Improvements in ophthalmoscopes for instructional purposes

摘要

318,487. Zeiss, C., [Firm of]. Sept. 3, 1928, [Convention date]. Ophthalanoscopes are constructed so that the image of the background of the eye illuminated by an illumination system 4, 6, can be viewed simultaneously by several observers. The opthalmoscope of the Gullstrand type comprises a non-spherical lens 1, an objective 2 and an eyepiece 3, 31 by which the eye 21 is viewed. In the path of the rays between the lens 1 and the objective 2 are placed two prisms 9, 10 diverting portions of the rays through objectives 11, 12 to semi-transparent reflectors 13, 14 whereby each pencil of rays is divided so that, in the example shown, four additional observers may examine the eye 21. Diaphragms 8, 19, 20 are imaged in the pupil of the eye 21 and constitute apertures for the corresponding examination systems.