Method and apparatus for continuously monitoring intracranial pressure

A method for continuously obtaining an indication of intracranial pressure, comprising the steps of:

• A. measuring the pulsatility index of blood flow in the intracranial portion of an eye artery (P.I.(int));
• B. measuring the pulsatility index of blood flow in the extracranial portion of an eye artery (P.I.(ext));
• C. applying an external pressure against an eye and measure said external pressure applied against the eye;
• D. calculating a ratio of P.I.(ext) to P.I.(int);
• E. if the ratio of P.I.(ext) to P.I.(int) does not equal to one (1), increasing the external pressure, and repeating steps C, D, and E until the ratio of the ratio of P.I.(ext) to P.I.(int) equals to one (1);
• if the ratio of P.I.(ext) to P.I.(int) equals to one (1), calculating a conversion factor to convert the ratio of P.I.(ext) to P.I.(int) into an absolute intracranial pressure, wherein said conversion factor is equal to the external pressure measured, and going to step F;
• and
• F. repeating steps A, B, and D and determine intracranial pressure (ICP) by applying said conversion factor to the calculated ratio of P.I.(ext) to P.I.(int).