Abstract: The invention is a low cost, low input power eye viewing device well suited for viewing wide field retinal images through an undilated pupil. Included in the device are a converging light illumination system and an aperture stop. The converging light illumination system provides ease of entry of light rays into an eye, wide field retinal illumination, reduced glare and reduced power consumption. The aperture stop blocks unwanted received glare light not forming part of the retinal image. The device is made especially well suited for retinal viewing through an undilated pupil if the aperture is sized in accordance with the diameter of an undilated pupil.

Abstract: The invention is a low cost, low input power eye viewing device well suited for viewing wide field retinal images through an undilated pupil. Included in the device are a converging light illumination system and an aperture stop. The converging light illumination system provides ease of entry of light rays into an eye, wide field retinal illumination, reduced glare and reduced power consumption. The aperture stop blocks unwanted received glare light not forming part of the retinal image. The device is made especially well suited for retinal viewing through an undilated pupil if the aperture is sized in accordance with the diameter of an undilated pupil.

Abstract: A focusing mechanism for an optical instrument includes an eyepiece having at least one lens element retained within an eyepiece housing, a stationary carrier for retaining the eyepiece, and a rotatable thumb wheel. A pair of levers operatively connect the eyepiece housing with the rotatable thumb wheel, the thumb wheel including corresponding pairs of cam channels on either side for receiving one end of a corresponding lever, the remaining end of each lever engaging the eyepiece housing, wherein rotational movement of the thumb wheel produces axial movement of the eyepiece relative to said carrier.

Abstract: The invention is an ophthalmoscope having an imaging path and imaging axis which includes a light source disposed in the imaging path at or in proximity with the imaging axis. Disposing the light source directly in the imaging path at or in proximity with the imaging axis provides numerous illumination and other operational advantages. When the light source is of sufficiently small size and is disposed in a sufficiently defocused position in relation to any retinal focal plane of the ophthalmoscope, the light source, for practical purposes, cannot be perceived by a user.

Abstract: A lamp assembly includes a condensing lens group disposed at one end for collecting and collimating a light from a light source, an exit lens group at the other end of the assembly, including at least one objective lens element for projecting an illuminated light spot at a predetermined distance, and an iris disposed between the condenser lens group and the exit lens group having a variable opening for varying the size of the illuminated light spot between a minimum and a maximum spot diameter at the predetermined distance. The invention allows the illuminated light spot to be focused for at least two separate iris positions at the predetermined distance by allowing relative movement between the objective lens element and the iris to provide enhanced edge definition and illumination uniformity.