Study for the development of new non-invasive methods for monitoring intracranial pressure using observation of the ocular retinal veins and optic disk.

This study is developing a new, safer way to measure the pressure of the fluid around the brain (intracranial pressure). Currently, measuring this pressure requires a tube placed directly into the brain, which carries risks. Researchers are exploring whether looking at the veins and optic nerve at the back of the eye using a camera could give accurate readings instead, without any invasive procedures. You may be eligible if: - You are 18 years or older - You already have an intracranial pressure monitor in place as part of your treatment - You are conscious and able to give informed consent You may NOT be eligible if: - You cannot sit upright - You cannot tolerate eye drops that dilate the pupil (mydriatic drops) Talk to your doctor about whether this trial might be right for you.