Name from west to east the four Great Lakes shared by Canada and the US Lake Superior, Lake Huron, Lake Erie, Lake Ontario Name the Great Lake that lies entirely in the boundaries of the US.
Definition of ophthalmology for English Language Learners. medical : the study of the structure, functions, and diseases of the eye.
Ophthalmologist - a doctor of medicine specializing in ophthalmology (medical science dealing with the anatomy, functions, and diseases of the eye.) Optician - a person who makes or sells eyeglasses and, usually, contact lenses, for remedying defects of vision in accordance with the prescriptions of ophthalmologists and optometrists.