Chapter 14 Flashcards
Eye
One of the body’s special senses that consists of two identical main organs with their associated structures. The function of the eyes is to provide sensory information of visual images that can be interpreted by the visual cortex in the brain to become the sense of sight
Accommodation
Change in the shape of the lens as the muscles of the colliery body contract or relax to move the suspension ligaments to the lens. The lens becomes thicker and more rounded to see objects close by or thinner and flatter to see objects at a distance.
Anterior cavity
Area at the front of the eye that consists of the anterior chamber and the posterior chamber
Anterior chamber
Very small space between the cornea and the iris. Aqueous humor circulates through it
Aqueous humor
Clear, watery fluid produced continuously by the ciliary body. It circulates through the posterior chamber, pupil, and the anterior chamber, as it carries nutrients and oxygen to the cornea and lens.
It drains through the trabecular mesh work, the canal of Schlemm, and is absorbed into the blood in a nearby vein.
Canal of Schlemm
Circular Canal around the iris. Aqueous humor from the trabecular mesh work flows through the canal of Schlemm and is absorbed by a nearby vein.
Choroid
Spongy membrane of blood vessels that begins at the iris and continues around the posterior eye.
In the posterior cavity, it is the middle layer between the sclera and the retina.
Ciliary body
Extension of the choroid. It has suspensions ligaments that hold the lens in place. Muscles in the ciliary body contract or relax to change the shape of the lens.
The ciliary body also produces aqueous humor,
Conjunctiva
Delicate, transparent mucous membrane that covers the inside of the eyelids and the anterior surface of the eye. It produces clear, watery mucus.
Cornea
Transparent layer over the anterior surface of the eye that allows light to enter the eye and bends the light rays.
It is the most sensitive area on the anterior surface of the eye.
It contains no blood vessels but receives oxygen and nutrients from tears on its surface and aqueous humor beneath it.
Cranial nerves III
Oculomotor nerve
Carries motor commands to move four extraocular muscles, move the eyelids, and change the size of the pupil.
Cranial nerve IV
Trochlear nerve
Carries motor commands to move the superior oblique extraocular muscle.
Cranial nerve V
Carries sensory information form the eyelids and eye brows to the brain.
Cranial nerve VI
Carries motor commands to move the lateral Rectus extraocular muscle
Cranial nerve VII
carries motor commands to the lacrimal glands to produce tears.
Extraocular muscles
Six muscles that are attached to the sclera by tendons and move the eye in all directions: Superior Rectus muscle Inferior Rectus muscle Medial Rectus muscle Lateral Rectus muscle Superior oblique muscle Inferior oblique muscle
Eyelashes
Hairs in the eyelids that form a protective barrier that extends outward and keeps foreign substances from coming in contact with the eye.
Eyelids
Pair of fleshy structures above and below the eye. They protect the eye as they blink involuntarily to prevent foreign substances from coming in contact with the eye and to spread tears to keep the eye surface moist.
The eyelids contain the eyelashes and sebaceous glands that secrete oil to keep tears on the surface of the eye.
Iris
Colored, circular structure around the pupil. The color of the iris is determined by genetics.
In dim light, muscles in the iris relax to dilate the pupil.
In bright light, those muscles constrict the pupil.
The iris is a dividing structure between the anterior chamber and the posterior chamber
Lacrimal gland
Gland in the superior-lateral aspect of the eye. It continuously produces and releases tears through the lacrimal duct.
Lacrimal sac
Structure that collects tears as the drain from the medial aspect of the eye. The sac empties into the nano lacrimal duct.
Lens
Transparent, flexible disk posterior to the pupil.
It is surrounded by the lens capsule. Muscles of the ciliary body change the lens shape to become thicker and mor rounded for near vision or thinner and flatter for far vision
Lens capsule
Clear membrane that surrounds the lens
Mitosis
Contraction of the muscles of the iris to constrict (decrease the diameter of) the pupil and limit the amount of bright light entering the eye
Mydriasis
Relaxation of the muscles of the iris to dilate (increase the diameter of) the pupil and increase the amount of light entering the eye
Nasolacrimal duct
Structure that carries tears from the lacrimal sac to the inside of the nose.
