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Canadian Certified Optometric Assistant > Module 4: Refraction and Ocular Health > Flashcards

Module 4: Refraction and Ocular Health Flashcards

1
Q

-case history
-analysis of visual needs/work
-Visual acuity
-depth percenption
-colour vision
-slit lamp/ophthalmoscope/ DFE
-neurological assessment
-glaucoma screening
-refraction

A

Exams inculde

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2
Q

-light rays bent/focused
-each eye has different refractive ability
-light bending relies on curve or cornea+ lens
-relies on clarity and density of cornea + lens
-ability of retina to recieve and transmit info
- length of eyeball (axial) changes refraction power

A

Refraction

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3
Q

-length from cornea to posterior pole
- average length 23-25mm (size of quater)
-light should focus at the fovea

A

Axial length

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4
Q

-cornea
-aqueous humor
-crystalline lens
-vitreous humour

A

Refracting system

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5
Q

-normal eye
-image lands right on the fovea
-no correction required

A

Emmetropia

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6
Q

-abnormal eye
- 3 types (myopia/hyperopia/astig)

A

Ametropia

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7
Q

-out of focus on the retina
-images land behind the retina
-farsightedness (blurry up close)
-cornea too flat/axial too short
-all babies start off this way
-corrected with convex lens (plus power)
-kids can accommodate/focus through

A

Hyperopia/Hypermetropia

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8
Q

-magnify objects
-objects seem bigger and closer
-px eyes look bigger
-can make “pincushion” effect(lines caved in)
-can alter depth perception

A

convex lenses

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9
Q
  • light focused infront of retina
    -near-sightedness (blurry distance)
    -physiologic (steep corneas/long axial)
    -requires concave lenses (minus power)
    -uncommon at birth
A

Myopia

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10
Q

-minifying
-objects appear smaller/further away
-px eyes look smaller
-can cause “barrel” distortion (lines look round)

A

Concave lenses

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11
Q

-parallel light rays equally not focused
-cornea unevenly shaped/unsymmetrical
-football shape
-weeakest curve & strongest curve

A

Astigmatism

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12
Q

-reduction in ability to accommodate upclose
-ciliary muscles cannot buldge the lens enough
-additional plus power
-contact lenses MF/monovision

A

Presbyopia

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13
Q

-focussing ability
-muscle tight/contracts = bulges= near
-muscle rest/pulls = flat= distance

A

Accommodation

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14
Q

at least one diopter diference between OS/OD

A

Anisometropia

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15
Q

unequal size/image on the retina between OS/OD

A

Aniseikonia

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16
Q

-breakage of blood vessel
-blood pools/covers white sclera
-resolves in a few weeks

A

Subconjunctival Haemorrhage

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17
Q

-commonly referred “pink eye”
-bactieral
-viral
-allergy
-tocicity

A

Conjunctivitis

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18
Q

-progressive disease
-thinning cornea
-conical shape
-induces irregular astigmatism
-treated with rigid CL
-possibly hereditary

A

Keratoconus

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19
Q

-styes
-infection of glands/eyelids
-whitehead-like

A

Hordeolum

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20
Q

-clear lens becomes cloudy
-capsule holds transparent lens like enevelope
-lens is size of aspirin
-cloudy = light distorted/blocked out
-vision reduced
-lens continually grows/becomes hard

A

Cataracts

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21
Q

-natural part of aging

A

Senile Catartacts

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22
Q

-injury/lens is disturbed
- medications/steroids
-chemicals
-UV
-radiation
-smoking
- eye diseases
-diabetes

A

Traumatic Cataracts

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23
Q

Congenital cataracts

A

-babies born with them

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24
Q

-colour vision loss
-hazzing
-dark spots in vision
-needing brighter lighting
-glare at night
-near-sighted
-double vision
-better without glasses
-yellow/white pupil

A

Signs of cataracts

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25
Q

-slit lamp biomicroscope
-ophthalmoscope
-DFE

A

Detecting Cataracts

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26
Q

-sunglasses
-vitamins A,C,E,Zinc, Selenium, Magnesium

A

Cataract prevention

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27
Q
  • surgery
    -removal of cloudy part
    -replacement of lens
A

