Dynamic changes in optic disc morphology, choroidal thickness, anterior chamber parameters, and intraocular pressure during Valsalva maneuver
ABSTRACT Purpose: To investigate the effects of the Valsalva maneuver (VM) on optic disc morphology, choroidal thickness, and anterior chamber parameters. Methods: This prospective observational study included 60 eyes of 60 healthy subjects. The anterior chamber parameters, including central corneal thickness (CCT), anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), pupil diameter (PD), axial length (AL), subfoveal and peripapillary choroidal thickness, optic disc parameters, and intraocular pressure (IOP), were measured at rest and during VM. Results: VM did not have any significant influence on AL, subfoveal and peripapillary choroidal thickness, optic disc area, rim area, cup area, cup-to-disc area ratio, vertical cup-to-disc ratio, rim volume, cup volume, and nerve head volume measurements (for all; p >0.05). IOP and PD significantly increased during VM (for both; p <0.001). VM significantly decreased CCT, ACD, ACA, and ACV values (for all; p <0.001). Moreover, the optic nerve cup volume decreased and the horizontal cup-to-disc ratio significantly increased during VM (for both; p <0.05). Conclusions: VM may cause transient changes in IOP, optic disc morphology, and anterior chamber parameters.