It is use by Eye Care Professionals To check the eyesight of a person.
If u would have visited a eye care centre u would have noticed a chart like this--
If a person can see all the letters from a distance his eyesight is Perfect.If that person misses a letter or a line from the grid eye treatment or spectacles are given to the person for improving their eyesight
you can ask questions that you dont know the answers to, and people on the platform can answer your question! you can also go along and look at other peoples questions and try to answer them for points. have fun!
B. To provide a standard way to orient body and enable precision when discussing human anatomy