<unk>  is<unk>  in which both eyes are used together. The word<unk>  comes from two Latin roots, bin for two, and oculus for eye. Having two eyes confers at least four advantages over having one. First, it gives a creature a spare eye in case one is damaged. Second, it gives a wider field of view. For example, a human has a horizontal field of view with one eye of about 150 degrees and with two eyes of about 180 degrees. Third, it gives<unk>  summation in which the ability to detect faint objects is enhanced. Fourth it can give stereopsis in which parallax provided by the two eyes' different positions on the head give precise depth perception. Such<unk>  is usually accompanied by singleness of<unk>  or<unk>  fusion, in which a single image is seen despite each eye's having its own image of any object.
Other phenomena of<unk>  include utrocular discrimination, eye dominance, allelotropia, and<unk>  rivalry.
Binocular vision
Myopia pathophysiology
Visual acuity
Visual perception
Eye pain pathophysiology
Ophthalmoparesis causes
Fundal height
Haptic perception