Refractive surgery in Valencia

What is PRK technique?

PRK technique (Photorefractive Keratectomy) is an Excimer laser based refractive surgery technique used to correct refractive errors (myopia, hyperopia, astigmatism).

Unlike LASIK technique, PRK removes the central part of the epithelium so that the corneal stroma can be reshaped using Excimer laser, without creating a corneal flap.

After laser treatment, a contact lens is used to protect the cornea until the epithelium is regenerated.

Treatment: how is the intervention carried out?

PRK surgery’s basic steps are:

  1. Anaesthetic eye drops are used to avoid eye discomfort during surgery.
  2. The central area of the corneal epithelium is removed, generally after using a 20% diluted ethanol solution.
  3. The cornea is reshaped in order to correct the eye’s diopters using Excimer laser.
  4. Antibiotic and anti-inflammatory eye drops are used.
  5. A protective contact lens is used to cover the cornea.

Step 1 - PRKStep 2 - PRKStep 3 - PRK

Pros and cons of PRK over LASIK

Advantages and disadvantages of PRK over LASIK are based on the fact that it is a flapless procedure.


  • Flap-related postoperative complications (displacement, incorrect healing…) are reduced. This is especially important for those people whose activities and/or work increase the risk of flap displacement (police, military, firefighter, sports people…).
  • It can be more widely used as it can be carried out in thinner corneas than LASIK.


  • Postoperative discomfort is greater than with LASIK and total vision recovery needs a couple more weeks.
  • Postoperative infection risk is higher.

Risks and complications

As with any other surgical procedure, there are some possible risks and complications associated to PRK technique.

  • Dry eye: Some patients develop dry eye due to the removal of the corneal epithelium which has a high density of nerve endings. These nerves inform the brain about the eye’s lubrication state so that tears are produced to humidify it. This problem disappears once epithelium regeneration has taken place.
  • Halos: This problem appears in patients with small optic areas which have a big pupil size. At night, as mydriasis (pupil dilation over 4mm) occurs and light rays go thorough not treated areas and therefore disperse, it is more frequent.
  • Over or undercorrection: During the first months and in high degree myopia, corneal and epithelial healing may determine the surgery’s stability and final result.
  • Corneal infection: The cornea has a higher infection risk as it is exposed to contamination due to the removal of the protective epithelial layer.
  • Corneal haze or opacity: Time after surgery (after 6 months), a reduced number of patients develop an opacification in the treated corneal area.

IMPORTANT: In all cases, problems are temporary and can be solved using topical or oral medication, or corrective reinterventions.

FAQ Refractive Surgery

Other considerations

  • PRK technique has been used for longer than LASIK.
  • Scientific studies reveal that PRK and LASIK visual outcomes were comparable at 6 months.
  • Excimer laser in PRK technique can be programmed to carry out a standard or a personalized (using Wavefront system) treatment.

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