To investigate the effects of intravitreal injection of bevacizumab (IVB) with or without anterior chamber paracentesis on intraocular pressure and peripapillary retinal nerve fiber layer (PRNFL) thickness.

In this prospective randomized clinical trial, 90 eyes of 90 patients with center involving diabetic macular edema or wet type age-related macular degeneration (AMD) were randomly assigned to receive intravitreal bevacizumab (IVB) either without (group A) or with (group B) anterior chamber paracentesis prior to the injection. Intraocular pressure was measured before and within 2 min, 30 min, 24 hours and 3 months after injections. Peripapillary SD-OCT was performed before and 3months after injections.

Mean age of participants was 66.4± 4.9 years. Mean IOP changes from baseline to 2 minute after injections was 26.4 ± 5.7 mmHg in group A and -1.3 ± 2.4 mmHg in group B that was statistically significant (P <0.001). Mean IOP changes after 30 minute, 24 hours and 3 months were 6.5 ± 6.3 (P<0.001), 0.2 ± 2.9 mmHg (P>0.99) and 0.5 ± 2.4 mmHg (P>0.99) respectively in group A and -3.2 ± 1.8 mmHg (P<0.001), -3.1 ± 1.8 mmHg (P<0.00) and -1.8 ± 2.2 mmHg (P<0.001) respectively, in group B. Mean baseline average peripapillary nerve fiber layer thickness was 85.3± 5.6 µm in group A and 85.6± 5µm in group B. Mean PRNFL thickness changes after 3 month was -2 ± 2 µm (P= 0.0001) in group A and 0 ± 2 µm ( P=0.101) in group B.

Conventional method of intravitreal injected of bevacizumab (without anterior chamber paracentesis) was associated with acute IOP rise and statistically significant PRNFL loss 3 months after injections.