Basic Science, Investigations and Lasers Flashcards

1
Q

What ocular structures are derived from the surface ectoderm?

A

Conjunctival nad corneal epithelium

NL duct

Lens

Lacrimal gland

Eye lids

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2
Q

What ocular structures are derived from the neuroectoderm?

A

NS retina
Pigment epithelium or retina, iris and CB
Pupillary sphincter and dilator muscles
Optic nerve

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3
Q

What ocular structures are derived from the neural crest?

A
Corneal endothelium 
Trabecular meshwork
Stroma of cornea, iris and CB
Ciliary muscle
Choroid 
Sclera
Orbital cartilage and bone
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4
Q

What ocular structures are derived from the mesoderm?

A

Extraocular muscles
Blood vessels
Schlemm’s canal endothelium
Sclera (temporal portion)

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5
Q

List some ocular disorders inherited in an AR fashion

A

Congenital glaucoma (commonly sporadic)
Oculocutaneous albinism
Strargardt disease
Retinitis pigments-like conditions

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6
Q

List some ocular disorders inherited in an XLR fashion

A

Fabry disease
Lowe syndrome
Ocular albinism
Retinoschisis

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7
Q

List some ocular disorders inherited in an XLD fashion

A

Alport syndrome (also AR)

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8
Q

List some ocular disorders inherited in a mitochondrial fashion

A

Kearns-Sayer Syndrome

Leber hereditary optic neuropathy

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9
Q

HLA is found on what arm of which chromosome

A

Short arm (q) of chromosome 6

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10
Q

What condition is associated with HLA-A29?

A

Birdshot choroidopathy

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11
Q

What condition is associated with HLA-A11?

A

Sympathetic ophthalmia

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12
Q

What condition is associated with HLA-B7?

A

Presumed ocular histoplasmosis syndrome (POHS)

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13
Q

What condition is associated with HLA-B22?

A

Vogt-Koyanagi-Harada Syndrome (VKH)

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14
Q

What condition is associated with HLA-B27?

A

Psoriatic arthritis
Reactive arthritis
Enteropathic arthritis

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15
Q

What condition is associated with HLA-B51?

A

Beçhet disease

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16
Q

What condition is associated with HLA-BW5?

A

Posner-Schlossman Syndrome

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17
Q

What condition is associated with HLA-DR2?

A

Pars planitis
POHS
MS

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18
Q

What condition is associated with HLA-DR4?

A

Sympathetic ophthalmia
RA
VKH

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19
Q

What condition is associated with HLA-DR5?

A

JIA

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20
Q

What condition is associated with HLA-DR15?

A

MS

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21
Q

What HLA types are included in MHC-1 category?

A

A, B and C

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22
Q

What is the function fo MHC-1?

A

Expressed on all cells and stimulate CD8+ cytotoxic T cells

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23
Q

What HLA types are included in MHC-2 category?

A

DR, DP, DQ

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24
Q

What is the function fo MHC-2?

A

Stimulate CD4+ T-helper cells and are expressed on specialised antigen-presenting cells such as macrophages

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25
Q

What are cytokines?

A

Molecules responsible for recruitment and proliferation of the innate and adaptive immune systems

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26
Q

List types of cytokines?

A

Tumour necrosis factor
Interleukins
Chemokines
Interferons

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27
Q

What is tumour necrosis factor?

A

Pro-inflammatory response produced by macrophages. They help in the activation and differentiation of immune cells and increase vascular permeability.

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28
Q

What are interleukins?

A

Mediate communication between different cells and are important in regulating immune response

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29
Q

What is the role of IL-1?

A

Induces immune responses and causes fever

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30
Q

What is the role of IL-2?

A

Proliferation of T and B cells

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31
Q

What is the role of IL-5?

A

Regulates growth and activation of eosinophils

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32
Q

What is the role of IL-6?

A

Involved in differentiation of B cells and production of CRP

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33
Q

What is the role of IL-8?

A

Attracts neutrophils, T cells, basophils and eosinophils

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34
Q

What is the role of IL-10?

A

Suppresses immune cells

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35
Q

What is the role of IL-12?

A

Differentiates T cells into TH1 and enhances cytotoxicity

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36
Q

What are interferons?

