Mystery Image Contest: January 6-20, 2014


The Ishihara color test was invented in 1917 by Japanese ophthalmologist Shinobu Ishihara to detect red-green color blindness in humans. The test consists of several dozen circular images, called Ishihara plates, made up of dots of different colors. When a person with normal vision views the Ishihara plate above, they would see the number 6 within the image. A person with red-green color blindness, on the other hand, would not be able to distinguish the red dots from the green and therefore wouldn't be able to see the number 6. If a person is not able to see a majority of the figures, they would be diagnosed with red-green color blindness. The Ishihara test is still commonly used today to help diagnose color blindness.


This image is of an Ishihara plate, an image used in the Ishihara color test.

Photo Credit

Public domain

Winning Entry

Abbey Lohr

For Educators

Teaching Support

This month's Mystery Image Contest ties in with Glaucoma Awareness Month in January. Glaucoma is a disease of the eyes that causes blindness, which an estimated 60 million people worldwide have. Vision loss occurs when the optic nerve becomes damaged. This disease is unique because it has no symptoms, so a person can start losing his/her vision without being aware of it.

Science NetLinks has a wealth of resources related to the eyes, including lessons and podcasts on nearsightedness and glasses, eye surgery, and eye movements—see below. There also are resources on color vision, which can be used in direct conjunction with this month's mystery image of the Ishihara color test plate.

You can use this month's Mystery Image as the beginning of a discussion of how our eyes work and how our brains interpret the visual information received from the eyes.

You also could challenge your students to brainstorm their own ideas for ways to test for color blindness. Your students could develop a hypothesis and then test it out.

Related Resources

Lasers Saving Sight
9-12 | LESSON
Light 3: All Those Seeing Color, Say Eye!
6-8 | LESSON
6-8 | LESSON
EyeDecide App
6-12 | TOOL
Reading in the Dark
Reading Glasses
Eye Tracking

Science NetLinks Mystery Image Contest Rules and Regulations

What Is the

Mystery Image Contest?

The Mystery Image Contest offers the chance to identify a science-related object based on a close-up picture of it.