keratometer การใช้

A keratometer may be used to measure the curvature of the steepest and flattest meridians in the cornea's front surface.
A keratometer is a diagnostic instrument for measuring the curvature of the anterior surface of the cornea, particularly for assessing the extent and axis of iris, natural crystalline lens, and cornea.
Our article Keratometer ( see previous question ) refers to " Scheiner's rule " and a " Scheiner disc " . talk ) 12 : 13, 5 July 2014 ( UTC)
A keratometer uses the relationship between object size ( O ), image size ( I ), the distance between the reflective surface and the object ( d ), and the radius of the reflective surface ( R ).
In converting the measurements obtained from the corneal surface into a dioptric value, the B & L keratometer uses the general lens formula ( n-n ) / R and assumes an n of 1.3375 ( compared to the actual corneal refractive index of n = 1.376 ).