This is a prospectively recruiting, database development study collecting images and videos of the spontaneous venous pulsation at the back of people's eyes - this is a pulse one can see on examination of the back of the eye, originating from the blood vessels around the nerve that connects the eye to the brain (the optic nerve), and is present in most people who have normal pressure around the brain. However, in people with raised pressure in the brain, this pulse disappears as the pressure rises. Many things can cause the pressure around the brain to increase, including tumours, swellings and trauma. The investigators want to test if high-quality images and videos of this pulse, taken using both hand-held and larger, fixed-platform machines, can be used to train a software tool to automatically detect this pulse. The investigators want to collect these images and videos in 2 groups of patients: those with no known or suspected brain pressure problems, and those who are suspected to have raised pressure and/or are due to undergo measurement of the pressure around the brain, called lumbar punctures or intracranial pressure bolt monitoring. These tests to check the pressure around the brain are invasive - they involve inserting needles in the back or directly into the brain to measure the pressure, and carry risks. The value of these two groups of people will be to help train the software to reasonably say whether a pulse is present or absent and, hopefully, estimate what the pressure around the brain may be without the need for an invasive test.