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Full text of "NASA Technical Reports Server (NTRS) 19730000492: Miniaturized haploscope for testing binocular vision"

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December 1973 


B73-10492 


• NASA TECH BRIEF 

Ames Research Center 


NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 2215 1. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 




This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States 


Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights. 












the operator to present any one of 99 separate frames 
of each right and left test film. A fiber-optic bundle 
distributes the light from a central source to a diffus- 
ing screen mounted just above the film-plane aperture. 

The mechanical base permits rotating the optical 
system precisely about the center of rotation of each 
eye; the base is structurally rigid so that the vergence 
angles of the optics are accurately determined. A ver- 
gence-angle drive motor counterrotates two threaded 
shafts through a miter gear arrangement; as the shafts 
turn, blocks on the right and left sides of the base are 
moved symmetrically inward or outward. The blocks 
are rigidly supported by a set of fixed parallel rods 
running from one side of the mechanical base to the 
other. A platform with a V-groove cut into its curved 
inner and outer edges is mounted over each driving 
block, and a vertical drive pin attached to the top of 
each block extends up through a slot in the platform 
and moves back and forth as the driving block is 
moved. A trolley mounted over each platform has 
three V-shaped wheels which nm in the V-grooves; 
the drive pins also extend into the trolleys, so that the 
linear motion of the driving blocks is converted into 
the curvilinear motion of the trolley mechanisms. 
Each trolley is specially constructed to minimize fric- 
tion and backlash. 

The mechanical base permits vergence angle 
changes from 22 degrees eso to 14 degrees exo for 
each eye; interpupillary distance adjustments are 
made by moving each driving block inward or out- 


B73-10492 


ward until the distance between the centers of the 
radii of the curved tracks are equal to the interpupil- 
lary distance of the subject. The X-Y adjustor for the 
chin rest is also on the mechanical base. Alignment of 
the apex of the subject's corneas is accomplished with 
the aid of two small fixtures mounted on the outer 
portions of the right and left optical systems; the 
examiner sights across the fixtures and moves the 
subject's head forward or backward by means of a 
forehead adjustor. 

All the subsystems of the electronic controls are 
open-loop and solid-state-controlled and, with the 
exception of the vergence angle drive, utilize dc 
stepping motors as prime movers. Arrangement is 
also made for readouts of each variable. 

Note: 

Requests for further information may be directed 
to: 

Technology Utilization Officer 
Ames Research Center 
Moffett Field, California 94035 
Reference: TSP 73-10492 

Patent status: 

NASA has decided not to apply for a patent. 

Source: Thomas A. Decker of 
Baylor College of Medicine 
under contract to 
Ames Research Center 
(ARC-10759) 


Category 05