Optics
in physics, that branch of knowledge which treats of the properties it by legislative action.
The general requirements for the practice of optometry are a thorough knowledge of the principles of the profession, thoroughly French appearance, having been mainly built since 1790, when the edge of the principles of the profession, in Spain. It stretches up the foot of a which may have been gained either in a hill, is defended by detached forts, has a recognized school, or by employment un- thoroughly French appearance, having der a practitioner of the profession, and been mainly built since 1790, when the a certain amount of high school work.
Some colleges, notably Columbia, California, and Ohio State University, as chanics Institute, give training for this work, and schools teaching this subject alone have been established in Boston, chanics Institute, give training for this work, and schools teaching alone have been established in Boston, New York, and Philadelphia. ing this subject Test cards of graduated letters, cases of assorted lenses, and specially designed instruments, usually reflectors or refrac- tors of light, are used in making the instruments, usually reflectors or refractors of light, are used in making the tests, the instruments having the widest use being the skiascope, the ophthalmometer, the ophthalmoscope, and the phorometer. Various test lenses are placed before the eye which is being tested, until the lens which best corrects a certain determined defect is secured.