASEK is not Food and Drug Administration-approved, but is an accepted off label use since 1999.
Excimer Laser Photorefractive Keratectomy (PRK)
PRK is a vision correction procedure in which excimer laser treatment is applied directly to the front surface of the cornea to change its curvature. The top layer of the cornea (the epithelium) is removed and laser treatment is applied. PRK can correct nearsightedness and farsightedness, with or without astigmatism. The advantage of this procedure is no flap complications, but the disadvantage is longer visual and comfort recovery.
Clear Lens Exchange (CLE)
Refractive lensectomy is also known as clear lens replacement surgery. This procedure is very similar to modern cataract surgery in that the natural lens of the eye is removed and replaced with an intraocular lens implant. Refractive lensectomy may be a better alternative to other refractive surgery procedures in certain patients with high degrees of nearsightedness or farsightedness. The procedure is performed under topical anesthesia, and is an outpatient procedure. The refractive lensectomy is normally reserved for patients who are already using reading glasses or individuals who are not a good candidate for any other laser refractive surgeries. Patients need to discuss specific risks and benefits of this refractive surgical approach with the surgeon and the decision is made on individual basis.
Astigmatic Keratotomy (AK)
AK is an incision procedure performed with a diamond knife that is used to correct astigmatism. Astigmatism is a condition in which the cornea is football-shaped instead of basketball-shaped. AK can be used to correct from one to five diopters of astigmatism. Although some patients have only astigmatism and can be treated with AK alone, AK is usually used in conjunction with excimer laser PRK to correct combined astigmatism and nearsightedness. Even following PRK in which concurrent astigmatism is corrected with the excimer laser, it is occasionally necessary to perform subsequent AK to provide the best possible vision for the patient.
Monovision is a technique in which one eye is intentionally left slightly nearsighted, which allows it better up close vision. Contact lens wearers often use this technique. The brain then compensates for the disparity between the two eyes so that the person can read without glasses. Many people who have had this procedure do not need glasses for 10 to 15 years after age 40. Patients generally try monovision with contact lenses in their normal working environment before they commit to this surgical procedure. If patients do not like monovision, another laser treatment called an enhancement can be done on the nearsighted eye to bring it to the desired distance vision. Glasses will be required for reading and looking at anything up close.
You should discontinue wearing soft contact lenses one week before your pre-operative exam, and for rigid gas permeable, you should discontinue wear three weeks before your pre-operative exam.
Patients experience very little discomfort during the procedures. Numbing drops administered prior to surgery are very effective. Your first week after surgery is typically the most symptomatic. That means that your eyes are more likely to feel dry and sensitive to lights. We recommend rest and planning ahead for activities during the recovery period with music and books on tape.
Everyone is different and their eyes heal at variable rates. In general, after surgery you will see well enough to navigate around your home comfortably. The first few days your vision will fluctuate. Toward the end of your first week of surgery, your vision will significantly improve.
You can expect to have some fluctuations the first month after surgery secondary to dry eyes. Nearsighted patients’ vision typically stabilizes at three months post-operatively, while farsighted and astigmatic patients stabilize at four to six months post-operatively.
Patients might also experience some light sensitivity and mild discomfort. These symptoms can be relieved by sunglasses and over-the-counter pain medications.
Patients may experience some dry sensation after the surgery. This may be relieved by using over-the-counter preservative-free artificial tears, such as Refresh Plus and Theratears four to eight times a day. The dryness experienced may cause mild, intermittent blurring of the vision.
Patients must be at least 18 years old and have documented refraction stability for one year. While there is no upper age limit, other factors, such as cataracts, need to be discussed prior to refractive surgery.
Are you a good candidate for refractive surgery?
- I have healthy eyes
- I am 18 years or older and highly dependent on my corrective lenses
- I have difficulty wearing contact lenses
- I am an active person
- Ilook better without glasses
- I adjust well to change
- I am not a perfectionist
- I would have better opportunities if I didn’t have to rely on my glasses
- I want to rely less on glasses, but am OK if I have to wear corrective lenses part time
- Not relying on contact lenses or glasses is more important to me than precise vision
- My vision has been stable over the last couple of eye examinations
- I have realistic expectations from my surgery
There are some medical contraindications that may prevent injury, which can be discussed at the consultation. They include corneal scarring, kerataconus, severe keloid formations, lupus erythematosis, past corneal herpetic infections, pregnancy or nursing mothers, uncontrolled diabetes and rheumatoid arthritis.
With all that has been written about refractive surgery in the past few years, there is a common misconception that patients can see 20/20 immediately. For most patients, recovery is more gradual and resulting vision can vary. While most patients eventually gain 20/20 vision, some will have 20/25, 20/30 or 20/40, which is the vision needed to drive without glasses. It is rare for vision correction procedures to result in less than 20/40 eyesight.
A small percentage of patients need enhancement procedures to fine-tune vision correction. There is no charge for enhancement procedures performed in the first year after the refractive surgery.
The goal of refractive surgery is to get you out of relying on glasses. For all patients older than 40, there is a normal aging process called presbyopia. It is an aging process in which the lens of the eye slowly loses its elasticity and thus its ability to focus up close. This process occurs regardless if you have refractive surgery or not. It usually occurs to all of us between the ages of 40 and 55. Patients that are nearsighted may notice better vision without their glasses or by pushing their glasses down their nose. If we remove the nearsightedness, your up close vision will be the same as if you always have your glasses on.
Risks associated with refractive surgeries could include:
- Glare, halos or starbursts usually noticed in dim light or at night when driving. Symptoms can include having difficulty seeing signs when night driving or being more sensitive to oncoming lights
- Dry eyes, which includes symptoms of burning, stinging, watery, red, irritated eyes
- Under or overcorrection with laser. Every eye responds differently, and it is possible that desired correction wasn’t achieved
- Regression: eye may shift towards old prescription over time
The potential advantages of LASEK compared to PRK are a reduction of postoperative discomfort, a decreased risk of infection, and decreased incidence of corneal haze. Other advantages include elimination of the possibility of any stromal flap complications during surgery or throughout the patient’s lifetime, including flap folds, inflammation, a decreased risk of temporary induced dry eyes and an increase in the overall thickness of the untouched area of the cornea.