Cataract treatment

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28
Q

-opening front of capsule
-pocket of side and back capsule left alone
-insert loop and pull out (still common)
-ultrasonic probe, 3mm incision (phacoemulsification)

A

Cataract extraction

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29
Q

-3mm incision
-probe vibrates at 40,000 times/second
-breaks up hard/cloudy lens
-suctioned out with vacuum
-femtosecond laser (bladeless)

A

Phacoemulsification

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30
Q
  • if not replaced becomes aphakic
    -intraocular lens (IOL)
  • IOL fits into capsule pocket left behind
  • made of plexiglass
    -use tiny spring loops to hold in place
    -clear vision immediate
A

Replacing lens

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31
Q
  • caspule pocket becomes yellow/cloudy
    -fixed with YAG laser capsulotomy
    -beams of light energy shot into eye
    -quick pulses of laser energy
A

Secondary clouding

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32
Q

-produced in ciliary tissue
-fliud passes through space between lens&iris
-goes through the pupil
-collects in anterior chamber
-drains into trabecular meshwork
-then released into canal of schlemm
-goes into bloodstream via blood vessels in sclera

A

Aqueous Humour route

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33
Q

-blocked passage of aqueous humour
-causes IOP pressure to rise
-nerve fibers/ optic nerve damage under pressure
-when destroyed suport tissue sinks back=cupped position
-dreakdown of messages sent to brain
-leading to blindness
-asymptomatic in early stages

A

Glaucoma

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34
Q

-over 40 years old
-family history
-near-sighted
-diabetes
-african american
-injuries

A

Risks of glaucoma

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35
Q
  • eye exam
    -tonometry
    -inspect drainage angles
    -check ONH cup - disc ratio
    -check peripheral vision
A

Dectecting glaucoma

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36
Q
  • most common type
    -gradual clogging of trabecular meshwork
    -fluid cannot drain
    -reason/cause unknown
    -dangerous/slow &no warning
    -irreversible
A

Chronic Primary Open Angle Glaucoma (POAG)

37
Q
  • no ONH changes
  • no peripheral changes
  • not glaucoma
  • at risk to develope glaucoma
A

Ocular Hypertension

38
Q
  • can’t unclog meshwork
  • prescription drops/ pills limits fluid production or increase drainage
    -surgery thinning the walls (trabeculectomy)
A

Glaucoma treatment

39
Q
  • small flap created under top lid
  • removes some sclera & meshwork
  • moves into anterior chamber
  • punctures small hole in iris
    -flap stitched closed
    -filtering bleb forms and absorbed into blood vessels
A

TrabeculeCTOMY

40
Q
  • alternate surgery
  • uses argon laser (gas) energy
  • aimed at meshwork
    -clear clogged cannals
    -temporary
    -excimer laser (UV) new technology
A

TrabeculoPLASTY

41
Q
  • build-up eye pressure
    1)blockage behind iris
    -space between iris & lens too small
    2)enlarged pupil makes iris bunch up
    -no space between iris & cornea
    -needs emergency laser surgery
  • unlikely to return again
A

Acute Glaucoma

42
Q

-severe headaches
-nausea
-eye pain
-redness
-distorted vision
-limited action time

A

Acute Glaucoma symptoms

43
Q

-uncommon
- babies born defective drainage
- resolved with laser surgery

A

Congenital Glaucoma

44
Q

-caused by injuries, drugs, inflammation
- possibly temporary
- medication or surgery treatments

A

Secondary Glaucoma

45
Q
  • ONH damage with normal IOP
  • possibly from hardend arteries that supple OHN
  • medication to drop IOP lower
A

Low-tension Glaucoma

46
Q
  • eye unable to lubricate naturally
  • seem too moist/too many tears
  • low qaulity tears
  • common over 50 years old
  • increased by screen time
A

Dry Eye Diesease

47
Q
  • questionaires DEQ-5/OSDI
    -tear meniscus height
    -tear break0up time
    -blink evaluation
    -meibography
A

Diagnosing Dry Eye

48
Q
  • invasive dry eye test
    -uses dyes fluoresence/lissamine green
  • stains cornea and conjunctiva
  • tear break-up time
A

