From Canvas (Eyes Disease Vocabulary) - Unit 13: Eyes and Ears

Astigmatism

A refractive error in which the cornea is abnormally shaped, causing light rays entering the eye to be focused irregularly on the retina and resulting in blurred vision; it can be corrected using contact lenses or eyeglasses to neutralize the defect.

Hyperopia

A refractive error, also known as farsightedness, in which the lens cannot focus an image accurately because the eyeball is shorter than normal, causing light rays to focus behind the retina and resulting in blurred near vision.

Myopia

A refractive error, also known as nearsightedness, in which the lens cannot focus an image accurately because the eyeball is longer than normal, causing light rays to focus in front of the retina and resulting in blurred distant vision.

Presbyopia

A refractive error occurring after age 40 in which the lens loses elasticity and can no longer focus accurately on near images, also called age-related farsightedness because distant objects remain clearer.

Bifocal

Referring to corrective lenses that contain two focal points: one for near vision and one for far vision.

Trifocal

Referring to corrective lenses that contain three distinct focal points for near, intermediate, and distance vision.

Blindness

The absence of vision or the need for assistive devices and support to accomplish daily activities due to an inability to see; legally blind is defined as visual acuity of 20/200 or worse with best correction.

Monochromatism (Color Blindness)

The inability to sharply perceive visual colors, which includes Daltonism (the inability to distinguish greens from reds) and Achromatic Vision (the inability to distinguish any color, perceiving only white, gray, and black).

Nyctalopia (Night Blindness)

Inadequate vision at night or in faint lighting caused by a reduction in the synthesis of rhodopsin, the compound in retinal rods that enables the eye to adapt to low-density light.

Diabetic Retinopathy

A progressive eye condition occurring as a consequence of having diabetes mellitus for 8 to 10 years, characterized by retinal capillary scarring from abnormal vessel dilation/constriction, hemorrhages, microaneurysms, and abnormal new vessel growth that leaks blood into the vitreous humor, leading to a permanent decline in visual acuity.

Macular Degeneration

An incurable, age-related, progressive eye disease affecting the macula (the retinal area critical for fine details) that serves as the leading cause of blindness in people ages 55 and older, affects over 10 million Americans, and has recently been linked to gene defects.

Retinal Detachment

A medical emergency involving the partial or complete splitting away of the retina from the underlying pigmented vascular choroid layer, which interrupts the retina's vascular supply.

Retinal Tear

An opening or break in the retina that allows vitreous humor fluid to leak behind it.

Retinitis

Inflammation of the retina.

Retinoblastoma

A malignant tumor arising from embryonic cells of the retina.

Retinopathy

Any disease or pathological condition affecting the retina; it stands as a leading cause of blindness overall.

Glaucoma

A group of ocular disorders characterized by increased intraocular pressure caused by a breakdown in the drainage system of aqueous humor circulation, leading to decreased blood supply to the optic nerve and retina and eventual loss of peripheral vision if untreated.

Chronic Open-Angle Glaucoma

A primary glaucoma disorder involving a gradual breakdown in the aqueous humor drainage system, causing a slow elevation in internal pressure, reduced blood supply to the optic nerve and retina, and gradual loss of peripheral vision if untreated.

Acute Closed-Angle Glaucoma

A rapid-onset emergency where the mouth of the aqueous humor drainage system closes completely and blocks all fluid flow, characterized by severe eye pain, blurred vision, photophobia, redness, and seeing halos around lights, potentially causing complete loss of sight within several days if untreated.

Cataract

A progressive clouding of the eye's crystalline lens that results in a loss of normal transparency and alters image perception by interfering with light transmission to the retina.

Conjunctivitis

Inflammation of the mucous membrane lining the eyelids and covering the front of the eyeball, commonly known as "pinkeye."

Corneal Abrasion

A disruption or scratch of the cornea's surface epithelium, commonly caused by foreign bodies, eyelashes, contact lenses, or a scratch from a fingernail.

Blepharitis

Inflammation of the eyelid margins originating from seborrheic, allergic, or bacterial causes.

Hordeolum (Stye)

A localized bacterial infection of an eyelash follicle or sebaceous gland that presents with redness, swelling, and mild tenderness along the margin of the eyelash.

Dacryocystitis

A bacterial infection affecting the lacrimal sac.

Dacryoadenitis

Inflammation of the tear-producing lacrimal glands.

Scleritis

Inflammation of the sclera (the white outer covering of the eyeball) characterized by intense redness, dull pain, and potential vision loss.

Ophthalmia Neonatorum

A purulent (pus-containing) conjunctivitis and/or keratitis in newborns resulting from exposure to viral, bacterial, chemical, or chlamydial agents during birth.

Xenophthalmia

An inflamed eye condition caused by the presence of a foreign material.

Xerophthalmia

An abnormal eye condition characterized by extreme dryness of the conjunctiva.

Blepharoptosis

Drooping of the upper eyelid that partially or completely covers the eye due to a weakened eyelid muscle.

Ectropion (Exotropia of Eyelid)

The turning outward (eversion) of the eyelash margins away from the eyeball, leading to exposure of the eyelid and eyeball surface and lining; it occurs most commonly in the lower eyelid.

Entropion

The turning inward of the eyelash margins toward the eyeball, resulting in lashes rubbing against the eye and producing foreign body sensations such as redness, tearing, burning, and itching; it occurs especially in the lower margins.

Trichiasis

An abnormal condition of ingrown eyelashes that grow backward and rub directly against the cornea.

Anisocoria

A condition characterized by unequal pupil sizes, which can be caused by glaucoma, head trauma, stroke, or a brain tumor.

Exophthalmia

An abnormal protrusion or bulging of the eyeball(s), usually making the sclera visible above the iris, typically caused by an increased volume of orbital contents.

Hyphema (Hyphemia)

A hemorrhage or collection of blood in the anterior chamber of the eye, usually resulting as a postoperative complication or from a blunt force eye injury.

Dacryoma

A tumor-like swelling caused by an obstruction in a tear duct.

Strabismus

A condition where the eyes fail to gaze in the same direction due to weakness in the muscles controlling eye position; the most common form is nonparalytic strabismus, an inherited defect where the positions of the two eyes have no coordinated relationship.

Convergent Strabismus (Esotropia)

A form of strabismus, also known as crosseye or esotropia, in which the affected eye turns inward toward the nose.

Divergent Strabismus (Exotropia)

A form of strabismus, also known as walleye or exotropia, in which the affected eye turns outward away from the nose.

Diplopia

The perception of two images of a single object; commonly known as double vision.

Hemianopia

Loss of vision or blindness affecting one-half of the visual field.

Nystagmus

Rhythmic, involuntary movements of the eye(s) that can be vertical, horizontal, rotary, or mixed; caused by alcohol or drug use, inner ear or brain lesions, congenital abnormalities, birth injuries to nerves, or abnormal retinal development.

Aphakia

The absence or surgical removal of the crystalline lens of the eye.

Intraocular

An anatomical term meaning situated or occurring within the eye.

Ischemia

An inadequate supply of oxygenated blood to an organ or tissue part, typically resulting from obstructed blood flow.