Using laser to correct sight. Essex optometrist Terence Mendoza discusses potential benefits and problems

Laser Eye Surgery

Surgery for the correction of vision defects (short-sightedness and long-sightedness) has been around for a few years.

Surgery on the cornea, the transparent front surface of the eye, was pioneered in Russia where a sliver of razor blade (yes, really!) or diamond-tipped scalpel was used to make a series of radial cuts through the outer layers of the cornea.

The cuts weakened the cornea to the extent that the pressure within the eye distorted the area of weakness, hopefully in a controlled manner, governed by the number and depth of the cuts. As you can imagine this procedure was not totally successful in all cases with a variety of complications, ranging from hazy, distorted vision to the occasional punctured eyeball.

Technology for the correction of vision has now moved on. For a long time the laser had been used in eye surgery to seal around leaky retinal blood vessels in diabetes. Retinal surgery relies on the frequency of the laser light beam allowing it to travel unhindered through the cornea, with its energy being absorbed by the retinal layers.

A different type of laser has been developed in which the light energy will be absorbed by the corneal tissue itself. The topmost layers of the cornea are being continually regenerated, so for a permanent correction of refractive error the surgery is carried out on the lower layers. In the early days of laser eye surgery correction the top layers of the cornea were scraped off using a scalpel, prior to using the laser to reshape the corneal profile. Unsurprisingly until the tissues regenerated the eyes were very sore indeed!

These days a 'flap and zap' technique has been developed. The topmost layer of the cornea is carefully peeled back (under anaesthetic!), and the laser used to reshape the base layers beneath, after which the corneal flap returned to its original position. The advantage of this system is that there is much less discomfort after the procedure.

Who is suitable for laser eye surgery...

You should be adult and your spectacle correction should have been stable for at least two years. If you only need a correction for reading you will not be suitable for laser refractive surgery.

If you are over forty and shortsighted you may be used to taking your spectacles off for reading, or may have multifocals or bifocals. Be aware that correcting you for distance vision is likely to mean you will need to rely on reading spectacles once the surgery has been done.

Are there complications with laser sight correction?

Just like any surgery there are risks involved. One survey showed a 'satisfaction rate' of 80% meaning that one in five people were not totally happy with the end result.

All reputable eye surgeons will advise you of potential complications. They will also expect you to sign a disclaimer in case things don't work out as well as you would expect. Many will advise that you may still need a mild prescription for critical visual tasks like night driving.

Some experience 'haze' at night, when the larger pupil area can pick up the border between the operated area and the margin where the laser has not reached (the laser does not go out to the margin of the cornea as this would weaken the cornea too much).

Do ask for the credentials of the person who would be carrying out this surgery. In some areas this may be a general medical practitioner aided by technical staff. Your safest option will be a qualified eye surgeon.

Where can I find out more about potential laser eye surgery problems?

LasicDisaster - an American site which pulls no punches...
"I have built this website because I want the public to know what I have learned about LASIK and other types of refractive surgery, after I had it done. I am gravely concerned about this area of medicine in which patients are SOLD a serious and possibly vision-robbing procedure as though it's a haircut..."

SurgicalEyes.org - Latest news about Lasik, Lasik Eye surgery, and other complications from vision correction.

Are there alternatives to laser sight correction?

Similar advances in contact lenses now allows multifocal lens fitting, doing away for the need for both distance and reading lenses. The range of corrections that can be fitted with these lenses is expanding all the time, so it is worth discussing them with your optometrist as an alternative option to surgery.