The term "heterophory" derives from the confluence of Greek words "different" and "carrier." Denote this term is a violation of the normal location of the eyeballs, provided that both eyes work together.
The world around us we perceive first of all with the help of the eyes. So, a lot depends on the correct operation of this pair of eyes. Eyes usually have to work a lot during the day, getting rest mainly at night.
Color blindness is a special type of visual impairment, which is manifested in the absence of perception of certain colors, most often green, red and purple. Basically, color blinds are not able to distinguish a particular color or several colors.
Today, in medicine, the need to restore vision is becoming increasingly important. Patients complain of reduced visual acuity, clarity of perception. For many, the perceived object is twofold, or "flies" appear before the eyes.