a special program of the National Emergency Medicine Association (NEMA)
Week: 549.3 Guest: Dr. Richard Grutzmacher, Ophthalmologist, Sacramento, CA Topic: Photorefractive Keratectomy, PRK, corrective laser eye surgery Producer/Host: Steve Girard
NEMA: Today, we're with Dr. Richard Grutzmacher, a Sacramento ophhamologist who uses a new procedure to help patients obtain good vision without lenses.
GRUTZMACHER: PRK, or photorefractive keratectomy, is where a very small, superficial layer of the cornea is, in effect, shaved away with an excimer laser ...thereby flattening the front corneal surface... that allows correction of the nearsightedness. Radial keratotomy causes a depression, or a flattening of the cornea by the effect of peripheral incisions...mid-peripheral and peripheral incisions in the cornea had a flattening effect on the central part of the cornea. The advantages of the excimer laser over radial keratotomy are significant. Perhaps the most significant advantage is the stability that the cornea has, about 90 to 95% of the cornea is left intact, a result that doesn't fluctuate, for example, morning versus evening vision...and tends to be stable over a period of time, once the original healing process is done.
NEMA: Who are the prime candidates for PRK?
GRUTZMACHER: It's a group of patients who have low to moderate nearsightedness, or myopia. on the low end, between one and one and a half diopters of myopia...that would be a patient that would see, for example, about 21 hundred to 22 hundred uncorrected...up to seven diopters of myopia. And that range really encompasses about 90% of the nearsighted population.
NEMA: Are there some possible complications... or drawbacks in the PRK procedure...?
GRUTZMACHER: Well, again....the results, for example, in people that are lowly myopic, are better generally, than people who are in the higher range. And the problems that generally occur with PRK are problems where you either achieve an under correction, meaning you didn't get the full effect you desired, the likelihood of that is small, but definite. The possibility of an over correction is more significant, where you get more effect than you desired. And that could result in a residual farsightedness, which we try to avoid at all costs. If you're under corrected, you can be retreated...so that is not so much of a problem. Fortunately, the likelihood of being significantly over corrected is small, and by small I mean certainly less than 5 %. There are other potential problems with PRK, say in comparison with radial keratotomy. They include pain during the first two or three days, usually not too severe...but can be severe in some patients. And then the second problem is the visual recovery with PRK typically is not rapid. And by that I mean it takes generally a few weeks, sometimes even a couple months for the vision to achieve what a patient would recognize as being clear vision.
NEMA: Who shouldn't consider PRK...?
GRUTZMACHER: Some patients that are more highly nearsighted, or particularly if they have a significant astigmatism, may have other problems with the eye that may even be unrecognized. One corneal condition is termed keraticonis, which can result in a nearsightedness, in astigmatism. Also, people can't have medical conditions that involve the eye, for example, people with severe dry eyes, particularly associated with arthritic conditions like rheumatoid arthritis, or a arthritic condition called lupus arithemitosis.
NEMA: What is coming as the next big thing' in this laser surgery field?
GRUTZMACHER: There's a newer procedure we haven't discussed yet called Lasik, and that is looking to be a much better procedure for people with higher degrees of nearsightedness. It allows for a much more rapid return in sight, much less pain...and I think in the higher degrees of correction, better result. And in fact, we've been performing that procedure here now for the past few months.
NEMA: Dr. Richard Grutzmacher practices laser surgery in Sacramento, California. I'm Steve Girard.