Scientists still have not known how the autofocus functions in the human eye and other animals. We know that it functions extremely fast and accurately. When the brain gets blurred image it instantly measures the distance to the object and changes the focal length, the curvature of crystalline lens to get a clear image on the retina.
There is a question, how does a focusing mechanism function in the human visual system? Now, the biologists have come close to answering this question. Experts from the Center of Perceptual Systems, University of Texas at Austin (USA) have developed a self-learning statistical algorithm, which eventually learned quickly and accurately to calculate the defocusing degree of any fragment of the blurred image.