Using any equipment producing a bright spot of light, such as the Welch Allyn #41100 transilluminator (page 15) or a #76600 PenLite (see below) the diagnostic procedure is performed at arm's length.
20-diopter all-glass indirect convex viewing lens allows for less distortion
Provides a larger field of view of the fundus than with direct ophthalmoscopy
Examination at a safe distance from fractious animals