A

Proinflammatory agents/immunomodulatory cells

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37
Q

What is the mechanism of beta-blockers in the treatment of glaucoma?

A

Decreased aqueous production

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38
Q

What is the mechanism of prostaglandin analogues in the treatment of glaucoma?

A

Increase aqueous drainage via uveoscleral outflow

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39
Q

What is the mechanism of alpha-2-agonists in the treatment of glaucoma?

A

Decrease aqueous production and increase uveoscleral outflow

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40
Q

What is the mechanism of topical and systemic CAIs in the treatment of glaucoma?

A

Decrease aqueous production

41
Q

What is the mechanism of miotics in the treatment of glaucoma?

A

Parasympathomimetics increase aqueous drainage via TM by contracting ciliary muscles

42
Q

What is the mechanism of osmotic agents in the treatment of glaucoma?

A

Lowers IOP by increasing vitreous volume

43
Q

Timolol is an example of what class of anti-glaucoma medication?

A

Beta-blocker

44
Q

Latanoprost is an example of what class of anti-glaucoma medication?

A

Prostaglandin inhibitor

45
Q

Apraclonidine is an example of what class of anti-glaucoma medication?

A

Alpha-2 agonists

46
Q

Topical dorzolamide and Systemic acetazolamide are examples of what class of anti-glaucoma medication?

A

Carbonic anhydrase inhibitors

47
Q

Pilocarpine is an example of what class of anti-glaucoma medication?

A

Miotics

48
Q

Mannitol is an example of what class of anti-glaucoma medication?

A

Osmotic agent

49
Q

List some side effects of beta-blockers in the treatment of glaucoma

A
Decreased corneal sensation 
Dry eye
Tachyphylaxis 
Bradycardia
Bronchospasm
Nocturnal hypotension
50
Q

List some side effects of prostaglandin analogues in the treatment of glaucoma

A

Conjunctival hyperaemia
Hyperpigmentation
Increased eyelash length
CMO

51
Q

List some side effects of alpha-2 agonists in the treatment of glaucoma

A
Follicular conjunctivitis 
Contact dermatitis
Tachyphylaxis 
Dry mouth 
Sedation
52
Q

List some side effects of CAIs in the treatment of glaucoma

A

Ocular stinging
Bitter taste
Punctate keratitis

Systemic:
Paraesthesia
Hypokalaemia
SJS
Metabolic acidosis
53
Q

List some side effects of osmotic agents in the treatment of glaucoma

A

Cardiovascular overload

54
Q

What drugs cause lens opacification and cataracts?

STACA

A
Steroids
Tobacco
Amiodarone 
Chlorpromazine
Allopurinol
55
Q

What drugs are associated with CMO?

A

Latanoprost, epinephrine, rosiglitazone and nicotinic acid

56
Q

What drugs are associated with Bull’s Eye Maculopathy?

A

Hydroxychloroquine and chloroquine

57
Q

What drugs are associated with crystalline maculopathy?

A

Tamoxifen

58
Q

What drugs are associated with optic neuropathy?

A
Ethambutol
Chloramphenicol
Amiodarone
Vigabatrin 
Isoniazid
59
Q

What is vortex keratopathy?

A

Deposition of asymptomatic grey opacities in a vortex pattern on the corneal epithelium

60
Q

What are the causes of vortex keratopathy?

A

Drugs (amiodarone, chloroquine, indomethacin, phenothiazines)

Fabry disease

61
Q

What is Fabry disease?

A

An XLR condition characterised by a deficiency of alpha-galactosidase

Causes burning pain in the extremities, angiokeratomas, renal failure, posterior sub capsular cataracts

62
Q

What is the purpose of keratometry?

A

Measures the anterior corneal surface curvature

63
Q

What is corneal topography?

A

Measures and quantifies the curvature of the whole cornea. It uses placido-disc systems

64
Q

What is ultrasonic pachymetry?

A

Can be used to measure central corneal thickness

65
Q

What is the normal central corneal thickness?

A

530-545 micrometers

66
Q

What type of light is used to measure cross-sectional images of the retina in OCT?

A

Near-infra red

67
Q

How does FA work?

