The following posts from the ROP list discuss opinions regarding the outcomes of laser and cryotherapy. The ROP list was moderated by Dr. Scott Richards until August, 2002. The list has closed now. For more information about lists of interest to people with visual impairments, please visit the email list index.
Date: January 20, 1999
From: Guido Bracke
Dear Susan,
we had a similar history. When our daughter (*19. Dec. 96, 27th GSA) was due for a surgery, I had a quick look at the relevant literature and got the impression that laser works better (less pain, less nearsightedness, better results vs. longer surgery) than cryotherapy. We asked for lazer but did not obtain (lack of experience?).
Later I had to realize that most ophthalmologists feel the same way. But they cite only the well known studies of the cryotherapy group which indeed show for the first time that a treatment lowers the risk of detachment if applied timely. Therefore cryotherapy was accepted for treatment of ROP generally.
There are a lot of minor studies indicating the lazer has better results for treating ROP.
Guido
Date: Wed, 20 Jan 1999 11:12:37 -0800 From: Scott Richards
"Are you aware of any studies or information on the success of lazer vs. chryotherapy in treating Stage 3 ROP. I find I have dealt really well with my son Daniel's eye condition but I still find I am having a hard time accepting that I wasn't given an option. He was rushed right from the eye clinic up for chryotherapy. Two Doctors have since told me that lazer works better."
There are some studies comparing cryo and laser, but they generally take the form of "before and after studies" (this is how we did with cryo, then we changed to laser, and this is how we're doing now) or comparisons with other results by other surgeons. Neither of these approaches really gives proof that laser is better than cryo, since there are a lot of potential confounding variables. The general impression from these studies is that laser works as well or better than cryo, with fewer side effects. To prove the superiority of laser would require a study in which patients are randomized to laser vs. cryo. That study will probably never be done, since most of us use laser now and have no interest in subjecting our patients to cryo any longer.
When I first got laser capability in 1992, I fully intended to randomize one eye of each patient to laser and the other to cryo to prove which was better. After two patients, it was obvious that the laser worked faster with less eyelid swelling and pain. The NICU nurses threatened to inflict bodily harm upon me if I ever did cryo again, so I chose the better part of valor and switched to laser.
The use of cryo for your child may have been determined by when the treatment was done and the availability of laser and the experience of the treating surgeon. For example, in 1992 when I started doing laser, some of the experts in my state felt I was doing dangerous experimental treatments, and that it was malpractice to not use the proven treatment of cryo. As it turned out, time has proven me right, but it could just as easily have proven me wrong. Medical opinion (like all scientific opinion) is constantly in flux. I would have been morally wrong to randomize patients or treat patients with cryo when I believed in my heart that laser was better; at the same time it would have been morally wrong for the other retina specialists to use laser if they felt it was unsafe.
Date: January 22, 1999
From: Clare Black
I came across the following references to cryo/lazer during one of my ROP searches on the net.