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Limited macular translocation offers greater visual improvement than PDT
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KOLOA, Hawaii – A comparison of limited macular translocation surgery to photodynamic therapy (PDT) in cases of choroidal neovascularization (CNV) indicates that there are fewer complications with photodynamic therapy, but also probably less chance for visual improvement, according to Andrew P. Schachat, MD.
Dr. Schachat, the Karl Hagen professor of ophthalmology at the Johns Hopkins University Wilmer Eye Institute, spoke about the current status of limited macular translocation surgery here at Retina 2001, presented with Hawaii 2001, the Royal Hawaiian Eye Meeting, sponsored by Ocular Surgery News in conjunction with the New England Eye Center. He said preliminary data indicate that twice as many CNV patients improve following limited macular translocation as do those following PDT.
“The chance to achieve driving vision, which is one of the main things patients are asking about, is real with macular translocation,” he said.
The goal of limited macular translocation (MT) surgery, which was developed by Eugene DeJuan, MD, of Johns Hopkins University, is to establish a normal subretinal space. The surgery involves “making a partial thickness incision in the sclera and then pulling up some sutures so you can either pull the sclera up or down, and therefore the retina, when it reattaches, moves the opposite way,” Dr. Schachat said.
Macular translocation’s role
The growing popularity of PDT has prompted researchers to re-evaluate MT and pinpoint exactly what role it might play in the treatment of retinal disease.
“Macular translocation was probably more exciting a year or two ago, before photodynamic therapy, so we have regrouped, re-thought about it and tried to decide really what the role for translocation is,” Dr. Schachat said.
This led to a small, randomized trial comparing MT to PDT. So far, patients are being enrolled in Baltimore, Cleveland, St. Louis and Lexington, Ky.
“We were optimistic enough about all of this that we thought it made sense to organize a clinical trial, and that trial is just getting started. The entry criteria are basically predominantly classic CNV from AMD, and the randomization is PDT versus translocation. We will try to see whether the chance for improvement is doubled with an acceptable complication spectrum,” Dr. Schachat said.
Regardless of the technique, Dr. Schachat stressed that vision loss in macular degeneration starts out being reversible and becomes irreversible.
“You want to consider doing something while it is still reversible,” he said. “Abnormal function of the photoreceptors, hypoxia, ischemia or subretinal fluid could be reversible, whereas, once the photoreceptors die, then you are getting into an irreversible situation, and whatever you do or don’t do is not going to make any difference.”
Although surgery should be attempted in the early stages, this is also when the risk is highest, according to Dr. Schachat.
“We like to consider it and try it in patients with good vision, early lesions, small lesions and healthy retinal pigment epithelium,” he said. “Then again, these are the patients who have the most to lose, so the approach is only going to make sense if the safety spectrum is acceptable.”
Translocation status
Dr. Schachat reported on the current status of limited macular translocation. He described the outcomes of approximately 200 patients who have reached at least 6-month follow-up. Approximately 20% had a 200 to 500-µm macula shift, 25% had a 500 to 950-µm shift, 35% had a 950 to 1,300-µm shift and 10% had more than a 1,300-µm shift.
Visual outcomes in a subset of MT patients 6 months postoperatively indicated that 10% gained six or more lines of Snellen activity, 23% gained two to five lines and 36% gained within two lines.
Of all of the MT cases observed, 96% of complications (except for progressive nuclear cataract) occurred within the first 3 months. Retinal detachments occurred in 17%, retinal breaks in 13%, various types of intraocular hemorrhage in 9%, macular holes in 8% and macular folds in 5%.
Dr. Schachat pointed out that the complication rate sounds poor until the obvious is considered: “With translocation, the median results are stable vision or better at 6 months versus deterioration with doing nothing.”
For Your Information:
- Andrew P. Schachat, MD, can be reached at Johns Hopkins Hospital, 600 N. Wolfe, Maumenee 713, Baltimore, MD 21287-9275; (410) 955-7411; fax: (410) 614-1683; e-mail: aschachat@jhmi.edu.