Dyop® - Dynamic Optotype™

Helping the world see clearly, one person at a time




Personal Vision Test

Infant Vision Test

Color Screening Test

Professional Test


How it works







The Mechanics of Vision 

(Vision as the Ultimate Illusion)


Introducing the Dyop® "revolutionary" method of measuring vision





Dyop Vision Webpage







Dyop Video





   Strobic Dyop® Stimulus



21st Century Vision Testing Can No Longer Rely on 1862 Technology


Your eyes are biological machines.   Your eyes developed as sensors for detecting motion, as well as distance and colors, and to enable us to detect predators and game – to be able to eat rather than be eaten.  

To see most efficiently, your vision has to also be an autonomic process - we have to be totally unaware of the mechanics of that process.  The current global vision “standard” is an 1862-based test dependent upon a cultural ability to detect the size and differences between static letters, such as “E” and “C.”  As a result, that 1862 test method is dependent upon cognition, rather than physiology, for improperly and imprecisely measuring vision.






Vision is the Ultimate Illusion.


Your eyes developed to detect motion.  As you are reading this, you think you are seeing lines and shapes and letters.  What you are actually seeing are pixels of light generated by the electronic phosphors within the surface of your computer screen.

Those electronic pixels are perceived by the photoreceptors of the retina in the back of your eye, which sees light as biological pixels.  Those retina photoreceptors combine their response (primarily the colors
red, green, and blue) into giving you the illusion of vision. 


The impetus for survival also gave your eyes a preference for detecting motion.  When you fixate on the Plus (+) in the circle image below, you will likely see a moving Green circle which appears as the Pink circles seem to rotate around that Plus.  The moving Green circle appears because of the refresh rate and depletion of the Red photoreceptors and their inability to respond to the color Red in the Gray background. 


The Lilac Chaser Illusion


The Lilac Chaser Illusion


Introducing the Dyop®


Dyop® (short for dynamic optotype) is spinning segmented ring which provides a strobic photoreceptor stimulus for use as a visual target (optotype).  A Dyop functions much as a visual tuning fork to precisely, consistently, and efficiently benchmark your acuity (visual clarity).  The apparent motion of the gaps and segments of the spinning Dyop create a binary strobic stimulus of the photoreceptors of your eye.  When the gap/segment area of a spinning Dyop gets too small as the Dyop ring appears to become smaller, that strobic visual stimulus gap/segment area is too small for the photoreceptors to detect that apparent gap/segment motion.  The smallest diameter Dyop ring whose gaps/segments are detected as spinning serves to precisely benchmark acuity (visual clarity) and can be used to determine refractions.  It also allows for the precise measurement of vision in color.


























1862 Snellen Vision Testing


21st Century Dyop® Vision Testing


The smallest Dyop gap/segment stimulus area detected as spinning is also the minimum visual stimulus threshold area (Minimum AREA of Resolution - MAR) which correlates to the response of about 20 photoreceptors.  That Dyop MAR threshold is significantly more precise, consistent, and efficient than staring at letters.  Note that the direction of Dyop spinning is irrelevant.  That process of detecting the minimum diameter of a spinning Dyop also lets the Dyop test be used for individuals who “can’t read,” infants and young children, and individuals with letter-processing problems such as dyslexia


“Classical” letter-based vision tests also use a theoretical gap stimulus area (the Minimum AREA of Resolution - MAR) of 1.0 arc minutes squared.   That letter-based stimulus AREA is significantly larger (almost 2X) than the empirically derived 0.54 arc minutes squared empirically determined Dyop Minimum AREA of Resolution.  Static letter-based tests are also inherently imprecise because they use the cognition of cultural shapes to benchmark vision rather than the actual physiological response of the eye.  Cognition of European-type letters based letters become a guessing game for both the doctor and patient and measures conceptual processing by the patient as much as it does visual clarity. 


How the Eye Works


Your eyes function similar to the pixels receptors of a computerized video camera.  The eye’s photoreceptors not only allow you to see in color (primarily red, green, and blue), but the refresh rate of the photoreceptors, the saccade process, and the matrix response of the photoreceptors allow you to track changes in the location of those images.  The response of about 100 photoreceptors combines to create the stimulus for each optic nerve fiber going to the brain which creates vision and brings that image into focus.  However, the neural ganglia layer of the retina “process” those photoreceptor responses in clusters of about 20 photoreceptors much as a biological circuit board with the emphasis on patterns of motion and proximity.  The comparative focal depth of the red, green, and blue colors of the images also regulates the shape of the biological lens and adjusts focal clarity.


Light passes through the lens

to reach the retina

Retina Structure

 4 Neural Layers

Photoreceptors as Pixels

Retina Color Perception

Wavelengths of light









Light => => Perception


The History of Vision Measurement


Thousands of years ago, visual clarity (acuity) was defined by the ability to see the nighttime gap between two of the smaller stars in the handle of the Big Dipper constellation.


Stellar Acuity

Static Letter-based Acuity

Dyop Strobic Acuity


In 1862 Dutch Ophthalmologist Herman Snellen used the ability to identify (European) letters as the benchmark for visual acuity.  Reading had become a dominant economic and social skill in Europe.  Snellen used the convenience of black letters on a white background as the benchmark although most of what we see is NOT in black and white and other cultures use pictographs rather than letter-based words.























1862 Snellen Vision Testing


21st Century Dyop® Vision Testing


The strobic Dyop stimulus lets you sense the pixel response to the images you are seeing.


While twenty first century technology is letter-based technology, today’s visual acuity is primarily measured by the clarity and ability to read text on an electronic display.  Unfortunately, vision science has not kept up with the precision and demands of those 21st century visual needs.



The increased precision and consistency of the Dyop® tests are intended as a global replacement for static letter-based tests such as Snellen, Sloan, and Landolt optotypes and provide a more universal and efficient method of vision measurement.


The personal version of the Dyop® test is intended to measure your visual clarity; however a prescription for glasses or contact lenses requires vision testing and refractions performed by an eye doctor and CANNOT be done on a two-dimensional display such as a computer.  Measure your vision with the Dyop test using the Dyop Personal Acuity Test, and if you can’t see clearly enough, GO SEE YOUR EYE DOCTOR.


Dyop® tests are for vision screening purposes only and are NOT a substitute for an examination by a licensed vision care professional. 



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


As a culture we are only as good as our memory.  As a species we are only as good as our vision.


Just as the hand, held before the eye, can hide the tallest mountain, so the routine of everyday life can keep us from seeing the vast radiance and the secret wonders that fill the earth.

-        Chasidic, 18th Century


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@Dyop.org

5035 Morton Ferry Circle, Alpharetta, GA, 30022   /   678-893-0580

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