Laser Eye Surgery Articles                

Excimer Laser Procedures (LASIK, PRK, PARK)..24 Aug 09

If you are considering laser eye correction, it can help if you have a basic understanding of the technical procedures involved in the surgery, as this can help to best inform your decision by giving you a clear understanding about exactly what the surgeons will be doing to your eyes.

For the same reason, it can also help you feel more relaxed about the procedure, avoiding anything unexpected once you're actually going ahead.

PRK surgery is short for Photo Refractive Keratectomy. PRK will often be recommended for patients who have conditions such as dry eyes, or a thin, scarred or atrophic cornea, for which the alternative LASIK surgery is not recommended.

This procedure uses an excimer laser to reshape the cornea of your eye.

It was the most common form of Excimer Laser Procedure from its introduction in the 1980s until the mid 1990s when LASIK was given medical approval.

The surface cells, called the epithelium, are taken from the cornea manually, before a laser reshapes the cornea by vaporising it, having been programmed according to your eye exam results.

 The laser will usually be very precisely programmed to track any movements in your eye, as well as being monitored by the surgeon, to ensure the correct area is treated. You will watch a target light through the procedure, rather than the actual laser and you will hear clicks as the laser operates. You may notice a slight 'singed' smell caused by the vaporised cells.

The surgery can be done in one day, taking literally minutes for most procedures and should also be painless, with only local anaesthetic (in the form of eye drops) needed.

To minimise the chances of cross contamination if one eye becomes infected and to allow the surgeons to assess the first eye, each one will usually be done on a separate day, usually at least a week apart.

PARK surgery is a variation of PRK surgery for those with astigmatism - PARK standing for Photo-Astigmatic Refractive Keratectomy.

This involves removing cells using an excimer laser as with PRK, but it removes more cells on one part of the eye than another, to help even out the astigmatism.

LASIK differs in that the procedure involves creating a flap of the outer cornea (rather than vaporising it as with PRK), prior to the laser reshaping of the inner cornea and this procedure is often favoured where patients have higher levels of myopia.

LASIK usually has a higher recovery time than PRK and has less associated discomfort, despite the incision required. Local anaesthetic is applied, before an eyelid holder and suction ring are applied to the eye, to keep it open and to hold the eyeball in place.

A sharp instrument called a microkeratome cuts a crescent on the surface of the cornea to create the flap, although no pain should be felt. This flap is lifted to allow the laser to reshape the lower cornea.

The flap is put back in place once this is done and begins healing immediately.

PRK, PARK and LASIK all have their own risks and their own aftercare issues to consider, as well as there being issues common to all forms of laser eye surgery, which your physician will be able to discuss.