US 4,786,163 AGranted

Auto-keratometer

AssigneeSun Contact Lens Co. Ltd.

InventorsMasatsugu Imamichi, Takashi Nishiguchi

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Abstract

An auto-keratometer attached to an operating microscope to measure the refraction and astigmatic condition of the cornea comprises a cornea irradiating light source section disposed below the operating microscope, and switching means for selectively switching the light source section between an irradiating position on the optical axis and a retracted position. When it is desired to measure the corneal condition, the light source section is set at the irradiating position below the operating microscope, so that the light from the light source section reflected by the cornea travels through a beam splitter and is detected by a detector, whereby the refraction or astigmatic condition of the cornea is measured. If the light source section is found interfering with the operation, the light source section is set at the retracted position by rotating it through 180 degrees, whereby the working region below the microscope is widened to facilitate the operator's surgical operation on the cornea.

Claims7

Dependent claims

An auto-keratometer which is adapted to be attached to an operating microscope having an optical axis, a main body, an eyepiece in an upper region of said main body, and an objective lens in a lower region of said main body for measuring the corneal refraction or corneal astigmatic condition by detecting light from a light source reflected by a cornea through the intermediary of said objective lens and a beam splitter, said auto-keratometer comprising:

(A) an annular light source unit having an axis and a circular slit formed in a horizontal plane for irradiation of light downwardly therethrough;
and
(B) means for holding said annular light source unit on said main body of said operating microscope in such a manner that said annular light source unit is movable in a horizontal plane between
(i) an irradiation position at which the axis of said annular light source unit is aligned with the optical axis of said operating microscope, and
(ii) a laterally retracted position at which said annular light source unit is removed from a workspace beneath said objective lens of said operating microscope.

2 more elements

Dependencies are inferred from the claim text.