Medical Terminology Chapter 11: The Eyes and the Ears

Adnexa of the Eyes

the structures outside of the eyeball, include the orbit, eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal apparatus

Adnexa

means the accessory or adjoining anatomical parts of an organ

Orbit

eye socket, the bony cavity of the skull that contains and protects the eyeball and its associated muscles, blood vessels, and nerves

Eye Muscles

six that are arranged in three pairs and are attached to each eye, make a wide range of very precise eye movements possible

Binocular Vision

occurs when the muscles of both eyes work together in coordination to make normal depth perception possible

Depth Perception

the ability to see things clearly in three dimensions

Upper and Lower Eyelids, Eyebrows, and Eyelashes

help protect the eyeball from foreign matter, excessive light, and injuries due to other causes

Canthus

the angle where the upper and lower eyelids meet

Cilia

small hairs that make up the eyebrows and eyelashes

Tarsus

tarsal plate, the framework within the upper and lower eyelids that provides the necessary stiffness and shape

Conjunctiva

the transparent mucous membrane that lines the underside of each eyelid and continues to form a protective covering over the exposed surface of the eyeball

Lacrimal Apparatus

consists of the structures that produce, store, and remove tears

Lacrimal Glands

secrete lacrimal fluid (tears), located on the underside of the upper eyelid just above the outer corner of each eye

Lacrimal Fluid

tears, maintain moisture on the anterior surface of the eyeball

Lacrimal Canal

consists of a duct at the inner corner of each eye, collect tears and empty them into the lacrimal sacs

Lacrimal Sac

tear sac, an enlargement of the upper portion of the lacrimal duct

Lacrimal Duct

the passageway that drains excess tears into the nose

Eyeball

the globe, a 1-inch sphere with only about one-sixth of its surface visible

Optic

pertaining to the eye or sight

Ocular

means pertaining to the eye

Extraocular

means outside the eyeball

Intraocular

means within the eyeball

Sclera

the hard, white of the eye, maintains the shape of the eye and protects the delicate inner layers of tissue, forms the outer layer of the eye, except for the cornea

Choroid

the opaque middle layer of the eyeball that contains many blood vessels and provides the blood supply for the entire eye

Retina

the sensitive innermost layer that lines the posterior segment of the eye, receives nerve impulses and transmits them to the brain via the optic nerve

Aqueous Humor

fills both anterior and posterior chambers of the anterior segment

Intraocular Pressure

a measurement of the fluid pressure inside the eye, regulated by the rate at which aqueous humor enters and leaves the eye

Posterior Segment

makes up remaining two-thirds of the eyeball, lined with the retina

Vitreous Humor

a soft, clear, jelly-like mass that contains millions of fine fibers, help eye maintain shape

Rods and Cones

receive images that have passed through the lens of the eye, images are converted into nerve impulses and transmitted to the brain via the optic nerve

Rods

the black and white receptors

Cones

the color receptors

Macula

the clearly defined light-sensitive area in the center of the retina that is responsible for sharp central vision

Fovea Centralis

a pit in the middle of the macula, color vision is best here because contains a high concentration of cones and no rods

Optic Disk

a small region of the eye where the nerve endings of the retina enter the optic nerve

Optic Nerve

transmits nerve impulses from the retina to the brain

Uvea

the pigmented layer of the eye, has rich blood supply and consists of the choroid, ciliary body, and iris

Ciliary Body

a set of muscles and suspensory ligaments that adjust the thickness of the lens to refine the focus of light rays on the retina

Iris

the colorful circular structure that surrounds the pupil

Cornea

the transparent outer surface of the eye covering the iris and pupil

Pupil

the black circular opening in the center of the iris that permits light to enter the eye

Lens

the clear, flexible curved structure that focuses images on the retina

Accommodation

the process whereby the eyes make adjustments for seeing objects at various distances

Convergence

the simultaneous inward movement of the eyes toward each other

Emmetropia

the normal relationship between the refractive power of the eye and the shape of the eye that enables light rays to focus correctly on the retina

Refraction

the ability of the lens to bend light rays so they focus on the retina

Visual Acuity

the ability to distinguish object details and shape at a distance

Ophthalmologist

a physician who specializes in diagnosing and treating the full spectrum of diseases and disorders of the eyes

Optometrist

provides primary eye care, including diagnosing eye diseases and conditions and measuring the accuracy of vision to determine whether corrective lenses are needed

Optician

a health care practitioner who designs, fits, and dispenses lenses for vision correction

