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Flashcards in LEC 8 - Eyes Deck (142):
1

What are the four possible entry into the cornea?

Destruction of corneal epithelium 

Penetration of corneal stroma 

Diffusion intro stroma via limbal blood vessels 

Injurt to corneal endthelium 

2

What are three examples that cause injury to the corneal endothelium?

Gluacoma 

Lens luxation 

Leukocyte mediated injury 

 

3

What is the main method by which there is entry into the uvea?

Hematogenous

4

What are the three hematogenous routes that go into the uvea?

Toxins 

Infectious agents 

Neoplastic emboli 

5

What are the methods of defense in the cornea?

Intact corneal epithelium 

Leukocytes 

6

What about the corneal epithelium protects the cornea?

Constant washing of corneal surfaces 

Tears rich in antimicrobial substances 

Surface mucus inhibits bacterial colonization 

7

What are the three antimicrobial substances in tears?

IgA 

Lysozyme 

Lactoferrin 

8

What are the three mechanisms by which the uvea are protected?

Scelra/Bony orbit 

Blood ocular barrier 

Anterior chamber immune deviation 

9

What is the blood ocular barrier?

Tight junctions between: 

Endothelial cells of iris + Retinal blood vessels 

Epitheliaum of non-pigmented ciliary epithelium + RPE 

10

What is ACAID?

Immune response by which infectious agents that enter into the anterior chamber induce a highly controlled immune response 

11

What are the benefits of the ACAID response?

Minimal tissue damage 

Very strong response

12

Why is the uveal tract no protected agains noxious agents in circulation?

It has free communicationwith peripheral blood 

13

When an antigen enters the eye how are T cells activated? Why?

NO lymphoid tissue in eye 

APC's exit normal aqueous outflow and go to marginal zones in the spleen 

T lymphocytes are then activated 

14

What does the blood-eye barrier in the retina consist of?

Tight junctions between 

RPE cells + Retinal vascular endothelium 

15

What is different about the retina in regards to immune defense compared to the rest of the eye?

No real defense at all against infectious agents, radiation, or noxious chemicals through the vitreous 

16

What are the two major pathological processes in which the cornea responds to injury?

Adaptive cutaneous metaplasia 

-- and -- 

Epithelial/Stromal Necrosis 

17

When does adaptive cutaneous metaplasia normally occur with corneal injury?

Mild persistant irritation 

18

What common eyelid disease causes adaptive cutaneous metaplasia in the cornea?

Entropion 

19

What is entropion?

Inversion of the margin of the eyelid 

20

What is adaptive cutaneous metaplasia a combination of? (5 processes)

Keratinization 

Epithelial hyperplasia 

Epithelial pigmentation 

Subepithelial fibrosis 

Vascularization 

21

Define: Corneal ulceration

Full thickness epithelial loss

22

How does edema occur with ulcerations of the cornea?

Water is absorbed from tear film into the anterior stroma 

23

What is the hallmark of corneal ulceration? How does it manifest?

Edema 

Opacity 

24

What is the diagnostic technique to diagnosis a corneal ulceration?

Fluorescein dye 

25

What is the severe form of corneal ulceration, that occurs once bacteria is present?

Neutrophil-induced keratomalacia 

aka Melting ulcer

26

What happens to the eye once there is a melting ulceration? Describe.

Desmatocele 

Decemet's membrane bulge anteriorly into defect created 

27

Term: Inflammation of the cornea 

Keratitis 

28

What happens if the Decemet's membrane ruptures?

Can lead to the loss of anterior chamber fluid 

-- and -- 

Iris prolapse

29

What bacteria can cause suppurative keratomalacia in a horse?

Pseusdomonas spp. 

30

What is the process by which suppurative keratomalacia occurs in a horses eye?

Proteolytic destruction of the stroma 

Caused by digestive enzymes that are released by the neutrophils in the inflammatory exudate 

31

How does a wound in the eye heal if there is only epithlial damage?

epithelial sliding 

-- and -- 

Mititotic regeneration 

32

If there is full thickness destruction in the cornea what do the epithelial cells first release? What do these cause?

IL-1 (cytokine) + PDGF (Growth Factor) 

Cause: Necrosis + Apoptosis of Stromal Cells 

33

If there is full thickness destruction in the corneal what do the epithelial cells at the margins of the ulcer release? What do these do?

