This is a personal ophthalmic web site run by Dr Stephen J Doyle BSc, MRCOphth for the benefit of patients and fellow professionals.
It is mainly concerned with refractive laser eye surgery for the correction of short sight (myopia), long sight (hyperopia) and astigmatism (eye shaped like a rugby ball).
The two popular modalities of this are:-
PRK (Photorefractive Keratectomy)
This was the original surface laser technique. This is where the excimer laser (an ultraviolet laser at 198nm) is applied directly onto the eye under the epithelium (top layer of the cornea). This is a "no knife" operation. It is mostly used for myopes of -8 Dioptres or less and for hyperopes of up to +2 Dioptres.
The latest variation of PRK is called LASEK (Laser assisted epithelial keratomileusis - epithelium taken off with alcohol) and EPI-LASIK (epithelium taken off with a machine)
This is not quite as quick and pain free postoperatively as LASIK but there is not the (slight) risk of making a flap. It can be used from about +4 to -8 Dioptres i.e. the same range as LASIK.
LASIK (Laser assisted in situ keratomileusis)
So called "flap and zap". In this a thin flap from the front of the eye is made with a special machine called a microkeratome and the laser is applied under the flap. The flap can also be cut with an femtosecond infrared laser. Results and safety profiles of mechanical and femtosecond flaps are very similar. LASIK can treat up to about 8 Dioptres of short sight and 4 Dioptres of long sight.
- Cornea flattening for myopia Cornea flattening for myopia
- LASIK LASIK
- Human hair cut by excimer laser Human hair cut by excimer laser
If you are outside these ranges, then you may be more suitable for intraocular lens surgery. There are many good ophthalmic surgeons who do this, including my colleague Chris Heaven whose website is at www.lens-exchange.co.uk
With LASEK The eye hurts for about 2 hours after the surgery but there is little to go wrong. LASIK is a nicer surgical experience for the patient as there is no pain and there is good sight from a few hours after the operation. 90% of complications with LASIK are flap complications. The end results are similar with both operations. With higher prescriptions LASEK takes longer for good vision than lower ones.
LASIK gets there faster with no pain whereas LASEK/PRK hurts a bit and takes about 1 week before there is clear vision, although there is useful vision from right after the operation. I have done up to about 120 eyes a month and had one or two eyes with complications for both LASIK and LASEK each year, so in absolute terms the risks seem to be about the same. The slight risk of "haze", with LASEK has been largely removed due to the prophylactic use of mitomycin-c. "Haze" is a deposition of glycosoaminoglycans or "GAG's" and is maximal at 6 weeks post op. (see LASEK complications)
Wavefront technology has been grossly oversold on the high street. As of March 2013, thin flap LASIK or SBK (Sub Bowman's Keratomileusis ) is the way to go, either using a machanical microkeratome or a femtosecond laser. Topography guided treatments can give better results than wavefront treatments.
The Royal College of Ophthalmology guidelines for refractive surgery (March 2006) are worth reading - Click Here