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PRK and LASEK

PRK (PhotoRefractive Keratectomy)


PRK is the first type of laser vision surgery to have been developed. It started in 1987, but became less frequently used by the mid-1990's as LASIK evolved. Later, a modified PRK technique, called LASEK, was developed, and this was further refined into the ASLA technique in use today.

Unlike LASIK, no corneal flap is created in the PRK procedure.  Instead, PRK involves removing the top layer of the cornea (the epithelium) so that the laser beam can access and re-shape the cornea below the surface.
Description of the procedure

The PRK procedure takes about 15 minutes per eye:
  • The cornea is anaesthetised.
  • Anaesthetic drops are applied to the eye, and an eyelid holder is put in place to keep the eye from blinking.
  • The corneal epithelium layer is removed.
  • The surgeon removes the top layer of the cornea (the epithelium) in order to gain access to the corneal bed below the surface.  The top layer will regenerate naturally within a few days.  Unlike LASIK, no corneal flap is created in the PRK procedure.
  • The corneal bed is re-shaped by the laser.
  • Pulses of laser energy are then applied to re-shape the corneal bed specifically to the prescription of the eye.  The laser uses a cool ultraviolet light beam to precisely ablate, or vapourise, a pre-determined amount of corneal tissue.
  • A soft contact lens is applied.
  • The eye is fitted with a "band-aid" soft contact lens for protection while the top layer of the cornea regenerates over the next few days.  (Sometimes an eyepad is used instead of a contact lens).
  • Antibiotic and anti-inflammatory eye drops are applied.
  • Because the recovery of the eye was relatively slow with PRK, it gave way to the LASIK technique.
  • Both eyes are not usually treated on the same day.

Post-op Visual Recovery

Vision is blurry for about a week after surgery. Also, because the 2 eyes are not usually treated on the same day, it takes longer for patients to resume normal activities.
Post-op Comfort

The eyes can feel uncomfortable or painful for about 2 days.
Post-op Stabilisation of Prescription

Stabilisation may take 3 months. Significant regression can occur, particularly with high prescriptions.
Post-op Corneal Haze

Some corneal haze is present for a few months.


LASEK (Laser Epithelial Keratomileusis)


LASEK is a type of laser vision surgery for the correction of refractive errors such as short-sightedness (myopia) and astigmatism.

LASEK was developed for use in cases where LASIK was considered unsuitable because the thickness or topography of the cornea was not adequate.

Both the LASEK and LASIK procedures involve creation of a corneal flap, followed by re-shaping of the cornea.  In LASEK, only the topmost (epithelial) layer of the cornea is used for the flap. In contrast, the LASIK procedure the flap is thicker.
Description of the procedure

The LASEK procedure takes about 15 minutes per eye:
  • The cornea is anaesthetised.
  • Anaesthetic drops are applied to the eye, and an eyelid holder is put in place to keep the eye from blinking.
  • The corneal epithelium layer is removed.
  • Eyedrops are applied to the corneal surface to help separate the epithelium layer from the corneal bed. The surgeon gently moves the top layer, or epithelium flap, to one side, thereby exposing the corneal bed.
  • The corneal bed is re-shaped by the laser.
  • The surgeon uses the laser to re-shape the corneal tissue immediately below the topmost layer (epithelium) of the cornea.  (This contrasts with the LASIK procedure in which deeper layers of corneal tissue are penetrated.)  The laser uses a cool ultraviolet light beam to precisely ablate, or vapourise, a pre-determined amount of corneal tissue for the required prescription of the eye.
  • The  corneal epithelium is placed back over the cornea.
  • The surgeon re-positions the epithelium layer to cover the corneal bed that was lasered.  A "band-aid" soft contact lens is applied to protect the eye while it is healing over the next few days.  Antibiotic and anti-inflammatory drops are also applied.
  • Both eyes can usually be treated on the same day.

Post-op Visual Recovery

Vision is blurry for about a week after surgery, but both eyes can be treated on the same day.
Post-op Comfort

The eyes can feel uncomfortable or painful for about 2 days.
Post-op Stabilisation of Prescription

Stabilisation takes about 2 months.
Post-op Corneal Haze

Some corneal haze is present for a few months but it does not usually affect the vision.