EGF + KGF + HGF 

Stimulated epithelial migration + Proliferation

34

What is the result of the KGF + HGF + EGF release in a corneal ulceration?

Flattening + Sliding of viable suprabasilar epithelium 

35

Where do the neutrophils in corneal wound healing come from? What do they do?

Come from: Tear film + Limbus 

Recruit blood vessels + Fibroblasts 

36

Term: Hypopion

Accumulation of Neutrophils + Fibrin 

Settles ventrally in the eye 

37

Term: Anterioir Uveitis 

Inflammation within Iris + Ciliary body 

38

Term: Choroiditis 

Inflammation only in choroid

39

Term: Hyalitis 

Inflammation in vitreous 

40

Term: Panuveitis 

Inflammation throughout uveal tract 

41

Term: Endopthalmatis 

Inflammation involving uveal tract + adjacent ocular cavities 

42

Term: Panopthalmatis 

Inflammation spreads to scleara

43

What are the three major causes of uveitis?

Infectious agents 

Immune-mediated reactions 

Trauma

44

What does trauma to the uvea cause?

Transient endopthalmatis 

45

What is the most common immune mediated reaction cause by in the Uvea?

Lymphoplasmacytic 

46

What virus in a cat can cause hypopyon?

Feline infectious peritonitis 

47

What are the eight types of delayed responses to injury in the uvea?

Synechiae 

Iris bombe 

Retinal detachment 

Cataracts 

Corneal endothelialitis 

Preiridal fibrovascualr membrane 

Hyphema 

Phthisis bulbi 

48

Term: Phthisis bulbi

Shrunken disorganized endstage globe 

49

Term: Hyphema

hemorrhage within the anterior chamber

50

Term: Preiridal fibrovascular membrane 

Layer of granulation tissue of the anterior surface of the eye 

51

What can happen if preiridal fibrovascular membrane migrates across the anterior surface of the lens?

Pupillary block occurs 

Secondary gluacoma occurs 

52

What can happen if preiridal fibrovascular membrane migrates across the anterior surface of the filtration angle?

Anterior synechiae

53

Term: Corneal endothelialitis 

Inflitration of neutrophils + lymphocytes into corneal endothelium 

54

How does corneal endothelialitis manifest as?

Corneal edema 

aka blue eye 

55

What are some causes of corneal endothelialitis?

Cats = FIP 

Dogs = Canine adenoviral hepatits 

56

Term: Cataracts

Lens opacity due to drop in production of aqueous humor 

57

What is an important job of the aqueous humor?

Provide nutrients to the lens 

58

What is cataracts a sequela to?

Uvetitis 

59

What is retinal detachment a sequlae to?

Uveitis 

-- and -- 

Endopthalmititis 

60

What are the two mechanisms that retinal detachment can occur?

Exudative 

-- and -- 

Tractional 

61

Describe exudative detachment of the retina

increased vascular permeability within the choroid 

Leads to: 

Effusion of fluid + cells into the subretinal space 

62

Describe tractional detachment of the retina?

Replacement of fibrinous exudate by fibrous tissue within vitreous 

63

Term: Iris bombe 

Bowing of iris due to increased pressure within posterior chamber in the presence of circumferential synchiae 

64

Term: Synechiae 

Adhesion between the inflammation between the inflammed sticky and either the lens or the cornea 

65

What is invovled in a anterior synechiae?

cornea

66

What is involved in a posterior synechiae?

Lens 

67

What is the progression of the adhesions in Synechiae?

Fibrinous to fibrous

68

What happens when synechiae becomes extensive?

Impairment of aqueous outflow from posterior to anterior chamber 

= Pupillary block --> Secondary gluacoma 

69

Term: Hematogenous retinal detachment

Leakage of liquefied vitreous subretinal space 

70

Term: Anopthalmia

No detectable development of even primary optic vesicle 

Noramlly bilatteral 

71

Term: Micropthalmia

Minature, disorganized globe in an orbit of normal size 

72

What are possible causes of micropthalmia? 