Meibomian gland expression

49
Q
  • invasive dry eye test
    -tests the amount of salt in tears
    -checking inflammatory markers
  • InflammaDry
A

Osmolarity

50
Q

1)-tear deficiency or excessive evaporation
-inner muscus layer not covering eye/creates dry patches
-common as we get older
2)- diseases
-medications
-infections
-CL wear
-blepharitis
-environmental (wind/AC/dry)
-arthritis
-Sjogren’s syndrome (mouth too)

A

Causes of Dry Eye

51
Q
  • irritating condition of eyelids
    -infect/plug meibomian glands (sebaceous)
    -interrupts oil layer production
  • sometimes causes by injury
  • use lid hygeine (wipes/ABMax/BlephEX) removes plaque in 10 mins. For only 4-6 months
A

Blepharitis

52
Q
  • Tiredness (end of day)
    -Redness
    -foreign body/burning
    -blurry vision
    -excessive tearing
    -pulling/pressure behind eyes
    -loss of lustre
    -corneal deterioration
A

Symptoms of Dry Eye

53
Q
  • no known cure
    1) blink often (18-20 blinks/minute)
    2) conserve natural tears (avoid wind & fans/ drink water/humidifier)
    -3) artificial tears daytime(use when needing to focus)
    -ointment/gel (at night before bed) distorts vision
    4) omega 3 (anti-inflammatory/ improve meibomian gland production)
    5) Special treatments
    -punctal plugs/ laser closure
  • prescription drops (restasis/Xiidra)
  • antiboitics/steroids
    -vitamin A
A

Treatment of Dry Eye

54
Q

-most common dry eye type
-glands inflammed/clogged
-dont produce enough oil
-glands need to be drained/expressed
-warm compress treatment
- O.D. forceps & squeeze/ thermal pulsation (lipiflow/iLux)
- new options (amniotic membranes/autologous serums)

A

Meibomian Gland Dysfunction (MGD)

55
Q

-breakdown of the macula
- 100 times more senstive than rest of retina
- macula contains most cones (detailed/colour vision)
- mono or binocular
- results in completes loss of central vision (peripheral is fine)
-leading cause of vision loss (1/3 over 65years)
- Dry AMD
-Wet AMD
-blisters/birthdefects/ injuries/infection/inflammation

A

Macular Degeneration (AMD)

56
Q
  • age
    -smoking
    -female
    -UV
    -family history
    -high blood pressure
    -diabetes
    -obesity/poor diet
    -light eye colour
A

Risks for AMD

57
Q

-most common type 90% cases
- tissue becomes thin/stops working
- vision loss via size/#/location of drusen
- vision loss gradual and moderate
- treated with vitamins/lifestyle

A

Dry AMD

58
Q

-small yellowish lesions that accumulate in the retinal layers

A

Drusen

59
Q
  • less common
  • more visually devastating
    -abnormal blood vessel growth behind macula causing choroidal neovascular membrans (CNVM)
    -blood vessels break>bleed>heal> scar tissue
    -new blood vessels in scar tissue>push retina away from wall
    -new blood vessels fragile> distorts/damages macula
  • the longer this continues= more damange
    -1/10 moves into both eyes
    -treated with injections
A

Wet AMD

60
Q

-symptoms may vary
-gradual loss of sharp vision
-distorted vision (shape/size/straight lines)
- gradual colour loss
- dark spot central vision

A

AMD symptoms

61
Q
  • Amsler grid test (card@ 30 cm> look at dot> wavy lines)
  • colour vision test
    -fluorescein Angiography Exam(OMD injects in arm>take pictures)
    -Fundus Photos
    -Digitial Imaging
    -DNA testing
A

Diagnosing AMD

62
Q
  • use UV protection
  • have good nutrition (limit fatty food)
  • maintain good blood pressure
    -don’t smoke
  • food with vitamin A,E,Zinc,Lutein,Zeaxanthin,Selenium, Omega3
A

AMD prevention

63
Q
  • diabetes mellitus (inability to produce insulin)
  • changes blood vessles that nourish retina
    -leakage of fluid/blood > big/disctructive branch vessels
  • retina cannot recieve/send clear images
    -leading cause blindess under age 65 (25% prone)
    -length of diabetes is most damaging (15% with under 4 years), (90% with 15 years +)
A

