Eyes Flashcards
Accommodation
adjustment of the eye for various distances through modification of the lens curvature
Amsler grid
a set of charts with various geometric shapes in black and white, used for detecting defects of the central visual field
Anisocoria
inequality of the diameter of the pupils; may be normal or congential. often normal if inequality is within 1mm.
Aphakia
a condition in which part or all of the crystalline lens of the eye is absent, usually because of surgical removal for treatment of cataracts.
Aqueous humor
the watery transparent liquid containing trace albumin and small amounts of salts produced by the iris, ciliary body, and cornea. It circulates through the anterior and posterior chambers of the eye.
Astigmatism
an abnormal condition in which light rays cannot be focused clearly in a point on the retina because of irregular curvature of the cornea or lens.
Cataracts
opacity of the lens; most commonly resulting from denaturation of the lens protein caused by aging.
Chalazion
small, hard tumor analogus to sebaceous cyst developing on the eye lids, formed by the distention of a meibomian gland with secretion.
Choroid
the middle vascular tunic of the eye lying between the retina and sclera. Dark brown vascular coat of the eye between sclera and retina, extending from ora serrata to optic nerve. consists of blood vessels united by connective tissue containing pigmented cells and is made up of five layers.
Ciliary body
the thickened part of the vascular tunic of the eye that joins the iris with the anterior portion of the choroid. Consists of three zones: ciliary disk, ciliary crown, and ciliary muscle.
Cones
the photosensitive, outward-directed, conical process of a cone cell essential for sharp vision and increasing numbers of rods toward the periphery of the retina
Confrontation
a test for estimating peripheral vision
Conjunctiva
the mucous membrane investing the anterior surface of the eyeball and the posterior surface of the lids
Conjunctivitis
inflammation of the conjunctiva caused by infectious agents or by allergies; commonly called pinkeye
Cornea
the clear, transparent anterior portion of the fibrous coat of the eye comprising about one sixth of its surface. It is the chief refractory structure of the eye.
Corneal arcus
opaque white ring about corneal periphery, seen in many individuals older than 60 years of age. This is due to deposit of lipids in the cornea or to hyaline degeneration. May indicate a lipid disorder, most commonly type II hyperlipidemia if present before 40 years of age ( younger people, its called arcus juvenillis)
Cotton wool spot
an ill-defined yellow area due to infarction of the nerve layer of the retina
Depth perception
perception of spatial relationships; three dimensional perception. The visual ability to judge depth or distance
Diabetic retinopathy (background)
a condition characterized by dot hemorrhages or microaneurysms and the presence of hard and soft exudates
Diabetic retinopathy (proliferative)
a condition characterized by development of new vessels as a result of anoxic stimulation; vessels grow out of the retina toward the vitreous humor
Diopter
refractive power of the lens with focal distance of 1 meter, used as unit of measurement in refraction
Diplopia
the condition in which a single object is perceived as two objects (double vision)
Drusen
tiny yellow or white deposits in the retina of the eye or on the optic nerve head
Ectropion
eversion (outward rolling) of an edge or margin; as the edge of the eyelid
Episcleritis
inflammation of the superficial layers of the sclera located in front of the insertion of the rectus muscle.
Entropion
inversion (inward rolling) of an edge or margin; especially the margin of the lower eyelid
Exophthalmos
an increase in volume of the orbital content, causing a protrusion of the globes forward. It may be bilateral or unilateral. The most common cause of bilateral is Graves’ disease (thryoid disease), but when unilateral protrusion is noted, a retro-orbital tumor must be suspected.
Farsightedness
an error of refraction in which, with accommodation completely relaxed, parallel rays come to focus behind the retina.
Glaucoma
a disease of the optic nerve wherein the nerve cells die, producing increased cupping appearance of the optic nerve. an abnormal condition of elevated pressure within an eye resulting from obstruction of the outflow of aqueous humor. Produces defects in the visual field and may result in blindness.
Hemianopia
blindness for half the field of vision in one or both eyes
Hordeolum
Sty. a suppurative inflammation of a sebaceous gland of the eyelid.
Hyperopia
Farsightedness. a refractive error in which light rays entering the eye are focused behind the retina.
Hypertelorism
eyes spaced widely apart
Hyphema
blood in the anterior chamber of the eye in front of the iris
Iris
the colored contractile membrane suspended between the lens and cornea in the aqueous humor of the eye, separating the anterior and posterior chambers of the eyeball and perforated in the center by the pupil. By contraction and dilatation, it regulates the entrance of light.
Iritis
inflammation of the iris
Legal blindness
in the US, a person is legally blind when vision in the better eye, corrected by glasses, is 20/200 or less, or in the case of a constricted field of vision; 20 degrees or less in the better eye
Macula
AKA fovea, site of central vision.
Mydriasis
pupillary dilation
Miosis
abnormal contraction of pupils
Myopia
Nearsightedness. a condition resulting from a refractive error in which light rays entering the eye are brought into focus in front of the retina
Night blindness
decreased ability to see in reduced illumination. Seen in patients with impaired rod function; often associated with deficiency of vitamin A
Nystagmus
involuntary rhythmic movements of the eyes; the oscillations may be horizontal, vertical, rotary, or mixed.
Papilledma
edema of the optic disc resulting in loss of definition of the disc margin; the cause often is increased intracranial pressure
Peripheral vision
vision resulting from retinal stimulation beyond the macula
Pinguecula
a harmless yellowish triangular nodule in the bulbar conjunctiva on either side of the iris that stops at the limbus
Presbyopia
Hyperopia (farsightedness) and impaired near vision from loss of lens elasticity, generally developing during middle age
Pterygium
a triangular (patchlike) thickening of the bulbar conjunctiva that grows slowly to the outer surface of the cornea, usually from nasal side, and may cover a portion of the cornea.
Ptosis
the drooping of one or both upper eyelids
Punctum
the tiny aperture (opening) in the margin of each eyelid that opens to the lacrimal duct
Red Reflex
a response caused by light illuminating the retina
Refraction
the act of determining the nature and degree of the refractive errors in the eye and correction of them by lenses.
Retina
the sensory network of the eye that transforms light impulses into electrical impulses, which are transmitted through the optic nerve.
Retinitis pigmentosa
a chronic progressive disease, which may occur in childhood, characterized by degeneration of the retinal neuroepithelium.
Retinoblastoma
an embryonic malignant glioma arising from the retina usually during the first two years of life. Initial diagnostic finding is usually a yellowish or white light reflex seen at the pupil (cat’s eye reflex)
Rods
The photosensitive, outward-directed process of a rhodopsin-containing rod cell in the external granular layer of the retina; mainly millions of such rods togather with the cones, form the photoreceptive layer of rods and cones.
Sclera
a tough white fibrous tissue which covers the so-called white of the eye. It extends from the optic nerve to the cornea
Scleritis
superficial and deep inflammation of the sclera
Strabismus
a condition in which both eyes do not focus on the same object simultaneously, however either eye can focus independently.
Uveitis
inflammation of the iris, ciliary body, and choroid, or the entire uvea.
Vitreous body
a transparent jellylike substance that fills the cavity of the eyeball, enclosed by the hyaloid membrane; it is composed of a delicate network (vitreous stroma) enclosing in its meshes a watery fluid (vitreous humor)
Xanthelasma
an elevated plague commonly found on the nasal portion of the eyelid due to elevated cholesterol.
