A haploscope is an optical device for presenting one image to one
eye
An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system.
In higher organisms, the ey ...
and another image to the other eye. The word derives from two
Greek root
The English language uses many Greek language, Greek and Latin Root (linguistics), roots, Word stem, stems, and prefixes. These roots are listed alphabetically on three pages:
* List of Greek and Latin roots in English/A–G, Greek and Latin roots ...
s: ''haploieides'', single and ''skopeo'', to view. The word is often used interchangeably with
stereoscope
A stereoscope is a device for viewing a stereoscopy, 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 ...
, but it is more general than that. A stereoscope is a type of haploscope, but not vice versa. The word has more currency in the
medical
Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...
field than elsewhere, where it refers to instruments designed to test
binocular vision Binocular vision is seeing with two eyes. The Field_of_view, field of view that can be surveyed with two eyes is greater than with one eye. To the extent that the visual fields of the two eyes overlap, #Depth, binocular depth can be perceived. Th ...
. These instruments include
Worth's amblyoscope and the
synoptophore.
Commonly haploscopes employ front-surfaced
mirror
A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera ...
s placed at different angles close to the eyes to reflect the images into the eyes. Reputedly the largest haploscope, with images of over a meter (in fact, 4 feet) square and a viewing distance for each eye of nearly five meters (16 feet), was constructed by
Vaegan in about 1975 to research
stereoacuity
Stereoscopic acuity, also stereoacuity, is the smallest detectable depth difference that can be seen in binocular vision.
Specification and measurement
Stereoacuity is most simply explained by considering one of its earliest test, a two-peg devi ...
.
The large images allowed very small
retinal disparities to be presented.
See also
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Cheiroscope
A cheiroscope (also: ''chiroscope'') is an optical device consisting of a viewing instrument equipped with a drawing pad, with the viewing instrument set up as a haploscope that blends a left and/or right image into view over the drawing.
The c ...
*
Diplopia
Diplopia is the simultaneous perception of two images of a single object that may be displaced in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often voluntary. However, when occ ...
*
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
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External links
International Orthoptics AssociationOrthoptics Association of Australia
Optical devices