Exogenous injury to the globe 

Utero trauma + Ischemia injury + Infections 

73

Term: Cyclopia 

Failure of division of very primative optic primordium into paired symmetirc optice stalks + vesicles 

74

Term: Synopthalmia 

Cyclopia 

with replication of intraocular structures 

(ie. retina or lens) 

75

What can cause cyclopia in ewes?

Veratrum californicum 

Day 15 gestation 

76

Term: Coloboma

Defect in closure of the optic fissure 

Retina grows outwardly 

77

What is coloboma a hallmark of?

Collie eye abnomaly 

78

Describe the process of glaucoma. 

Increase in intraocular fluid pressure 

Detrimental to health of optic nerve + retina 

79

What are the end results of glaucoma?

Decrease in vision 

Evenutally blindness 

80

What causes primary glaucoma?

Ocurring without any known aquired intraocular disease 

Developmental errors 

 

81

What is one malformation that can cause primary glaucoma?

Goniodysgenesis 

82

Term: Goniodysgenesis

Imperfect developemnt of trabecular meshwork 

83

What are three examples of things that can cause secondary glaucoma?

pupillary block 

trabecular occulsion 

tumors 

84

How can a trabecular occulsion occur?

Infiltration of neoplastic cells 

Peripheral iridiocorneal adhesions 

mechanical compression of the base of the iris 

85

What are two tumors in dogs that can cause secondary gluacoma?

Anterior uveal melanocytoma 

-- and -- 

Metastatic lymphoma 

86

What are two tumors in cats that cause secondary glaucoma? 

iris melanoma 

-- and --

Metastatic lymphoma 

87

What are the eight secondary changes with glaucoma?

Bupthalmos 

Corneal edema 

Corneal striae 

Atrophy of iris + ciliary processes 

Cataracts 

Lens luxation 

Retinal degeneration 

Optic nerve changes 

88

Term: Buphthalmos

Stretching of the globe secondary to increased intraocular pressure 

89

Term: Corneal striae 

breaks in the Descement's membrane secondary to corneal scratching 

90

Why is there atrophy of the iris and cilliary process with glaucoma?

Due to chronic pressure induced ischemia 

 

91

What is the clinical sign that there has been atrophy of the iris?

Permanent dilation of the eye 

92

Define: Lens luxation

Due to stretching of the zonules secondary to ocular enlargement. 

Pressure induced degenerative changes in zonules 

93

What is the most important secondary change with glaucoma? Why?

Retinal degeneration 

This is where most glaucoma treatments are targeted 

94

What are the contribution factors in glaucoma that cause retinal degeneration?

Pressure induced ischemia changes 

Interference with ganglion cell nutrition 

Direct damage to ganglion cells by elevation local production of excitatory AA's 

95

What causes the optic nerve changes in glaucoma?

Posterior displaced of lamina cribosa 

-- and -- 

Cupping of optic disc 

96

How is a dermoid formed?

Failure of the fetal ectoderm to undergo corneal metaplasia 

97

What causes superficial stromal sequestration?

Injury to corneal epithelium followed by increase in amount of superficial stromal apoptosis  

98

In dogs and horses, what is the result of superficial stromal apoptosis? 

Inability of sliding corneal epithelium to properly adhere to underlying stroma, meaning full epithelial regeneration cannot occur 

99

In cats, what is the result of superficial stromal apoptosis? 

Stromal devitalization is normally greater 

Imbition of brown-colored pigemnt into dead stroma 

100

What is the pathognomonic feature of corneal sequestrum in a cat?

Brown-colored pigment 

101

What are the four common systemic mycoses that affect the eye?

Blastomycosis 

Cryptococcosis 

Histoplasmosis 

Saprophytic fungi 

102

What species of blastomycse?

Dermatitidis 

103

What species of cryptococcus?

neoformans 

104

What species of histoplasma? 

capsulatum 

105

What species of saprophytic fungi?

Aspergillus + Candida 

106

What does balstomyces cause?

Dogs 

Severe diffues pyogranuloatous endopthalmitis 

107

What does cryptooccus neoformans cause in the eye?

Lesions mostly in the retina + choroid + optic nerve 

Minimal granulomatous response 

Cats + Dogs

108

What does histoplasmosis capsulatum cause?

Diffuse granulomatous  + lymphocytic choroditis with little suppuration 

109

When causes lens induced uveitis?

