Typical heart rate variation.

<p>(A) A heart rate variation in a healthy volunteer. (B) A pressure increase of 4 mmHg per pressure Pe(t) step (time period of approximately 30 sec each) was used on the ocular globe from 0 mmHg to 48 mmHg.</p

Histogram of HR_diff (parameter for the detection of the oculocardiac reflex) for subjects from all groups and 870 external pressure steps applied during all of the non-invasive intracranial pressure measurements.

<p>Histogram of HR_diff (parameter for the detection of the oculocardiac reflex) for subjects from all groups and 870 external pressure steps applied during all of the non-invasive intracranial pressure measurements.</p

Example spectrograms of pulse waves of blood flow in the ophthalmic artery collected by a transcranial Doppler using different external pressure steps.

<p>(A) 0 mmHg; (B) 48 mmHg. HR—heart rate.</p

Schematic representation of the non-invasive intracranial pressure (ICP) measurement equipment Vittamed 205.

<p>(A) Relevant orbit and brain anatomy in contact with the ICP measurement device. (B) Block diagram of the system control unit. ICA—internal carotid artery; IOA—intracranial part of the ophthalmic artery; EOA—extracranial part of the ophthalmic artery; TCD—transcranial Doppler; Pe—external pressure applied to the ocular globe.</p

Protocol parameters for the non-invasive intracranial pressure measurement according to group.

<p>Protocol parameters for the non-invasive intracranial pressure measurement according to group.</p

Demographic data of the included subjects in this retrospective study.

<p>Demographic data of the included subjects in this retrospective study.</p

Heart rate (HR) variation at every external pressure step (Pe) applied on the ocular globe in the case of a 10% decrease in the MHR compared to the BHR.

<p>(A) Healthy subject. (B) Glaucoma patient. (C) Healthy subject. (D) Healthy subject.</p