Laser Eye Sugery
Glasses and their Alternatives
Laser Eye Surgery is a relatively new process. For hundreds of years glasses have enabled people to see clearly. In recent decades contact lenses have been used successfully by millions of people. Many people are happy with these two methods of managing their visual needs, and don’t need to consider laser surgery to their eyes. Others however find strong glasses produce distortion, or they may feel uncomfortable in glasses. Other patients find contact lenses troublesome or intolerable due to sensitivities or allergies. It is these groups of patients who consider that surgical treatment of their refractive errors may be desirable.
In the 1970′s and 1980′s radial keratotomy (“the Russian Operation”) received some public attention. It worked by cutting spoke like incisions into the edge of the cornea in order to flatten it centrally.
Cataract surgery can also eliminate short-sightedness by replacing the eye’s natural lens with a weaker implant lens. This procedure is usually reserved for patients with cataracts, however a similar technique called Clear Lens Extraction can be used to achieve similar results in suitable patients. As the procedure is more invasive than Excimer laser there are small risks of retinal detachments and infection following surgery within the eyeball.
Other refractive surgical procedures that are developing and practiced in much fewer numbers than Excimer Laser include phacic implant lenses, intrastromal corneal rings, and radio frequency tightening of the cornea.
How Does the Excimer Laser Work?
Excimer laser eye surgery has revolutionised the treatment of shortsightedness , longsightedness and astigmatism since the early 1990′s.
In 1983 scientists first used the Excimer Laser to engrave plastic, and an American ophthalmologist named Dr Steve Trokel later realised that the laser could be used to re-shape the cornea, thus overcoming the need for some patients to need glasses.
The name originally given to the correction of refractive errors with laser applications to the surface of the eye is Photorefractive Keratectomy (PRK).Excimer laser works by sending brief pulses of ultraviolet light onto the cornea. The light’s energy breaks apart molecules on the very surface of the cornea. Each pulse removes one quarter of one micron of tissue (it would take four thousand pulses of laser to pass through one millimetre of tissue). The laser gradually sculpts the cornea to the desired shape.
“this microscopic picture of a human hair with ridges cut into it with a Excimer laser demonstrates the precision of the laser in removing minute amounts of tissue”
The removal of 10 microns of corneal tissue corrects one dioptre of myopia. This is an extremely small change to the corneal thickness. (As a comparison, a human hair is 50 to 100 microns thick).
Since the mid 1990′s the excimer laser has been used to reshape the cornea after a flap of tissue is cut, this is called LASIK.
What is LASIK?
The flap is very thin (110-120 microns). Dr Cherny now uses the Intralase system to create the flap without the need for a surgical blade. He believes this is a safe and more controlled technology. Intralase is a more expensive technology than the blade LASIK, but Dr Cherny believes it provides a safer and more accurate result.
The flap is still attached to the eye at its edge, so that it can be folded back into position after the laser has been applied. Overnight the flap secures itself by healing across the surface cells at the edge of the flap. Patients can return to most normal activities the next day and the procedure has very little discomfort for almost all patients.
|The Intralase laser creates microscopic bubbles to form the flap.||After the corneal flap is formed the laser is delivered to the cornea|
What are the Advantages of LASIK Compared to PRK Laser Treatment?
The short-term advantage for the patient is that the eye is less painful after LASIK than after PRK, the visual recovery is faster and eye drops are usually only needed for one week.
The long term advantages of LASIK include reduced risk of scarring and increased stability of the vision for higher levels of myopia. Stable vision returns faster after LASIK, and eye drops are usually only needed for one week.
The long-term disadvantages of LASIK include potential complications relating to the creation or healing of the flap.
The flap may be incorrectly formed, or material (dust, germs, and cells) can theoretically become trapped under the flap.
Lasik is slightly more expensive because it requires additional technology to create the flap.
A large proportion of excimer laser patients are now treated with Lasik rather than PRK.
Dr Cherny can discuss with each patient the relative advantages and disadvantages of LASIK in their individual situation.
“I have been told I should have PRK or ASLA”…
A WORD OF CAUTION:
Patients should be aware that not all centres performing laser eye surgery have equipment for Lasik or Intralase. Sometimes the terms ” Blade-Free” and “Flap” are used in reference to PRK (ASLA), but this is NOT Lasik .
Dr Cherny cautions patients to ask any centre offering them surface treatment (PRK or ASLA) to clarify if that is the ONLY laser option available at the centre. You might want to ask …. “Do you offer Intralase and how many Lasik treatments were done here in the last year”.
We believe many patients are not aware that some centres do not have the technology to deliver Lasik , one of the most commonly performed and respected treatments internationally.
Many patients also prefer LASIK because of the increased speed of healing, rapid return to normal activities, and almost total absence of pain.