March 6, 2012 (New York, New York) — Patients with chronic uveitis who receive steroid-eluting ocular implants have a much greater rate of glaucoma than those who receive oral steroids, according to data from the Multicenter Uveitis Steroid Treatment (MUST) trial of fluocinolone-acetonide-emitting ocular implants, presented here at the American Glaucoma Society 22nd Annual Meeting.
"If you want to control inflammation, the implant is quite good at doing that," said David Friedman, MD, MPH, PhD, director of the Dana Center for Prevention Ophthalmology at the Wilmer Eye Institute of Johns Hopkins University, Baltimore, Maryland. "Patients with uveitis that has been ongoing for years suddenly have relief."
The efficacy can be striking, but so is the elevated risk for glaucoma that goes with it.
To gain a greater understanding of that risk, Dr. Friedman and colleagues looked at the 2-year incidence of elevated intraocular pressure (IOP) in patients with uveitis who had been randomized to either steroid-eluting ocular implants or systemic corticosteroids.
MUST, sponsored by the National Eye Institute, involved 255 patients with noninfectious intermediate, posterior, or panuveitis involving one or both eyes. Subjects were all older than 13 years, had a baseline IOP of 24 mm Hg or less, and had a best corrected visual acuity of 'hand motion' or better in at least 1 eye. Patients with advanced glaucoma were excluded.
In the cohort, median age was 46 years, 74% was female, the median duration of uveitis was 3.7 months, bilateral inflammation was 88%, and uveitis was intermediate in 38% and posterior or panuveitis in 62%.
Dr. Friedman's team collected IOP data at baseline, at 4 and 13 weeks, and then every 3 months for 2 years. Humphrey visual field was measured at baseline and at 1 and 2 years. Disc photos were obtained at baseline, at 4 weeks, at 6 months, and at 1 and 2 years. The study end point was incident glaucoma at 2 years.
"Glaucoma diagnosis is not easy in this population," said Dr. Friedman. "As you can imagine, they have a fair number of visual-field defects just on the basis of their disease."
Of the 129 patients in the implant group, 28 developed glaucoma in 37 implanted eyes after 2 years. In the systemic group, only 7 of 114 patients developed glaucoma, and 3 of these had crossed over to the implant group. Therefore, only 4 patients who received systemic treatment alone developed glaucoma.
"Eye pressure went up by 10 mm Hg or more in a very large proportion of the implant group, and it continued throughout the second year," Dr. Friedman said. "Even at the end of year 2, there is a little bump, so there are people still having IOP spikes 2 years out with the implant."
"More than half of the implant patients had developed a pressure of 30 mm Hg or greater by 2 years, compared with almost [none] in the systemic group," Dr. Friedman reported.
For the relative risk of developing a pressure that was 10 mm Hg above baseline in the implant group, compared with the systemic group, the hazard ratio (HR) was 4.3 (95% confidence interval [CI], 2.8 to 6.6). Further, patients in the implant group were 4.2 times as likely to need additional glaucoma medications (69% vs 32%) and 8 times more likely to require surgery to lower IOP (32% vs 5%) than those in the systemic group.
"One out of 3 implanted patients ultimately had to have an operation to lower pressure," Dr. Friedman reported.
Risk factors for incident glaucoma for the entire cohort were a steroid-emitting implant (HR, 4.2; CI, 1.9 to 9.5), active uveitis (HR, 3.6; CI, 1.2 to 9.5), use of IOP-lowering medications (HR, 2.1; CI, 1.1 to 3.9), and being black (HR, 2.0; CI, 1.1 to 3.8).
IOP elevations with the implant were most common in the first year. "If I had one of these in my eye, I'd want somebody checking my pressure monthly," Dr. Friedman said. Patients with implants need to be aware that there is a potential for large shifts in IOP over relatively short periods of time. Frequent IOP monitoring is therefore essential.
Prophylactic Surgery for IOP?
"I was not really surprised at these data," said Sanjay Asrani, MD, associate professor at the Duke Eye Center, Duke University Health System, in Winston-Salem, North Carolina. "We are seeing this all the time. The solution is to do prophylactic glaucoma surgery on patients who are at high risk of losing vision. We are already doing this at the Duke Eye Center."
Patients who are already on more than 1 glaucoma medication or who already have moderate to advanced glaucoma at the time of implant receive the prophylactic surgery. "It's either in the form of a tube or trabeculectomy."
Although the standard practice procedures at his institution are not drawn from current treatment guidelines, Dr. Asrani was quick to point out that the approach is supported by previous studies.
Dr. Friedman reports consulting in the past for Bausch & Lomb. Dr. Asrani reports receiving lecture fees from Alcon, Merck, Heidelberg Engineering, and Lumenis.
American Glaucoma Society 22nd Annual Meeting: Abstract 17. Presented March 2, 2012.
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