Cataracts 

110

How do cataracts cause uveitis?

lens proteins begin disintegrate + leak through intact lens capsule 

= Phacolytic uveitis 

111

What is seen in dogs with phacolytic uveitis?

Suppurative to pyogranulomatous reaction centered around the lens 

112

What animals are uveal neoplasms most common?

Dogs and Cats

113

What are the primary tumors of the eye?

Melanocytic 

-- and -- 

Iridiocillary epithelail tumors 

114

What is the most common canine primary uveal tumor?

Canine aterior uveal melanocytoma 

115

What does anterior uveal melanocytoma arise from?

Melanocytes within the stroma of the iris + ciliary body 

116

What is the clinical presentation of feline diffuse iris melanoma?

Unilateral coalescing hyperpigmentation of iris 

Slowly progressing to thickening + secondary glaucoma 

117

Where do irdiociliary tumors come from?

neuroectoderm of posterior iris or ciliary body 

118

What causes feline primary ocular sarcoma?

Spindle cell neoplasm 

Arises from lens epithelium that espcased through ruptured capsules 

119

What is normally the end result of a completely dislocated lens?

Cataract 

120

Why does a cataract result from the complete dislocation of the lens?

inadequate access to aqueous humor 

121

What causes a primary lens luxation?

Occurs without any known trauma 

Developmental error that causes abnormal or insufficent zonules 

122

What causes a secondar lens luxation?

Blunt trauma 

Avulsion of zonules 

-- or -- 

Excess stretching of zonules 

123

What is thought to be the reason for diabetic cataracts?

Excessively high level of glucose within the aqueous humor 

124

What is the basic reason for equine keratomycosis for occurring?

Opportunistic contamination of corneal wounds by fungi 

125

What is the most common fungus to cause equine keratomycosis?

Aspergillus 

126

What are the the two different things that can occur with equine keratomycosis?

Infection of dead superficial stroma by large amount of hyphae with almost no inflammation 

-- or -- 

Deep stromal infection that evokes intense suppurative keratomalacia 

127

If keratomalacia occurs with equine keratomycosis what can it lead to?

Corneal perforation 

-- and -- 

Iris prolapse

128

What is Equine recurrent uveitis?

Unpredictable episodes of severe uveitis 

Increase in frequency 

Immunologic reaction against intraocular leptopsiral antigens 

129

What is the cause of infectious bovine keratoconjunctivitis?

Moraxella bovis 

130

What is the vector for moraxella bovis?

Flies 

-- or -- 

Fomites 

131

Why does moraxella bovis cause infectious bovine keratoconjunctivitis?

Have capsular pili that are hemolytic 

132

How does infectious bovine keratoconjunctivitis present?

Shallow corneal ulcers 

With severe conjunctival hyperemia 

--> Circumferential superfical vascular growth 

133

What is the presentation of bovine malignant catarrhal fever-associated uveitis?

Peripheral midstromal corneal vascularization 

-- and -- 

Anterior Uveitis 

134

What breed of dog tends to get canine pannus keratitis?

German shephards

135

Where does canine pannus keratitis begin? How does it spread?

Starts at lateral limbus 

Moves to axial cornea 

136

What is uveodermatologic syndrome?

Facial dermal depigmentation 

-- and -- 

Severe bilateral uveitis 

137

What breeds are affected by uveodermatologic syndrome?

Akitas 

Siberian Huskies 

Samoyeds

138

What is the histologic appearance of uveodermatologic syndrom?

Destructive granulomatous endophtalmitis 

Abundant dispersal of melanin 

Consequence of T-lymphocyte mediated destruction of melanin producing cells 

139

What virus causes feline herpetic keratitis?

Feline herpesvirus 1 

 

140

What occurs with feline herpetic keratiits?

Acute to chronic keratitis 

Shallow intraepithelial branching tracts of nerocis 

= Dendritic ulcers

141

What is the physical characteristic of eosinophilic keratitis?

Granular, white proliferative lesion extending inward along corneal surface from medial to lateral limbus 

142

What is seen on histologic examimination of eosinophilic keratitis?

Nonulcerative superfical stromal infiltration of: 

Eosinophils 

Plasma cells 

Mast cells 

Macrophages