Transcript Diseases of the Eyes and Ears

Diseases of the Eyes
and Ears
INAG 120 – Equine Health
Management
December 5, 2011
The Equine Eye
The Equine Eye
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Recognize the normal
Ocular – pertaining to the eye
Periocular – area around the eye
Examine eye in bright sunlight or shaded
area with flashlight
Eye Examination
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Overall appearance of head
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Erectness of ears
Symmetrical eyelids?
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Appearance
Position
Eye Sockets
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Assess placement of
eyes in sockets
Symmetrical?
Eye Examination…
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Eyelids
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Lightly touch
Symmetrical?
Make note of normal
pigmentation of third eyelid
Third eyelid – visible
when horse retracts eye into socket
Eye Examination…
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Anterior Chamber
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Space between the cornea and colored portion of
the eye (iris)
Filled with transparent fluid
Symmetrical?
Conjuctiva
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Mucous membrane lining
inner surface of eyelid and
outer surface of sclera
Should be moist and shiny
Eye Examination…
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Iris, Pupil and Lens
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Iris = eye color
Pupil (horizontal hole) should constrict with light
Corpora nigra above and below pupil
Pupil should be dark
Posterior Chamber / Eye
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“Fundus”
Requires special
instrumentation
Contains “tapetum”
Recognizing the Abnormal
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PAIN
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CHANGE IN COLOR
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Blepharospasm
Photophobia
Epiphora
Redness
Milky-white color
SWELLING
Specific Problems of the Eye
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Eyelids:
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Entropion
Lacerations
Pockets of inflammation
Tumors
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Sarcoid
Squamous cell carcinoma
Melanoma
Tetanus/Lockjaw
Specific Problems of the Eye
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Conjunctiva:
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Dermoid
Conjunctivitis
 Redness and swelling
 Irritating rather than painful
 If pain is evident – may be
due to another problem
 Dirt/foreign materials
 Flush with mild eyewash
Squamous cell carcinoma
Angiosarcoma  highly malignant
Specific Problems of the Eye
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Cornea:
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Congenital dermoid
Trauma = corneal ulcer
Treatment usually requires antibiotic application
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NO STEROIDS
Be sure antibiotic used is Optic
Puncture
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Eye will appear partially collapsed
Requires immediate surgical intervention
Specific Problems of the Eye
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Iris and Ciliary Body:
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Uveitis
Iris Cysts
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Cause iris to bulge forward
Related to Silver Dapple
coat coloration!
 Inflammation of iris
Recurrent Uveitis
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Aka Periodic Opthalmia, Moon Blindness
Clinical signs:
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Multiple Causes
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Acute pain
Redness to eyes and lids
Darkened iris
Iris appears moth-eaten
Leptospirosis main cause
Onchocerchiasis
Treatments
Complete recovery unlikely
MICHAEL A. BALL, DVM
Classic appearance of long-standing uveitis. Note the
scarring of the iris and the white reflective cataract.
Specific Problems of the Eye
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Lens:
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Flattened, transparent & malleable marble behind
the iris (helps focus images
Diseased lens is usually opaque
Cataracts
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Progressive in nature
Congenital in foals 
more successfully removed
Specific Problems of the Eye
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Retina/Choroid:
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Usually go undetected until blindness is evident
Appaloosas & Congenital Stationary Night
Blindness
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Autosomal recessive gene
Malfunction of motion-detecting retinal cells (rods)
which function best in low light
Day vision = normal
When to Call the Vet…
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Increased discharge
Squinting and/or
excessive blinking
Cloudy appearance
Vision problems
Blood in the eye
Any foreign object in
the eye or eyelids
Any sign of tumor
development on the eye
or eyelids
Do’s
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Call the vet early – don’t wait
Only remove a foreign object if it’s confined to the
eyelid
Flush dirt, ash, sand or plant material with water or
saline
Treat chemicals in eyes as you would humans
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Flush with lots of water
Call the vet
Did I mention to call the vet?
Don’ts
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Don’t ignore eye problems
Be careful using leftover ointment (some
ointments can make problems worse)
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Triple antibiotic probably ok; avoid atropine or
steroid until vet advises
Don’t remove foreign
object from eyeball itself,
let a vet do it.
Head Shaking
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Poorly understood disease
Horse may flick, nod and/or
shake head
Causes:
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Behavioral
Ill-fitting tack
Teeth
Middle Ear disorders
Ear Mites
Eye Disorders
Allergies
Gutteral Pouch Infection
Symptoms of Headshaking
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Behavior/Ill-fitting tack:
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Physical head movements
No disease process (i.e., nasal discharge)
Dental Disease:
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Nasal discharge
Foul breath
Pain, swelling over facial bones
Difficulty eating
Abrasions on tongue/cheeks
Weight Loss
Symptoms of Headshaking
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Gutteral Pouch Infection:
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White non-odorous nasal discharge
Swollen lymph nodes
Painful distension of area behind ears
Noisy breathing
Ear Disease:
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Rub ears
Sensitive ears
Can be VIOLENT (dangerous for rider/handler)
Head tilt (due to affected balance)
Symptoms of Headshaking
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Eye Disease:
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Nasal Disease:
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Cancerous growth
Difficult to catch
Spook easily
Previous slides…
Discharge
Allergies:
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Sneezing
Snorting, rubbing nose on legs
Photic Headshake
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Caused by exposure to light
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Overstimulation of eye  stimulation of opthalmic
branch of trigeminal nerve  impulses to face
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Probably causes sensation in nasal cavity similar to hayfever sufferers!
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Treat by lowering light (fly mask or darkened
environment); use of cyproheptidine (0.3 mg/kg BW
2x per day) ± melatonin therapy in summer
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Present in spring/summer, worsens with exercise
Ear Problems – Aural Plaques
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Caused by same virus as warts
Respond poorly to treatment and do not
spontaneously regress
Once thought to be caused by biting flies
Can become severely irritated during biting fly
season  horses may become defensive about
having ears touched!
Soothing ointment such as mentholatum can be
helpful; panalog may also help
Warts and Aural Plaques
Ear Problems – Middle Ear
Infection
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Problem in gutteral pouch can migrate
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Bacterial or fungal
Doesn’t burst eardrum like other species
Causes fusion of stylohyoid bone and temporal
bone of the middle ear
Can lead to stress fractures and neurological
problems
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Ear rubbing, head tossing, chomping movements, pain
around ear, depression, head-tilt, dizzy, facial paralysis
Ear Problems – parasites
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Most common problem
of the equine ear
Chiggers, ticks, and
psoroptes mites
Ear mites:
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Head rubbing, shaking
and irritability
Not always visible
Treat with dewormer and
ear drops