Tonometer

Claim 1

A PROBE-LIKE DEVICE FOR MEASURING THE INTRAOCULAR PRESSURE OF AN EYEBALL COMPRISING: A MAIN BODY PORTION HAVING AN AXIALLY EXTENDING CAVITY; A FORWARD BODY PORTION ATTACHED AT ONE END TO AND AXIALLY ALIGNED WITH SAID MAIN BODY PORTION AND HAVING A PLANE CONTACT SURFACE AT ITS OTHER END, SAID FORWARD BODY PORTION HAVING AN ELONGATED INTERNAL CAVITY THAT IS REDUCED IN SIZE AT ONE END TO FORM AN OPENING IN SAID CONTACT SURFACE; AN ELONGATED ROD EXTENDING AXIALLY THROUGH SAID FORWARD BODY PORTION AND INTO SAID MAIN BODY PORTION, SAID ROD HAVING A FLAT FACE AT ONE END NORMALLY POSTIONED COPLANAR WITH THE SAID CONTACT SURFACE OF SAID FORWARD BODY PORTION AND A FERROUS METAL MEMBER ATTACHED TO ITS OTHER END WITHIN SAID MAIN BODY PORTION; MOUNTING MEANS OF ELASTOMERIC MATERIAL BONDED TO SAID ROD ALONG A PORTION OF ITS LENGTH WITHIN THE INTERNAL CAVITY OF SAID FORWARD BODY PORTION, SAID MOUNTING MEANS EXTENDING RADIALLY FROM SAID ROD AND BEING ALSO BONDED TO THE INSIDE SURFACE OF SAID FORWARD BODY PORTION, THEREBY SUPPORTING SAID ROD IN A CENTRALLY LOCATED POSITION WITHIN SAID CONNECTED BODY PORTIONS WHILE ALSO ENABLING THE ROD TO MOVE AXIALLY RELATIVE THERETO IN RESPONSE TO A FORCE RESULTING FROM INTRAOCULAR PRESSURE WHEN THE DEVICE IS PRESSED AGAINST IN EYEBALL, SAID MOUNTING MEANS ALSO PROVIDING MEANS FOR RESTORING THE END SURFACE OF SAID ROD TO ITS COPLANAR POSITION WITH THE SAID CONTACT SURFACE OF THE FORWARD BODY PORTION WHEN THE DEVICE IS REMOVED FROM THE EYEBALL; AND MEANS WITHIN SAID CAVITY OF SAID MAIN BODY PORTION FOR PROVIDING AN ELECTRICAL SIGNAL RESPONSIVE TO A CHANGE IN AXIAL POSITION OF SAID ROD AND SAID FERROUS METAL MEMBER RELATIVE TO SAID MAIN BODY, SAID SIGNAL BEING PROPORTIONAL TO THE INTRAOCULAR PRESSURE WHEN THE INSTRUMENT IS PRESSED AGAINST AN EYEBALL SO THAT ITS SURFACE IS ENGAGED BY THE SAID FLAT CONTACT SURFACE AND THE FLAT END OF THE ROD.