Even without eye movement, the human field of vision extends over 180 degrees - we can see things out of the corner of our eye that are slightly behind us. When we allow our eyes to move, the field of vision increases to about 200 degrees. ¹⁾

Correct focusing is called emmetropia. ²⁾

Deuteranopia is the defect of not recognizing the color green. ³⁾

Protanopia is the defect of not recognizing the color red. ⁴⁾

Monochromacy is a complete inability to recognize colors. ⁵⁾