What is refractive surgery?
Refractive surgery is used to correct common eye disorders such as nearsightedness, farsightedness, and astigmatism. Refractive surgery is designed to alter the shape of the cornea in order to improve the patient’s vision. Although patients experience varying degrees of discomfort after surgery, the procedure is usually painless and the improvement in vision is noticeable almost immediately.
What is PRK?
PRK, which stands for photorefractive keratectomy, is a form of laser refractive surgery, which uses the excimer laser to treat common refractive errors. Like other types of refractive surgery, the goal of PRK is to reshape the cornea so that light traveling through it is properly focused onto the retina located in the back of the eye. During PRK the corneal epithelium is removed and the corneal stroma is reshaped. Following the procedure, the corneal epithelium must heal over the treatment zone. A flap, such as with LASIK, is not made during PRK.Who qualifies for PRK?
People with myopia, or nearsightedness, with or without astigmatism, and those with moderate amounts of hyperopia, or farsightedness, with or without astigmatism, are potential candidates for PRK. Pre-exiting eye conditions, the amount of refractive error and the thickness of the cornea all play roles in determining who qualifies for PRK.What are the risks of PRK?
Many patients experience some discomfort in the first 24 to 48 hours after surgery and almost all experience sensitivity to light. Other side effects may include:
- Dry eyes.
- Seeing halos around images. These are most noticeable when you’re viewing lights at night, such as while you’re driving.
Within the first six months after surgery, other potential side effects may include:
What are the differences between LASIK and PRK?
- Loss of best vision achieved with glasses.
- Seeing a minor glare which can be permanent, depending on a patient’s pupil size in dim light.
- Mild halos around images.
- Dry eyes.
The primary difference between PRK and LASIK refractive surgery is that in LASIK, the vision correction occurs under an epithelial plus stromal flap, while in PRK, the vision correction is performed on the surface of the cornea after the epithelium has been removed. The epithelial cells then heal over the following three to four days in order to cover the treatment zone on the cornea. In general, patients tend to report less postoperative discomfort with LASIK than with PRK. However the full set of risks and benefits to each procedure and the patient’s individual medical and occupational requirements must be considered when choosing the most appropriate procedure.
What is custom ablation?
Another form of PRK and LASIK is referred to as custom ablation. Custom ablation is a variation of standard PRK and LASIK and is used to treat many of the same conditions that are currently treated by standard PRK and LASIK.
Custom ablation does more than reshape your cornea to treat nearsightedness, farsightedness, or astigmatism based on your eyeglasses prescription alone. During custom ablation the entire optical pathway of the eye is analyzed and the treatment is tailored to specifically treat your eyes and your individual condition. Custom ablation takes into consideration higher order aberrations of the optical pathway. Treatment of these higher order aberrations has been reported to improve contrast sensitivity. Although custom ablation is becoming more widely used, at this time custom ablation has not been definitively proven to provide a better outcome than standard PRK and LASIK.
Will I need glasses after surgery?
This is a common and often misunderstood question for many patients who are considering refractive surgery. There are instances where you may need glasses following refractive surgery. Some of those are listed below.
I have cataracts. Should I have refractive surgery before I have cataract surgery?
- For special situations (such as night driving) in which the sharpest vision is desirable, you may still want or need to wear glasses or contact lenses with a mild correction.
- If following your procedure, you still have a small amount of refractive error, you may need glasses to achieve your best corrected visual acuity.
- During the normal development of presbyopia, patients who have had refractive surgery may need reading glasses. Presbyopia is a decrease in the ability to focus on near objects, which occurs naturally in the early- to mid-40s and is unrelated to the surgical procedure. Patients with presbyopia and a small amount of nearsightedness who are used to removing their glasses to be able to read can sometimes see very noticeable change. These patients may find they can see well at a distance without glasses, but need glasses to read following refractive surgery.
This is a discussion to have with your physician. In general, since cataract surgery also can correct for many pre-existing refractive errors, only the cataract surgery would be needed. Refractive surgery can be used following cataract surgery to correct minor residual refractive errors in some instances.