A recent study on the effects of the excimer laser on corneal tissue: Joshua Ben-num (Tzriffin, Israel)
Photorefractive Keractectomy and Laser in situ Keratomileusis: A Word From the Devil's Advocate.
Archives of Ophthalmol. Vol.118, Dec.2000, p.1706-1707.
At a time when there has been a significant improvement in the technology of treatment of refractive errors by laser in-situ keratomileusis (LASIK), this author has issued a very timely warning both to patients undergoing the procedure and to the people performing LASIK.
The procedure involves a laser beam at 193nm that evaporates part of the cornea, breaking cells and molecules to create the smooth corneal surface necessary for best optical results.
The creation of free radicals, is an inseparable part of the cornea reshaping process.
Both photorefractive keratectomy (PRK) and LASIK are known to cause keratocyte apoptosis in the cornea of laboratory animals and hence, though there is no short-term damage, long-term damage must be considered.
These procedures are also known to have caused biochemical and ultrastructural modifications in the lens, both of which are markers of cataractogenesis. The vitreous base, located just posterior to the lens may be affected by the same process that affects the cornea, anterior chamber and the lens. Free radicals damage the vitreous collagen, leading to vitreous liquefaction. They have also been shown to promote tumours.
PRK might initiate a cascade of events leading to slowly developing abnormalities of the cornea, lens, vitreous retina and choroid.
On one hand there is a marked increase in the popularity of LASIK promulgated by massive advertisement. Hence there is an urgent need for intensive research into the potential threats to ocular function caused by LASIK which may occur in patients decades after the initial procedure, slowly but almost surely.
Fatal Focus, a novel by Jonathan Maxx
The long-term effects of photorefractive eye surgery remain unknown. It’s clear that LASIK and other forms of eye surgery using the excimer laser are not as promised –“quick, painless and effective.” And we know that some people will never recover their vision, lost as a result of this next “miracle of modern medicine.” If, after ten years, we look back and see that laser eye surgery was simply a mistake, a risk-prone procedure imprudently pushed for the sake of the money to be made, it will indeed be a sad day for the medical profession. However, might there be an even greater evil lurking?
The excimer laser is a source of ultraviolet radiation, a form of energy closely associated with mutagenicity and carcinogenesis. For more than a decade, researchers have questioned whether this laser-generated radiation might trigger the growth of cancer in human tissues. A clear-cut answer has never been obtained.
While some researchers proclaim that the 193 nanometer argon-fluorine laser does not produce radiation in the known mutagenic wavelengths, (the blanket statement that even the primary radiation from the 193 nm laser is entirely safe is not presently accepted by all researchers), and therefore cannot be mutagenic, others have pointed out that the interaction of human tissues with laser radiation causes the radiation to change— changing its wavelength into the mutagenic ranges. What is the effect of this “secondary radiation?”
Consider the facts. Last year over 800,000 people underwent laser refractive eye surgery. In each instance the patient’s eye was irradiated with ultraviolet radiation. The secondary radiation produced during the photoablative process has the potential of scattering into the surrounding tissues. Since this secondary radiation falls into the known mutagenic ranges, these tissues may be genetically altered by this radiation, and some cells may become malignant. If only one-half of one percent of those 800,000 patients sustained DNA damage—that may be as many as four thousand people whose lives are NOW threatened by the onset of cancer.
There is practically no research being conducted into the long-term effects of laser eye surgery. Is there a lack of interest? Or, is it more a matter of the ostrich hiding its head in the sand? At this time more than 1 million people have been prompted to undergo laser eye surgery. If laser radiation triggers cancer it may become apparent soon. (Alternatively, the histopathological effects may mimic the effects of x-ray exposure, and become apparent after several years.) However, determining the existence of a correlation between photorefractive surgery and cancer depends entirely on whether or not researchers are looking for it.
Jonathan Maxx is the author of the fictional novel entitled, “FATAL FOCUS”, which follows the lives of two physicians attempting to publish research about the potential deadly effects of the excimer laser. A portion of the proceeds from this book will go to long-term research concerning laser eye surgery.
Available by e-mailing the author, Jonathan Maxx.
Bibliography
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