| 摘要 |
PURPOSE:To enhance measuring accuracy and to accurately display alignment, by detecting the contact state between the ultrasonic probe brought into contact with the cornea of an eye to be examined and the cornea. CONSTITUTION:When the cornea C of an eye to be examined is brought into contact with an ultrasonic probe 1, the cornea C of the eye to be examined is brought to an applanation state and the applanation surface P is positioned at the almost center of the ultrasonic probe 1 when both of them are accurately brought into contact with each other. When the pressure sensor groups B1-B8 arranged to the circular end surface 1a of the ultrasonic probe 1 at the equal distance from the center thereof and the pressure sensor groups A1-A8 outside said sensor groups B1-B8 are embedded in circular frames 1b, 1c, the values detected by the sensor groups B1-B8, A1-A8 change according to the position of the applanation surface P. When an eccentric applanation surface P' is present at the leading end part of the ultrasonic probe 1, the sensor groups B3, B4, B5, B6, B7 and A4, A5, A6 are present within the applanation surface P' and the other sensor groups B1, B2, B8 and A1, A2, A3, A7, A8 are present out of the applanation surface P' or partially present in said surface P' and, therefore, an eccentric state is detected on the basis of the difference between the outputs of the sensors. As a result, measuring accuracy is enhanced and alignment can be accurately displayed from the obtained data. |
