amblyopia
reduction or dimness of vision with no apparent organic cause; often referred to as a lazy eye syndrome
cones
structures in the retina that make the perception of color possible
fovea centralis
small pit in the center of the retina that is considered the center of clearest vision
gonioscopy
procedure in which a mirrored optical instrument is used to visualized the filtration angle of the anterior chamber of the eye; the procedure is used to diagnose glaucoma
optic disk
region at back of the eye where the optic nerve meets the retina' it is considered the blind spot of the eye, because it contains only nerve fibers and no rods or cones and thus is insensitive to light
optic nerve
the second cranial nerve which carries impulses for the sense of sight
rods
structures in the retina of the eye that form the light-sensitive elements
tonometer
an instrument used to measure intraocular pressure
ophthamology
science of the eye and its disorders and diseases
ophthamologist
physician who specializes in the diagnosis and treatment of disorders and diseases of the eye
optometrist
not a medical doctor but is licensed and has earned a degree as a Doctor of Optometry (OD)
opticians
trained to fill prescriptions written by ophthalmologists and optometrists for corrective lenses by grinding the lenses and dispensing eyewear
eyes
are the smallest, yet most detailed and complex, organs of the body
bony orbit
protects and supports the eye
eyelid
helps protect the eye from trauma
eyebrows
help keep irritants out of the eyes
eyelashes
line the margins of the eyelids and help trap foreign particles
conjunctiva
thin mucous membrane that lines the eyelid and covers the outside of the eyeball except for the most central portion, which is covered by the cornea
eyes blink every
2 to 3 seconds, causing lacrimal gland to secrete tears
sclera
outtermost layer is made up of the white, opaque ______ and the transparent cornea. tough fibrous lining that protects the entire eyeball lying with the orbit
cornea
acts as a clear window that allows light to enter the eye. Also refracts or changes, the direction of light rays after they enter the eye
choroid posterior
posterior portion of the middle layer of the eye. It's the eye's vascular layer and it contains many blood vessels that supply nutrients to the outer layers of the retina.
choroid anterior
anterior part of this layer, creates the iris and the ciliary body.
iris
colored portion of the eye, contains muscles that regulate the size of the pupil according to the intensity of the light
ciliary body
contains both the muscle, which regulates the shape of the lens and the processes which secrete aqueous humor
retina
delicate tissue, composed of light-sensitive neurons that convert light into neurological impulses
lens
is a transparent, biconvex body that helps focus light after is passes through the cornea
vitreous humor
helps maintain normal pressure within the eye and provides nutrients to the lens and the cornea
vision
requires light and depends on the proper functions of all parts of the eye
visual impulse
begins with the passage of light through the cornea, where the light is refracted; then passes through the aqueous humor and the pupil into the lens
refraction
ability of the lens of the eye to blend parallel light rays coming into the eye so that the rays are focused simultaneously on the retina
error of refraction
that the light rays are not refracted or bend properly and consequently do not focus correctly on the retina
hyperopia (farsightedness)
when light enters the eye and focuses behind the retina; eyeball is too short from the anterior to the posterior wall
myopia (nearsightedness)
occurs when light rays entering the eye focus in front of the retina, causing objects at a distance to appear blurry and dull; eyeball is elongated from the anterior to the posterior wall
presbyopia
as people age, lens of the eye becomes less flexible, and the ciliary muscles weaken; consequently changing the point of focus from distance to near becomes difficult
astigmatism
occurs when light rays entering the eye are focused irregularly, occurs because the cornea or lens is not a smooth sphere.
strabismus
failure of the eyes to track together, which means that both eyes do not look in the same direction at the same time
diplopia
means double vision
nystagmus
a constant, involuntary movement of one or both eyes is called
hordeolum (stye)
localized purulent infection of a sebaceous gland of the eyelid.
chalazion
small cyst that results from blockage of a sebaceous gland that lubricates the posterior margin of each eyelid
keratitis
inflammation of the cornea that results in superficial ulcerations
conjunctivitis
inflammation of the conjunctiva caused by irritation, allergy, or bacterial infection
blepharitis
inflammation of the glands and lash follicles along the margins of the eyelids that may be caused by staphylococcal infection, allergies, or irritation
corneal abrasion
pain, inflammation, tearing, photophobia, usually is caused by a foreign body in the eye or by direct trauma such as from poorly fitting or dirty contact lenses
cataract
cloudy or opaque area in the normally clear lens of the eye that blocks the passage of light into the retina, causing impaired vision
glaucoma
one of the most common and serious ocular disorders is a group of diseases known as _____. Characterized by increased intraocular pressure, which damages the optic nerve and causes blindness if left untreated
macular degeneration
progressive deterioration of the macula lutea, which causes loss of central vision. the patient can only see the edges of the visual field.
blepharoptosis
drooping of the upper eyelid that can be caused by a disorder of the third cranial nerve, muscular weakness as seen in muscular dystrophy, or myasthenia gravis
PERRLA
pupils
equal
around
reactive to
light and
accommodation
distance visual acuity (Snellen chart)
displays various letters of the alphabet, which the patient must identify in ever smaller font sizes
Ishihara Color Vision Test
simple, convenient and accurate procedure that detects total color-blindness as well as red-green blindness that is prevalent in congenital blindness
eye irrigation
to relieve inflammation, remove drainage, dilute chemicals, or wash away foreign bodies.