PRK for Myopia - Stable Outcomes in Long-Term Study

PRK surgery for myopia

Medically known as myopia, nearsightedness is a condition in which a person sees near objects clearly while objects in the distance are blurred. Images of distant objects are focused in front of, instead of on the retina, usually because the eye is too long.

Clinically, myopia is a refractive error in which the cornea and lens focus light rays from distant objects in front of the retina, causing images of distant objects to appear blurry.

What happens in myopia?
The common signs and symptoms of myopia are:

  • Distant objects appear blurry
  • You need to squint to see clearly
  • You have headaches caused by excessive eyestrain
  • You sit very close to the television, movie screen or chalkboard
  • You hold books very close while reading
  • You seem to be unaware of distant objects

What can myopia lead to?
Nearsightedness gets worse as you get older. The retina can be very thin in people with who are significantly nearsighted. Sometimes the retina can tear or detach. Symptoms of a tear or detachment include sudden flashes of light, floaters or a dark curtain of shadow across part of your eye. This is a medical emergency and you must go to the emergency room or ophthalmologist immediately.

How is myopia diagnosed?
A basic eye exam will diagnose nearsightedness.

How is myopia treated?
The following approaches are commonly used to manage or treat the problem of nearsightedness.

Corrective lenses: Corrective lenses work by counteracting the curvature of the cornea or increased length of your eye. There are two choices: eyeglasses or contact lenses. However, you should remember that glasses and contact lenses do not cure nearsightedness. Glasses correct the vision without making physical changes.

Surgery: There are several surgical options for correcting nearsightedness. LASIK, LASEK and PRK are surgical procedures that physically change the eye to cure nearsightedness. All three are surgical procedures, all use lasers (different types), and some require an incision in the cornea. The procedures surgically reshape the cornea. Implantable lenses can be surgically inserted into the eye.

PRK serves as an excellent secondary option for corrective laser eye surgery when LASIK or LASEK are not available for any of the following reasons: thin corneas, flat corneas or especially large pupils. It generally preserves more corneal tissue and there have been no reported complications of stromal flap. There is also less risk of dry eye, During operation, there is some extremely mild pain (“only scratchy sensation”), With respect to the results, the long-term outcome is same or even better than with LASIK and 20/20 vision or better is typically achieved.

What is PRK?
An abbreviation of the Photo Refractive Keratectomy, PRK is the refractive error correction for nearsightedness, farsightedness, astigmatism and presbyopia. It is an outpatient procedure in which laser treatment requires less than one minute for each eye; total procedure lasts about 15 minutes per eye.

Results of the study
In 2010, an important, benchmark study was conducted at St. Luke’s International Hospital (Tokyo, Japan) to determine the long-term effect of PRK on 42 eyes of 29 patients, all suffering from myopia.

The study was started about a decade ago, when PRK was performed in all these 29 patients who had some form of myopia. After the completion of 10 years, responses of each of the subjects were noted as follows:

Better natural (uncorrected) visual acuity: According to the results, about 40% of eyes of the subjects had uncorrected visual acuity (UCVA) of 20/20 or better and 81 % had UCVA of 20/40 or better.

Best spectacle corrected visual acuity: Best spectacle-corrected visual acuity (BCVA) was unchanged or improved in 95% of treated eyes, and two eyes (4.8%) lost one line of BCVA.

High level of patients' satisfaction: As much as 90 percent of the subjects reported that they were either “pleased” or “very pleased” with the results of PRK.

Improved safety: After 10 years, there were no significant reported side effects in any of the subjects related with the PRK surgery. Similarly, there are no long term destructive corneal effects following PRK and none of the eyes was found to display any abnormal changes. 

Based on the above discussion, it can be confidently concluded that PRK is one of the recommended, effective and safe alternatives especially for the correction or treatment of myopia. The best part that the study showed is: the advantages of the PRK procedure can be fully retained even after 10 years of surgery.

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