How Do Optical Illusions Work?

Published on
January 5, 2022

We’ve all encountered optical illusions at one point or another; but the thing you’ve likely wondered is: How do they work? How do they trick us into seeing something different from what is actually in front of us?

While nearly all optical illusions take advantage of the way our minds have learned to interpret the world around us, different types of illusions demonstrate different things about our visual system.

However, here we’ll just be going a bit deeper into the general idea of how our brain can be fooled by visual input.


The Brain-Eye Connection

As smart as our brain is (and it is smarter than many give it credit for), it cannot see on its own, relying on visual input from the eyes. However, the eyes function more like cameras, and aren’t capable of always effectively conveying complex visuals to the brain. So, at times, the brain gets confused.

This confusion can lead the brain to making mistakes like thinking something is moving when it is not, or “seeing” colors or shapes which aren’t actually there.

For one example, look at the image below. 


The two squares marked A and B are the same shade of gray, despite how it may appear. This is due to our brain trying to determine the color by looking at the other squares around them.


Filling in the Blanks

Because of the simple means of communication between the eyes and the brain, sometimes there is information that can’t get accurately communicated, so the brain makes its best guess based on what information it has received from the eyes. Most of the time, it’s correct.

But sometimes those guesses are wrong, due to the imperfect communication.

An Ongoing Mystery

Despite a great deal of research by many scientists into exactly how these illusions work, for many, we don’t know how the brain-eye link creates them. We do know now that the path the information from our eyes takes to get to the brain is rather long and complex, so confusion can arise at any stage of that journey. Generally, illusions in which the confusion arises later in that journey, the less we know about exactly why and how it happens.

However, more research is being done all the time, so maybe one day someone--perhaps even you!--will finally solve the mystery.



  • Vision therapy is well worth the response, time and effort. Our Son had a hard time focusing and writing neatly. After vision therapy Seth could complete a task in half the time if previously took. His abilities to focus improved greatly and so did his handwriting.

    Also, he was better at listening. As a parent, we wanted learning to be fun for our Son, and vision therapy made this possible.

    Amanda T.

  • Vision Therapy is well worth the expense, time and effort. Our son had a hard time focusing handwriting neatly. After vision therapy Seth could complete a task in half the time it previously took his abilities to focus and improved greatly and so did his handwriting.

    Also, he was better at listening. As a parent you wanted learning to be fun for our son and vision therapy made this possible.

    Alexa H.

  • Vision Therapy has given or son the tools he needs to be able to scan and read the written word more effectively and efficiently.

    He love working with John and these working sessions give him the motivation to gladly work on his homework assignments.

    It amazed us to see the difference in the tracking of his eyes and along a line of it's from the beginning to the end of the treatment.

    Dr. McBryar , Kristen and John  are all marvelous and we would recommend them to anyone I only wish that we would have found them sooner!

    Charlotte M.

  • Prior to coming to the institute for vision development my son complained of daily headaches. Therapy has eliminated his headaches completely. I love knowing my son is able to learn pain-free for the rest of his life because of the work that has been done over just a few weeks in this office. He he absolutely loved coming that didn't even feel like going to a doctor or therapy. We are grateful for the relief he was able to find by coming here.

    Thank you!

    Olivia C.

  • Seems much less frustrated with life

    Reads non-stop and fast

    Spelling abilities have been hugely improved

    Seems much more confident

    Thank You!!!

    Kelly O.



Vision Among Us

One of the challenges with visual impairments and visual deficits is that it's difficult to detect them just by looking […]

Read More

Vision Therapy for Neurological Conditions

Each year an estimated 1.5 million Americans sustain a traumatic brain injury (TBI). According to the Neuro Optometric Rehabilitation Association, […]

Read More

Vision Therapy for Adults

Adults generally accept changes in themselves as part of aging, and think that there's nothing they can do about it. […]

Read More
see all blogs

Contact Us To Amplify Your EyeCare

Amplify EyeCare Chattanooga Logo

Working Hours

Monday - Tuesday
7:30AM - 5:15PM

Wednesday - Thursday
8:00AM - 5:15PM

Friday - Sunday

1043 Executive Drive Suite #101 Hixson, TN 37343
(423) 710 3966
Website Accessibility Policy
Safety protocols page
privacy policy
Cancellation Policy
For Patients
Call Us
eyefile-adduserphone-handsetcalendar-fullarrow-uparrow-right linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram