Short-term Course of Intraocular Pressure after Intravitreal Injection of Triamcinolone Acetonide

Objective: To describe the natural history of intraocular pressure (IOP) within the first 30 minutes after intravitreal injection of triamcinolone acetonide (TA). Design: Prospective, interventional, consecutive case series. Participants: Thirty-eight consecutive patients who met inclusion and exclusion criteria and underwent intravitreal injection of 0.1 ml (4 mg) of TA were studied. Methods: Intraocular pressure was measured by Goldmann applanation tonometry at baseline; immediately after injection; and at 2, 5, 10, 20, and 30 minutes after injection. Main Outcome Measures: Intraocular pressure measurements at baseline; immediately after intravitreal injection; and 2, 5, 10, 20, and 30 minutes after injection, and percentage of patients with IOP ≤ 24 mmHg at 30 minutes. Results: Patients who did not experience vitreous reflux (30/38 [78.9%]) at the site of injection had a significant initial elevation of IOP that rapidly normalized. Patients who experienced vitreous reflux (8/38 [21.1%]) at the site of injection had either no change in IOP or a small drop in IOP that rapidly normalized. The IOP measured in millimeters of mercury immediately after injection (45.9 [no reflux], 12.6 [reflux]), 2 minutes after injection (39.9 [no reflux], 13.5 [reflux]), 5 minutes after injection (33.3 [no reflux], 13.8 [reflux]), 10 minutes after injection (26.4 [no reflux], 15.1 [reflux]), and 20 minutes after injection (21.8 [no reflux], 15.0 [reflux]) showed a statistically significant difference between the 2 groups. The difference in IOP between the 2 groups was not significant at baseline or 30 minutes after injection. At 30 minutes, 90% (95% confidence interval, 85.8%-95.2%) of patients without vitreous reflux had an IOP < 24mmHg. Conclusions: Patients undergoing intravitreal injection of TA with no vitreous reflux have a risk of short-term elevation of IOP that rapidly normalizes over 30 minutes. In patients with vitreous reflux after the injection, the IOP declines immediately after injection and rapidly normalizes over 10 minutes.