Diabetic Retinopathy

64
Q
  • non-proliferative
    -most common/ least seerious (80% cases)
  • first stage of blood vessel deterioration
  • only 20% progress further
    -blood vessels in retina weak/change
    -vessels small or big (balloon-like sacs)
  • burst and leak serum/exudate (fatty material)
  • appear as yellow flecks
  • leaks cause retina wet & swollen
    -bloodstream normally reabsorbs= swelling temporary
  • can be both peripheral or macular
  • only symptom = blurred vision
    -typically dont need treatment
    -serves cases need laser (focal/grid)
A

Background Diabetic Retinopathy

65
Q
  • leakage not extensive
  • targets only certain spots
  • cauterizes tissue>creates healing scar tissue
    -scar tissue shuts/stops leak
A

Focal laser treatment

66
Q

-too many leakages
-uses grid over the entire surface
- doesnt restore vision
-prevents further damage by drying retina
- may need serveral treatments/ can reopen

A

Grid laser treatment

67
Q
  • 20% of background progress to this
  • leads to blindness when not caught early
    -vessels close = no nutrients to areas of retina
  • happens in peripheral = narrow sight/poor night vision
    -creates new blood vessels/very dangerous
    -vessels increase rapidly
    -bleeding into vitreous cavity/blocking light
    -scar tissue>detach retina from choroid
    -distort iris> blocks fluid > glaucoma
  • no pain/symptoms
A

Proliferative Diabetic Retinopathy

68
Q
  • lasers/ injections
    -detroys/inhibits new vessels
  • panretinal laser photocoagulation (destroys new blood vessels growing), honey comb pattern, sacrifice peripheral vision to save detail and colour
    -vitrectomy= last resort (prevents detatchment), suctions out vitreous> removes vessels> replace with air/gases until vitreous returns
A

Treatment Proliferative DR

69
Q
  • complication of diabetic retinopathy
  • leaking = swelling of macula
  • blurry vision/gradual loss
    -occurs at any stage
    -affects 2.5% diabetics
  • treamtent= focal laser/corticosteriods
A

Diabetic Macular Edema (DME)

70
Q
  • intact retina is crucial for vision
    -1/10,000 effects by RD every year
  • various causes
  • tears lead to detachments
  • can also detach without a tear
    -vision saved by immediate medical attention
A

Retinal Tears/Detachments

71
Q
  • age> vitreous shrinks> pulls away>pull retina> tear peripheral> fluid behind retina> detach from wall> no longer sensitive to light= blindness
  • can thin and deteriorate= detach on its own
    -serious hit/injury
  • eye surgeries
  • increased in ner-sighted (grow oblong=pulling)
    -severse internal inflammation
    -tumours
  • diabetes
A

Causes of RD/Tears

72
Q

-sudden flashes (response to trauma)
-increased floaters (impurties from tear)
- haze/strands
- sometimes no symptoms until detaching
-detachment= dark growing shadow peripheral (can become permenant without treatment)

A

Symptoms of RD/tears

73
Q

-direct ophthalmoscopes = magnified small area of retina
-indirect ophthalmoscope= less magnified but larger area
-DFE

A

Diagnosing RD/tears

74
Q
  • can be reversed depending on intial damage
  • tears easier than detachment
    -40% regain vision
  • up to 6 months to fully heal
    1) tears= laser beam/freezing cryoprobe> heat/cold>burn/freeze area>scar tissue>forms bond.
    2) RD= A)remove fluid behind retina> press wall inward with pressure pad/silicone band> laser makes scar tissue (cryoprobe/radio freq diathermy)>bond tissue.
    B)seperated far back/shrunk/puckered= vitreous broken up>suctioned out> air/gas replace (vitrectomy)
A

RD/tear treatments

75
Q
  • eye vision problems related to near work via computer
    -50-90% of computer users
    -22% have musculoskeletal disorders
  • greater risk in presbyopes (PAL = tilting head back/leaning foward= neck issues)
  • presbyopia happening younger via computer use
A

Computer Vision Syndrome (CVS)

