Dyop® - Dynamic Optotype™

Helping the world see clearly, one person at a time




Personal Vision

Infant Vision

Color Screening

Professional Use





Dyslexia Screening




Not everyone sees color in the same way.

Color perception affects your visual skills and personality.


FREE Dyop Color Screening Test


Dyop® Color Screening may be indicative of symptoms of dyslexia, migraines, and epilepsy.


To screen for color vision, select the FREE Dyop® Color Screening Test above on a PC, iPad, or SmartPhone.  Move away from the identical-diameter spinning Dyop® images until you CAN ONLY detect either the spinning Green-on-White Dyop® OR the Blue-on-Black Dyop®.  You can also use the Minus (-) symbol to make the images smaller.  For valid color perception screening, the test should be taken without wearing your glasses or corrective lenses. 


If you can detect only the rotating Green you have Letter-based Green-Focused Vision (GFV).   If you can detect only the rotating Blue you have Graphic Red-Focused Vision (RFV).  (Graphic implies that you see words as pictographs rather than as letter-based combinations.)


You may also use the colored animated GIF files on this webpage (below) by moving away from the spinning images and noting, when they get sufficiently small, as to whether you CAN ONLY detect spinning by the Green-on-White Dyop® OR the Blue-on-Black Dyop®.    


Detecting spinning of ONLY the Blue-on-Black Dyop® is potentially indicative of symptoms of dyslexia, migraines, or epilepsy.


The spinning Dyop® color images below are for use on a Smart Phone




















The spinning Dyop® images below are for a 10 foot Viewing Distance on a PC when the line is 10 inches long


































IN THEORY, individuals with chromatic dyslexia-type symptoms have Graphic Red-Focused Vision (RFV) and have an excess ratio of L (red) photoreceptors in their eyes.  The excess of red photoreceptors induces visual dissonance when reading, thus the symptoms are associated with “slow reading.” 


Photoreceptor Response/Distribution

Vision / Photoreceptor Type

Red % (L)

Green % (M)

Blue % (S)

Letter-based Green-Focused Vision




Graphic Red-Focused Vision





Your comments, feedback, and test results would be greatly appreciated.  Please send them to Allan@Dyop.org.

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


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©2018 DyopVision™ Associates.  All Rights Reserved.