Risk factors for hyphema following goniotomy or trabecular bypass stent placement combined with phacoemulsification.

Purpose: To report the rates and risk factors for layered hyphemas after goniotomy (PG) and trabecular bypass stent (PTBS) surgery combined with phacoemulsification.

Methods: Patient data was obtained using a retrospective chart review from adult patients (18 years of age or older) undergoing either PG or PTBS at the West Virginia University Eye Institute between 2013 and 2023. Generalized estimating equations were used to identify significant predictors of layered hyphema on post-operative day one. Predictors evaluated included age, race, glaucoma severity, glaucoma type, surgical time, complex cataract extraction, pre-operative intraocular pressure, post-operative day one intraocular pressure, peri-operative anti-thrombotic therapy (ATT) use, body mass index, and surgery type (i.e., PG or PTBS).

Results: Of the 405 eyes from 279 patients included in the study, the overall layered hyphema rate was 10.1% in the whole sample. In multivariate generalized estimating equation model controlling for glaucoma stage and preoperative IOP, only surgery type (PG vs PTBS) predicted post-operative day one hyphema (β = 2.47, SE = 1.01, p = 0.02). The hyphema rates in the PG group and PTBS groups were 40/316 (12.7%) and 1/89 (1.1%), respectively. Eyes of patients on ATT had a hyphema rate of 16/189 (8.5%) compared to 25/216 (11.6%) in eyes of patients not on ATT.

Conclusions: Performing PG over PTBS was a significant predictor of a post-operative day one layered hyphema. No other systemic or ocular features, including the use of ATT, showed a statistically significant relationship with post-operative hyphemas.

Key messages: What is Known. • The prevalence of minimally invasive glaucoma surgery has significantly increased in recent years. • Hyphema is a common postoperative complication of minimally invasive glaucoma surgery, however risk factors for hyphema in this setting have not been thoroughly evaluated.

What is new: • The use of perioperative antithrombotic therapy did not significantly increase the risk for postoperative hyphema following angle based minimally invasive glaucoma surgery. • Hyphema risk was significantly higher in patients undergoing goniotomy combined with phacoemulsification compared to trabecular bypass stent surgery with phacoemulsification.