Orbit
Hollow bony socket in the anterior skull. It surrounds all but the anterior part of the eye and contains a layer of fat to cushion and protect the eye.
Posterior chamber
Very narrow space posterior to the iris. Aqueous humor circulates through it.
Pupil
Dark, round, central pending in the iris that allows light rays to enter the posterior cavity. In dim light, muscles in the iris relax to dilate the pupil (mydriasis). In bright light, these muscles contract to constrict the pupil (miosis).
Sclera
White, opaque, tough, fibrous, connective tissue that forms the outer layer around most of the eye, protects the internal structures, and maintains the shape of the eye.
Also known as the white of the eye.
The extraocular muscles are attached to the sclera
Trabecular mesh work
Interlacing fivers around the edge of the iris. Aqueous humor drains through it and then goes into the canal of Schlemm.
Uvea
Collective word for the iris, choroid, and ciliary body. Also known as the uveal tract.
Fovea
Small depression in the center of the macula. It is the area of sharpest vision and lies directly opposite the pupil.
Fundus
General word for the retina because it is the area that is farthest from the opening (the pupil)
Macula
Dark, yellow-orange circular area with in distinct edges located on the retina. It contains the fovea.
Optic disk
Bright, yellow-white circle in the retina where the optic nerve and retinal arteries enter, and the retinal veins leave, the posterior cavity. It is not stimulated by light or color images and is known as “the blind spot.”
Optic nerve
Cranial nerve II. It enters the posterior cavity at the optic disk and carries sensory information of visual images from the retina to the optic chias in the brain.
Posterior cavity
Large space between the lens and the retina that is filled with vitreous humor.
Retina
Thin layer of tissue that lines the posterior cavity. Landmarks on the retina include the optic disk and the macula. The retina is also known as the fundus.
Vitreous humor
Clear, gel-like substance that fills the posterior cavity and helps maintain the shape of the eye.
Cones
Light-sensitive cells concentrated in the macula of the retina that detect color. There are three types of cones, each of which responds only to red, green, or blue light.
Optic chiasm
Area of the brain where part of each optic nerve crosses over to join part of the optic nerve from the other side. These combined nerves carry images that merge part of the visual field of one eye with part of the visual field of the other eye.
Optic nerve
Cranial nerve II. It enters the posterior cavity at the optic disk and carries sensory information of visual images from the retina to the optic chiasm in the brain.
Refraction
The bending and focusing of light rays as they pass through the cornea and then through the lens.
Rods
Light-sensitive cells in the retina that detect black and white but not color. Rods function in daytime and nighttime vision.
In low light, they produce a grainy, black-and-white image.
Stereoscopic vision
Three dimensional vision with depth and distance perception
Thalamus
Area in the brain where sensory images can be quickly interpreted so there can be a quick motor reflex to blink or move away.
Visual cortex
Area in the right and left occipital lobes of the brain. It merges the images from both eyes to create a single image, then turns the image right side up and facing in the direction of the original object.
Visual field
The field of vision, including all objects that can be seen, centrally and to the side (peripheral vision)
Blepharitis
Infection or inflammation of the eyelid with redness, crusts, and scales at the bases of the eyelashes. Acute blepharitis is caused by an infection or an allergy.
Chronic blepharitis is caused by rosacea, inflammation of the skin, or microscopic mites that live in the sebaceous glands.
Blepharoptosis
Drooping of the upper eyelid from excessive fat or sagging of the tissues due to age. It can also be from a disease that affects the muscles or nerves.
Ectropion
Injury or a growth on the lower eyelid that causes it to turn outward. Ectropion may also be seen as a birth defect in patients with Down Syndrome or from nerve damage to the facial muscles in patients with Bell palsy.
