CONTACT-FREE TONOMETER AND CONTACT-FREE METHOD OF MEASURING INTRAEYE PRESSURE Russian patent published in 1996 - IPC

FIELD: medicine. SUBSTANCE: central part of cornea is irradiated by narrow light beam directed at some angle to optical axis of eye. The cornea is deformed by pneumatic action performed periodically within sonic frequency range. Value of amplitude of electric signal till achieving maximal value is changed due to shifting diaphragm and photoreceiver in perpendicular to direction of propagation of beam reflected from cornea. Value of amplitudes of received signal is measured. Average values of these amplitudes are found. This value is used for determination of desired value of intraeye pressure by using calibration dependence designed preliminary. Contact-free tonometer has radiation source. Optical axis of the radiation source is disposed at specific angle to optical axis of eye. Slit diaphragm and photoreceiver are mounted sequently along path of light beam reflected from cornea. Output of photoreceiver is connected with registrar. Pneumatic action device is made in form of hollow narrowing channel. Diameter of exit window of the channel is comparable with size of cornea. Entrance window is coincided with plane of diffuser of low-frequency acoustic dynamic loudspeaker, which is mounted inside the case and connected with low-frequency signal generator. Moreover, diameter of entrance window of the channel is no shorter than diameter of diffuser. Photoreceiver and diaphragm are mounted for movement at plane, perpendicular to direction of propagation of light beam reflected from cornea of eye. EFFECT: improved precision. 2 cl, 5 dwg