So why is the internet dress photo that went viral, fooling so many?
In Health Works, Deena Centofanti speaks with a medical expert to explain the science behind the debate. Ophthalmologist Robert Granadier from the Beaumont Eye Institute explains how two people can see very different images.
"Two people can see the very same image and their retinas will generate different colors," he said. "That's because of the cone pigments in the back of their eye.
"They absorb light at different wavelengths and two people might have slightly different pigments that absorb wavelengths of light at different efficiencies."
Granadier added that the atmosphere makes a difference in how you see the dress whether in natural light or depending on the settings of the television screen or computer monitor.
"The background light makes a very large difference," he said. "This picture (lighter) is over exposed. This picture (darker) is over exposed, and the lighting really brings out color. The under exposed bleaches it out.
Gold and white vs. black and blue - is one better than the other? He says nothing is wrong with one's brain either way.
And what does Granadier see?
"In that picture it appears to be powder blue and brown," he said.
Everyone has an opinion.