Abstract

Retinal imaging is a highly specialized form of microscopy. The microscope objective is the subject's lens and cornea, not what any microscopist would choose. The working distance is fixed at about 20 mm, and the object is shielded from any light except what comes through the objective or (in rare cases) through the eyeball from "behind". As the objective's numerical aperture (NA) increases, the resolution goes through maximum and quickly gets worse. Unless the response is medically inhibited, the NA decreases dramatically whenever enough light is introduced to see the object. .And the object itself is nearly transparent, always in motion and susceptible to damage from too much light.

© 1991 Optical Society of America