| 摘要 |
PURPOSE:To detect the direction and degree of the distortion in the spherical body readily, by providing a circular index which surrounds an optical axis in an optical observing system for the spherical body, providing an optical element which rotates an image light beam in the divided light paths in the optical system, and superimposing the images which cross at a right angle to each other. CONSTITUTION:The light emitted from the annular light source (index) 6 is reflected by the surface of the cornea of an eyeball 1 to be checked, converted into the parallel light by an objective lens 2, reflected in rotatable trapezoidal prisms 10 and 11 once, and outputted. The light is observed as the optical image through an image forming lens 3 and eyepiece lens 4. When the angles of the reflecting surface of the trapezoidal prisms 10 and 11 are adjusted to be 45 deg., the reversed images 15 and 16 are superimposed so that they cross at a right angle to each other. When the eyeball 1 is distorted, the circular images become ellipses. Therefore the direction and the degree of the distortion can be readily detected from said images. |
