Optometry (Greek: optos meaning seen or visible and metria meaning measurement) is the health care profession concerned with examination, diagnosis, and treatment of the eyes and related structures and with determination and correction of vision problems using lenses and other optical aids .
An optometrist is an eye care professional who is a primary care practitioner for most vision and ocular health concerns. Optometrists, or optometric physicians, as they are sometimes called in the United States, are trained to diagnose, manage, and treat a multitude of visual and ocular health-related concerns, including, but not limited to, fitting and prescribing glasses and contact lenses, diagnosing and treating muscular abnormalities, treating minor ocular injuries, diagnosing and treating diseases such as glaucoma and diagnosing others such as diabetic retinopathy. They also diagnose eye related to systemic disease. Optometric Physicians in Oklahoma may perform certain laser procedures.
Optometrists are experts in determining one's refractive error and prescribing the appropriate correction. In the United States they perform comprehensive eye exams and diagnose and treat eye diseases and disorders whether they be visual or physical. As with all medical practitioners, referrals are made when more specialized care is needed.
 Licensing and education
In the United States, optometrists are health care professionals who complete optometry school, a four year doctoral level program. This is preceded by a 4 year undergraduate program and results in the Doctor of Optometry (OD) degree. They are required to receive licensure through state boards, and some go on to complete post-graduate residencies. Some optometrists further their education with advanced training (a fellowship) in a specific subspecialty. These specialties can include pediatric care, geriatric care, pre and post surgery care, specialty contact lens (for keratoconus patients or other corneal dystrophies) and many others. The American Optometric Association characterizes doctors of optometry as "primary eye care providers."
The scope of practice for optometrists is limited by local legislature and sometimes overlaps that of ophthalmologists. In general, Optometrists practice primary and preventive eye care, while ophthalmologists perform eye surgery; however, in Oklahoma current legislation allows optometrists to perform some non-refractive laser surgery.
Copied from wikipedia: http://en.wikipedia.org/wiki/Doctor_of_Optometry