Researchers at Queen’s University in Belfast, Northern Ireland, working with teams from St. Andrews and Aberdeen Universities, have discovered that standard cataract surgery is actually more effective than current surgical procedures at treating PCAG.
The Industry Standard
The current surgical treatments for primary closed-angle glaucoma usually begin with laser peripheral iridotomy, which opens the drainage pathways to allow fluid to drain. If this fails, it is usually followed by a trabeculectomy, which creates an opening in the wall of the eye that allows a slow drainage of fluid. In both cases, medical management with eye drops often follows to further control fluid pressure. These standard procedures do not always work, and can sometimes lead to severe complications.
The researchers at Queen’s University have been working to explore new approaches to glaucoma treatment, and have recently settled on the cataract-correcting clear lens extraction surgery as a particularly promising candidate.
Clear Lens Extraction: The Trial and the Results
The clinical trials were conducted between 2009 and 2011 in thirty hospitals in five countries, with 419 participants enrolled. Inclusion criteria were:
- Age 50 years or older
- Absence of cataracts
- Newly diagnosed primary closed-angle glaucoma with intraocular pressure 30mm Hg or higher (n = 155) or PACG (n = 263)
The experimental group underwent the clear lens extraction surgeries, while the control group had the traditional surgical procedures. Both groups were tracked and brought back three years later for a progress check. The researchers discovered that:
- Patients in the clear-lens extraction group had a higher mean health status score, as measured by the European Quality of Life-5 Dimensions questionnaire, compared with that for the standard care group
- The health status score increased over time in the clear-lens extraction group, but decreased for those in the standard care group
- Mean intraocular pressure was lower in the experimental group compared with the control group
- The procedure proved to be a highly cost-effective way to treat primary closed-angle glaucoma
There were complications in 75 of the patients in the experimental group, and 25 from the control group, but none of them were considered serious. Meanwhile, far fewer participants from the experimental group required further treatment to control their fluid pressure, either through medications or more surgery. And those patients who had the cataract surgery enjoyed better vision as compared with patients in the standard care control group. Overall, the study authors concluded that the trials offer “robust evidence that initial clear-lens extraction is associated with better clinical and patient-reported outcomes, and that this approach is likely to be cost-effective in a publicly funded health system.”
This is a promising step in the right direction. According to Carlo E. Traverso, MD, from Università di Genova, Italy, this study’s findings highlight advances in cataract surgical techniques and that the findings are both clinically relevant and have widespread practical implications. “While not yet sufficient to justify using clear-lens extraction to treat all patients with primary angle closure with or without glaucoma, the findings of this trial could have positive implications for areas where angle closure is most prevalent, particularly east Asia, or where health-care resources are scarce and patients might not have easy access to medications and monitoring. A not yet proven potential additional benefit with clear-lens extraction is that early intervention might prevent blindness.”
1Azuara-Blanco, A, Burr, J, et al, and the EAGLE study group. “Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial.” Lancet. 2016; 388: 1389 – 1397.
2Traverso, Carlo E. “Clear-lens extraction as a treatment for primary angle closure.” Lancet. 2016; 388: Issue 1352 – 1354.
First Posted January 11, 2017; Reviewed on March 31, 2022