Abstract
Purpose:
Acute intraocular pressure (IOP) elevation is a complication of intravitreal injection of agents targeted to vascular endothelial growth factor (VEGF). We evaluated the relation between this phenomenon and optic nerve head circulation with the use of laser speckle flowgraphy.
Methods:
Twenty-two eyes of 20 subjects (17 eyes of 15 men and 5 eyes of 5 women; mean age ± SD, 74.2 ± 15.7 years) who had received an intravitreal injection of 0.05 ml of aflibercept at Yamaguchi University Hospital for the treatment of wet age-related macular degeneration were enrolled. Blood pressure and pulse were measured before the injection for calculation of ocular perfusion pressure (OPP). IOP and blood flow at the optic nerve head both before and 10 minutes after injection were also determined. Blood flow at the optic nerve head was examined by laser speckle flowgraphy (LSFG-NAVI; Softcare Co. Ltd., Fukutsu, Japan), and blood flow values for the entire optic nerve area (MA: Mean of All area), the main optic nerve vessels (MV: Mean of Vascular area), and optic nerve tissue (MT: Mean of Tissue area) were determined with LSFG Analyze software. The subjects were divided into two groups on the basis of whether the postinjection increase in IOP was ≤10 mmHg (unchanged group) or >10 mmHg (elevated group).
Results:
Thirteen and nine eyes were assigned to the unchanged and elevated groups, respectively. Age and pre-injection IOP did not differ significantly between the two groups. Postinjection IOP elevation in the elevated group (12.9 ± 2.66 mmHg) was significantly (P < 0.01) higher than that in the unchanged group (5.31 ± 2.43 mmHg). Pre-injection OPP in the elevated group (53.6 ± 6.63 mmHg) was significantly (P < 0.01) smaller than that in the unchanged group (63.1 ± 5.93 mmHg). The differences in MA, MV, and MT between pre- and postinjection were -2.31 ± 2.12, -5.33 ± 4.75, and -0.24 ± 0.81, respectively, in the unchanged group, and -2.91 ± 2.73, -8.72 ± 4.52, and -1.64 ± 0.96 in the elevated group. The MA (P = 0.56) and MV (P = 0.11) values did not differ significantly between the two groups, whereas the MT showed a significant difference (P < 0.01).
Conclusions:
Whereas acute IOP elevation after intravitreal injection of an anti-VEGF drug did not affect blood flow of main optic nerve vessels, it reduced blood flow for optic nerve tissue.