Simple method for auto-ophthalmoscopy.

Auto-ophthalmoscopy, the process by which one's own fundus can be viewed, is an old technique which has been subject to many slight refinements throughout the years. Purkinje described 3 methods by which an impression of the vascular system could be obtained as far back as the 1820s (see von Helmholtz'). The reason why ordinarily we do not perceive the outline of our eyes' vascular system is because the 'shadow' image is suppressed. The best of his methods can be demonstrated with a pocket torch. With the eye closed the torch is moved rapidly backwards and forwards on the eyelid. In 1856 Hermann von Helmholtz described his invention of the ophthalmoscope.' Even so, this instrument was not at first used in auto-ophthalmoscopy. Coccius2 was probably the first to see his own retina rather than a shadowed outline of his retinal vessels. His instrument consisted of a Correspondence toMr J. Craggs, 42 Old Lodge Lane, Purley, Surrey.