SPECULAR REFLECTION

Another type of illumination is specular reflection.  This is when the angle between the light source and microscope is such that a specular reflection is obtained from the cornea. (Remember your geometrical optics-angle of incidence is equal to the angle of reflection?)

A bright reflection is obtained from the surface of the cornea and a less bright reflection from the posterior surface of the cornea.  It is obtained by using a narrow parallelepiped and placing the microscope directly in front of the patient’s eye and the light source approximately 45 degrees to the side.  The angle of the light source is moved until a very bright reflection is obtained from the corneal surface.