diseases of the eyes and ears
DESCRIPTION
Diseases of the Eyes and Ears. INAG 120 – Equine Health Management December 5, 2011. The Equine Eye. The Equine Eye. 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. - PowerPoint PPT PresentationTRANSCRIPT
Diseases of the Eyes and Ears
INAG 120 – Equine Health Management
December 5, 2011
The Equine Eye
The Equine Eye 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 Overall appearance of head
Erectness of ears Symmetrical eyelids?
Appearance Position
Eye Sockets Assess placement of
eyes in sockets Symmetrical?
Eye Examination… Eyelids
Lightly touch Symmetrical? Make note of normal
pigmentation of third eyelid Third eyelid – visible
when horse retracts eye into socket
Eye Examination… Anterior Chamber
Space between the cornea and colored portion of the eye (iris)
Filled with transparent fluid Symmetrical?
Conjuctiva Mucous membrane lining
inner surface of eyelid and outer surface of sclera
Should be moist and shiny
Eye Examination… Iris, Pupil and Lens
Iris = eye color Pupil (horizontal hole) should constrict with light Corpora nigra above and below pupil Pupil should be dark
Posterior Chamber / Eye “Fundus” Requires special
instrumentation Contains “tapetum”
Recognizing the Abnormal PAIN
Blepharospasm Photophobia Epiphora
CHANGE IN COLOR Redness Milky-white color
SWELLING
Specific Problems of the Eye Eyelids:
Entropion Lacerations Pockets of inflammation Tumors
Sarcoid Squamous cell carcinoma Melanoma
Tetanus/Lockjaw
Specific Problems of the Eye Conjunctiva:
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
Cornea: Congenital dermoid Trauma = corneal ulcer Treatment usually requires antibiotic application
NO STEROIDS Be sure antibiotic used is Optic
Puncture Eye will appear partially collapsed Requires immediate surgical intervention
Specific Problems of the Eye
Iris and Ciliary Body: Uveitis Iris Cysts
Cause iris to bulge forward Related to Silver Dapple
coat coloration!
Specific Problems of the Eye
· Inflammation of iris
Recurrent Uveitis Aka Periodic Opthalmia, Moon Blindness Clinical signs:
Acute pain Redness to eyes and lids Darkened iris Iris appears moth-eaten
Multiple Causes 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.
Lens: Flattened, transparent & malleable marble behind
the iris (helps focus images Diseased lens is usually opaque Cataracts
Progressive in nature Congenital in foals
more successfully removed
Specific Problems of the Eye
Retina/Choroid: Usually go undetected until blindness is evident Appaloosas & Congenital Stationary Night
Blindness Autosomal recessive gene Malfunction of motion-detecting retinal cells (rods)
which function best in low light Day vision = normal
Specific Problems of the Eye
When to Call the Vet… 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 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
Flush with lots of water Call the vet
Did I mention to call the vet?
Don’ts Don’t ignore eye problems Be careful using leftover ointment (some
ointments can make problems worse) 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 Poorly understood disease Horse may flick, nod and/or
shake head Causes:
Behavioral Ill-fitting tack Teeth Middle Ear disorders Ear Mites Eye Disorders Allergies Gutteral Pouch Infection
Symptoms of Headshaking Behavior/Ill-fitting tack:
Physical head movements No disease process (i.e., nasal discharge)
Dental Disease: Nasal discharge Foul breath Pain, swelling over facial bones Difficulty eating Abrasions on tongue/cheeks Weight Loss
Gutteral Pouch Infection: White non-odorous nasal discharge Swollen lymph nodes Painful distension of area behind ears Noisy breathing
Ear Disease: Rub ears Sensitive ears Can be VIOLENT (dangerous for rider/handler) Head tilt (due to affected balance)
Symptoms of Headshaking
Eye Disease: Cancerous growth Difficult to catch Spook easily Previous slides…
Nasal Disease: Discharge
Allergies: Sneezing Snorting, rubbing nose on legs
Symptoms of Headshaking
Photic Headshake Caused by exposure to light Overstimulation of eye stimulation of opthalmic
branch of trigeminal nerve impulses to face Probably causes sensation in nasal cavity similar to hay-
fever sufferers! Treat by lowering light (fly mask or darkened
environment); use of cyproheptidine (0.3 mg/kg BW 2x per day) ± melatonin therapy in summer
Present in spring/summer, worsens with exercise
Ear Problems – Aural Plaques 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 Problem in gutteral pouch can migrate
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 Ear rubbing, head tossing, chomping movements, pain
around ear, depression, head-tilt, dizzy, facial paralysis
Ear Problems – parasites Most common problem
of the equine ear Chiggers, ticks, and
psoroptes mites Ear mites:
Head rubbing, shaking and irritability
Not always visible Treat with dewormer and
ear drops