Dyop® - Dynamic Optotype™

Helping the world see clearly, one person at a time




Personal Vision

Infant Vision

Color Screening

Professional Use


How it works








The Dyop® - The revolutionary 21st century way of measuring vision


A Dyop® (short for dynamic optotype) is a segmented, circular visual target whose rotating/moving equally spaced gaps and segments rotate at constant velocity to create a strobic photoreceptor stimulus which can be used to measure visual acuity and refractions.  That strobic stimulus lets you sense the pixel response to the images you are seeing.


Twenty-first century electronic images use pixels which change their color and intensity to create the images we see.  The photoreceptors of the eye function much like those pixels.  Your brain uses the photoreceptor response to create vision and bring that image into focus.  When the moving gaps and segments of a Dyop get too small, their strobic stimulus is too small for the pixel effect to be detected by the photoreceptors of the eye. The smallest Dyop gaps and segments detected as moving create an acuity and refraction endpoint.


Faster and more accurate visual acuity testing


Unlike static image vision tests, such as a logMar or Snellen chart which get increasingly blurry as they get smaller, the rotation of a Dyop appears to stop when the acuity threshold is reached. A patient is presented with 2 Dyops, side by side, one moving and one static and is asked to determine the direction of the spinning Dyop.


What is detected is not so much the motion of the gaps and segments, but that strobic stimulus on the photoreceptors in the eye.


As the angular width of the Dyop diameter and the gap/segments gets sufficiently smaller, the strobic stimulus is no longer sufficiently large enough for the motion of the gap/segments to be detected.


The added precision and reliance upon a visual physiological response, rather than cognition of European-type letters, provides a more precise, consistent, accurate, and efficient method for measuring visual acuity. It also lets the Dyop test be used for people with limited literacy and vision for children.


The History of How We See


Thousands of years ago our eyes developed primarily to spot predators and game as tools for survival.  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

Strobic Stimulus Acuity


In 1862 visual acuity was re-defined as the ability to identify letters when reading became the dominant social skill.  However, European vision science used the convenience of black letters on a white background as the benchmark, although much of what we see is NOT in black and white, only a small portion of the earth’s population could read European letters, and letter-based testing was, and is, frequently inconsistent and imprecise.


Today’s visual acuity is measured by the comfort and ability to read text, especially text on an electronic display.  However, vision science has not kept up with the precision and demands of 21st century visual needs


Much like using the metaphor of the steam engine to describe your heart as pumping blood through the body, or using a computer to describe how we think, the functioning of the eye is similar to the metaphor of an electronic digital camera.


The photoreceptors in the back of your eye function much like the pixelized receptors in that electronic camera.  What you really see (if you can see clearly) are really pixels rather than lines or shapes.  The photoreceptors in your eyes send that pixelized image to your brain which uses it to bring the image into focus and give you your sense of vision.


When you look at a TV, or the display in front of you, your biological eyes see the world as pixels (very small dots of light) rather than as lines and shapes.  The pixels are so small, and pixel density so great that they merge to give the impression of lines and shapes.  Unless you get VERY close to that display, you can ONLY see the lines and shapes rather than those pixels.  In fact, being aware of the pixels gets in the way of comprehending them as lines and shapes or words.


The uniformly rotating/moving gaps and segments of a Dyop provide the photoreceptors with a strobic stimulus which can be to measure visual acuity and refractions. 



Light passes through the lens

to reach the retina

Retina Structure

Epithelium  =>  4 Neural Layers  =>  Photoreceptors


Photoreceptors as Pixels


Retina Color Perception

Wavelengths of light


Light   => 


 => Perception


The pixel response of the photoreceptors functions as biochemical switches in response to light, primarily in red, green, and blue.  Clusters of about 100 photoreceptors have their signal converted by the neurons in the retina into the impulse of one optic nerve fiber.  That optic nerve fiber stimulus is then transmitted to the brain where the brain turns that stimulus into the perception/illusion of lines and shapes.


The visual clarity (acuity) of what we see is also regulated by those color-responsive photoreceptors in the back of the eye.  Light transmitted by the biological lens is separated into wavelengths of color.  That color separation effect typically has red focused slightly BEHIND the retina, green focused ON the retina, and blue focused in FRONT of the retina.  The disparity of the red/green/blue focal intensity is compared by the retina, and used by the brain, to autonomically transmit a stimulus to the muscles controlling the shape of the biological lens, and regulates the instantaneous adjustment of the focal length of the image (accommodation).


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


























1862 Snellen Vision Testing


21st Century Dyop® Vision Testing


Calibrated Dyop® tests are intended as a global replacement for Snellen, Sloan, and Landolt optotypes.


The personal version of the Dyop® test is intended to measure your visual clarity; however getting glasses or contact lenses requires a refraction by your eye doctor which 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

Copyright©2017 Dyop® Vision Associates.  All Rights Reserved