A description of two adaptations to the May Model of the Bausch and Lomb ophthalmoscope follows.
First to be described is a system of apertures drilled through from the face of the head of the ophthalmoscope into the light chamber. As shown in figure 1, the opening in the face of the instrument is just above the center pin, which acts as a pivot for the lens carrier. One hole is drilled through into the light chamber with the aperture or zero lens in position. Thus, when the zero lens comes into position for use, a small round light presents itself through the drilled opening in the face of the ophthalmoscope.