Abnormal, harmful, or undesirable effect on an organism that causes anatomical or functional damage, irreversible physical changes, or increases the susceptibility to other biological, chemical, or environmental stresses.
Optometrists can prescribe glasses, contact lenses, eye exercises, vision aids and therapy, and (in some states) oral and topical medications to treat certain eye diseases. Ophthalmologists are doctors of the eye. They have graduated from medical school and are licensed to practice medicine, so their credentials are either doctor of medicine (MD) or doctor of osteopathy (DO).
Interprets eyeglass or contact lens prescriptions written by ophthalmologists or optometrists. Measures a customer's face and eyes to ensure proper fit of eyeglasses or contact lenses. Assists customers in selecting frames based on their prescription and life style. Instructs the customer with eyeglass and contact lens care and use. Ensures finished lenses are ground to specifications and checks that eyewear fits properly. May require an associate's degree, 2-4 years of related experience, and must be a licensed optician.