Not necessarily, it depends on how different you perceive a shape/object from its original version. If you tend to see something quite different then you could have symptoms of optical illusion. As far as color goes, most people have some percentage of color blindness and that doesn't necessarily relate to this illness. You could perhaps be considered color blind if you tend to lack difference in perception about some/all colors.
because its the clash of colours that basically make the illusion?
No, it is not an optical illusion.
It is in your question already. An illusion will never be real. If it was real then it would be no illusion. Optical illusions are in a way real. They are real optical illusions. We can however not fake an illusion because the illusion is fake from start.
Because he can.
yap.. its just an optical illusion
All mirages are optical illusions but all optical illusions are not mirages.
OpTiCaL ILlUsIoN WaZ MaDe fOr ArT AnD FoR tHe InJoyMeNt oF thE PeOpLE
both because the eye sends the pic to your brain
Optical illusion challenges will increase sharpness of your brain. Also the increasing visual literacy is also possible through optical illusion challenges.
Bored Panda is a great website which offers a number of different optical illusion pictures. You can also find optical illusion pictures from Yahoo! Images.
NO
The fog created an optical illusion.