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Dyop® - Dynamic Optotype™

Helping the world see clearly, one person at a time.



Personal Vision

Children’s Vision

Color Screening

Professional Use


How it works

Experimental Dyop Test

Visual Impairment

Dyslexia Screening

Using the Test

Induced Dyslexia



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Dyop® Gap/Segment Motion


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Dyop® Gap/Segment

Photoreceptor Cluster Path


The Dyop® is a Strobic Visual Stimulus


People who see clearly are typically more productive and able to successfully participate and benefit from 21st century technology.  Seeing “clearly” is not just a problem of images being too blurry, but it also a problem of images being too crisp (overminused).


Our eyes developed as sensors for detecting motion, distance, and colors.  The strobic response to a spinning Dyop visual target lets you perceive images and creates a more precise measure of visual acuity and refractions.


As the spinning Dyop ring diameter gets smaller, or your viewing distance increases, the arc width diameter of the Dyop appears to get smaller, and the strobic area of the black/white gap/segments get smaller.  The Dyop acuity endpoint is the minimum angular width (diameter) of the Dyop where that spinning gap/segment motion can still be detected.


Static image and letter-based vision tests tend to overminus refractions due to depletion of the photoreceptor response.  Rather than enhancing visual acuity, static image tests tend to increase visual stress, increase decision fatigue, and create a less precise visual acuity measurement. The use of static letters to measure acuity measures cognition as much as it does acuity. 




Scaled static images are not as accurate in determining visual clarity as calibrated rotating Dyop® images

The sample Dyop images below are calibrated for a 19-inch diagonal monitor and a 10 foot (3.05 meter) viewing distance.





























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Dyop angular arc width controls the acuity endpoint




The 1862 Snellen test is inherently imprecise.

As you move further from the screen, or as the spinning Dyop rings get smaller, the ability to detect the spinning of a Dyop disappears.  Static letters get blurrier but are still visible and static letter “acuity” is dependent upon cognition rather than visual clarity


The static-image visual acuity gap (the Minimum AREA of Resolution) was determined in 1862 by Snellen to be 1.0 arc minutes squared. The actual, empirically determined, Minimum AREA of Resolution is 0.54 arc minutes squared based upon the detection of a moving visual stimulus.  A reason for the larger Snellen stimulus is the photoreceptor stimulus depletion from fixating on static images which creates a visual preference for motion detection.




Photoreceptors also function to focus the lens and detect motion.

When you see the colors Red, Green, and Blue the focal depth of each color is different.  That difference in focal depth stimulates the respective color photoreceptors. The lens adjusts its shape to enable Red light to be focused BEHIND the retina, Green light ON the retina and Blue light in FRONT of the retina.  That color disparity allows the eye to use Chromatic Triangulation to modulate the shape of the lens to regulate the focal depth of light and correlate to the distance of the visual target.





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The eye uses Chromatic Triangulation to regulate acuity via the shape of the lens.




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Retina Segment

Photoreceptors are at the BACK of the Retina


Motion Detection

Having the light receptive part of the photoreceptors at the BACK of the retina allows the photoreceptors to have an ability to detect motion based on the changing intensity and movement of light across a grid of photoreceptors.

The smallest diameter Dyop where spinning can be detected  (the Minimum AREA of Resolution) is an acuity endpoint with a stimulus area of 0.54 arc minutes squared or equivalent to a grid of about 20 photoreceptors




Dyop Refraction Optimization

The Dyop test also allows the optimization of refraction since deviations from the optimum Sphere, Cylinder, and Axis will increase the arc width of Dyop acuity endpoint.


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 “Any sufficiently advanced technology is indistinguishable from magic.”
Arthur C. Clarke’s Third Law


The Dyop® (Dynamic Optotype™) tests and concept are covered under U.S. Patent US 8,083,353

and International Published Patent WO 2011/022428.

For further information contact: Allan Hytowitz at Allan@DyopVision.org

5035 Morton Ferry Circle, Alpharetta, GA, 30022   /   404-281-7798

Copyright©2023 Dyop® Vision Associates.  All Rights Reserved.