Can intraoperative intraocular pressure during primary trabeculectomy predict early postoperative pressure?

Purpose: To study the association of intraoperative intraocular pressure (IOP) at the conclusion of primary trabeculectomy with postoperative IOP on days 1, 7, and 30 and report the ability of intraoperative IOP to predict early postoperative IOP.

Patients And Methods: Prospective, observational, case series. Ninety-seven consecutive patients with primary open-angle or angle-closure glaucoma underwent primary trabeculectomy. The IOP was measured 3 minutes after the closure of scleral flap with a formed anterior chamber. Clinical details and complications were recorded over a 30-day follow-up. The patients were grouped as A (intraoperative IOP≤10.0 mm Hg), B (>10, ≤15.0 mm Hg), and C (>15 mm Hg).

Results: Mean age was 60.8±9.9 years. Forty (41.3%) patients were males. Eighty-two (84.5%) had primary angle-closure glaucoma. Mitomycin-c (MMC) was used in 75 (77.3%) eyes. Mean IOP in group C was significantly higher than group A at all visits (P=0.005, 0.002, and 0.05). Postoperative IOP was associated with intraoperative IOP, age, duration, and dose of MMC in univariable regressions. On multivariable analysis, the intraoperative IOP was associated with postoperative IOP's on day 1 (regression coefficient b=0.24, P=0.039, R(2)=0.24) and day 7 (b=0.47, P<0.001, R=0.42), but not on day 30 (b=0.22, P=0.065, R(2)=0.12). IOP on day 7 was predicted by -8.6+0.47×(intraoperative IOP)+0.27×age-11.7×(dose of MMC in mg/mL). Prediction for day 30=9.8+0.27×(intraoperative IOP).

Conclusions: In patients undergoing uncomplicated primary trabeculectomy, intraoperative IOP is associated with and may predict early postoperative IOP. Adjusting the IOP during the operation may optimize postoperative IOP.