Final Flashcards

1
Q

emmetropia

A

a normal eye with no refractive error

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2
Q

ametropia

A

an eye abnormality (hyperopia, myopia and astigmatism) resulting from a faulty refractive ability of the eye

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3
Q

Presbyopia

A

farsightedness caused by loss of elasticity of the lens of the eye, occurring typically in middle and old age

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4
Q

Hyperopia

A

AKA farsightedness.
Distant light rays of light focus behind the retina when the eye is at rest.
Plus lens is used for correction.
Causes: short axial length, flatter than normal corneal curvature, smaller eye

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5
Q

Latent

A

hyperopic error that can be corrected by the eye’s accommodation

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6
Q

Manifest

A

hyperopic error that can be corrected by either plus lenses or by the patient’s own accommodation

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7
Q

Absolute hyperopia

A

hyperopic error that is not compensated for by accommodation (needs corrective lenses)

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8
Q

Myopia

A

AKA nearsightedness.
Parallel light rays of light focus in front of the retina when the eye is at rest.
Minus lens is used for correction.
Causes: steeper than normal cornea, a longer than normal eye

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9
Q

Axial myopia

A

eyeball is too long for the normal refractive power of the lens and cornea

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10
Q

Curvature myopia

A

eye is of normal size but the curvatures of the cornea and lens are steeper

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11
Q

Index myopia

A

change in the index of refraction of the lens (cataracts or diabetes can cause); requires minus lens to compensate

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12
Q

Astigmatism

A

condition where light rays are not refracted equally in all directions, so a focus point on the retina is not attained

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13
Q

Regular astigmatism

A

correctable by spherocylinder lenses and the principal meridians are at right angles to each other

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14
Q

Simple (astigmatism)

A

one of the focal lines always falls on the retina, the other falls in front (myopic) or behind (hyperopic) it

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15
Q

Compound (astigmatism)

A

both focal points lie either in front (myopic) of the retina or behind (hyperopic) it

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16
Q

Mixed astigmatism

A

one focal point lies behind the retina, whereas the other focal point lines in front of it

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17
Q

Irregular astigmatism

A

the surface of the cornea is not smooth (irregular) and therefore light rays do not refract in a predictable way to a single point.
Causes: trauma, inflammation and/or scar tissue

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18
Q

Outer coat

A

cornea, sclera and limbus

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19
Q

Middle coat

A

uvea, which consists of iris, ciliary body (ciliary muscles and ciliary processes) and choroid

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20
Q

Inner coat

A

retina, optic nerve and optic disc

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21
Q

Outer lipid layer

A

prevents evaporation of aqueous layer

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22
Q

Aqueous layer

A

provides nutrition and defense

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23
Q

Inner mucoid layer

A

keeps tear film on the epithelium

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24
Q

Focal power formula

A

F=1/f

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25
Q

Pupillary distance

A

distance between the centers of each pupil in each eye. Determines where to put the optical center in each lens

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26
Q

COBC Code of Ethics

A
General
Duty to the public
Duty to clients
Duty to the profession 
Duty to colleagues
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27
Q

General

A

honest and knowledgeable, improve clients well being

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28
Q

Duty to the public

A

educating the public in promotion of ophthalmic health

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29
Q

Duty to clients

A

confidentiality, maintain records

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30
Q

Duty to the profession

A

don’t warrantee or guarantee success of care or treatment

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31
Q

Duty to colleagues

A

don’t compete for clients, compare professional competence

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32
Q

Three regulatory documents

A

HPA Opticians Regulation
Standard of Practice
Code of Ethics

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33
Q

Authorization document

A

Rx for glasses or an assessment record

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34
Q

Assessment record

A

record produced by an independent automated refraction

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35
Q

Prescription

A

authorization to dispense a vision appliance

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36
Q

Automated refraction

A

refraction for assessing visual acuity, using computerized components

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37
Q

Independent automated refraction

A

automated refraction conducted without the involvement of a prescriber

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38
Q

Eye examination

A

includes both eye health assessment and refractive error assessment, conducted by an optometrist or ophthalmologist

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39
Q

Refraction

A

when light travels from one medium into another the path of light ray will be diverted

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40
Q

Reflection

A

when light changes direction as result of “bouncing off” a surface like a mirror

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41
Q

Index of refraction (RI) formula

A

RI = Speed of light in air / speed of light in new substance

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42
Q

What are the units for focal length?

A

Unit is in Metres

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43
Q

What are the units for power?