Entropion
The lower eyelid turns inward becasue of weakening of the muscles and tendons. This causes the lower eyelashes to touch the eye, causing chronic conjunctivitis and pain.
Hordeolum
Red, painful swelling or a pimple containing pus on the eyelid. It is caused by a bacterial infection in a sebaceous gland. Also known as Stye.
Dacryocystitis
Bacterial infection of the lacrimal sac. The sac is painful and contains pus.
Xerophthalmia
Insufficient production of tears resulting in eye irritation. It occurs with aging, because of an ectropion, or as a side effect of certain drugs. Also known as dry eyes syndrome.
Conjunctivitis
Inflamed, reddened, and swollen conjunctiva with dilated blood vessels in the sclera. It may be caused by a foreign substance in the eye, a chemical splashed in the eye, allergens or pollution in the air, chlorinated water in swimming pools, mechanical irritation from eyelashes, or dryness due to a lack of tears.
Corneal abrasion
Damage to the cornea due to trauma or repetitive irritation, such as a foreign particle under a contact lens. A chronic bacterial infection in a corneal abrasion can create a corneal ulcer with sloughing-off of necrotic tissue.
Exophthalmos
Pronounced outward bulging of the anterior surface of the eye with a startled, staring expression. If just one eye is affected, it often has a tumor behind it.
Sclera icterus
Yellow discoloration of the conjunctival, which makes the sclera also appear yellow. It is caused by jaundice due to liver disease.
Nystagmus
Involuntary rhythmic motions of the eye, particularly when looking to the side. Each back and forth motion is known as a “beat”.
Strabismus
Deviation of the eye, either medically or laterally. Medial deviation is esotropia or cross-eye.
Anisocoria
Unequal sizes of the pupils. It is caused by glaucoma, head trauma, stroke, or a tumor that damages the cranial nerve that controls the iris.
Glaucoma
Increased intraocular pressrure (IOP) because aqueous humor cannot circulate freely. Glaucoma can progress to blindness.
One-angle glaucoma
The angle where the edges of the iris and cornea meet is normal and open, but the trabecular meshwork is blocked. Open-angle glaucoma is painless, but it destroys peripheral vision, leaving the patient with tunnel vision.
Closed-angle glaucoma
The angle itself is too narrow and blocks the flow of aqueous humor. Closed-angle glaucoma causes severe pain, blurred vision, and photophobia.
Hyphema
Blood in the anterior chamber. It is caused by trauma or increased intraocular pressure from the glaucoma.
Photophobia
Abnormal sensitivity to bright light. It can be associated with inflammation of the eye, or it can be due to increased intracranial pressure or meningitis in the brain.
Uveitis
Infection or inflammation of the uvea, which is a collective word for the iris, choroid, and ciliary body. It can be caused by infection in the eye, infection in another part of the body, an allergy, trauma, or an autoimmune disorder.
Iritis
Infection or inflammation that affects the iris
Choroiditis
Infection or inflammation of the choroid.
Aphakia
Condition in which the lens of the eye has been surgically removed because of a cataract.
Cataract
Clouding of the lens. Protein molecules in the lens begin to clump together. This is caused by aging, sun exposure, eye trauma, smoking, and some drugs.
Presbyopia
Loss of flexibility of the lens with blurry near vision and loss of accommodation. It is caused by aging.
Color-deficient vision
Genetic condition in which the cones are absent or do not contain enough visual pigment to respond to the light from colored objects.
Diabetic retinopathy
Chronic, progressive condition of the retina in which a large number of new, fragile blood vessels form in patients with uncontrolled diabetes mellitus.
Floaters and flashers
Floaters are clumps, dots, or strings of collagen molecules that form in the vitreous humor because of aging and appear as spots in the visual field.
Macular degeneration
Chronic, progressive loss of central vision as the macula degenerates. In older patients, this is known as age-related macular degeneration (AMD, ARMD)
Night blindness
Marked decrease in visual acuity at night or in dim light. This occurs with aging or when the diet does not contain enough vitamin A.
