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Advanced Surface Treatment (PRK)

 

Photorefractive Keratectomy (PRK) is the original excimer eye laser technique. Dr David Kent was the first surgeon to perform PRK in the South Island in 1997.

PRK is recommended as an alternative to LASIK or SMILE eye laser for people with a thin cornea; a cornea that does not have a symmetrical shape; or anyone whose lifestyle places them at high risk of an eye injury.

Advanced Surface Treatment is also the chosen procedure for re-treatment to anyone who had LASIK many years ago, and to correct under corrections after SMILE eye laser.

Patients with the very early stages of keratoconus  and a low correction can have PRK combined with corneal collagen cross linking.

The evolution of PRK laser eye surgery has continued since the 1990s with large improvements in excimer laser technology such multi-dimensional eye tracking, customised treatments, the use of Mitomycin-C (MMC) and much better management of post operative discomfort. Advanced Surface Laser Ablation is the new term to refer PRK to acknowledge the newer, superior delivery of PRK.

At the end of the procedure Dr Kent will place a soft therapeutic contact lens on the eye to help to reduce post operative discomfort.

We give you Voltaren Ophtha eye drops for pain relief that are like “aspirin for the eye” . This will give good pain relief for 4-6 hours.

COMMON QUESTIONS

FAQ about Advanced Surface Treatment (PRK)

Pros and cons of having Photorefractive Keratectomy (PRK)?

PRK is a good option for people who are not suitable for HD LASIK® due to having a thin cornea; a cornea that does not have a symmetrical shape; or anyone at high risk of eye injury. Advantages of Photorefractive Keratectomy (PRK)
  • Leaves more corneal tissue untouched, making it safer if the cornea is thin.
  • Almost no long-term risk of developing keratectasia (bulging cornea).
  • Proven to have no visually significant complications after 10 years of follow up.
  • None of the possible flap-related complications of LASIK.
  • The structural strength of the cornea is not significantly altered.
Disadvantages of Photorefractive Keratectomy (PRK)
  • Can be painful for 2-3 days afterwards (although this is much less of a problem that it was in the past)
  • May take 7-10 days to achieve clear vision, requiring up to a week off work.
  • Some people develop a pronounced healing response in the cornea leading to deposition of new tissue. This causes corneal haze.
  • Not very predictable results in higher myopia or high astigmatism.

What happens if I move my eye?

Active 7D eye tracking The 7D active eye tracker impresses through a number of benefits: Apart from the linear movements (1st and 2nd dimensions) it compensates rolling movements of the eye (3rd and 4th dimensions). Compensation of the eye’s rotation around its optical axis is achieved with the static and dynamic Advanced Cyclotorsion Control (5th dimension). Movements along the z-axis (sixth dimension) are actively compensated by means of the z-tracking. Automatic pupil size control and pupil centroid shift compensation ensure additional safety. Latency-Free Tracking in the 7th dimension The new, ground-breaking Latency-Free Tracking considers the time factor, i.e. the 7th dimension. Latency-Free Tracking compensates for eye movements that occur in the period between acquisition of the eyetracker image and triggering of the subsequent laser pulses

Possible PRK complications

While modern PRK surgery is very effective, it is still possible to be under or over corrected. Other possible complications include corneal haze, dry eye and problems with healing of the front cell layer of the cornea.

Why do we use Mitomycin-C (MMC)?

The use of Mitomycin-C (MMC) has also improved PRK results by reducing the chance of over aggressive healing responses. It has been in use for 20-25 years now with no reports of any adverse consequences. It has to be made up fresh by a compounding pharmacist. A round sponge is soaked in the MMC solution and placed onto the cornea for 12 to 60 seconds immediately after the excimer laser treatment. It works by both inhibiting cell activity and reducing the number of activated cells in the healing cornea. With all PRK procedures we irrigate the cornea with chilled balance salt both to wash away the MMC but also give the corneal nerves a “cold shock” and hence give pain relief for up to 48 hours
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