A

Sodium fluorescence absorbs blue light (465-490nm) and emits yellow-green light (530nm). It is injected in a peripheral vein and passes through the short posterior ciliary artery into the choroicapillaris in 8-12s post injection and the retinal circulation 1s later

68
Q

What are the side effects of FA?

A

Urine discolouration, nausea, vasovagal syncope and anaphylaxis

69
Q

What allergy is a contraindication to FA?

A

Shellfish

70
Q

What are the benefits of indocyanine green angiography?

A

Better choroidal vasculature observation

71
Q

What is fundus autofluorescence?

A

Detects lipofuscin in the RPE

72
Q

What is autofluorescence used for?

A

Best disease, RP and monitoring geographic atrophy

73
Q

Tonometry is important in the diagnosis and investigation of glaucoma. How does it work?

A

Follows the Imbert-Fick Law which says the amount of force required to flatten a corneal area of 3.06mm assuming a CCT of 520 micrometers

74
Q

What factors may decrease the measurements of IOP?

A

Excessive fluorescein: over-estimates

Low or high CCT - underestimates and over respectively

Astigmatism

Calibration errors

75
Q

What structures visualised in gonioscopy indicate a wide open AC angle

A
Schwalbe line
Non-pigmented TM
Pigmented TM
Scleral spur 
Ciliary Body
76
Q

What are scleral spurs?

A

Anterior protrusions of the sclera that marks the attachments of the CBs longitudinal fibres

77
Q

What is perimetry?

A

Used to detect visual fields

E.g. Humphrey or Goldmann visual field testings

78
Q

List some types of glaucomatous visual field defects

A
Nasal step
Paracentral depressions 
Arcuate defects
Ring scotoma 
Tunnel vision with temporal sparing
79
Q

What are the fundamental properties of lasers?

A

Coherency (same phase)

Monochromaticity (single wavelength)

Collimation (minimal divergence)

80
Q

What structures are required for the construction of a laser?

A

Light source
Medium (determine wavelength - e.g. gas, liquid or solid)
Optical resonator to amplify light

81
Q

Lasers are classified by their hazardous effects. What types of lasers are used in Ophthalmology?

A

Class 3B or 4

82
Q

Laser-tissue interaction occurs in what three ways

A

Photothermal
Photochemical
Photo-ionising

83
Q

What is photothermal laser-tissue interaction

A

Uses photovapourisation (high temp) and photocoagulation (protein denaturation)

84
Q

List some different types of photocoagulative lasers?

A

Argon-blue - not used on macula

Krypton red

Frequency doubled
Nd:YAG

Diode (highest wavelength)

85
Q

Give examples of photochemical lasers

A

Photorefractive keratectomy (PRK)

Laser-assisted in situ keratomileusis (LASIK)

Laser epithelial keratomileusis (LASEK)

86
Q

What are examples of photo-ionising laser and what are they used for?

A

Nd:YAG for posterior capsulotomy in PCO and peripheral iridotomy for PACG

87
Q

What are the two registered sight impairment categories?

A

Severely sight impaired (blind) and sight impaired

88
Q

What are the requirements for blindness registration?

A

VA <3/60 or
VA <6/60 with reduced VFs
VA >6/60 with severe VF changes

89
Q

What is the DVLA sight requirements for driving?

A
  1. Read number plate at 20m
  2. VA >6/12 in both eyes
  3. VF of 120 degrees with extension of 50 degrees. No defect encroaching 20 degrees of horizontal meridian
90
Q

What specific cases must be reported to the DVLA?

A

Diplopia
VF defects
Nyctalopia
Blepharospasm

91
Q

What type of sutures are suitable for eyelids and sclera?

A

Silk

92
Q

What type of sutures are suitable for conjunctiva, muscles and cornea?

A

Polyglactin 910

93
Q

What type of sutures are suitable for cornea, sclera and limbus?

A

Polypropylene

94
Q

What type of sutures are suitable for the limbus?

A

Polyglycolic acid

95
Q

What is the most common cause of blindness in the world?

A

Cataracts

96
Q

What is the most common causes of infective blindness?

A

Trachoma

Onchoceriasis

97
Q

What is the most common cause of visual impairment?

A

Refractive errors

98
Q

What is the most common cause of childhood blindness?

A

Vitamin A deficiency

Measles

Retinopathy of prematurity

Cataract