Papilledema
Inflammation and edema of the optic disk. It is caused by increased intracranial pressure from a brain tumor or head trauma. Also known as choked poetic disk.
Retinal detachment
Separation of the retina from the choroid layer beneath it. This can be caused by head trauma or can occur gradually during aging as the vitreous humor changes from a gel-like substance to a watery consistency that flows into small tears in the retina and separates the two layers.
Retinitis
Infection or inflammation of the retina. It can also have a genetic cause.
Cytomegalovirus retinitis
an opportunistic infection that occurs in patient with AIDS whose immune systems are immunocompromised.
Retinitis pigmentosa (RP)
A hereditary condition linked to 70 different genes. The retina has abnormal deposits of pigmentation behind the rods and cones, causing loss of night vision or color vision and loss of central or peripheral vision.
Retinoblastoma
Cancerous tumor of the retina in children, arising from abnormal embryonic retinal cells.
Retinopathy of prematurity
The retina in a premature baby develops abnormal blood vessels that can cause vision loss. If the blood vessel ruptures, it forms a scar that pulls on the retina and can cause a detached retina.
Astigmatism
Surface of the cornea is curved more steeply in one area, so there is no single point of focus on the retina. The patient’s vision is blurry both near and at a distance
Hyperopia
Light rays from a distant object focus correctly on the retina, and so the patient sees a distan object in sharp focus.
Myopia
Light rays from a a ear object focus correctly on the retina, and so the patient sees a near object in sharp focus.
Amblyopia
Condition in which the brain ignores the visual image coming from an eye with strabismus or coming from an eye in which the vision is unfocused or cloudy. The brain does this to avoid having double vision. Also known as lazy eye.
Blindness
Condition of complete or partial severe loss of vision. It is caused by trauma, eye diseases, or defects in the structure of the eye, optic nerve, or visual cortex in the brain
Diploid
Two visual fields are seen rather than one fused image. It can be caused by amblyopia, by a tumor or trauma that increases intracranial pressure, or by multiple sclerosis that affects nerve conduction to the visual cortex.
Scotoma
Temporary or permanent visual field defect in one or both eyes.
This is seen as a dark spot, an area, or a curtain in the field of vision.
Fluorescein angiography
Procedure in which fluorescein is injected intravenously. The dye travels to the retinal artery in the eye, where it glows fluorescent yellow-green on flash photography of the retina.
Ultrasonography
Radiologic procedure that uses ultra high-frequency sound waves to create an image of the eye. The ultrasound image is a sonogram.
Accommodation
Procedure to test the ability of the muscles in the ciliary body to accommodate as demonstrated on near and distance visual acuity tests.
Color-deficient vision testing
Procedure to determine if the patient has a defect in the red, green, or blue cones in the retina.
Dilated funduscopy
Procedure to examine the posterior cavity. Eye drops are used to dilate the pupil and to temporarily keep the pupil in a dilated position.
Ophthalmoscope
Handheld instrument with a light and changeable lenses of different strengths, is used to look though the dilated pupil and examine the retina from all angles.
Eye examination
During an eye examination, the opthalmologist asks about the patine’s medical history and specifically any problems with vision.
Eye patching
Procedure in which the eye is covered with a soft bandage and a hard outer shield after eye trauma or eye surgery.
Fluorescein staining
Procedure in which a fluorescein strip or drops are applied topically to the cornea to detect corneal abrasions and ulcers.
Gaze testing
Procedure to test the extraocular muscles. The patinet’s eyes follow the health care providers finger from side to side and up and down.
Gonioscopy
Procedure to look for blockage of the trabecular meshwork In open-angle glaucoma.
Peripheral vision
Procedure to test visual acuity at the edges of the visual field.
Phorometry
Procedure to select from many different lenses to find the strength of lens that corrects the patient’s refractive error and produces 20/20 vision.
Pupillary response
Procedure to test that the pupils constrict briskly and equally in response to a bright light.
