Trabectome and glaucoma index: Larger pressure reduction in more severe glaucoma

In a study recently published in PLoS One, we developed a simple glaucoma severity index that combines IOP, number of eye drops and visual field damage to estimate how challenging treatment currently is. We demonstrated in another recent study that cataract surgery contributes almost nothing to IOP reduction when combined with Trabectome and excluded such combined procedures to focus purely on pressure and medication reduction. We hypothesized that more severe glaucoma might have a relatively more reduced outflow facility compared with mild glaucoma and would respond with a larger IOP reduction to trabecular meshwork ablation.The background of the current study was that microincisional glaucoma surgery has traditionally been reserved for ocular hypertension up to mild glaucoma. In patients who refused to undergo a repeat traditional glaucoma surgery, we were surprised to find that plasma-mediated ablation of the trabecular meshwork with the Trabectome (NeoMedix) works well. It was generally assumed that subendothelial trabecular deposits and amorphous material accumulate in the juxtacanalicular tissue while the collector channels atrophy when bypassed for an extended time. This got us to think about what defines glaucoma severity clinically and how more treatment-resistant glaucoma might respond to simple trabecular meshwork removal because most of the outflow resistance is thought to reside here.