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112 Cards in this Set
- Front
- Back
Oculomotor, trochlear, and abducens cranial nerves do what?
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Work as extrinsic and rectus muscles of the eye
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Wall of the eye has how many layers?
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3; Outer sclera, middle choroid, inner retina.
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What is the first part of the eye that refracts light rays
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Transparent Cornea
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Choroid layer of eye contains
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blood vessels, melanin that absorbs light to protect eyeball from glare
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What parts of the eyes have no capillaries?
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Cornea, ciliary body
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Constriction of the eye is a __________ response.
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sympathetic
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Contraction of the eye is a ______________ respone.
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parasympathetic
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Retina lines what?
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The posterior two thirds of the eyeball and contains the cones and rodes.
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Cones
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detect color
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Rods
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Detect light
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Optic disc
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Can be called the blind spot because no rods or cones are present
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Larger posterior cavity of the eye contains
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Vitreous humor and is between the lens and retina.
Vitreous humor keeps retina in place. |
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Anterior cavity of the eye contains
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Aqueous humor, which nourishes the lens and cornea.
Aqueous humor is formed by capillaries, flows anteriorly through pupil and reabsorbed by canal of Schlemm. Reabsorption normally equals rate of production. |
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The ____ is the only adjustable part of the focusing system.
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Lens
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When the eye focuses on a distant item...
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Ciliary muscle is relaxes and lens is elongated and thin
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When the ye focuses on a close object...
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Ciliary muscles contract and form a smaller circle.
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Light absorbing molecule....
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Retinal
(A derivative of vitamin A) ..Which binds to a protein called opsin |
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In rods the light stiulates
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The breakdown of rhodopsin into opsin and retinal which results in nerve impulse for transmission
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Cones also contain
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Retinal.
Opsins of the cones respond to visible light spectrum (red-absorbing, blue-absorbing, green-absorbing) |
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Impulses from rods and cones are transmitted to
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Ganglion neurons
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The optic nerves of both eyes converge at
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the optic chiasma in front of the pituitary gland
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When two images are put together is called
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binocular vision which also provides depth perception
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Most common changes in the aging eye is
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The lens
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Lens may become
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Partially or totally opaque and loses elasticity
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Most people become ________ sighted as they age.
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Far
May need corrective lenses at age 40 |
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Things that happen to aging eye
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Peripheral vision loss
Depth perception decreases Color vision fades (red yellow orange are best seen) |
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Tests used for visual acuity
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Snellens chart, E chart, hand-held visual acuity chart (Rosenbaums card)
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Visual impairement occurs at....
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20/70
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Legal blindeness =
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20/200
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E chart is used for patients who are
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Illiterate
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Peripheral vision tests are also called
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Testing visual fields by confrontation
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Nystagmus
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Involuntary cyclical rapid movement of the eyes in response to vertical horizontal or rotary movement
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Cover test
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Used for abnormal corneal light reflex to evaluate muscle balance
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Tropia
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Deviation of eye away from visual axis
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Esotropia
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Deviation of the eye toward the nose
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Exotropia
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Eye movement laterally
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Hypotropia
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Downward deviation of eye
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Consensual response
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Both pupils constrict
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Accommodation
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Ability of pupil to respond to near and far distances
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PERRLA
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Pupils equal, round, reactive to light, accommodation
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Presbycusis
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Hearing loss
Due to loss of hair cells and decreased blood supplying ear |
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Palpebral Fissure
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Distance b/w upper and lower eyelid
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Pterygium
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Thickening of conjunctiva
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Arcus Senilus
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Older than 40, bilateral opaque whitening of outer rim of cornea caused by lipid deposits
Doesnt affect vision |
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Tonometer
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Test IOP
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Fluoresein Angiography
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Used to monitor, diagnose, treat eye diseases.
Uses dye |
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Electroretinography
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Diagnosing diseased of the rods and cones.
Contact lense with electrodes directly on eye |
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Ultrasonography
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Eye anesthetized with drops and probe is put on eye for ultrasound
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Corneal damage and night blindness are r/t
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Lack of vitamin A
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Optic neuritis is r/t
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Lack of vitamin B
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Macular degeneration and cataracts r/t
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Lack of antioxidants
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Reduce change of MD by 27% with
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High doses of vit C, E, beta carotene and zinc
Spinach, broccoli and eggs reduce risk by 40% |
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60% reduction of risk of cataracts with
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Vitamin C supplements for 10 years or more
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Punctum
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Tear duct
Hold punctum after admin meds to eye to prevent systemic reaction to med |
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Three Auditory Bones
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Malleus, Incus, Stapes
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Rinne Test
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Normal AC>BC 2:1
Conductive loss= BC>AC Sensorineural loss= AC>BC less than 2:1 |
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Webers Test
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Tuning fork on top of head
Conductive loss= Sound louder in ear thats affected Sensorineural loss= Sounds better in good ear |
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DX Tests for hearing
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Audiometric testing= headphones/raise hand
Tympanometry= Find hole in ear via pressure Caloric Test= Assess cranial nerve 8, squirt cold or hot water in ear and watch for nystagmus Electronystagmogram= Find unilateral hearing loss w/electrodes |
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Unsafe lvl of noise
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90dB
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Conjunctivitis
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Inflammation of conjunctiva
Viral or bacterial Bacterial=Pink eye Can be caused by decongestant eye drops that vasocontrict -Trachoma-form of conjunctivitis (Eyelids shrink) |
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Mannitol (Osmotic)
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Reduce IOP
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Atropine (Mydriatics)
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Dilate pupils
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Blepharitis
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Inflammation of eyelid margins
Two Types: Seborrheic blepharitis= Red eyes, scales, flaking Ulcerative blepharitis= Crust, red eyes, inflammed corneas |
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Hordeolum
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Staph abscess in sebaceous gland
Sty/Spontaneously heals in 24-36hrs |
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Chalazion
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Bigger abscess in meibornian glands
Internal May need surgically drained |
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Keratitis
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Inflammation of cornea
Herpes simplex keratitis most common Painful |
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Hyperopia (Farsightedness)
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Rays focus behind retina
Corrected with convex lenses |
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Myopia (Nearsightedness)
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Rays focus in front of retina
Corrected with concave lenses |
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Astigmatism
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Unequal curvatures in cornea
Blurred vision with distortion |
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Presbyopia
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Lose elasticity, decreased ability to focus on close objects.
