Evaluation of microvascular changes in optic disc and retina by optical coherence tomography angiography during Valsalva maneuver.

Abstract

Optical coherence tomography angiography (OCTA) is an increasingly widespread imaging tool that allows the visualization of the microvascular structures of the eye. It should be kept in mind in clinical practice, Valsalva maneuver (VM) may have an effect on OCTA findings. We aimed to evaluate the effect of VM on the optic nerve and retinal blood flow parameters measured by OCTA. Sixty age- and sex-matched healthy volunteers were included into this prospective study. Optic disc status for radial peripapillary capillary (RPC) network [whole image, inside disc and peripapillary capillary densities], superficial and deep capillary plexus whole, foveal, parafoveal and perifoveal densities and foveal avascular zone (FAZ) densities of volunteers were examined by OCTA both at rest and during VM. The mean age of the subjects was 31.48 ± 7.49 (18-50) years and 51.7% were male. Superficial whole, parafoveal and perifoveal vessel densities were found to be significantly decreased during VM (p = 0.008, p= 0.015, p = 0.017, respectively). Lower levels of deep whole, parafoveal and perifoveal vessel densities were also detected while VM (p < 0.001 for all). However, there were no significant differences in terms of foveal vessel and FAZ densities. Additionally, VM significantly decreased RPC densities for whole image, inside and peripapillary capillary (p = 0.005, p < 0.001, p = 0.039, respectively). VM may cause a significant decrease in optic nerve and para-perifoveal blood flow. Therefore, patient instruction about not holding breath is required before OCTA scanning.