Trabeculectomy surgery is a common treatment option for patients with progressing glaucoma, yet few studies detail the post-op OCT parameters comanaging clinicians can expect. Now, investigators recently found patients who had a trabeculectomy showed anatomical changes to their optic nerve head rim associated with reduced glaucomatous cupping. Based off this finding, they note that retinal nerve fiber layer (RNFL) thickness as measured with OCT may actually be a more stable measure of disease progression.
This longitudinal cohort study evaluated 20 eyes of 16 subjects with primary open-angle glaucoma who had undergone trabeculectomy. The team calculated the change in OCT parameters from the pre-op and post-op visits, a span of approximately six months. They also calculated changes in the same eyes that did not undergo trabeculectomy to serve as controls.
Not surprisingly, the researchers noted the trabeculectomy eyes showed a significant decrease in intraocular pressure (-9.2mm Hg) compared with controls. However, they also found several neuroretinal rim parameters showed significant changes with trabeculectomy: greater minimum rim width (+6.04μm), minimum rim area (+0.014mm2), and lower mean cup depth (-11.6μm) and mean anterior lamina cribrosa surface depth (-18.91μm). They add that this is consistent with an increase in rim tissue thickness and a more anterior position of the inner limiting membrane and anterior lamina cribrosa surface depth relative to the Bruch’s membrane opening plane. Conversely, they found that RNFL thickness changes were not significantly different between trabeculectomy and control eyes.
|Sanchez FG, Sanders DS, Moon JJ, et al. Effect of trabeculectomy on optical coherence tomography (OCT) measurements of the optic nerve head neuroretinal rim tissue. Ophthalmology. October 4, 2019. [Epub ahead of print].|