Keratoscope: a device for noncontact measuring the shape of the anterior corneal surface of the human eye

摘要

Abstract: To treat for some eye diseases by means of the modern methods of sight correction (microsurgical operation of keratotomy, contact lens fitting, etc.) it is necessary to know the exact shape of the anterior surface of a cornea (or the corneal topography). In order to use these methods successfully it is required that the optical power distribution be determined with the precision of 0.25 diopter. For this purpose at present special devices, keratoscopes, are usually used. A main disadvantage of these devices is a great sensitivity of measurement precision from displacements of eye relative to device. Therefore, in these keratoscopes the eye should be located relative to the apparatus very accurately, with the error less than 0.25 mm. This disadvantage decreases the possibilities of the keratoscopes. That is why the main problem of keratoscope designing is to eliminate the influence of eye alignment on the measurement precision. !6