Evaluation of intraocular pressure change and anterior segment parameters after intravitreal bevacizumab injection - Cannula size matters.

Purpose: To determine the changes in intraocular pressure (IOP) and anterior chamber parameters following intravitreal bevacizumab injection with different sizes of cannulas.

Methods: This clinical trial was conducted with 70 eyes of 70 patients who received an intravitreal injection of bevacizumab with 26 G (Group 1) or 30 G (Group 2) needle. Preinjection and postinjection 30-min IOP and pentacam measurements were obtained. Anterior chamber depth (ACD), anterior chamber volume (ACV), central corneal thickness (CCT), corneal volume (CV), and iridocorneal angle (ICA) measurements were evaluated in pentacam.

Results: Preinjection mean IOP values in Group 1 and 2 were 14.7 ± 3.29 mm Hg and 15.1 ± 2.87 mm Hg, respectively. Postinjection mean IOP in Group 1 was 16.8 ± 6.24 mm Hg and in Group 2 was 20.3 ± 3.66 mm Hg. Postinjection mean IOP values were significantly higher than preinjection values in both groups (Group 1 < 0.005 and Group 2 < 0.001). IOP change was significantly higher in Group 2 after injection ( < 0.05). In both groups, the change in IOP found to be more significant in phakic eyes than pseudophakic eyes (Group 1 < 0.001, Group 2 < 0.001). CCT and CV were significantly higher in both groups 30 min after the injection than preinjection (Group 1 and Group 2; < 0.01). In Group 2 ACD, ACV and ICA values were significantly lower than preinjection values ( < 0.05).

Conclusion: Needle bore size is an important parameter that influences anterior segment parameters and IOP change in the intravitreal injection. IOP rise and anterior segment changes are more prominent with a thinner cannula.