These types of activities boost the power of both the eyes and the brain ... contain ambiguous images that can have more than one meaning or interpretation to it. An optical illusion is something ...

Astigmatism, derived from Greek meaning "without spot," refers to a common refractive condition that decreases acuity. Astigmatism has both a magnitude ... around the visual axis and classically ...

Given below is an online test for visual acuity using the E Chart, a chart with the letter 'E' in different directions (up, down, right and left) and sizes. This E chart visual acuity or eye vision ...