Trabeculectomy May Significantly Slow Visual Field Loss Progression

Trabeculectomy may yield a significant decrease in the rate of progression of visual field (VF) loss, according to research published in Eye. 

Researchers obtained clinical and VF data from 199 patients with glaucoma who underwent trabeculectomy from 2015 to 2016. Among these patients, the research team analyzed 80 eyes from 74 patients (median age, 67 years, 54.1% women) who fulfilled the inclusion criteria of at least 3 reliable VFs pre and postoperatively (false positive rate <15%). The cohort included eyes with primary open angle glaucoma (61.3%), normal tension glaucoma (27.5%), secondary glaucoma (5.0%), and other glaucoma types. 

Participants underwent assessment of 10 VFs. Intraocular pressure (IOP) and rate of progression were 18 mm Hg  and -0.94 dB per year, respectively, at the time of surgery. Patient IOP improved to 10 mm Hg and rate of progression improved to -0.33 dB per year, indicating a VF progression slowing of 0.62 dB per year (P <.001). According to the report, these findings indicate a significant effect of postoperative IOP at 1 year following surgery on the amount of progression reduction (−0.09 dB/year of RoP change per mm Hg).

“This study adds data on expected visual function outcomes to clinicians, surgeons and patients without focusing on surrogate outcomes” according to the researchers. “It provides evidence that surgically IOP-lowering results in a markedly decreased rate of progression of the visual field without aiming for a specific postoperative IOP level.”

Study limitations include a retrospective nature, absence of a control arm, and a relatively short pre and postoperative follow-up.