Usually after age 40 |
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Cycloplegic drugs
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Dilate pupil and paralyze ciliary muscles temporarily
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Diabetic Retinopathy
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Changes in retinal blood vessels
Found in diabetic pts 1)Background retinopathy=Microaneurysms 2)Preproliferative retinopathy= dilated veins (blocked/sluggish blood flow) 3)Proliferative retinopathy= formation of new blood vessels May need vitrectomy |
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Retinal Detachment
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Separation of retina from choroid layer of eye that allows fluid to enter between layers
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Rhegmatogenous retinal detachment
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Hole or tear in retina
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Nonrhegmatogenous Tractional Detachment
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Pulls retina away from normal position
Occurs in pts with sickle cell disease or DM |
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Exudative Detachment
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Fluid or exudate accumulates and separates layers
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S/S of Retinal Detachment
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No pain
See "floaters", cobwebs, darkness. |
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DX Test for Retinal Detachment
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Indirect ophthalmoscopy to examine eye inside/ looks bumpy instead of smooth
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Laser Reattachment
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Causes controlled burn and adheres layers together again.
Used for small areas only |
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Cryosurgery
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Probe on sclera causes injury to tissue forming an adhesion
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Electrodiathermy
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(Least used)
Needles into sclera to drain, retina later adheres to choroid layer |
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Sclera Buckling
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Silicon implant in conjuction with beltlike device around sclera to bring choroid in contact with retina (Cryo or laser first to repair)
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Pneumatic Retinopexy
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Injects gas or air into chamber to hold retina in place
Recline for 16hrs preop Recline 8 hours a day for 3 weeks postop |
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Glaucoma
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Increased IOP
Pressure causes damage to optic nerve Damage is silent, progressive, irreversible |
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AACG
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Narrowed angle where iris meets cornea, blocking flow of AH.
MEDICAL EMERGENCY S/S: Rainbows around light DONT GIVE MYDRIATICS=DILATE |
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POAG
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Trabecular meshwork and Schlemms canal degenerate and block AH
S/S: Halos around lights |
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Treatment for Glaucoma
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Miotics--Isopto, Pilocar (constrict pupil
Anhydrase inhibitors--Propine, beta blockers Timoptic Steroid eye drops to decrease inflam |
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Cataracts
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Opacity in the lens of the eye
Light rays unable to get to retina Increases risk: UV rays, DM, smoking, alcohol S/S: Halos around eyes |
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Macular Degeneration
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Leading cause of visual impairement
Deterioration in macula, area on retina where lights converge for sharp central vision needed for reading and seeing small objects Macula is responsible for color vision TWO TYPES: Dry and Wet |
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Dry Form of Macular Degeneration
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(Atrophic)
Photoreceptors in macula fail to function and not replaced r/t aging 70-90% of cases SLOW ONSET |
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Wet Form of Macular Degeneration
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Retinal tissue degenerates allowing vitreous fluid or blood into subretinal space.
New blood vessels are formed and compromise macular tissue causing edema. Scars are formed and limit central vision SUDDEN ONSET |
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Amsler grid
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Helps dx MD
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Wet Type of ARMD is treated with...
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Argon laser photocoagulation
Meds:Macugen, Lucentis |
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Chemical Eye Burns need irrigated for
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15-20 minutes of water
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Enucleation
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Entire removal of eyeball
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Conductive Hearing Loss
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Due to obstruction of sound waves from reaching inner ear.
Mechanical problem |
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Sensorineural Hearing Loss
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Originates in cochlea and involves hair cells and nerve endings. Originates in nerve or brainstem.
Caused by disease or trauma of inner ear. |
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Pts with presbycusis cant decipher high frequency sounds such as
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Consonants like s,z,t,f,g
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Ear Canal Furuncle
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Infection of hair follicle
Erupt and drain spontaneously |
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Perichondritis
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Infection of auricle, can result in necrosis of carilage
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Repeated infections in middle ear can cause
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cholesteatoma cystlike sac
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Typanosclerosis
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Complication of repeated middle ear infections
Deposits of collagen and calcium on tympanic membrane |
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Myringotomy
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Drain of tympanic membrane of fluid
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Most ear tubes spontaneously extrude at
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3-12 mnths
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Myringoplasty
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Reconstruction of tympanic membrane
-One type used Gelfoam over perforation |
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Otosclerosis
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Formation of new bone along stapes causing it to become immobile causing a conductive hearing loss
Pink/Orange tympanic membrane |
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Stapedectomy
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Stapes removed and replaced with prosthesis
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Labyrinthitis
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Inflammation or infection of inner ear
Usually due to alcohol consumption Nystagmus on affected side |
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Acoustic Neuroma
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Tumor of 8th cranial nerve
Most common benign tumor |
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Menieres Disease
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Balance disorder
Dilation of membranous labyrinth |
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If pt has acute angle closure glaucoma dont give
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Atropine or Vistaril and Benadryl
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Lasix can cause
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Hearing loss
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