The early work in ophthalmology at Mayo Clinic was initially centered on the activities of Dr. Charles H. Mayo. By 1895, Dr. Charlie was handling most operations on the eye, ear, nose, throat, bones and joints. Along with these surgical activities, he did eye refractions and cared for patients who had ophthalmologic diseases.

In 1898, Dr. Gertrude Booker became Dr. Charlie's clinical assistant in treating disease of the eye, ear, nose and throat. She later took charge of eye refractions at Mayo. She remained active in Mayo's eye refraction work until 1914, when she became health officer of Rochester under Dr. Charlie's direction.