A

Unit is in Diopters

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44
Q

Prism bends light towards ___

A

the base

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45
Q

Prism displaces image towards ___

A

the apex

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46
Q

Meibomian

A

eyelid glands that create the lipid layer of the tear film

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47
Q

Horizontal Visible Iris Diameter

A

Size of the average iris (~12mm)

Size of the average eye (~24mm)

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48
Q

Lid margin

A

flat part of the lid that meet when your eyes blink

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49
Q

Caruncle

A

sweat and oil glands for the tears

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50
Q

Plica semilunaris

A

fleshy tissue beneath the caruncle

51
Q

Palpebral Fissure

A

distance between the upper and lower lids

52
Q

5 steps that tear flow

A
  1. secretions from the lacrimal, meibomian and conjunctival goblet cells are distributed onto the cornea
  2. secretions separate to form the 3-tier film layer
  3. With each blink, tears are directed towards the nasal canthus and into the puncta
  4. Afterwards, tears flow through the canaliculi to the lacrimal sac
  5. tears drain through the nasolacrimal duct and into your nose
53
Q

5 angle structures for proper aqueous humor outflow to prevent glaucoma

A
  1. root of the iris
  2. ciliary body
  3. scleral spur
  4. Schlemm’s Canal
  5. Trabecular Meshwork
54
Q

3 tear film functions

A
  1. forms a smooth refractive optical surface
  2. maintains a moist environment of the epithelium
  3. carries oxygen to the eye
55
Q

Hyperemia

A

Redness of the conjunctiva.

  • caused by exposure to dust, wind or air pollutants
  • fatigue
  • excessive reading
  • excessive dryness
56
Q

Conjunctival Hemorrhage

A

Extreme redness beneath conjunctiva.

  • Subconjunctival hemorrhage is caused by a ruptured conjunctival blood vessel
  • coughing or high blood pressure
57
Q

Conjunctivitis

A

Inflammation of the conjunctiva

  • infection
  • allergy
  • toxicity
58
Q

Allergic Conjunctivitis

A

Inflammation of the palepebral conjunctiva

- allergy response to allergen

59
Q

Pinguecula

A

Wedge-shaped tissue mass not on cornea

- irritation of the conjunctiva associated with dry, hot climate

60
Q

Pterygium

A

Wedge-shaped tissue mass on cornea

- irritation of the conjunctiva associated with dry, hot climate

61
Q

Keratoconus

A

Degenerative condition of the cornea. Early resembles normal myopia. Later = thinning, steepening, irregular astigmatism, scarring

62
Q

Keratitis (4)

A

Inflammation of the cornea
Bacterial - caused by bacteria such as psuedomonas and acanthameoba
Viral - caused by virus such as the herpes virus
Toxic - caused by harmful chemicals or solutions
Mechanial - caused by directly contact with the cornea

63
Q

Entropion

A

in-turning eyelids

64
Q

Ectropion

A

out-turning eyelids

65
Q

Ptosis

A

drooping of the upper lid

66
Q

Trichiasis

A

in-turning eyelashes

67
Q

Blepharitis

A

inflammation of the lid margin

68
Q

Hordeolum (acute)

A

localized infection or inflammation of the eyelid margin involving hair follicles of the eyelashes

external (stye) - zeis glands
internal - meiobomian gland

69
Q

Chalazion (chronic)

A

cyst in the eyelid due to a blocked oil gland

70
Q

Basal cell carcinoma

A

90% of malignant lid tumors

71
Q

Dry eyes (Marginal or severe)

A

insufficient tears to lubricate and nourish the eye

72
Q

Central Retinal Artery Occlusion

A
  • retinal artery is blocked by an embolus.
  • sudden and total loss of vision, retina is grey, blood vessels are unnaturally thin and segmented.
  • (cherry red spot)
73
Q

Central Venous Occlusion

A
  • blockage of the central retinal vein.
  • diabetes, any conditions that causes stasis of blood flow.
  • blockage causes the walls of the vein to leak blood and excess fluid into the retina.
  • (leaking blood vessels)
74
Q

Diabetic retinopathy

A

caused by damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina).

75
Q

Retinal detachments

A
  • usually tear induced

- retina peels away from its underlying layer of support tissue

76
Q

Age-related macular degeneration (AMD)

A
  • loss of central vision, degradation of macular tissue
77
Q

Wet AMD

A
  • exudative (oozing)
  • more severe (acute)
  • quick onset
78
Q

Dry AMD

A
  • atrophic (decreasing in size/drying)
  • chronic (persisting or constantly reoccurring)
  • slow forming
79
Q

Hypertension (high blood pressure)

A
  • flame-shaped hemmorrhages
  • exudates
  • “cotton-wool” spots
  • narrowing of the retinal arterioles
  • decreased visual acuity
80
Q

Glaucoma

A

a condition of increased pressure within the eyeball, causing gradual loss of sight.

