Eye diseases and disorders

How does the pupil present

horizontal shape

what is the PLR response

slower than dogs and cats

What is a disorder of the pupil

corpora nigra

what are eyelid disorders

entorpion- rare

lacerations- common

squamous cell carcinoma

sarcoids

melanoma

what do you want to check for with lacerations

periorbital fractures and corneal lacerations

that the globe is intact

repair quickly

what is the most common tumor of the equine eye

squamous cell carcinoma

what are sarcoids

solitary or multiple tumors of the eyelids and periocular region

how do sarcoids present

firm, wart-like, slow growing mass on the lids and surroundign skinh

how are the eyes positioned

laterally on the head

what is the visual field of a horse

350 degrees

blind spots: directly infront and behine

corpora nigra

shades the retina

entropion

can be found in foals or dehydration

SCC is what if left untreated

locally invasive

signalment for sarcoids

>7 yo

more seen in darker horses

what should be done for anything removes

histopath

what is rare in sarcoids

metastasis is rare

recurrence is common

TX for sarcoids

topical irritants

immunotherapy

chemotherapy

surgical excision

hyperthermia

gamma radiation

what is a melanoma

single or multiple leasion

signalment for melanoma

grays

arabs

percherons

what % of melanomas are on the eyelid

24%

melanoma TX

surgical excision w/ CO2 laser

cryo

photodynamic therapy

what is conjunctivitis

nonspecfic indicator of ocular inflammation

What can cause conjunctivtis

almost anything

FB

predisposing factors for SCC

environment

UV

breed: clydesdale, appys, paints

age, increases with age: averge is around 11

color: white, gray, palomino

SCC clinical signs

blepharitis/spasm

mucopurulent discharge

tissue bleeds easily

SCC location

eyelids

nictitan: third eyelid

conjuctiva

limbus

cornea

SCC treatment

medical

surgical debridement

cryotheraphy radiation

enucleation

exenteration: get everything down to the bone

SCC prognosis

recurrence is common

metastasis is low

locally invasive

what is the most common disease of the 3rd eyelid

SCC

protrusion of the nictitans

associated with several conditions

pain, tetanus, inflammation, enophthalmos, orbital fat: kind of looks like cherry eye, horners syndrone, FB

Common cornea disorders

ulceration

lacerations/perforation

equine ulcerative keratomycosis (fungal eye infection)

stromal abscess

scc

ulcer confirmation

fluorescein stain

corneal ulcer Clinical signs

blepharispasm

epiphora

photophobia

any ulcer not responding to therapy requires what

cytology as well as culture and sensitivities for bacteria and fungus

best off label use for corneal ulcers

SSD

corneal ulcer therapeutic methods

topical tx is difficult

place subpalpebral lavage

corneal ulcer surgical therapy

debride ulcer and infected cornea

place conjunctival flap

corneal lacerations/perforations TX

sugical: needed for full thickness corneal perforations, deep, or irregular lacerations

what is equine ulcerative keratomycosis

very common; fungi is normal in the conjunctival microflora and in the environment can cause the horse to loose its sight

stromal abscesses

can be vision threatening

stormal abscess TX

often require combined medical and surgical therapy

clinical observation of stromal abcess

focal, yellow/white stromal infiltrate with corneal edema

lens disorders

acquired cataracts

congenital cataracts: in foals; 4-6 month window time to get fix; the brain will not recognize anything coming in if after time window

juvenile cataracts

senile cataracts

nuclear lenticular sclerosis: same as dog and cats

lens luxation: equine w/ reaccuring uveitis or glaucoma

equine glaucoma normal pressures

18-28 mmHg is normal in equine

more horses are sedated for exam, make sure head is not dropped

lens luxations

glaucoma

glaucoma predisposing factors

ERU: equine recurring uveitis

>15

appys

Glaucoma Clinical signs

corneal edema

corneal band opacitites

fixed and dilated pupil

glaucoma TX

medical

surgical: laser, valve/shunt

haab’s stria

breaks in membrane: basically stretch marks

what is a ahmed valve

glaucoma shunt

How is a ahmed valve placed

a small plate with a valve system that regulates IOP

attached to the plate is a tube that drains the aqueous out of the eye

implant is placed between the sclera and conjunctiva

ERU common names

moon blindness

periodic ophthalmia

etiology of ERU

not known, but suspect immune mediated

What is the number 1 cause of blindness in adult horses

ERU

ERU clinical signs

epiphora: excessive tearing

blepharospasm: blinking and squinting

photophobia: sensitive to light

corneal edema: fluid in corneal

conjunctival hyperemia: redness of conjunctiva

miotic pupil: small

low intraocular pressure: single digits

ERU Tx

goal is to perserve vision

keep comfortable

minimize recurrence

ERU Prognosos

usually poor

TX is time consuming and expensive

infectious bovine keratoconjunctivitis

AKA pink eye

highly contagious

cause of great ecnomic loss to procedures

occurs primarily during the summer months

IBK predisposing factors

Breed: herefords and hereford cross

age: high risk among younger cattle, increase severite among calves, older cattle more resistant

environment: increased levels of UV radiation, #of face flies, solar radiation during the summer months

