More than 70m people worldwide suffer from glaucoma, a condition that causes a build-up of fluid and pressure inside the eye and can eventually lead to blindness. Treatment options have traditionally included eye drops to reduce the fluid the eye produces or surgery to unclog the eye’s drainage.
But a study from the University of Missouri School of Medicine and MU Health Care provides insight into which patients might benefit most from the non-invasive treatment, laser trabeculoplasty (SLT), which relieves pressure by using a laser to alter the eye tissue, resulting in better fluid drainage.
“There’s been a lack of evidence about how well SLT works, how safe it is and the ideal candidate,” said senior author Dr Jella An, an assistant professor of ophthalmology and a fellowship-trained glaucoma specialist at MU Health Care’s Mason Eye Institute. “Because so little is known about SLT, there is a lot of apprehension among specialists about using it as a first-line treatment for glaucoma. Our research findings have helped me redefine the ideal patient for this procedure.”
An’s research team reviewed 252 SLT procedures on 198 adult patients with open-angle glaucoma to determine what percentage of these surgeries achieved a 20% or greater reduction in intraocular pressure (IOP). Two months after surgery, 33.6% of patients met success criteria. At the six-month mark, 38.5% achieved the threshold. The researchers discovered patients with a higher baseline IOP had larger reductions in pressure.
“We discovered significant improvement in patients with more severe cases, which convinced me that patients with the highest pressure will benefit the most from this laser therapy,” An said.
Age, type and severity of glaucoma did not significantly predict a successful outcome. In addition, less than 5% of patients studied experienced the most common adverse event of an IOP spike after the procedure.
“This study really increased my comfort level to offer SLT as a primary therapy,” An said.
“Prior to this research, I would prescribe these patients multiple medications, creating the possibility of side effects and poor adherence, which could lead to disease progression. Now I offer this laser first if they are a good candidate because of its safety profile. If it doesn’t work, we can always move forward with other options.”
In addition to An, the study’s lead author was MU School of Medicine ophthalmology resident Dr Matthew Hirabayashi. Dr Vikram Ponnusamy, a recent graduate of MU School of Medicine, also contributed to the findings.
Abstract
We sought to determine predictive factors for selective laser trabeculoplasty (SLT) outcome. 252 eyes from 198 adult patients with open-angle glaucoma who underwent SLT between July 2016 and February 2018 with a minimum 6 month follow up were reviewed. We defined success as ≥20% IOP reduction or ≥1 medication reduction without an IOP lowering procedure. We also evaluated the relationship of these factors to postoperative IOP elevation >5 mmHg (IOP spikes). Our primary outcome measure was association between age, type and severity of glaucoma, pigmentation of the trabecular meshwork (PTM), total energy delivered, and baseline intraocular pressure (IOP) with success. At 2 and 6 months, 33.6% (76/226) and 38.5% (97/252) of eyes met success criteria respectively. Baseline IOP > 18 mmHg was significantly associated with success both at 2 and 6 months, reducing IOP by 5.4 ± 5.3 mmHg (23.7% reduction), whereas those with lower baseline remained at −0.7 ± 4.6 mmHg (4.9% increase) at 6 months (P < 0.001). No other baseline characteristics significantly predicted success or IOP spikes. Patients with higher baseline IOPs had greater success rates and mean IOP reduction at both 2 and 6 months following SLT. Age, type and severity of glaucoma, PTM, or total energy delivery had no association with procedural success or IOP spikes. Patients with higher baseline IOP may experience greater lowering of IOP after SLT. However, SLT may be equally successful for patients with a variety of other characteristics.
Authors
Matthew Hirabayashi, Vikram Ponnusamy, Jella An
[link url="https://medicine.missouri.edu/news/researchers-discover-predictor-laser-treatment-success-patients-glaucoma"]University of Missouri material[/link]
[link url="https://www.nature.com/articles/s41598-020-66473-0?utm_source=etoc&utm_medium=email&utm_campaign=toc_41598_nature&utm_content=etoc_nature_HS_10_20200616&sap-outbound-id=B4B13FB72B534AE5C5CBB6D0D51C45960B71AF93"]Nature abstract[/link]