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SS - Exam 2 > External Ocular Pathology > Flashcards

External Ocular Pathology Flashcards

1
Q

Developmental anomalies of the globe

A

Anophthalmia
Microphthalmia
Cyclopia

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2
Q

Developmental anomalies of globe

A

Dermoid
Coloboma
Collie eye anomaly
Merle ocular dysgenesis

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3
Q

Anophthalmia

A

No development of optic vesicle
Usually bilateral
Uncommon - often misdiagnosed as severe microphthalmia

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4
Q

Microphthalmia

A

Miniature globe in normal sized orbit/socket
Involution following injury to globe
-in utero trauma
-ischemic injury
- infection

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5
Q

Cyclopia*

A

Single midline globe
If diplication of Intra ocular structures = Synophthalmia - often misdiagnosed

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6
Q

cause of cyclopia

A

Spontaneous - RARE
Ewe ingests Veratrum califonicum on day 14 of ingestion
Usually other developmental anomalies in other organs

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7
Q

Dermoid

A

Presence of haired skin in the corneal or conjunctival epithelium
CLIN SIG: depends on degree of corneal irritation caused by hair

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8
Q

Coloboma

A

Defect resulting from incomplete closure of optic fissure
Can result in outpouching of retina
One in the lesions of collie eye anomaly

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9
Q

Collie eye anomaly

A

Heritable disease of rough and smooth collies
Multiple concurrent anomalies
- choroid hypoplasia & hyperpigmentation
- posterior Coloboma
- retinal detachment
- microphthalmia

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10
Q

Merle ocular dysgenesis

A

Merle gene = color dilute
Homozygous dogs have light coat and can have multiple congenital ocular lesions

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11
Q

Merle gene congenital ocular lesions

A

Microphthalmos
Iris abnormalities: Coloboma, hypoplasia, persistent pupillary membranes
Lens abnormalities: microphakia (small lens), cataract, lens luxation
Sclera Coloboma
Retinal dysplasia or detachment

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12
Q

Extra ocular neoplasia

A

Squamous cell carcinoma
Meibomian Adenoma
Melanocytic neoplasms

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13
Q

Squamous cell carcinoma

A

Common in cattle & horses w non pigmented eyelids /conjunctiva exposed to sunlight
Cats: affects eyelids of white faced cats
Dogs = uncommon

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14
Q

Meibomian adenoma

A

Most common tumor of eyelid in dogs
Meibomia- modified sebaceous gland in eye
Similar to sebaceous adenoma = benign

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15
Q

Melanocytic neoplasms

A

Eyelid = benign —> melanocytoma
Limbus = benign
Conjunctiva = malignant melanoma

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16
Q

Corneal epithelium

A

Keeps tear film out of cornea

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17
Q

Corneal endothelium*

A

Not endothelium, specialized epitheliu, cells
Main job to actively pump out fluid /aqueous humor from the anterior chamber to keep cornea dehydrated

18
Q

Corneal edema

A

Fluid in the interstitial space = blindness

19
Q

Corneal responses to injury

A

Adaptive cutaneous metaplasia
Epithelial stromal necrosis
Wound healing/repair

20
Q

Adaptive cutaneous metaplasia

A

Reponse to persistent mild irritation
Keratinization, epithelial hyperplasia, neovascularization - sprouting of new blood vessels from limbus

21
Q

Epithelial/stromal necrosis

A

Response to more severe external injury
Corneal ulceration - secondary edema

22
Q

Causes of epithelial/stroma necrosis

A

Dessication (KCS) - keratoconjunctivitis sicca, when eyelids don’t fully cover eye or inadequate production of eye fluid /tears
Mechanical injury
Chemicals
Infection

23
Q

Keratomalacia

A

Secondary softening of the cornea, a result of infected corneal ulcer

24
Q

desemetocele

A

Deep central corneal ulcer
High risk of rupturing leading to perforating ulcer

25
Q

Wound healing/repair

A

Epithelium - sliding of cells followed by mitosis
Stroma - repaired stroma/collagen, not transparent with chronic/larger damage

26
Q

Feline corneal sequestrum

A

Increased superficial stromal necrosis compared to normal corneal epithelial injury
Accumulation of brown pigment from tear film into corneal stoma
Central dark brown corneal pigment from iron(porphyria’s)
Persians and Himalayan’s= predisposed

27
Q

Canine ulcerative keratitis

A

Endogenous trauma
-eye lash disorders, e troponin, KCS
Can result in secondary bacterial infection

28
Q

Canine persistent ulcer syndrome

A

Boxer ulcer

29
Q

Infectious bovine keratoconjunctivitis

A

“Pink eye”
Caused by moraxella bovis
Specific virulent strains are able to colonize in cornea
Transmitted by flies, direct contact or fomites
Differentiate from IBR

30
Q

lesion for pink eye

A

Corneal ulcer that progresses to suppurative keratomalacia
Similar lesions in sheep/goats - chlamydia, mycoplasma

31
Q

Feline herpes virus I

A

Causes keratitis and corneal ulceration
VERY COMMON
Corneal edema is secondary to ulceration

32
Q

Canine pannus keratitis

A

German shepherd pannus
Chronic superficial keratitis
Lesions begin at lateral limbus and spreads toward central cornea = bilateral
Response to immunosuppressive therapy

33
Q

Equine mycotic keratitis

A

Due to secondary fungal infection of corneal wound (exogenous trauma)
Aspergillus most common (like descemets membrane)
Can progress to suppurative keratomalacia and corneal perforation

34
Q

Bovine conjunctivitis

A

Infectious bovine rhinotracheitis
Parasitic conjunctivitis

35
Q

Infectious bovine rhinotracheitis

A

Caused by bovine herpes virus I
Does not produce corneal ulceration
Primary differential DX
- infectious bovine keratoconjunctivitis = corneal involvement, pink eye starts in cornea

36
Q

Parasitic conjunctivitis

A

Thelazia
Inhabit conjunctival sac and lacrimal duct
Larvae transmitted by flies

37
Q

Canine conjunctivitis common causes

A

Allergic disease
Mechanical irritation
Dessication

38
Q

Nodular granulomatous episcleritis

A

NGE - canine conjunctivitis
Nodular lesion of episclera or conjunctiva
Proliforation of
- histiocytes
- fibroblasts
- lymphocytes
- Plasma cells

39
Q

Feline conjunctivitis

A

Feline herpes virus I
Initial infection in young cats = keratitis (cornea)+ conjunctivitis
Recurring infection in older cats may cause conjunctivitis alone
Chlamydiophila felis

40
Q

equine conjunctivitis

A

Habronemiasis
Nematode larvae of habronema deposited in conjunctiva
Lesion = eosinophilic granulomas

SS - Exam 2 (18 decks)

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