Device and method for measuring working distance of corneal topography instrument

Abstract

The invention discloses a device and method for measuring the working distance of a corneal topography instrument, and the device is characterized in that the device comprises a cornea shooting assembly and a distance measurement light path assembly, and the cornea shooting assembly comprises a placido disc, a first lens, a second lens and a first photoelectric detector which are coaxially and sequentially arranged; the distance measuring light path assembly comprises a beam splitting unit, a transmitting and receiving unit and a driving motor, the beam splitting unit is arranged on the optical axis of the cornea shooting assembly, and the beam splitting unit is located between the first lens and the second lens and used for transmitting light entering the cornea shooting assembly and reflecting light entering the transmitting and receiving unit; the driving motor is used for driving the transmitting and receiving unit to move back and forth in the direction perpendicular to the optical axis of the cornea shooting assembly. The measuring device and the measuring method have the advantages that the working distance of the corneal topography instrument can be accurately measured when the cornea is shot by the corneal topography instrument, so that the restoration precision of the corneal curvature is higher, and the corneal topography instrument can more accurately diagnose corneal diseases.

Description

technical field [0001] The invention relates to a corneal topography instrument for checking the cornea, in particular to a measuring device and a measuring method for the working distance of the corneal topography instrument. Background technique [0002] The corneal topography instrument based on the Placido (Placido's) disc has diopter visualization, can draw various topographic maps of the cornea more accurately, can diagnose a variety of corneal diseases, and guide various corneal operations effectively. It has many advantages such as diverse measurement data and strong analysis ability, and it is very popular in the medical market. [0003] In general corneal topographs, in order to clearly capture the apex of the cornea and the surrounding cornea, and to keep the magnification β constant, an object space telecentric lens is often used, which is characterized by a larger object space Depth of field, so when collecting images, clear images can also be captured under di...

AI Technical Summary

Problems solved by technology

[0003] In general corneal topographs, in order to clearly capture the apex of the cornea and the surrounding cornea, and to keep the magnification β constant, an object space telecentric lens is often used, which is characterized by a larger object space Depth of field, so when collecting images, clear images can also be captured under different working distances (that is, the distance from the corneal apex to the first lens), but it brings great uncertainty to the restoration of the final corneal curvature radius Therefore, in order to improve the restoration accuracy of the corneal curvature, it is necessary to determine a more accurate value of the working distance

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