Per capita is a Latin prepositional phrase: per (preposition, taking the accusative case, meaning âby, by means ofâ) and capita (accusative plural of the noun caput, âheadâ).The phrase thus means âby headsâ or âfor each headâ, i.e., per individual/person.The term is used in a wide variety of social sciences and statistical research contexts, including government statistics, economic indicators, and built environment studies.he phrase thus means âby headsâ or âfor each headâ, i.e., per individual/person. The term is used in a wide variety of social sciences and statistical research contexts, including government statistics, economic indicators, and built environment studies.
Medical Definition of trichromatism. 1  1: the quality or state of being trichromatic. 2  2: color vision based on the perception of three primary colors and especially red, green and blueâcompare deuteranomaly, protanomaly.
Astigmatism is an eye condition with blurred vision as its main symptom. The front surface of the eye (cornea) of a person with astigmatism is not curved properly-the curve is irregular-usually one half is flatter than the other-sometimes one area is steeper than it should be.When light rays enter the eye they do not focus correctly on the retina, resulting in a blurred image.auses of astigmatism. Corneal astigmatism. The cornea is a clear (transparent) layer of tissue that covers the front of the eye. As well as transmitting and focusing light into the eye, it protects the eye from infection and damage.