Glossary of Optical Terms


Explanations about many of the medical terms used before, during, or after your visit to the optician

We want to make sure you’re completely comfortable when you visit us for your eye exam. This comprehensive glossary will help explain many of the medical and procedural words and terms you may hear before, during, or after your visit and exam. As always, if you have any questions regarding your exam, or would like to have something explained a little more clearly, don’t hesitate to ask your Optometrists. Feel free to also give us a call beforehand.

Amblyopia Commonly called “lazy eye.” It is the loss or lack of central vision in one eye or the inability of the eye to focus.
Cataracts Opacity or cloudiness that usually develops gradually as the lens in the eye loses transparency and the lens material yellows. Cataracts are the leading cause of visual disability in people older than 65.

Automated Visual Fields Determine peripheral and central vision disorders.
Autorefractor Determines nearsightedness, farsightedness and astigmatism.
Biomicroscope/Slit Lamp Examines the eye in layer-by-layer detail.
Intraocular Pressure is pressure of the fluid inside the eye; normal IOP varies among individuals.
Keratometer An instrument used to check the front curvature of the cornea’s surface. This test is important for anyone interested in contact lenses.
Lensometer Measures the power of your current prescription lenses.
Ophthalmoscope A noninvasive, handheld instrument that allows the doctor to examine the internal portion of the eye for a wide range of problems.
Phoropter A mask-like instrument positioned so that each eye sees through a separate lens.

Optician are individuals in the field of designing, finishing, fitting and dispensing of eyeglasses and contact lenses, based on an eye doctor’s prescription. The optician also might dispense colored and specialty lenses for particular needs, as well as low-vision aids and artificial eyes. However an Optician does not have qualification to check and examine your eyes.
Optometrist is a professional who examine, diagnose, treat and manage diseases and disorders of the visual system, the eye and associated structures. They are also trained to diagnose related systemic conditions. Optometrists are individual with a doctorate in optometry thus fully qualified to examine your eyes. They prescribe glasses, contact lenses, low-vision rehabilitation, vision therapy and medications.
Ophthalmologist A physician (doctor of medicine or doctor of osteopathy) who specializes in the comprehensive care of the eyes and visual system and the prevention of eye disease and injury. The ophthalmologist is a physician who is qualified by lengthy medical education, training and experience to diagnose, treat and manage all eye and visual system problems, and is licensed by a state regulatory board to practice medicine and surgery.