Slit pattern projecting apparatus having alignment detecting means

摘要

A slit lamp device having a slit pattern projecting optical system for projecting an illumination light in a pattern of a slit to a patient's eye. An alignment detecting device is provided for detecting the alignment between the optical axis of the projecting system and the axis of the patient's eye. The device comprises one or more light receiving elements such as phototransistors which are located at one or both sides of the projecting optical axis and in the slit plane.