New findings from a study published in Translational Vision Science & Technology compared the safety and efficacy of standalone trabeculectomy and trabeculectomy combined with intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections in the treatment of neovascular glaucoma (NVG).
Tell me about NVG and anti-VEGF therapies first.
NVG is a form of secondary glaucoma with a high risk of poor prognosis. The main pathogenesis of most cases is retinal ischemia due to vascular occlusion or diabetic retinopathy (DR).
Of note, VEGF plays a key role in promoting intraocular neovascularization in patients with ischemic retinal diseases.
Go on…
As such, intravitreal anti-VEGF treatments have been increasingly used as adjunctive therapy for refractory NVG to potentially improve the outcome of glaucoma surgery in high-risk patients.
There have been limited studies to compare the surgical outcomes of trabeculectomy alone vs. a combination of trabeculectomy and anti-VEGF injection, which inspired the research team to investigate this further.
Now, talk about the study.
In this systematic review and meta-analysis, researchers compared the surgical outcomes of both standalone trabeculectomy and trabeculectomy with anti-VEGF injection groups at baseline, 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively.
They extracted data examining three surgical outcomes from four databases (Cochran, PubMed, Embase, Web of Science):
- Postoperative intraocular pressure (IOP)
- Success rate
- Complications
How did they analyze the results?
In total, seven studies were included with 353 eyes.
This data was analyzed with a random-effects model to determine the pooled relative risk (RR) or standardized mean difference (SMD) estimates, and 95% confidence intervals (CIs).
Findings?
Compared to trabeculectomy alone, trabeculectomy with anti-VEGF treatment had a lower risk of postoperative complications (RR 0.60, 95% CI 0.41-0.89) and higher success rate (RR 1.19, 95% CI 1.02-1.40).
The research team observed that the timing, dosage, location, and type of anti-VEGF drugs may influence the surgical outcomes, and these tended to vary between the included studies.
What about the impact on IOP?
The IOP reduction was significantly greater in the trabeculectomy with anti-VEGF group compared to the trabeculectomy group from 1 week (SMD -1.36, 95% CI -2.76-0.40) to 6 months (SMD -0.79, 95% CI -1.50 to -0.07).
Expert opinion?
While there is currently no precise standard for defining the surgical success or failure of NVG, the study authors noted that, “After reviewing literatures, we found that IOP is one of the most important criteria for assessing the success of surgery.”
They mentioned additional criteria to consider, such as the percentage reduction in IOP and the type of antiglaucoma medication compared between pre- and post-surgery.
Any limitations to know about?
A few … including only having three outcome measures (which were selected because they were reported in all studies), patients having varying primary diseases, and the inclusion of only anti-VEGF drugs that are currently used in clinical practice and published studies.
Take home.
Based on these findings, the authors concluded that adding intravitreal anti-VEGF injections to trabeculectomy may improve the short-term outcomes (up to 6 months) of patients with NVG.
These results could aid in determining the optimal timing and frequency of anti-VEGF injections in refractory NVG management.
Next steps?
The study authors highlighted that for future studies, “developing a single set of criteria to evaluate the success of glaucoma surgery may help to advance glaucoma treatment research.”