The Effect of Early Posttrabeculectomy Intraocular Pressure Spike in the Collaborative Initial Glaucoma Treatment Study

Purpose: To examine effects of early postoperative intraocular pressure (IOP) spike in patients undergoing primary trabeculectomy in the Collaborative Initial Glaucoma Treatment Study. Patients and Methods: We identified patients with IOP spike >= 5mm Hg above the baseline IOP on postoperative day 1 and those without IOP increase. The mean deviation (MD), pattern standard deviation (PSD), and corrected PSD of the visual field (VF) were compared at 6 months and years 1, 2, 3, and 5 after surgery, as was the IOP. Results: Seventeen of 300 patients (5.7%) had IOP spike. After controlling for baseline VF severity in a generalized linear regression model that addressed change in MD, PSD, and corrected PSD, or in a logistic regression model for >= 3 dB of MD change, comparison between the groups revealed no significant difference at all time points examined (P > 0.05). Patients with IOP spike had significantly higher mean IOP at years 3 and 5 of follow-up (P <= 0.04). Conclusions: Among Collaborative Initial Glaucoma Treatment Study patients, early posttrabeculectomy IOP spike >= 5mm Hg above baseline IOP was not associated with subsequent VF loss, but was associated with significantly higher IOP during long-term follow-up.