Basic Optometric Definitions

the ability of the eye to focus from distance to near

refractive condition in which, when accomodation is relaxed, parallel light rays entering the eye do not focus on the retina.

Examples would be myopia, hyperopia, and astigmatism.

absence of the crystalline lens

clear fluid that is produced in the ciliary process and fills the space between the cornea and the iris. Maintains intraocular pressure and nourishes the cornea, iris and lens.

the practice to reduce or eliminate contaminants (such as bacteria, viruses, fungi and parasites) from entering the operative field in surgery or medicine to prevent infection

optical defect in which the light entering the eye does not form a single point of focus, but forms two focal points; corrected by the use of cylindrical eyeglasses or contact lenses (spherical or toric)

measurement of the back curvature of the lens

a lens that provides both distance and near correction

simultaneous use of both eyes

an opacity of the crystalline lens capsule

patient's reason for the office visit

a lens that is thinner in the center and thicker at the edges; parallel light passing through this type of lens is diverged, or refracted, away from the midline; also known as a minus lens

a technique used to screen for visual field defects using the fingers of the examiner

a lens that is thicker in the center and thinner at the edges; parallel light rays passing through this type of lens are refracted by each surface to converge toward the midline behind the lens; also known as a plus lens

unit of refractive power; abbreviated "D"

to destroy harmful bacteria and viruses

swelling of the tissues due to fluid influx

The condition of the normal eye when parallel rays are focused exactly on the retina and vision is perfect; requires no vision correction

a dye used topically to evaluate corneal integrity and intravenously to evaluate blood vessel integrity; the tear film quality is best observed when a flourescein drop is used

central area of the macula; responsible for the sharpest vision, fine discrimination and high visual acuity, area of the highest concentration of cone cells and no blood vessels; also called the fovea centralis

interior portion of the eyeball that can be seen on ophthalmoscopy or photography; includes the retina and the optic disc

intraocular pressure disease

a refractive condition in which, when accommodation is relaxed, parallel light rays entering the eye focus behind the retina; also known as farsightedness

an instrument used to take stereoscopic views of the fundus

fluid pressure maintained in the eye by the aqueous humor; measured with a tonometer

intraocular pressure

instrument used to measure the corneal curvature

instrument used for determining the power of an eyeglass or contact lens

the area of the eye dividing the cornea from the sclera

central portion of the retina surrounding the fovea; responsible for acute central vision

a disease of the eye involving loss of structure and function of the macula

a lens that diverges light (used in myopes)

use of only one eye

a refractive condition in which, when accommodation is relaxed, parallel light rays entering the eye focus in front of the retina; also known as nearsightedness

an instrument used in examining the interior of the eye

conjunctiva that lines the inside of the eyelids

the angle the frame front makes with the temples when viewed from the side - lower rims are closer to the face than the upper rims

pupillary distance

the study of the visual fields

the visual fields representing side vision

an instrument used for determining the refractive state of the eyes

symptom causing pain on viewing a light; light sensitivity

a lens that converges light; used in hyperopia

a clear plastic material used for rigid contact lenses; first material used after glass

the condition in which lost elasticity of the lens leads to the inability to accommodate

a lens that bends light

term used for aphakic correction after a lens implant

the distance between the centers of the pupil of each eye

an instrument that measures the curvature of a contact lens

altering of the pathway of light as it passes from one medium to another

an instrument used to perform refraction

the angle the frame front makes with the frontal plane of the wearer's face when the lower rims are farther from the face than the upper rims

the vertically measured distance from the lowest point on the lens or the lens opening to the level of the top of the seg

examination of the eye performed using a biomicroscope

a ringlike band of muscle fibers that constricts a passage or closes a natural orifice

system of sorting a prioritizing

a lens that provides correction for distance, intermediate, and near

the distance from the back surface of the lens to the front of the eye