Special senses

Question 1

development of the ocular globe in carnivores continues after birth until

Answer 1

5-6 weeks

Question 2

what does the eye develop from

Answer 2

outpouching of the brain

Question 3

The three layers of the ocular globe are

Answer 3

outer/fibrous (sclera, cornea)
middle/uvea (iris, ciliary body, choroid with tapetum lucidum)
inner/nervous (retina)

Question 4

What are the three chambers of the eye

Answer 4

anterior, posterior (both have aqueous humor) and vitreous (Gives the globe its shape)

Question 5

Purpose of the eye

Answer 5

gather and permit entry to photons of light -> absorbed by retina to convert to electrical energy -> interpreted by the brain as sensory info

Question 6

vision requires a ____ cornea, lens and humors

Answer 6

clear. anything that changes clarity impairs vision

Question 7

What contributes to the adnexa of the eye

Answer 7

eyelids, conjunctiva, orbit. Important first line of protection

Question 8

the eye has a ____ repertoire of responses, which means clinical exams while the patient is still living is super improtant

Answer 8

limited. Hard to determine inciting cause of eye problems post mortem

Question 9

How does the clinical and pathological definition of uveitis differ

Answer 9

clinical - fibrin flare
pathological - inflammatory leukocytes in uvea

Question 10

regeneration in the eye is ____

Answer 10

limited, except for the lens and cornea

Question 11

Uveitis

Answer 11

Inflammation of the vascular layer/uvea

Question 12

anterior uveitis vs panuveitis

Answer 12

Anterior uveitis = inflammation of the iris and ciliary body
* Panuveitis = inflammation of all 3 parts, iris, ciliary body and choroid

Question 13

ophalmitis

Answer 13

Endophthalmitis = inflammation of the uvea and three ocular chambers
(anterior, posterior and vitreous)

Panophthalmitis = endophthalmitis + inflammation of the sclera

Question 14

hypopyon

Answer 14

accumulation of neutrophils and fibrin that settles ventrally in the anterior chamber

Question 15

hyphema

Answer 15

accumulation of blood in the anterior chamber

Question 16

phthisis bulbi

Answer 16

end stage eye, atrophy, collapse, fibrosis

Question 17

What is not present in the cornea?

Answer 17

blood vessels and pigment -> these would obstruct light

Question 18

Largest component of the cornea

Answer 18

stroma -> dehydrated parallel bundles of collagen and rare keratinocytes

Question 19

What are types of damage that can occur to the cornea

Answer 19

dessication, trauma, chemical injury

Question 20

defenses of teh cornea

Answer 20

Tears, blinking, which have small numbers of leukocyets

Question 21

keratitis

Answer 21

inflammation of the corena

Question 22

neovascularization

Answer 22

new blood vessels grow from limbus into cornea

Question 23

what are the two most common causes of corneal damage

Answer 23

trauma, dessication

Question 24

causes of desiccation

Answer 24

breed related exophthalmos (protruding eyes in brachys)

defective eyelids structure or function

acquired ocular enlargement such as glaucoma

Question 25

chronic keratitis

Answer 25

corneal response to injury. Abnormal tear film or mechanical injury leads to chronic corneal irritation, leading to metaplasia. Cornea becomes skin like

Question 26

Superficial corneal ulcers

Answer 26

corneal edema with epithelial regeneration which covers the defect. Heals rapidly

Question 27

Indolent ulcer

Answer 27

failure of normal ulcer healing with no underlying specific cause.

Question 28

indolent ulcers are most common in what species

Answer 28

dogs

Question 29

in indolent ulcers, the newly formed epithelium fails to adhere to the______

Answer 29

underlying stroma, and a cleft forms

Question 30

Melting ulcer/ keratomalacia

Answer 30

ulceration leads to a release in lytic enzymes from neutrophils and/or pathogens, leading to stromal malacia/necrosis

Question 31

Keratomalacia can involve what pathogens?

Answer 31

Fungal (keratomycosis) or bacterial

Question 32

Descemetocele

Answer 32

deep ulcer that reaches descemets membrane

Question 33

corneal sequestrum is most common in what species

Answer 33

cats

Question 34

corneal sequestrums occur secondary to

Answer 34

chronic ulceration

Question 35

Sequelae of corneal ulcers

Answer 35

* healing * Indolent ulcers * Melting ulcers * Descemetocele * Corneal sequestrum * Perforation & Iris Prolapse * phthisis bulbi

Question 36

keratoconjunctivitis sicca (KCS)

Answer 36

Immune-mediated lacrimal adenitis (main cause) → ↓ tear film → desiccation → KCS

Question 37

KCS is most common in

Answer 37

dogs

Question 38

Dermoid

Answer 38

developmental abnormality due to ectopic hair follicles and adnexal glands

Question 39

Infectious bovine keratoconjunctivitis (PINK EYE) caused by

Answer 39

Moraxella bovis

Question 40

Infectious Bovine Keratoconjunctivitis Aka Pink Eye: more severe in calves or adults?

Answer 40

calves

Question 41

Herpesvirus Keratitis

Answer 41

caused by FHV-1, usually a disease of kittens

Question 42

Eosinophilic keratitis is most common in what species

Answer 42

cats >horses

Question 43

gross features of eosinophilic keratitis

Answer 43

white to pink plaques on the cornea/ conjunctiva

Question 44

Chronic superficial keratitis affects which specific breeds?

Answer 44

German shepherds and sighthounds

Question 45

What causes chornic superficial keratitis

Answer 45

immune-mediated disease targeting altered antigen of the cornea

Question 46

Melanocytic neoplasia

Answer 46

darkly pigmented neoplasia derived from melanocytes of the limbus