chap 20 - disorders of the eye (start of final unit) Flashcards

1
Q

three layers of the eye

A

1) outer sclera
2) uveal layer
- iris, ciliary body and choroid
3) retinal layer

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2
Q

conjunctiva

A

tissue on the inner surface of the eyelids

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3
Q

cornea

A

light enters, first refraction

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4
Q

lens

A

second site of refraction, accomodation

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5
Q

accomodation

A

by changing shape the lens can focus light rays
- Either flatten out the lens or round out the lens, important for when you are looking at something in the distance versus something close up

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6
Q

pupil

A

controlled by your iris which is made of smooth muscle
- controls how much light is allowed into the eye

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7
Q

retina

A

photoreceptors

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8
Q

macula

A

post on the retina that provides the greatest visual acuity, most cones are located here

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9
Q

fovea

A

central portion of the macula

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10
Q

aqueous humor

A

watery fluid that nourishes and cleanses the avascular lens and retina
- continually recirculating

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11
Q

lacrimal gland

A

keeps eyes moist, flush foreign debris away, produce mucus that allows eyelid to slide smoothly over eye

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12
Q

lens and accomodation

A

lens changes shape by ciliary muscle

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13
Q

most frequent and serious problems

A
  • decrease in visual acuity
  • Age-related macular degeneration
  • Trauma
  • Acute conjunctivitis
  • Cataract
  • Glaucoma
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14
Q

symptoms and signs

A

Decreased visual acuity resulting from:
Visual field defects
Focal areas of blindness
Pain
Manifestation of trauma, infection or increased intraocular pressure
Blurred vision
Accompanies various systemic diseases
Strabismus
amblyopia
nystagmus

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15
Q

strabismus

A

“Crossed eyes”
Etiology
- Eye muscles don’t work together - 6 different muscles on each eye
- Confuses the brain
- Brain ignores image from weaker eye
Amblyopia “lazy eye”

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16
Q

nystagmus

A

Fast, uncontrollable eye movements
One eye or both eyes
Etiology
- Congenital
- Acquired
- Head injury
- Stroke
- Inner ear disorders
- drugs/medication

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17
Q

tests

A

Visual acuity tests
Ophthalmoscope
- Used to examine the retina
Tonometer
- Measures intraocular pressure
Slit-lamp
- Used to examine the cornea, iris, and lens

18
Q

refraction disorders

A

hyperopia, myopia, presbyopia, astigmatism

19
Q

hyperopia

A

(farsighted)
Can see far things
Trouble seeing close things
Eyeball is too short

20
Q

myopia

A

(nearsighted)
Trouble seeing far things
Eyeball is too long

21
Q

presbyopia

A

Accommodation changes
Age

22
Q

general symptoms of refraction disorders

A

General
Poor vision
Headaches
Eyestrain
Fatigue
Burning

23
Q

symptoms of myopia

A

Blurred vision
Squinting when looking at distance objects

24
Q

hyperopia symptoms

A
  • difficulty focusing on near objects
25
treatment
Procedures - Laser-assisted in situ keratomileusis (lasik) - Both types of disorders - Phakic intraocular lens implant - Nearsightedness - Myopia - Concave lens - Hyperopia - Convex, lens - Astigmatism - Glasses or hard contact lenses - Presbyopia - Reading glasses or bifocal lenses
26
conjuctivitis
Inflammation = can be bacterial, fungal, viral or related to allergy - Most commonly associated with bacteria and most often found in children - Contagious - Treated with antibiotics Also known as: pink eye
27
corneal keratitis
Infection (bacteria, viral, fungus, protozoa) Typically unilateral Can lead to vision loss from scarring Keratin gets into the cells of the cornea = could be from infection
28
corneal keratopathy
(band keratopathy) Deposition of calcium salts within cornea Leads to pain, decreased acuity
29
corneal dystrophy
Bilateral Genetic - which is why it affects both eyes Abnormal accumulation in cornea Clouding of cornea Could be treated with a cornea transplant - doesn't have to be a specific match because the immune system doesn't go into the anterior chamber of the eye
30
cataracts
= opacity of lens - Age related degeneration - constant UV light coming into the eye over long periods of time - Leading cause of blindness in adults worldwide - Age associated - By 65, 90% adults will have some Symptoms - Pupil looks milky white Treatment - Surgery = swap out the old lens for a new lens
31
glaucoma
Optic nerve is damaged by abnormally increased intraocular pressure (IOP) - Irreversible Second most common cause of blindness in world Build up of aqueous humor - Intraocular pressure Signs and symptoms - Acute glaucoma: possible loss of vision within 1 day = emergency - Severe eye pain - Blurred vision - Eye redness - Light halos - Nausea - Vomiting - Risk factors - Age - Refractive disorders - Genetics Other diseases - Hypertension -Diabetes
32
retinal detachment
Retinal peels away from underlying support tissue Medical emergency - Can lead to blindness Symptoms - Spots, floaters, flashes of light - Not painful Surgical treatment to reattach Etiology - Trauma to eye - Genetic disease - Marfan syndrome - disease of connective tissue, the CT is too weak to hold on to the retina - Extreme nearsightedness
33
macular degeneration
Leading cause of vision loss in people over 60 Damage to macular - only one part but one of the most important parts - Does not lead to complete loss of vision Risk factors - Age-associated - Obesity - UV light exposure - why its important to wear sunglasses - Smoking - Family history - Ethnicity Treatment - No cure - try to prevent it from happening
34
hypertensive retinopathy
Etiology - Damage to retina due to hypertension - high blood pressure causes pathology of the retina - Vessel narrowing - Microinfarcts = small areas of tissue death - Hemorrhages - exudates/edema = fluid leakage Leads to: - Dim vision - Vision loss - Double vision Can be reversible with treatment - bring blood pressure down
35
diabetic retinopathy
Retina sensitive to hyperglycemia - Diabetes 20x to go blind than non-diabetics - Damage to blood vessels in cornea Can lead to: - Microhemorrhages = small bleeding - Edema - Neovascularization = new blood vessels, we don't want a lot of blood vessels in the eye because they can interrupt light waves coming in Symptoms - spots/floaters in eyes - Blurred vision - Empty spot in vision Treatment - Blood glucose control - Surgery - Seal leaking vessels
36
eye diseases in diabetics
glaucoma, retinal detachment, diabetic retinopathy
37
color deficient (blindess)
Color vision determined by cones - Three types (red, blue, and green cones) - Depends on relative output of these three types of cones X-linked recessive = more common in men, most receive from their mothers Types - Red-green color vision defects - most common - Defects in… - Either red cone output or green cone output - one or the other - Blue-yellow color vision defects - Trouble differentiating shades if blue and green - Complete absence of color vision - No working cones = only black and white
38
retinoblastoma
Children Rare malignant tumor of retinal cells - usually the cones Autosomal dominant inheritance - Rb1 gene Treatment = remove the eye = want to treat it early so it does not metastasize to the brain (which is super close by)
39
malignant melanoma
Adults Ocular melanoma Arise from melanocytes - just like in the skin - Choroid layer - Iris Worse prognosis than skin melanoma - because it metastasizes early
40
organ failure - blindness
Defined as visual acuity 20/200 4/1000 people legally blind Causes - Lesions - Developmental - Trauma