Valve implantation effective in patients with refractory glaucoma

September 1, 2008

A study conducted at the University of Dresden confirms the short-term effectiveness of implantation of a proprietary shunt (Ahmed, New World Medical) in patients with refractory glaucoma. Patients in this 1-year study experienced statistically significant declines in IOP and number of medications, and best-corrected visual acuity (BCVA) remained stable in approximately half of the group. The cumulative probability of success after 1 year of follow-up was 83.3%.

Key Points

Dresden, Germany-A study conducted at the University of Dresden confirms the short-term effectiveness of implantation of a proprietary shunt (Ahmed, New World Medical) in patients with refractory glaucoma. Patients in this 1-year study experienced statistically significant declines in IOP and number of medications, and best-corrected visual acuity (BCVA) remained stable in approximately half of the group, reported Naim Terai, MD, a registrar in the Department of Ophthalmology at the German university.

The cumulative probability of success after 1 year of follow-up was 83.3%, he said.

The retrospective analysis was performed to compare results of implantation of the valve in the university's ophthalmology program with those reported in the literature. The procedure was successful in 35 eyes and a failure in seven, a rate that was similar to that reported elsewhere. Dr. Terai added, however, that follow-up of longer than 1 year is needed to obtain a more complete assessment of the effectiveness of valve implantation in eyes with refractory glaucoma.

The primary outcome was the cumulative probability of success, defined as an IOP of less than 21 mm Hg and of 5 mm Hg or more with a minimum of 15% reduction from baseline without additional glaucoma surgery or loss of light perception. Secondary outcomes included IOP and the number of medications at 3, 6, and 12 months after surgery, surgical complications, and final BCVA.

Outcomes

According to Dr. Terai, the IOP was reduced from a mean of 37.45 ± 10.3 mm Hg at baseline to 10.9 ± 5.1 mm Hg at month 12 (p < 0.001).

The number of medications the patients were taking also declined. At baseline, patients used a mean of 3.3 medications, and at month 12, 0.53 ± 0.80 (p < 0.0001).

Visual acuity in this group of patients already was quite poor preoperatively, Dr. Terai reported. Afterward, BCVA remained stable in 57% of patients, worsened in 28.5%, and improved in 14.3%.

The investigators analyzed the risk factors for failure of valve implantation and found that prior glaucoma filtering surgery was a significant component (p < 0.05), whereas patient age was not a statistically significant risk factor for success.

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