POTENTIAL COMPLICATIONS WITH PRK
In general, the complications of PRK and LASIK are very similar. Just like all other surgical procedures, there are PRK Risks. However, when PRK is performed by an experienced surgeon, the risk of complications is quite low. In fact, this surgery is among the safest procedures today when performed properly.
One advantage of PRK over LASIK is that there is no risk of flap complications because no corneal flap is created. Striae and epithelial ingrowth don’t occur with PRK.
I’ve listed both the rare and serious complications and the less rare and mild ones. Although this list is not exhaustive, it includes the possible complications that you need to know about in order to be comfortable proceeding with PRK surgery.
CORNEAL HAZE
Corneal haze is clouding of the cornea during the healing process. This clouding may cause blurry or hazy vision. As a general rule, the worse your eyesight was going into the procedure, the more you are at risk for developing corneal haze. Significant corneal haze following PRK is extremely rare with today’s equipment and medications. Haze eventually disappears by itself, but this can take months or years. If it develops, corneal haze is usually re-treated with the laser to physically remove it, although this is necessary in fewer than 1 percent of patients.
RECURRENT EROSIONS
During the PRK procedure, the epithelium is removed and then heals. Rarely after PRK, a small area of epithelium can slip off on its own. This usually happens at night during sleep or on awakening in the morning. When this happens, the eye hurts and waters for a few minutes to several hours. These small epithelial slips are called recurrent erosions and can recur over several weeks or months. Recurrent erosions can be treated with medicines or with a laser treatment.
UNDERCORRECTION
Undercorrection means that your refractive error wasn’t fully corrected by PRK. If you were nearsighted before surgery, it means you are still a little bit nearsighted afterward. A slight undercorrection will not seriously affect your vision and may even be desirable in nearsighted patients over forty to help with their reading vision. If the undercorrection is enough to cause significant blurring of vision, we will recommend an enhancement procedure for you, generally after six months have passed.
OVERCORRECTION
Overcorrection means that your refractive error was corrected more than intended. If you were initially nearsighted, overcorrection means that you are farsighted after PRK, making it hard to see clearly up close. If you were farsighted before PRK, an overcorrection would make you nearsighted. In this case, your distance vision would be somewhat blurred and your near vision rather good.
An initial, temporary overcorrection is not uncommon and usually rights itself in the first month as the eye heals. Patients can manage a temporary overcorrection by wearing glasses until the problem resolves. As with undercorrections, a significant overcorrection can be treated with an enhancement procedure. An enhancement for overcorrection is usually performed six months after the initial treatment, once your vision has stabilized.
PROBLEMS WITH QUALITY OF VISION
Rarely, patients after PRK experience a slight decrease in quality of vision. Vision can seem slightly dirty or hazy, like wearing glasses or contacts that aren’t clean. Vision tends to improve over time. This complication is very rare except in those with very high levels of nearsightness or astigmatism. This is another reason I prefer implantable contacts lenses for extreme myopia.
DRY EYE
Just as with LASIK, PRK makes the eyes somewhat drier than before surgery, usually for the first few months. Some doctors think that PRK causes less dryness after LASIK so they recommend PRK to patients with dry eyes. That is not my experience. My colleagues and I studied this question a decade ago and found no difference in postoperative dryness between PRK and LASIK. Other studies have similarly found no difference. I avoid both PRK and LASIK in patients with significant dryness preoperatively. The treatment of dryness after PRK is the same as LASIK; refer to the LASIK chapter for a discussion of this.
CORNEAL ECTASIA
Keratoconus is a hereditary weakness in the cornea that causes the cornea to bulge outward, causing blurred vision. When keratoconus develops after PRK or LASIK, we call it corneal ectasia. Corneal ectasia is rare in any case, but is less common after PRK. It may be that the LASIK flap slightly weakens a cornea already predisposed to bulging outward. PRK is the preferred procedure in someone in whom we are concerned about the possibility of ectasia after surgery.
OTHER POTENTIAL COMPLICATIONS
Starburst and halos at night can occur after PRK, just as they can after LASIK. Similarly, serious PRK complications like infection can occur after PRK also, although very rarely. Refer to the section on these potential complications in the LASIK chapter.
Comparing PRK With LASIK
