A Simple Optical Apparatus for Measuring the Corneal Thickness, and the Average Thickness of the Human Cornea

Abstract

PREVIOUS methods of measuring the corneal thickness in the living eye have recently been extensively reviewed and criticized by von Bahr (1948a), who devised an ingenious method (1948a, b) of overcoming the practical difficulties and theoretical objections of its forerunners. He employed an apparatus consisting of two rotating glass plates, coupled by gearing, which were mounted in front of the condensing lens and microscope of a slit lamp, so that the aperture of each was half covered by one of these plates. On rotation, the reflection of the slit in the corneal endothelium may be displaced in the field of view of the microscope and brought into coincidence with that in the epithelium. By noting the angle of rotation, the thickness of the cornea may be obtained from a curve derived by calculation. Von Bahr claimed for this instrument that it was simple and easy to handle and gave a satisfactory degree of accuracy and consistency.