81
Q

Types of glaucoma (4)

A
  • primary open angle (chronic)
  • angle closure (acute)
  • secondary glaucoma
  • congenital or infantile
82
Q

Tonometry

A

-Measurement of intraocular pressure
14 - 20 mmHg is normal
“Puff of air” measures ocular resistance

83
Q

Amblyopia

A

reduced vision in one eye caused by abnormal visual development early in life

84
Q

Cataracts

A
  • Result from the natural aging and degeneration of crystalline lens tissue causing cloudiness = reduced VA
  • Removed when they are “ripe”
85
Q

Types of cataracts (5)

A
Nuclear sclerosis cataract
Cortical cataract
Posterior subcapsular cataract
Traumatic cataract
Diabetic cataract
86
Q

Cataract treatment

A
common = phacoemulsification
aphakia = crystalline lens is removed
pseudophakia = new intraocular lens (IOL) is inserted
87
Q

Strabismus

A

abnormal alignment of the eyes; the condition of having a squint.
a muscle imbalance occurring in one or both eyes

88
Q

CR-39

A
1.498
lighter than glass
more impact resistant
higher UV protection
tintable
89
Q

Water

A

1.33

90
Q

Air

A

1

91
Q

Segment types

A
Round seg
flat top
curved top
panoptik
B-seg (ribbon)
R-seg (ribbon)
executive (Franklin)
blended
92
Q

Neutralizing bifocals

A

checking front vertex

93
Q

Image jump

A

unintended but predictable consequence in almost all segmented bifocal designs

94
Q

Polycarbonate

A

1.49/1.50
safest material
low ABBE value

95
Q

Crown glass

A
1.523
heavy
not as impact resistant
scratch resistant
good optics
stable material
96
Q

Abbe value

A
x>35 =  no chromatic aberration
x<35 = chromatic aberration
97
Q

Photochromic lenses

A

changes, gets darker to UV lights or cold conditions

98
Q

Polarized lenses

A

eliminates horizontal glare from reflective surfaces

99
Q

Higher refractive index

A

higher the chromatic aberration
lower ABBE value
thinner lens

100
Q

Medial rectus

A

in towards the nose

101
Q

Lateral rectus

A

out towards the temple

102
Q

superior rectus

A

up

103
Q

inferior rectus

A

down

104
Q

superior oblique

A

intorsion

105
Q

inferior oblique

A

extorsion

106
Q

levator palpebrae superioris

A

elevates the upper eyelid

107
Q

orbicularis oculi

A

closes the lids

108
Q

Fusion

A

the ability of the rectus and oblique muscles to keep the position of the eyes aligned so that both fovea project to the same point in space

109
Q

Heterophoria

A

when muscular imbalance occurs that means that there is one muscle working better than another and fusion cannot be maintained with both eyes

110
Q

esophoria

A

inward drifting of the eye when it is covered

111
Q

exophoria

A

outward drifting of the eye when it is covered

112
Q

hyperphoria

A

upward drifting of the eye when it is covered

113
Q

Prism diopter

A

1 prism diopter displaces an image 1 cm at a point 1 meter away from the prism

114
Q

Snell’s law

A

n(sin i) = n’ (sin i’)

115
Q

Prentice’s rule

A

each centimeter of decentration of a lens results in 1 prism diopter of deviation of light for each diopter of lens power.

116
Q

aqueous humor

A

clear, watery fluid that fills the anterior and posterior chambers within the front part o the eye

117
Q

ciliary processes

A

produce aqueous humor and provides attachment for zonules

118
Q

crystalline lens

A

a transparent, biconvex structure in the eye that along with the cornea, helps to refract light to be focused on the retina

119
Q

choroid

A

vascular layer of the eyeball between the retina and sclera, furnishes nurishment to the other parts of the eye

120
Q

uvea

A

entire vascular coat of the eyeball, consisting of the iris, choroid and ciliary body

121
Q

ciliary body

A

portion of vascular coat between the iris and the choroid; consists of ciliary muscles and ciliary processes

122
Q

trabecular meshwork

A

a drainage network which aqueous humor exits the eye

123
Q

canal of schlemm

A

circular a canal that drains the aqueous humor from the anterior chamber into the veins draining the eyeball

124
Q

limbus

A

boundary between the sclera and the cornea