A cheiroscope (also: ''chiroscope'') is an
optical device consisting of a
viewing instrument
A viewing instrument is a type of optical instrument that is used to assist viewing or visually examining an object or scenery
Types
* binoculars
* contact lenses
* cystoscope
* electrotachyscope
* endoscope
* eyeglasses
* fibrescope
* findersco ...
equipped with a drawing pad, with the viewing instrument set up as a
haploscope A haploscope is an optical device for presenting one image to one eye and another image to the other eye. The word derives from two Greek roots: ''haploieides'', single and ''skopeo'', to view. The word is often used interchangeably with stereoscop ...
that blends a left and/or right image into view over the drawing.
The cheiroscope was presented in an article published in 1929.
[ ()] The author E. E. Maddox writes that compared to the earlier
amblyoscope A haploscope is an optical device for presenting one image to one eye and another image to the other eye. The word derives from two Greek roots: ''haploieides'', single and ''skopeo'', to view. The word is often used interchangeably with stereoscop ...
,
:"
e cheiroscope approaches the problem from a different and complementary angle, on the simple principle of pressing the ''hand'' into service to educate the eye."
A cheiroscope can be operated in different manners. For example, using a cheiroscope, a line image can be presented to one
eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
and the image of a blank sheet to the other eye, and the subject is intended to make a drawing that reproduces the line image.
The cheiroscope is used for diagnostic purposes to test
binocular vision
In biology, binocular vision is a type of vision in which an animal has two eyes capable of facing the same direction to perceive a single three-dimensional image of its surroundings. Binocular vision does not typically refer to vision where an ...
, to assess certain conditions of
strabism
Strabismus is a vision disorder in which the eyes do not properly align with each other when looking at an object. The eye that is focused on an object can alternate. The condition may be present occasionally or constantly. If present during ...
in particular related to binocular stability and alignment,
, and the presence and extent of
suppression.
It can also be used in
vision therapy
Vision therapy (VT), or behavioral optometry, is an umbrella term for alternative medicine treatments using eye exercises, based around the pseudoscientific claim that vision problems are the true underlying cause of learning disabilities, parti ...
to train
amblyopic subjects in desuppression and
eye–hand coordination
Eye–hand coordination (also known as hand–eye coordination) is the coordinated control of eye movement with hand movement and the processing of visual input to guide reaching and grasping along with the use of proprioception of the hands to ...
.
A
stereoscope
A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image.
A typical stereoscope provides each eye with a lens that makes the ima ...
can be modified to function as a cheiroscope.
Cheiroscope
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See also
* Diplopia
Diplopia is the simultaneous perception of two images of a single object that may be displaced horizontally or vertically in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often ...
* Amblyopia
Amblyopia, also called lazy eye, is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye. It results in decreased vision in an eye that typically appears normal in other aspects. Amb ...
* Orthoptist
Orthoptics is a profession allied to the eye care profession. Orthoptists are the experts in diagnosing and treating defects in eye movements and problems with how the eyes work together, called binocular vision. These can be caused by issues with ...
References
{{reflist
Optical instruments
Stereoscopy