Monocular indirect ophthalmoscope

Claim 2

An ophthalmoscope for projecting a view of the fundus of a patient''s eye through the patient''s pupil to the practitioner through his pupil, the ophthalmoscope having an optical system comprising an illumination system on a folded illumination axis, a viewing system on a viewing axis, said axes converging at the fundus, and a beam splitter, the illumination system including a light-emitting element and a condensing lens system for transmitting light rays from said element along the illumination axis to the beam splitter, the beam splitter reflecting said rays through the patient''s pupil to illuminate the fundus, and the viewing system including a demagnifying lens system along the viewing axis, the beam splitter partially reflecting rays passing along the illumination axis, the demagnifying lens system including an objective to provide a real image of the patient''s fundus and an erecting lens to erect and reverse said image, and means for focusing the image of the patient''s fundus, wherein the condensing lens system comprises lenses having characteristics as set forth in the following table, wherein thickness (T) and radii (R) are given in millimeters:

Claim 3

A unitary portable ophthalmoscope for observing the fundus of a patient''s eye, including: an angular housing including a handle, a viewing tube, and a bridge member disposed between and joined to said handle and said viewing tube, an illumination system disposed within said housing along a folded illumination axis and including in series a light source, a variable iris, a battery of filters selectively positionable in said illumination axis, a condensing lens, and a partial reflector to reflect light from said source and toward said fundus, said iris and said battery having external control means, a viewing system disposed within said housing along a straight viewing axis and including in series said partial reflector, an objective lens, an erector lens, and an axially movable eyepiece, said eyepiece being operatively connected for axial movement to an external control means, the control means for the iris, battery, and eyepiece being disposed in juxtaposition for operation by a single digit of the user, said condenser effective to concentrate light on the fundus under observation, said objective lens effective to receive, through said partial reflector, light reflected from the fundus and to inversely image said fundus at the focal plane of said objective along said viewing axis, said erector lens effective to erect the inverse image and, said eyepiece effective to demagnify and conjugate the erected image at the pupil of an observer.

Claim 4

A unitary portable ophthalmoscope for observing the fundus of a patient''s eye, including: an angular housing including a handle, a viewing tube, and a bridge member disposed between and joined to said handle and said viewing tube, an illumination system disposed within said housing along a folded illumination axis and including in series a light source, a variable iris, a battery of filters selectively positionable in said illumination axis, a condensing lens, and a partial reflector to reflect light from said source and toward said fundus, said iris and said battery having external control means, a viewing system disposed within said housing along a straight viewing axis and including in series said partial reflector, an objective lens, an erector lens, and an axially movable eyepiece, said eyepiece being operatively connected for axial movement to an external control means, the control means for the iris, battery, and eyepiece being disposed in juxtaposition for operation by a single digit of the user, said condenser effective to concentrate light on the fundus under observation, said objective lens effective to receive, through said partial reflector, light reflected from the fundus and to inversely image said fundus at the focal plane of said objective along said viewing axis, said erector lens effective to erect the inverse image and, said eyepiece effective to demagnify and conjugate the erected image at the pupil of an observer.