Glossary
-
Opaque tint
Tint applied to a contact lens which blocks all light passage; allows total eye color change (e.g., from brown to blue eyes).
-
Ophthalmologists
Are doctors who provide comprehensive eye care with medicine and surgery.
-
Ophthalmometer (keratometer)
Optical instrument for measuring the radius of curvature of the cornea in any meridian. By measuring along the two principal meridians, corneal astigmatism can be deduced.
-
Optic zone diameter
Diameter of the optic zone (front or back) of a contact lens measured to the surrounding junction. It is commonly specified in millimetres. Specifically, there are the back optic zone diameter (BOZD), formerly called back central optic diameter (BCOD), and the front optic zone diameter (FOZD).
-
Opticians
Fit and adjust eye glasses.
-
Optometrists
Provide routine primary eye care and can prescribe eyeglasses and examine vision.
-
Orthokeratology
Programmed application of contact lens fitting for the purpose of altering the curvature of the cornea, especially to reduce the eye's refractive power in myopia.
-
Over refraction
A refraction performed over a patient's contact lenses to determine what power is needed to provide optimum visual acuity.
-
Overwearing syndrome
Risks of injury to the eye from overwearing, incorrect fit, and improper care of the lenses with clinical findings that include central epithelial erosions, pronounced injection (redness), lid edema, and constricted pupils.
-
Oxygen permeability
The amount of oxygen diffusing through a given amount of lens material in a given amount of time, under specified testing conditions
