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What is PRK (Photorefractive Keratectomy)?


What is PRK (Photorefractive Keratectomy)?

If you have been considering laser eye surgery, the term ‘PRK’ would most likely have come up in your research.

Short for photorefractive keratotomy, this was the very first laser eye surgery procedure (pre LASIK). It was first performed by Dr Theo Seiler in 1987 but not offered commercially until the 1990s.

You may know it by one of a number of other names – ASLA (advanced surface laser ablation), LASEK, M-LASEK or ASL LASEK.

Today, most ophthalmologists call it ASLA or PRK. At Vision Eye Institute, we refer to the procedure as ASLA.

How well does PRK work?

Historically, this form of vision correction worked very well (and continues to work well). Pre-LASIK, if you did not wish to depend on contact lenses or glasses in order to see properly, photorefractive keratectomy was the surgical procedure exclusively performed by ophthalmologists to correct vision abnormalities such as nearsightedness (myopia) or farsightedness (hyperopia).

Any laser eye surgery procedure is designed to alter the shape of the cornea (the clear window on the front of the eye) in order to correct vision to the point that you will not need to wear corrective lenses.

How does it work?

This vision correction procedure has been performed successfully for many years now. It involves several steps.

  • Removal of the top layer of the cornea. The surgeon needs access to the stromal layer of the cornea. However, there is another layer on top of it which needs to be removed. The surgeon usually does this by putting a few drops of a liquid on the top layer of the cornea and gently removing the loosened cells. This exposes the stroma, which is where the reshaping of the cornea must take place in order to correct vision.
  • Reshaping. An excimer laser is used to re-shape the stroma to the exact shape that is required for the particular patient. This is accurate to one micron, which is one thousandth of a millimetre.
  • Protection. After surgery, a bandage contact lens is placed on the eye, which will be removed by the surgeon in three to five days after the eye has naturally regenerated the thin layer of superficial cells.

Vision may fluctuate for around four weeks, but once this settled, ASLA will provide the same visual results as LASIK.

What are the benefits of this form of vision correction?

Whilst LASIK or SMILE® are the procedures of choice for most people due to a faster and more comfortable recovery, ASLA is often recommended for people who have corneas that are not suitable for the flap that is necessary for LASIK.

There are benefits to this form of vision correction surgery, including a lower incidence of ocular dryness (dry eye) that may happen with other procedures.

Why does it take longer to recover from PRK?

One of the down sides of PRK is that it takes longer to recover than LASIK. As the initial days after the procedure can be uncomfortable, patients are provided oral and topical pain management in order to keep them as comfortable as possible. The vision is functional within a number of days and these patients will be able to return to most normal activities within one week.

If you are considering laser eye surgery and do not qualify for LASIK, rest assured that the ASLA/PRK procedure has been performed successfully on thousands of people since 1991 in Australia. There is no doubt that the long-term benefits outweigh the short-term discomfort.

Your laser eye surgeon will be able to assist in answering any questions you may have about your expected recovery.

SMILE® is a registered trademark of Carl Zeiss Meditec

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