Ptosis

the dropping of the upper eyelid that is usually due to paralysis

Chalazion

a nodule or cyst, usually on the upper eyelid, caused by obstruction in a sebaceous gland

Hordeolum

stye, pus-filled and often painful lesion on the eyelid resulting from an acute infection in a sebaceous gland

Blepharitis

swelling of the eyelid, often at the location of the eyelash hair follicles

Ectropion

the eversion of the edge of an eyelid

Entropion

the inversion of the edge of an eyelid

Periorbital Edema

swelling of the tissues surrounding the eye or eyes

Conjunctivitis

pinkeye, an inflammation of the conjunctiva that is usually caused by an infection or allergy

Dacryoadenitis

an inflammation of the lacrimal gland caused by bacterial, viral, or fungal infection

Subconjunctival Hemorrhage

bleeding between the conjunctiva and the sclera, usually caused by an injury, creates a red area over the white of the eye

Xerophthalmia

dry eye, drying of eye surfaces, including the conjunctiva, because the tear glands do not produce enough tears

Uveitis

an inflammation of the uvea causing swelling and irritation

Iritis

the most common form of uveitis, inflammation affects primarily structures in the front of the eye

Corneal Abrasion

an injury, such as a scratch or irritation, to the outer layers of the cornea

Corneal Ulcer

pitting of the cornea caused by an infection or injury

Diabetic Retinopathy

damage to the retina as a complication of uncontrolled diabetes

Keratitis

an inflammation of the cornea

Keratoconus

occurs when the cornea becomes irregular and cone-shaped, causing blurring and distortion of vision

Scleritis

an inflammation of the sclera

Anisocoria

a condition in which the pupils and unequal in size

Cataract

the loss of transparency of the lens that causes a progressive loss of visual clarity

Floaters

particles of cellular debris that float in the vitreous humor and cast shadows on the retina

Photopsia

the presence of what appears to be flashes of light

Miosis

the contraction of the pupil, normally in response to exposure to light but also possibly due to the use of prescription of illegal drugs

Mydriasis

the dilation of the pupil

Nystagmus

an involuntary, constant, rhythmic movement of the eyeball that can be congenital or caused by a neurological injury or drug use

Papilledema

swelling and inflammation of the optic nerve at the point of entrance into the eye through the optic disk

Retinal Detachment and Retinal Tears

the separation of some or all of the light-sensitive retina from the choroid

Retinitis Pigmentosa

a progressive degeneration of the retina that affects night and peripheral vision

Glaucoma

a group of diseases characterized by increased introcular pressure that causes damage to the retinal nerve fibers and the optic nerve

Open-angle Glaucoma

most common form, trabecular meshwork gradually becomes blocked, causing a build-up of pressure

Closed-angle Glaucoma

acute condition, opening between the cornea ad iris narrows so that fluid cannot reach the trabecular meshwork, causes sudden increase in intraocular pressure

Macular Degeneration

a gradually progressive condition in which the macula at the center of the retina is damaged, resulting in the loss of central vision but not total blindness

Diplopia

double-vision, perception of two images of a single object

Hemianopia

blindness in one-half of the visual field

Monochromatism

color-blindness, inability to distinguish certain colors in a normal manner

Nyctalopia

night blindness, a condition in which an individual with normal daytime vision has difficulty seeing at night

Photophobia

excessive sensitivity to light, can be result of migraines, excessive wearing of contact lenses, drug use, or inflammation

Presbyopia

the condition of common changes in the eyes that occur with again

Strabismus

a disorder in which the eyes point in different directions or are not aligned correctly because the eye muscles are unable to focus together

Esotropia

cross-eyed, strabismus characterized by an inward deviation of one or both eyes

Exotropia

walleye, strabismus characterized by the outward deviation of one eye relative to the other

Refractive Disorder

focusing problem that occurs when the lens and cornea do not bend light so that it focuses properly on the retina

Ametropia

any error of refraction in which images do not focus properly on the retina

Astigmatism

a condition in which the eye does not focus properly because of uneven curvatures of the cornea

Hyperopia

farsightedness, a defect in which light rays focus beyond the retina

Myopia

nearsightedness, a defect in which light rays focus in front of the retina

Amblyopia

a dimness of vision or partial loss of sight, especially in one eye without detectable disease of the eye

Scotoma

blind spot, an abnormal area of diminished vision surrounded by an area of normal vision

Snellen Chart

used to measure visual acuity, results are recorded as a fraction of 20/20