Paul Glaucoma Implant shows efficacy at 3 years for uveitic glaucoma treatment
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Key takeaways:
- Failure of the Paul Glaucoma Implant occurred in 8% of cases.
- Only five cases of hypotony occurred out of 50 cases of implantation.
The Paul Glaucoma Implant, a novel glaucoma drainage device, safely and effectively managed uveitic glaucoma in children and adults, according to an analysis of midterm results published in Eye.
Typical treatment for uveitic glaucoma consists of lowering IOP by bypassing the trabecular meshwork outflow through trabeculectomy or tube shunt surgery, Jay Richardson, MD, a fellow in pediatric glaucoma at Birmingham Children's Hospital, and colleagues wrote. Although tubes, such as the valveless Baerveldt tube (Johnson & Johnson Surgical Vision), have successfully lowered IOP, they have higher rates of hypotony, which can lead to poor ocular outcomes.
The Paul Glaucoma Implant (Advanced Ophthalmic Innovations) is similar in design to the Baerveldt tube but has a much smaller internal tube lumen. After being stented, it instantly drains aqueous humor, lowering risk for hypotony, according to the researchers.
Although previous studies have demonstrated that the Paul Glaucoma Implant effectively lowers IOP, it has not been studied as a treatment for uveitic glaucoma.
This inspired the researchers to conduct a single-center, multi-surgeon retrospective analysis of 50 consecutive cases of the Paul Glaucoma Implant being utilized to treat uveitic glaucoma from April 2019 to August 2021. Following “very promising” early results, the researchers conducted this analysis based on 3-year follow-up.
The primary endpoint of the study was the complete success or failure of the implant, which was measured every 6 months until end of follow-up. The researchers defined success as IOP of 5 mm Hg to 21 mm Hg with IOP reduction of at least 20%. They defined failure as IOP outside of goal criteria, additional glaucoma procedures, implant removal, severe visual loss or progression to no light perception.
The researchers also evaluated secondary outcomes at each visit, including visual acuity, IOP, complications and more.
In total, 41 patients aged 6 to 81 years (48% female; 60% white; mean age, 45.8 ± 19.8 years) with a previous diagnosis of uveitis received the Paul Glaucoma Implant.
Prior to the operation, mean IOP was 30.6 ± 9.8 mm Hg, and patients were using 3.9 ± 0.9 medications. More than half (62%) required oral acetazolamide, and 64% needed systematic immunosuppression.
Mean follow-up was 35.8 ± 9.8 months.
The researchers reported an initial success rate of 48%, which increased to 92% after the addition of medications. Most of the failure cases were due to elevated IOP, with only one case failing because of prolonged hypotony.
At final follow-up, mean IOP was reduced to 12.2 ± 4.4 mm Hg, and patients were using 1.1 ± 1.3 medications (P < .0001 for both), with no patients requiring acetazolamide. The researchers noted these reductions were comparable to those of a population who received the Baerveldt tube at their center.
Finally, Richardson and colleagues found that there were five cases of hypotony in the cohort. Of those cases, three self-resolved within 8 weeks, and only one case required resuturing of a leaking paracentesis. The final hypotony case occurred 3 months after surgery and met failure criteria. Comparatively, patients in a study who received the Baerveldt tube were much more likely to experience hypotony, and 26% required anterior chamber reformation.
The researchers noted several limitations to this study, including the potential introduction of attrition bias due to the longer data collection window and their decision not to include visual field data.
“[The Paul Glaucoma Implant] shows IOP reduction and surgical success rates comparable to Baerveldt tube but with lower rates of postoperative hypotony,” Richardson and colleagues wrote.
“We feel this represents a promising change in practice and, as such, in our unit, the Paul Glaucoma Implant is now the preferred tube of choice in cases of uveitic glaucoma,” they added.
Perspective
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Alek Karthikeyan, OD, FAAO
Managing uveitic glaucoma presents a significant challenge for eye care providers. When medical therapy fails, surgical intervention is often required. Researchers of this retrospective study analyzed the effectiveness of the novel Paul Glaucoma Implant in managing uveitic glaucoma by primarily targeting up to a 20% reduction in IOP after the initial 3 months.
This study found that the Paul Glaucoma Implant had an approximately 50% reduction in mean preoperative IOP at the 3-month mark. At the final follow-up, complete success was achieved in 48% of cases, which increased to 92% with the addition of medications. There was an 8% failure rate, with the majority of the cases being due to raised IOP as opposed to hypotony.
These results show that the Paul Glaucoma Implant offers excellent surgical success rates, with the added benefit of reducing risk for postoperative hypotony. Additionally, the inclusion of pediatric and adult patients (aged 6 to 81 years) showed the versatility of the Paul Glaucoma Implant in varying demographics and disease stages.
One future recommendation would be to include visual field data to assess the device’s impact on long-term visual function. In addition, direct comparative studies between the Paul Glaucoma Implant and other glaucoma drainage devices across different types of glaucoma will solidify its place in clinical practice.
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