GB1383158A - Tonometers - Google Patents

Abstract

1383158 Tonometers AMERICAN OPTICAL GORP 26 March 1973 14385/73 Addition to 1226709 Heading ASK In a tonometer of the kind in which a pulse fluid is directed towards a patient's corneal surface, and having a monitoring system for determining the effect of the pulse on the surface, which system includes a source of radiant energy directed on to the corneal surface and reflected therefrom onto a radiation detector, the wavelength of the radiant energy is outside the visible spectrum. As shown, the patient's cornea 20 is viewed by an operator's eye 60 through an eyepiece 36, aiming reticle 34, telescope lens 30 and an objective lens 14. Air pulses are directed to the cornea by means described in Specification 1226709 and represented by a tube 18. For alignment, light from a source 38 passes through a condenser lens 40, a transparent plate 42 and a target 44, is reflected by a beam splitter 46 and a mirror 48 through a collimating lens 50 and a lens in a turret 62, and is reflected along the main axis 26 of the instrument to be focused at a plane 58 for viewing by the operator. Alternatively, the light source 38 may be replaced by light emitting diode 54. Light from a source 22 of non-visible radiation is reflected from a beam-splitter 8 along the axis 26 to the patient's cornea 20, whence it is reflected back to a beam-splitter 32 to a detector 24. Signals from detector 24 may be used as described in Specification 1226709. In an alternative, the light source 22 and the beam-splitter 8 are omitted, and the light source 54 is used for alignment If source 54 is a source of non- visible light, it may be used both for alignment and for illuminating the cornea.