PERRLA
Pupils Equal, Round, and Reactive to Light and Accomodation
Slit-lamp examination
Procedure to look for abnormalities of the cornea, anterior chamber, trabecular meshwork, iris or lens.
Tonometry
Procedure to detect increased intraocular pressure and glaucoma.
Visual acuity testing
Procedure to test near and distance visual acuity. Each eye is tested separately. A card with typed sentences of decreasing print size is held at a press distance of 16 inches to test the near vision.
Antibiotic drug
Treats bacterial infection of the eye
Antiviral drug
Treats viral infections of the eye, specifically herpes simplex virus.
Corticosteriod drug
Treats severe inflammation in the eye.
Drug for glaucoma
Lowers the intraocular pressure by decreasing the amount of aqueous humor or by constricting the pupil to pen the angle between the iris and the cornea.
Mydriatic drug
Dilates the pupil to prepare the eye for an internal examination
Blepharoplasty
Plastic surgery procedure on the eyelids to remove fat and sagging skin. It is often done in conjunction with a facelift.
Capsule to my
Procedure that is only done during a cataract extraction if the posterior part of the lens capsule is cloudy or wrinkled.
Cataract surgery
Procedure of phacoemulsification to remove a lens affected by a cataract.
Corneal transplantation
Procedure to replace a damaged or diseased cornea. The cornea is removed, and a donor cornea is sutured in place.
Enucleation
Procedure to remove the entire eye from its bony orbit because of trauma or a tumor.
Hyperopia surgery
Procedure to correct farsightedness by creating a greater curvature in the cornea, and that corrects the refractive error.
Conductive keratoplasy (CK)
Noninvasive procedure that uses radio waves delivered by a probe as thin as a hair to spots around the edge of the cornea.
Laser thermal keratoplasy (LTK)
Uses a laser that heats small areas in two concentric rings around the cornea
Myopia surgery
Procedure to correct nearsightedness
laser-assisted in situ keratomileusis (LASIK)
Preoperational you, a three dimensional map of the cornea is created and programmed into the laser. A microkeratome is used to create a very thin flap on the surface of the cornea.
Photorefractive keratectomy (PRK)
A very thin outer layer of the cornea is removed and discarded. Then a cold laser is used to reshape the curvature of the remaining cornea.
Photodynamic therapy (PDT)
Procedure to rest we age-related macular degeneration. A light-sensitive drug is injected into the blood.
Retinopexy
Procedure to reattach a detached retina
Cryopexy
Used to freeze the tissue and fix all three layers (sclera, choroid, retina) together.
Laser photo coagulation
Used to heat spots on the retina to coagulate and seal the detached retina to the layers beneath it.
Vitrectomy
If there is bleeding from the detached retina and the vitreous humor contains blood, the laser’s light cannot reach the retina.
Pneumatic retinopexy (PR)
A gas bubble is injected into the posterior cavity and positioned against the retinal tear.
Strabismus surgery
Procedure to correct esotropia or exotropia. During a resection the extraocular muscle on one side is shortened. During a recession, the extraocular muscle on the other side is lengthened and reattached.
Trabeculoplasty
Procedure that uses a laser to treat open-angled glaucoma. The laser creates small holes in half of the trabecular meshwork to increase the flow of aqueous humor.
AMD
Age related macular degeneration
ARMD
Age related macular degeneration
CK
Conductive keratoplasy
EOM
Extraocular muscles
EOMI
Extraocular muscles intact
IOL
Intraocular lens
IOP
Intraocular pressure
LASIK
Laser-assisted in situ keratomileusis
LTK
Laser thermal Keratoplasty
OD, O.D.
Right eye
O.D.
Doctor of Optometry
OS, O.S.
Left eye
OU, O.U.
Both eyes, each eye
PDT
photodynamic therapy
PERRL
Pupils equal, round and reactive to light and accomodation
PR
Pneumatic retinopexy
PRK
Photorefractive keratectomy
RP
Retinitis pigmentosa.
