Depth Perception Test; Purpose; Interpretation Limits; Definition - FIM MEDICAL Visiolite Series User Manual

5.6.

Depth perception test

5.6.1.

Purpose

To qualify depth perception acuity.
This test can be useful, for example, for forklift operators who require precise docking of loads, or for
perception of distances in vehicle driving.
5.6.2.

Interpretation limits

Depth perception results from the brain integrating two slightly differently-positioned images. This test is only
possible if both eyes have identical, or nearly identical, visual acuity and normal convergence (at least normal
fusion). This test is impossible when there is an important difference in acuity between the two eyes, or
disparity of fixation. However, total absence of depth perception acuity cannot be deduced so easily.
Physiologically, even with low acuity in one eye, even to the point of simple light perception, and normal acuity
in the other eye, depth perception vision is made through cerebral compensation. In theory, only one-eyed
individuals cannot have depth perception vision.
5.6.3.

Definition

Depth perception is screened with 6 separate, numbered boxes. Each box contains 4 shapes: a square, a circle, a
star and a triangle.
For each box, one of the shapes has a binocular horizontal disparity, expressed in arcseconds (1 arcsecond =
1°/3600). This causes a stereoscopic parallax in relation to the three other shapes in the box. Consequently, this
shape should be perceived by the patient in front of, or behind, the three other shapes. The value of binocular
disparity is different for each box: large for the first box and decreasing by half for each consecutive box.
Normal depth perception acuity should perceive the disparities of all the tests.
Box
Disparity
(in arcseconds)
Expected responses
5.6.4.

Patient instructions

"Certain shapes seem to be behind or in front of the others; give the answer for groups 1 to 6".
 Note responses on the response form.
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This document is the property of FIM MEDICAL. Its contents cannot be reproduced or divulged without the company's approval
1 2
1600" 800"
Triangle Circle
3 4
400" 200"
Star Square
V04.02.00
March 2018
5 6
100" 50"
Star Circle
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