Effect of prior glaucoma surgery on intraocular pressure immediately after anti-vascular endothelial growth factor injection.

Background: To characterize how prior incisional glaucoma surgery affects the intraocular pressure (IOP) elevation immediately following intravitreal anti-VEGF injections (IVI).

Methods: Single institution, experimental study. Patients with a history of incisional glaucoma surgery who were receiving anti-VEGF injections were recruited as well as control eyes. Pre- and post-injection IOP measurements were compared as well as time to recovery to within 5 and 10 mmHg of baseline IOP.

Results: Ten eyes with a history of glaucoma surgery and 29 control eyes receiving anti-VEGF injections were included. The most common indication for intravitreal anti-VEGF injection was proliferative diabetic retinopathy in both surgical and control eyes (50% vs 45%, p = 1.00). Post-injection IOP was significantly decreased compared to baseline IOP after anti-VEGF injection in surgical versus control eyes (26.5 ± 8.9 mmHg vs 44.2 ± 8.5 mmHg, respectively, p < 0.001). The mean change in IOP following intravitreal anti-VEGF injection was lower in surgical eyes (10.7 ± 6.6 mmHg vs 28.6 ± 8.3 mmHg, p < 0.001). The mean time for the IOP to return to within 10 mmHg of pre-injection IOP was less in surgical eyes (5.2 ± 4.1 min vs 13.3 ± 7.6 min, p = 0.002).

Conclusions: Eyes with prior incisional glaucoma surgery demonstrated a significantly lower post-injection IOP elevation and a faster recovery to within 10 mmHg of their pre-injection IOP. Incisional glaucoma surgery may be considered for patients where the attenuation of post-injection IOP elevation is needed and other less invasive measures have failed.