Dynamic changes in optic disc morphology, choroidal thickness, anterior chamber parameters, and intraocular pressure during Valsalva maneuver Mudanças dinâmicas na morfologia do disco óptico, espessura da coroide, parâmetros de câmara anterior e pressão intraocular durante a manobra de Valsalva

The Valsalva maneuver (VM) is performed frequently in daily activities. It causes various transient physiological changes, including elevated blood pressure, increased intrathoracic pressure, increased peripheral venous pressure stimulation of the peripheral sympathetic system, and increased intraocular pressure (IOP). The mechanism for the transient increase in IOP during VM has not been completely explained. One hypothesis is that the increased systemic venous pressure is transmitted through the jugular, orbital, and vortex veins to the choroid, causing vascular engorgement and increases in choroidal volume and IOP. Another hypothesis relates this IOP increase to an increase in episcleral venous pressure. The pathophysiology of glaucoma is likely multifactorial, with IOP-dependent and vascular factors involved. Patients with primary open-angle glaucoma (POAG) have been shown to have vascular dysregulation that leads to either local vasospasm or impaired autoregulation. Researchers have showed that VM causes significant changes in anterior chamber parameters and an increase in uveal thickness that leads to a transient increase in IOP in healthy subjects. These dynamic changes may also induce acute angle-closure glaucoma (AACG). Moreover, normotensive glaucoma (NTG) has been reported to be more common in patients with exposure to increases in IOP caused by intrathoracic and intra-abdominal pressure, such as that from playing wind instruments, lifting weights regularly, asthma, or having chronic urinary tract or intestinal obstruction. We hypothesized that VM may facilitate glaucomatous optic neu ropathy (GON). Based on this theory, we designed this study to in vestigate the acute changes in IOP, optic disc morphology, choroidal thickness, and anterior chamber parameters during VM in healthy subjects. To the best of our knowledge, this article is the first report on the acute effects of VM on peripapillary choroidal thickness and the second report on the acute effects of VM on optic disc morphology. Dynamic changes in optic disc morphology, choroidal thickness, anterior chamber parameters, and intraocular pressure during Valsalva maneuver