Episcleral Venous Fluid Wave Correlates with Trabectome Outcomes: Intraoperative Evaluation of the Trabecular Outflow Pathway.

PURPOSE

To determine whether the characteristics of an intraoperative episcleral venous fluid wave (EVFW), a potential indicator of trabecular outflow patency, correlates with Trabectome (NeoMedix Corp, Tustin, CA) outcomes.

DESIGN

Retrospective, observational study.

PARTICIPANTS

A total of 68 eyes of 49 patients with glaucoma who underwent phaco-Trabectome (63 eyes) or Trabectome alone (5 eyes).

METHODS

The EVFW was evaluated in a masked fashion for wave degree (0-4) and clock hours (0-6). A diffuse EVFW (4, 5, 6 clock hours) was a near complete blanching of the episcleral vasculature, and a poorly defined wave was minimal change in the vasculature. Patients were grouped into wave categories to determine whether there was a correlation with postoperative intraocular pressure (IOP). Patients requiring further glaucoma surgery were considered failures.

MAIN OUTCOME MEASURES

Degree and extent of EVFW, IOP, and glaucoma medications.

RESULTS

For all eyes, there was a statistically significant correlation between wave clock hours and postoperative IOP at month 1 (P = 0.043) and month 3 (P = 0.002), but not a statistically significant correlation at month 6 (P = 0.12) or 1 year (P = 0.86). A strong correlation was found among IOP, medications, and EVFW in eyes with an extensive EVFW when compared with eyes with a poorly defined EVFW. At 12 months, the mean IOP in the extensive EVFW group was 13.3±2.7 mmHg on 1.4±1.2 medications compared with an IOP of 18.4±3.1 mmHg on 2.9±0.9 medications in the poorly defined group (both P = 0.001). Overall, 5 of 68 eyes (7%), required further glaucoma surgery. Eyes with a poorly defined EVFW had a higher likelihood of further glaucoma surgery (36%).

CONCLUSIONS

The EVFW is an intraoperative gauge of patency through the trabecular outflow pathway. Absence of the EVFW implies obstruction in the collector channel-intrascleral aqueous outflow pathway, preventing flow to the visible episcleral veins. In contrast, eyes with a diffuse EVFW had sufficient flow through their collector channels, had a lower IOP, required fewer glaucoma medications, and had a lower requirement for further glaucoma surgery. The characteristics of an EFVW may be able to predict surgical outcomes after Trabectome surgery.