As Far as the Eye Can See

Created on 02nd March 2009

If you've had enough of groping around for your glasses in the morning, then laser eye surgery may be for you. Jenny Pitt takes a look at the benefits

If you have to constantly wear contact lenses and glasses, then you're no doubt intrigued by laser eye surgery. It's now so advanced that both eyes can be treated in under an hour and in most cases people have restored vision within 48 hours. Laser eye surgery alters the shape of your cornea (at the front of your eye) so that the images fall correctly on to the retina in the back of your eye to give you a clear image.

How does it work?

There are two main types of surgery: Lasik (laser assisted in-situ keratomileusis) and Lasek (laser assisted epithelial keratomileusis). Lasik is the most common procedure for around 93 per cent of patients, where a flap is cut in the cornea. Lasek is used for 7 per cent of patients, where the surface of the eye (the epithelium) is moved aside.

"With some people their corneas are too thin to cut a flap, so Lasek is used and similarly for people who participate in sports and are more likely to suffer eye injuries," explains Professor David Gartry, consultant ophthalmic surgeon and director of refractive surgery at Moorfields Eye Hospital.

With Lasik a femtosecond laser creates the corneal flap, while an excimer laser corrects the cornea bed. The flap is then replaced and natural forces encourage it to heal immediately. With Lasek, the top surface of the eye is moved aside as the laser works, after which it's repositioned. This procedure causes discomfort and takes longer to heal than Lasik.

"With Lasek treatment, the first couple of days are very sore. Patients will have to wear special contact lenses and have anaesthetic drops. With Lasik, the corneal nerves are undamaged as the flap is cut and the front of the eye isn't scratched, so the healing process is much quicker," explains Professor Gartry.

Before surgery, you will have undergone a rigorous consultation to establish your prescription and your expectations. Anaesthetic drops will be placed in each eye and you will be positioned under the laser. The corneal flap will be cut, then the excimer laser will reshape the cornea bed. The actual laser work takes seconds and within 20 minutes both eyes are finished.

Choosing a surgeon

It goes without saying that a surgeon should be fully qualified with hundreds of refractive procedures under their belt.

"Get to know your surgeon," suggests Professor Gartry. "Ask about their success and complication rates. Bear in mind that refractive surgeons don't have to be consultants but they should have undergone four years' specialist training for official accreditation," he says.

The General Medical Council's website, www.gmc-uk.org, holds lists of specialist registrars, while the Royal College of Ophthalmology's website, www.rcophth.ac.uk, has patient information. It has also, this year, developed an independent certificate in refractive surgery for eye surgeons.

"The aim is to provide the public, and the industry, with the confidence of a consistent basic level of training, knowledge and understanding," says Jeremy Prydal, chairman of the college's Laser Refractive Surgery Committee.

What the Experts Say

Mr Pillai, medical director at Advance Vision Care, was one of the first consultants in this country to carry out bilateral LASIK (both eyes are treated in the same procedure) and is now widely regarded as one of the UK's most experienced refractive surgeons.

Can you explain the level of discomfort a patient may experience?

The procedure itself is painfree. With Lasik the patient may experience a very light pressure sensation at times during the five minute procedure and some mild discomfort, irritation or light sensitivity for one or two hours after  the procedure. Lasek takes longer to heal (4-7 days) and visual recovery to driving standard might take up to a week. A special contact lens is used for four days (Lasek) and sometimes there might be discomfort for a few  days. The results will be similar for both the procedures even though the recovery period is different.

What questions should you ask when choosing a clinic and surgeon?

Ideally, choose a clinic where:

• The surgeon should be experienced, doing laser refractive surgery full time and have several years of experience in eye surgery in the NHS and preferably a cornea fellowship (ideal). The absolute minimum will be six months of formal training in laser surgery, with a minimum of 100 supervised procedures and a minimum of 250 professionally.
• The clinic provides the following: a dilated pupil exam; dry eye evaluation; infrared pupil size measurement; front and back surface corneal topography; Ultrasound pachymetry to measure corneal thickness, wave front analysis and comprehensive follow-ups at intervals for one year.
• It is ideal for the patient to have a consultation with the surgeon and the operating surgeon. who makes the surgical plan, oversees the pre- and post-operative care all times.
• The clinic continually monitors its success rate for individual surgeons and can provide you with a table of results. (At least 75 per cent of cases should result in 20/20 vision.)
• The enhancement rate for short-sighted patients varies between 2-5 per cent, and the enhancement rate for long-sighted patients should be about 15-20 per cent.
• The surgeon performs at least 500 procedures per year.
• The patient should not be motivated by tempting financial offers and do their research diligently before making a decision about the clinic and the surgeon.