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Goniotomy effective in treating glaucoma complicating childhood uveitis
The condition of the trabecular meshwork is a “common denominator” for success, surgeon says
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SARASOTA, Fla. – The standard goniotomy procedure that is universally used in infants can be applied with good success to glaucoma complicating childhood chronic anterior uveitis, according to a surgeon speaking here.
The “common denominator” for the procedure’s success is the character of the trabecular meshwork, David S. Walton, MD, said at the meeting of the American Glaucoma Society. Dr. Walton reported on a study that he conducted with co-author Ching Lin Ho, FRCSEd. When the trabecular meshwork was in good condition, they found that goniotomy is safe and efficacious in both children and adults with the disease.
The procedure was performed on 40 eyes of 31 patients who had developed childhood chronic anterior uveitis. The patients ranged in age from 4 to 22 years, with a mean age at surgery of 10.3 years.
With a mean 10-year follow-up, Dr. Walton reported that 55% of eyes achieved complete success, defined as IOP less than 21 mm Hg without use of glaucoma medications. Another 17.5% of eyes achieved qualified success, IOP less than 21 mm Hg with medications. Twenty-seven percent of eyes experienced failure.
Importance of meshwork
The success of the procedure is closely correlated with the condition of the trabecular meshwork, Dr. Walton noted. In contrast to glaucoma surgeries that bypass the meshwork, he described goniotomy as a procedure that is “trying to get what’s there to work better.”
“Anything that affects the trabecular meshwork adversely is going to potentially decrease the success rate,” he said.
Factors that seemed to adversely affect the trabecular meshwork, and subsequently the patient’s prognosis, included previous eye surgery, lens status, extent of peripheral anterior synechia (PAS) and duration of glaucoma, he said.
Patients younger than 11 years had a greater success rate than older patients, according to the study. A statistically significant 79% of patients under age 11 achieved success compared with 63% of older patients.
Older patients
Dr. Walton told Ocular Surgery News that even though older patients were more likely to have more factors associated with a poor prognosis, goniotomy can be performed successfully in adulthood.
“It seems to work as well on adults as on children, or has the potential to,” Dr. Walton said. “Older patients don’t have quite as good a success rate as younger patients, but it’s probably because they often have had other surgery and the duration of their illness is longer.”
Eighty-seven percent of eyes without previous surgery achieved success. Phakic patients had a higher success rate than patients who had undergone cataract extraction.
“If you have had other kinds of surgery, such as cataract surgery, it’s just an added trauma to the meshwork,” Dr. Walton said.
Dr. Walton noted that he and Dr. Ho were somewhat surprised to find that the duration of glaucoma also significantly affected the trabecular meshwork. The chronic inflammation associated with uveitis similarly traumatizes this structure, he added.
Angle abnormalities
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Photograph courtesy of David S. Walton, MD. |
Other evidence of injury to the angle, particularly the presence of PAS, also suggested a more unfavorable prognosis, according to the study. Eyes in the success group had a mean of 0.9 clock hours of PAS compared with a mean of 3.0 hours in the failure group.
Conversely, 82% of eyes without PAS achieved success. None of the eyes with more than 6 hours of PAS achieved had a successful outcome.
Factors that did not have a statistically significant effect on success included gender, etiology of uveitis, age at disease onset, preoperative IOP and the number of preoperative glaucoma medications or steroids used, according to the study.
Dr. Walton noted at the meeting that he and Dr. Ho have now performed 54 goniotomy procedures for this disease with no complications. Transient hyphema, a common occurrence after goniotomy, was reported in 90% of patients.
“The technique is very familiar to those doctors who do it for infants, and it’s not a technique that was devised for this kind of surgery, but in fact it’s a technique that’s universally used for infantile glaucoma,” he said. “That’s really the exciting part of this procedure … is this application of the standard goniotomy procedure.”
Using the results
Dr. Walton noted that the procedure should be considered even when patients have seemingly poor prognostic factors; its potential should be weighed against the riskier alternatives that are typically chosen.
“I think one may use these prognostic factors to be able to discuss why you’re choosing this procedure or not and what your feelings are about the chance of it working,” he said.
The procedure is performed under standard illumination using standard goniotomy instruments, Dr. Walton noted. It is accomplished with direct observation of the filtration angle.
“This is an operation that can be done with very little risk,” he said. “This is our procedure of choice for these patients.”
For Your Information:
- David S. Walton, MD, can be reached at the Massachusetts Eye and Ear Infirmary, Glaucoma, 2 Longfellow Place, Suite 201, Boston, MA 02114; 617-227-3011; fax: 617-227-4352; e-mail: blacki@worldnet.att.net.