Diagnostic Contact Lens.

Two methods can be employed to carry out this examination after insertion of the lens in an anaesthetized eye: (1) Examination by Reflected Light.-A very narrow slit-lamp beam is projected on to the area of angle to be examined, with the eye looking slightly away from the direction of the beam. The beam is focused on the angle and the various structures in it, and the examination is carried out along the direction of the beam. (2) Examination by Transmitted Light.-The slit-lamp beam is projected approximately on to the angle from the same side as the area of angle under examination. Two reflexes will be seen, one on the cornea and one on the iris. The beam is then moved outwards, and when the light is on the angle the two reflexes come close together, being separated only by the narrow space of the angle itself. The angle can thus be examined by transmitted light. This method is very useful for examining the trabecula and cells in the angle. Yours faithfully,