IBK transmission

organism: Moraxella BOVIS

gram-negative, aerobic, oxidase-positive diplococuss

Action: handlers, direct contant with infected, fomites, mechanical vectors

face flies are biggest transmitter

Clinical signs of IBK

earliest

epiphora

blepharospasm

photophobia

conjunctival hyperemia

chemosis

75% of cases are unilateral

cattle are reluctant to compete for food

decreased milk production

weight gain suppressed

IBK Prevention

Insecticides: impregnated ear tags, pour-on face dust bags, back rubbers, feed additives

personal disinfection between animals

grass, weed, and brush should be cared for

manure management: clean high traffic areas

ample shade

pigmented eyelid and dark hair on face

IBK vaccination

current proto: calves 21-30 days with booster 21 days later

\vac, 30 days before fly season

variable efficacy

IBK treatment

Closure of the lids (tarsorrhapy): in order to aid healing by preventing furster insult to the eye; client will remove sutures in 7-10 days

place a local block above the upper and under the lower eyelashes on the lid with lidocaine

± subconjuctival injection of dex and penicillin

oxytetracycline: either as LA-200 or biomyacin

subconjunctival injection of oxytetracycline

parenteral NSAID: Banamine or meloxicam

atropine to relieve ciliary spasm

ocular SCC

AKA cancer eye

slaughter 80% were OSCC

3rd leading caue of carcass condemnation

estimated $20 million loss in the us

OSCC signalment

older cattle, uncommon in younger than 5, average is 8yo

hereford, hereford cross, holstein

sites may be single or multiple, uni or bilateral

OSCC causes

specific cause has not been identified

age, breed, pigmentation, exposure to UV radiation, viral infection, and nutrition can all be contribute to the development

southwest region and in lower latitides with higher levels of sunlights

7-8 years of age

OSCC clinical signs

lesions differ in appearance

most common sites- lateral conjunctiva and corneolimbal junction

OSCC tx

surgery

cyrosurgery

radiation therapy

immunotherapy

hyperthermia

OSCC prevention and control

selective breeding

select animals with large amounts of periocular pigment

BVD

if pregnant cow is infected; will be present in the calf born

Silage eye

listerial keratoconjunctivitis and uveitis

silage eye cause

big bales of silage can have the fungus

silage eye clinical signs

iritis ± keratoconjunctivitis

lesions are mostly unilateral but can be bilateral

uveitis has been reported in deer, sheep, and cattle

3 weeks to run it’s course if not treated

silage eye DX and TX

• DX: clinical signs of uveitis with history of feeding silage

  • PCR: Listeria

  • uveal change make the disease distinct from IBK

• TX

  • antibiotics: systemic and topical

  • subconjunctival: oxytetracycline and dexmethasone

cattle orbit/globe disorders

microphthalmia

convergent strabismus

oribital inflammation

orbital neoplasia

microphthalmia

smaller than the normal eye

convergent strabismus

cross-eyed

orbital inflammation

common

orbital neoplasia

lymphosarcoma

eyelid/ 3rd eyelid/ nasolacrimal system disorders

supernumerary opening of the NL duct

entropion

eyelid trauma

supernumerary opening of the NL duct

signal ment and what is ti

brown swiss and holstein, increased drainage from the eye

bovine entropion

simmental , rare

bovine conjunctical/corneal disorders

dermoids: hair growing from cornea

subconjunctical hemorrhage: usually resolves with no therapy

IBK
OSCC

camelid ocular anatomy

very similar to other livestock species

iris color varies: dark to light brown to bluw

large pupillary ruff: dorsal and ventral, funtion: shade the eye

pupil: oval

Camelid normals

Schirmer: >20mm/min

IOP: 14 mmHG

PLR’s are slow and movement of iris is minimal

dilation usually takes 20-45 mins

#1 cause for seeing llamas

corneal damage/disease is number one

uveitis is 2md

Iris color caries for camelids

dark brown to light brown to blue

2 reported cases of blue-eyed llamas that were deaf

Camelid pupillary ruff

large

dorsal and ventral

function = shade the pupil

pupil shape for camelid

oval

what iscommon in camelids

conjunctivitis

Clincal signs: mild squinting, hypermia, epiphora

commonly caused by irritation

can be caused by chlamydiae and parasites

what disorder is mostly congenital for camelids

nasolacrimal disorders

many llamas with ocular problems had what

concurrent problems with other body systems

what paralysis was frequently seen in camelids with conjunction w/ ulcers

tick and facial nerve paralysis

what three diseases are associated with blindness on camelids

menigitis

brain edema

toxoplasmosis

Llamas had a low rate of what

traumatic eyelid diseases

glaucoma is rare

low rate of SCC

what does the camelid fundus lack? what can it look like

lacks a tapetum appears highly reflective

can appear brown, red, blue and brown

what is the most common cause of “pink eye” in goats

mycoplasma and chlamydophila

Goat pink eye transmisson

animal handlers, direct contact with infected animal, fomites, mechanical vector

Goat pink eye clinical signs

young animals are affected most frequently

uni or bi lateral

early signs: photophobia, blepharospasm, epiphora

later in disease process, discharge may become mucopurulent

conjunctivitis ± keratitis

depressed appetite

few days to several weeks

most severe: corneal rupture and permanent blindness