Ophthalmic photography apparatus

Abstract

A monocular image of a fundus of an eye under examination is captured via a photographic stop for monocular photography, and two stereographically viewed images are captured with a parallax via two photographic stops for stereographic photography that are decentered from a photographic optical axis. Defocused images are captured in the stereographic photography due to the deviation of the photographic stops from the optical axis. A corrective lens is inserted into the photographic optical path in order to correct the defocus in the stereographic photography. This makes it possible to readily correct defocus generated by deviation of the photographic stops from the photographic optical axis even when switching between monocular and stereographic photography modes.

1 . An ophthalmic photography apparatus comprising:
 imaging means for capturing a monocular image of a fundus of an eye under examination via a photographic stop for monocular photography and capturing stereographically viewed images of the fundus with a parallax via two photographic stops for stereographic photography that are decentered relative to a photographic optical axis; and   a corrective optical element for correcting defocus resulting from the photographic stops for stereographic photography that are decentered relative to the photographic optical axis.   
   
   
       2 . An ophthalmic photography apparatus according to  claim 1 , wherein the corrective optical element is an optical lens. 
   
   
       3 . An ophthalmic photography apparatus according to  claim 1 , wherein the corrective optical element is an optical element for correcting an optical length corresponding to a difference between a length of an optical path in monocular photography and a length of an optical path in stereographic photography. 
   
   
       4 . An ophthalmic photography apparatus according to  claim 1 , wherein the corrective optical element is inserted in the stereographic photography into a photographic optical path between the photographic stops and the imaging means, and retracted therefrom in the monocular photography. 
   
   
       5 . An ophthalmic photography apparatus according to  claim 1 , wherein the corrective optical element is inserted in the monocular photography into a photographic optical path between the photographic stops and the imaging means, and retracted therefrom in the stereographic photography. 
   
   
       6 . An ophthalmic photography apparatus according to  claim 1 , wherein a black spot plate for withdrawing needless light that has been reflected by a surface of an objective lens is disposed in an illuminating optical system, a black spot that is formed on the black spot plate being changed in position, shape, size and quantity depending upon monocular or stereographic photography. 
   
   
       7 . An ophthalmic photography apparatus comprising:
 imaging means for capturing a monocular image of a fundus of an eye under examination via a photographic stop for monocular photography and capturing stereographically viewed images of the fundus with a parallax via two photographic stops for stereographic photography that are decentered relative to a photographic optical axis; and   an optical element capable of moving along the photographic optical axis to bring the fundus into focus;   wherein in monocular or stereographic photography the optical element or imaging means is caused for focus adjustment to move along the photographic optical axis by a length corresponding to a difference between a length of an optical path in the monocular photography and a length of an optical path in the stereographic photography.   
   
   
       8 . An ophthalmic photography apparatus according to  claim 7 , wherein a black spot plate for withdrawing needless light that has been reflected by a surface of an objective lens is disposed in an illuminating optical system, a black spot that is formed on the black spot plate being changed in position, shape, size and quantity depending upon monocular or stereographic photography. 
   
   
       9 . An ophthalmic photography apparatus comprising:
 an illuminating optical system for illuminating a fundus of an eye under examination via an objective lens;   a black spot plate disposed in the illuminating optical system for withdrawing needless light that has been reflected by a surface of the objective lens;   a photographic optical system for guiding light from the fundus through the objective lens to imaging means via a photographic stop; and   means for selecting the photographic stop in different positions;   wherein a black spot that is formed on the black spot plate is changed in position, shape, size and quantity depending upon the selected photographic stop.   
   
   
       10 . An ophthalmic photography apparatus according to  claim 9 , wherein a plurality of black spots is provided, and at least one of the black spots is moved in a direction along the optical axis of the illuminating optical system, or in a direction perpendicular to the optical axis thereof. 
   
   
       11 . An ophthalmic photography apparatus according to  claim 9 , wherein a plurality of black spots is provided, and at least two of the black spots are disposed so at to be superimposed as viewed from the optical axis of the illuminating optical system depending upon the position of the photographic stop.