76
Q
  • eyestrain
  • blurred vision
  • headaches
  • dry/irritated eyes
  • light sensitivity
  • double vision (diplopia)
  • poor ergonomics
A

Computer Vision Syndrome symptoms

77
Q
  • condition of the px eyes
  • visual ergonmics
  • SV reading for low add px
    -advanced presbyope =intermedaite/near bifocal
    -PAL is good for intermittent computer use
  • best is task/computer lens (occupational lens)
  • boost/antifatigue/bump add +0.50-0.75
  • 20-20-20 rule
  • adjust your chair (90 degrees/ floor to knee 2”-4”)
    -set up your workspace (leg room 25”/ monitor height 26”)
    -monitor/keyboard (16-30” from eyes/tilt away 10-20 degrees)
    -Lighting (match room brightness 20-70 candles)
A

CVS treatment

78
Q
  • previously used to correct myopia
  • reduced curvature of cornea
  • tiny cuts with diamond blade
  • temprorally relaxes peripheral cornea > allowing slight buldge out
A

Radial Keratotomy

79
Q
  • newest = wavefront analysis (no aberrations with pupil dilation)
  • custom corneal ablation (removal of tissue)
A

Laser surgery

80
Q
  • excimer laser
  • removes corneal tissue = curve change
  • UV rays without heat= breaking molecule bonds
  • computer controls energy required
  • at depth of 10% corneal thickness
  • takes 1 minute
    -px wears CL lens/ drops 2-3 days post-op
  • stroma does not regenerate= permentant results
  • 3 months for deeper layers to stablize
  • mild to moderate myopia and thinner corneas
A

Photo-refractive keraectomy (PRK)

81
Q
  • epithelium/bowmans peeled back with flap
    -excimer laser same as PRK
  • flap put back
  • less healing involved
  • faster clear vision
  • moderate-severe myopia & astig
    -less post-op haze/pain
  • newest form = sub-bowmans keratomileusis (SBK)> flap with cold laser = thinner/smaller flap
A

Laser in-situ keratomileusis (LASIK)

82
Q
  • Intracorneal rings “phakic IOL” (behind cornea) for low myopia
    -Thermokeratoplasty (TKP)= heat to periphery>cornea steepens> reducing hyperopia
    -Conductive keratoplasty (CK) newer = controlled release radio-freq
    -Refractive/Clear Lens Exchange (RLE) = some process cataract surgery
    -Implantable Contact Lens (ICL)= small CL inside eye
    -KAMRA Inlay= small ring/pinhole into ONE eye
A

Other Refractive Surgeries

83
Q
  • 1/10 risk of undiagnosed vision problems
    -1/30 amblyopia (lazy eye)
    -1/3 refractive error
    -1/100 eye disease
A

Children

84
Q
  • Amblyopia (lazy eye)
  • congenital strabimus (eye turn)
    -Anisometropia (uneven refractive error)
    -high or oblique astig
    -retinopathy of prematurity
  • congenital cataracts
  • congenital glaucoma
  • retinoblastoma (cancer)
    -Nystagmus
    -Coloboma (hole in iris/retina)
  • dislocated cyrstalline lens
    -blindness
A

Childhood disorders

85
Q
  • first exam at 6 months (sooner if concerns)
  • 80% hyperopic> intermittent strabismus
    -common blocked tear ducts
A

Infants/Toddlers (birth-2 years)

86
Q
  • next exam at 3 years old (better idea of refraction)
  • test depth perception/ colour vision
A

Pre-School (3-5 years)

87
Q

-annual exams
- farsightedness stabilizes at age 7/8
-myopia can increase
- delayed learing could be visual

A

School age (6-18 years)

88
Q
  • Chemicals
  • sudden loss of vission/veil
    -penetrated injury
    -forceful trauma/blow
    -sudden halos/red, eye/brow pain
  • sudden eye pain
    -foreign body
    -sudden flashing lights/floaters
  • sudden droopy lid
  • sudden red eye/crusting
A

Emergencies

89
Q
  • blurred vision gradual
    -CL wearer discomfort
  • lost/broken CL in eye
A

Urgent issues

Canadian Certified Optometric Assistant (9 decks)

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