Lee T. Nordan, MD, presented a powerful case against hexagonal keratotomy at the American Society of Cataract and Refractive Surgery meeting in San Diego, Calif
"Hexagonal keratotomy does not work and should be condemned," he said in a prepared speech during a panel discussion.
"You can improve the uncorrected visual acuity, but the problem is all these patients have some degree of irregular astigmatism so you are reducing their best corrected vision," said Nordan. "I would ask you, is it a reasonable risk/benefit ratio to reduce people's final best corrected vision at the expense of better uncorrected vision?"
Nordan, who is an author and early investigator of refractive surgery has examined about 50 eyes that have undergone hexagonal keratotomy by other surgeons in Southern California. He has also performed hexagonal keratotomy
"I think Nordan is excited about eyes from the old procedures and I think he is comparing apples to oranges," J. Charles Casebeer, MD, told Refractive and Corneal Surgery. Casebeer is a well-known teacher of refractive surgical techniques, including hexagonal keratotomy, in private practice in Flagstaff Ariz.
"It is not fair," said Charles R. Moore, MD, "to compare the old Méndez procedure to the modern 'T' hexagonal keratotomy. The modifications that have been made from the original Méndez procedure are equivalent to the modifications that were made from the original Fyodorov procedure in radial keratotomy," he said.
But Nordan says "T" hexagonal keratotomy is hexagonal keratotomy. Tn my opinion, they have tried to create a new method of doing hexagonal like it is different and better - it is the same thing," he said in an interview. "The problem is you are isolating the central cornea and once you do that, it is free to wobble."
"That is not true," Moore said in an interview "It can't wobble if the hexagonal incisions are not connected anymore than it can wobble if you have 16 radial incisions in an eye."
Casebeer says he has had good results with "T" hexagonal keratotomy and so have about 10 other American surgeons. "When performed well, T' hexagonal keratotomy is really quite a controlled procedure with very good results," he said.
Early data from Casebeer's "T" hexagonal keratotomy study are better than the results of the PERK study and hexagonal keratotomy eyes tend to get more effect with time.
"We have the statistical data to show hexagonal keratotomy works quite well, is very safe, and probably has a very strong future," Casebeer said.
In his study, 74% of the 46 eyes were 20/40 or better uncorrected at 4 months. While irregular astigmatism wasn't specifically measured, Casebeer said all of the patients corrected to the same as or within one line of their preoperative visual acuity.
Gregory S. Baer, MD, of Rome, Ga also reports good results with "T" hexagonal keratotomy in more than 100 eyes done within the last year. "We have not had a single case of irregular astigmatism, not a single patient who could not be refracted to 20/20," he said.
"The healing and final visual rehabilitation of patients who have hexagonal keratotomy is longer than with radial keratotomy, but it still remains a very effective procedure," Baer said. "We have quite a number of happy patients in our practice who no longer have to wear hyperopic spectacles because of hexagonal keratotomy."
There are plenty of surgeons with other experiences. David M. Schneider, MD, of Cincinnati said there has been some induced astigmatism in almost every case he has seen and in the 15 cases he performed. He has only done one "T" hexagonal keratotomy.
"I do not like to do the procedure because I have found it to be certainly disappointing in results compared with radial keratotomy and astigmatic keratotomy," Schneider said in an interview. Although all of Schneider's patients have been happy with the results.
"T" hexagonal keratotomy is not exempt, according to W. Andrew Maxwell, MD. "I have seen a significant number of complications with all different hexagonal keratotomy procedures," he said. "I see unpredictability in the results, I see a significant regression in the results, I see irregular astigmatism in the patients, and I see wound healing."
Casebeer said he has never seen a hexagonal keratotomy regress.
"There are some very important steps a surgeon should follow when performing hexagonal keratotomy," Moore said. "First, the pupil should be constricted with pilocarpine and second, a circular optical zone marker with brilliant green should be placed on the cornea before a hexagonal marker is placed."
"If there is an excessive variance in the optical diameter of the hexagonal marker versus the circular marker, you know the circular marker is the more accurate of the two and that ehminates putting the "T" incisions in the wrong place and possibly inducing a large cylinder or not achieving expected correction," Moore said.
"Squaring up both ends of the hexagonal incisions with an enhancement blade is another key factor in preventing astigmatism and standardizing results," he said.
The final important step is to avoid placing all six "T" marks on the cornea at one time. "You can lose your positioning as the cornea starts drying out and that is why all these bad results with hexagonal keratotomy came out," Moore said. He suggested placing three marks at a time.
"Hexagonal keratotomy is not a procedure I recommend to patients," said Schneider in an interview. "The cases I have done in the last year have been done because the patients were insistent on it or because they knew a friend who had had it done and were quite willing to accept the risk/benefit ratio as it was presented to them."
Surgeons, said Nordan, have the responsibility to protect patients from themselves. "The patient has the right to ask for anything they want, but you have a moral, ethical, and professional obligation not to do an operation that you know to be defective," Nordan said.
"He is right, we should not go around doing unsafe procedures on people," Casebeer said. "But my point is that this is not an unsafe procedure and we can prove it."
"I certainly believe that hexagonal keratotomy is defective, since it lowers the patient's best corrected visual acuity," Nordan said. "It surprises me that surgeons performing hexagonal keratotomy have not witnessed the same phenomenon to a significant degree."
In his condemnation of hexagonal keratotomy, Nordan used the example: a surgeon would never insert an intraocular lens that would only allow for best corrected vision of 20/40.
"If somebody subscribed totally to this idea that it must be completely iron-clad, we wouldn't be doing any of these things - there is a 3% or 4% incidence of very significant complications in phacoemulsification," Casebeer said.
Schneider said he cannot see anything unethical about offering hexagonal keratotomy with the caveat that they can't guarantee the results; there may be some loss of best corrected vision and there will be some astigmatism.
"There seems to be a double standard developing - one for refractive surgery and one for IOL surgery - that is incorrect," Nordan said. "Lets keep these standards consistent. Excellence is excellence and if we don't have something that works as well as it should, let's call it like it is."
Hexagonal keratotomy is not for everyone and that may be what is causing some of the problems, Casebeer said.
"There are definitely some people out there who probably shouldn't be doing hexagonal keratotomy," he said. "They probably don't do it well, don't understand it, and are making some eyes that aren't real good and those eyes are probably getting a lot of attention."
"Casebeer claims that the special way he teaches people to make these cuts makes it a better operation somehow in his hands. I am afraid I just don't believe that," Nordan said.
Hexagonal keratotomy should be a personal choice; not everyone should be encouraged to do the procedure, Schneider said.
"Apparently some people are able to successfully do things that others are not," Schneider said. "Hexagonal keratotomy is one of the things that seems to be universally extremely difficult to achieve without inducing astigmatic problems."
Performing hexagonal keratotomy over radial keratotomy has also created considerable controversy. Nordan, in his speech, called it "hamburger."
"That is ludicrous," said Moore. "I have been doing hexagonal keratotomy over radial keratotomy for many years and they are the best results of any hexagonal keratotomy you see."
Casebeer feels it should be performed in limited circumstances.
"There is no question that hexagonal keratotomy over over-corrected radial keratotomy, except in very unusual cases, can lead to disaster," Casebeer said. "I have no argument with that, but I'm not a big believer in making such a blanket statement, as long as the radial keratotomy is a year postoperative or more."