| 摘要 |
A hand-held non contact tonometer includes a piston (30) having a transparent plane parallel window (31) normal to a measurement axis (20) of the tonometer along which the piston (30) travels to discharge a fluid pulse without interfering with optical alignment functions of the instrument. In a first embodiment an alignment guidance system utilizing a concave mirror (50) and a target source (52) in a plane containing the center of curvature of the concave mirror (50) present an alignment image to the patient for guiding self-alignment. An infra-red light source (60) at the focal point of the concave mirror (50) irradiates the concave mirror (50) so that a collimated beam is reflected along the measurement axis and focused by an objective lens. <IMAGE> |
