Physiology of the Autonomic Nervous System Intraocular Pressure Variation Evaluation in Healthy Subjects During Cold Pressor Test Master in Biomedical Engineering, IST/FML 1st Year, 1st Semester Lisbon, Portugal

Matos, Alexandre¹; Saraiva, Joana Catela²; Serafim, Joana³; Sousa, Joana⁴ ¹[email protected], ²[email protected], ³[email protected], ⁴[email protected]

Group VI

Abstract Autonomic nervous system (ANS) by regulating body homeostasis and homeodynamics plays a important role in the maintenance of ocular function influencing intraocular pressure (IOP) by regulating the outflow of the aqueous humor through the direct control of blood flow in the ciliary body and aqueous-venous outflow. There are several eye disorders that are often associated with changes in IOP which, when not treated or controlled, can damage the optic nerve provoking loss of nerve cells and leading progressively to blindness. A category of eye diseases that is often associated with changes in IOP is glaucoma which pathogenesis is not yet well understood despite in terms of physiopathology ,the lower the IOP at which the damage occurs or progresses, the higher the chance of finding additional risk factors. The autonomic imbalance has been suggested as a risk factor, as systemic autonomic neuropathies were been reported in patients with glaucoma. However, in order to evaluate ANS as a risk factor in glaucoma patients, normal function tests need to be defined. With the present work, we intended to evaluate with an autonomic provocative manouvre – the cold pressor test (CPT)the changes in IOP in correlation with modifications of arterial blood pressure (BP). Seven healthy subjects (3M, 4F) with a mean age of 59±12 years were included in this study. IOP and BP were continuously monitored and evaluated during basal and CPT periods. Medium (mPP), diastolic (DPP) and systolic (SPP) perfusion pressures were also calculated for the same periods. For statistical analysis, the t-Student test was used and differences considered significant when p