Download Ophthalmic Diseases - Dr. Brahmbhatt`s Class Handouts

LIVE IN THE MOMENT!
“The secret of health for both mind and body
is not to mourn for the past, not to worry
about the future, or not to anticipate
troubles, but to live in the present moment
wisely and earnestly.”
-Buddha
Ophthalmic Diseases
Chapter 4
Common Diseases of Companion Animals
Ophthalmic Diseases
Conjunctivitis
• CONJUNCTIVA: pink tissue that lines the inner surface of the
eyelids and covers the front portion of the eyeball except for the
cornea
• Causes
– Allergy (atopy)
– Anatomic (ectropion, entropion)
– Bacterial infection (predisposed by):
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Injury
↓Tear production
Foreign body
Respiratory disease (bacteria, virus)
• Causes (in cats it is usually infectious)
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Feline herpes virus (most common cause of bilateral conjunctivitis)
Calicivirus
Chlamydia psittaci bacteria
Mycoplasma
Red, congested/swollen, painful
Conjunctivitis
• Signs
– Redness
– Chemosis (swelling of conjunctiva)
– Ocular discharge (tears, mucus)
• Diagnosis
– Determine 1º disease, if any
– Rule out FB
– Rule out ‘dry eye’ in recurrent cases
• Schirmer tear test
– 1 min- tears show as blue dye
SCHIRMER TEAR TEST
Cats: 11-23mm
Conjunctivitis
• Rx
– Topical antibiotic ointment
• neomycin/bacitracin/polymyxin B(BNP or triple antibiotic)
• Gentamicin ophthalmic ointment
• Antibiotic w/ cortisone (if cornea is intact)
• Client info
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Do not allow dogs to ride with head out window
Keep medial canthus of eye clean (warm water, clip hair)
Vaccinate kittens to prevent URI
Do not touch eye with applicator
Discard unused medication
Epiphora
• EPIPHORA: excessive tearing
• Causes (2 causes)
– Overproduction of tears
• Ocular pain, irritation (from hair, etc)
– Faulty drainage by lacrimal system
• Blockage of duct (swelling, inflam)
• Blockage of puncta (hair, debris)
• Imperforate puncta (no opening)
– Cockers
– Poodles
• Trauma
Epiphora
• Signs
– Watering of eye
– Discoloration of hair
• Dx
– Fluorescein dye test
• Dye at nose shows duct is open
• Rx
– Treat 1º cause
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Flush lacrimal ducts
Surgically open imperforate puncta
Topical antibiotic ointment
Keep hair trimmed around eyes
– May act as a wick
• Client info
– Staining due to pigment in tears, not blood
– Some dogs have life-long problem
EPIPHORA
FLUSHING THE NASOLACRIMAL DUCT
Entropion: eyelids that roll in against the cornea
• Causes
– Congenital
• large orbits w/ deep-set eyes (poor lid support)
– Collies, G. Dane, I. Set, Dobe, G. Ret, Rott, Weim
• Poor ocular muscle development
– Chesapeake, Labs, Chow, Samoyed
– Trauma → scarring with distortion of lid
– 2º to painful corneal lesion, conjunctiva inflammation (most
common cause in cats)
• Signs
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Epiphora (tearing)
Chemosis (swelling of conjunctiva)
Conjunctivitis
Pain
Corneal ulceration (±)
Photophobia
Entropion
• Treatment
– Surgical correction is treatment of choice
• Temporary mattress suture to evert eye (young animal)
• Lateral canthoplasty (to shorten eye lid)
• Hotz-Celsus: Remove elliptical piece of tissue from under eye
Ectropion
• Causes
– Congenital
• Bassets, Blood, C Span, E Bull, St Bern
• Signs
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Conjunctivitis
Epiphora
Keratitis (corneal inflammation/scarring), usually from exposure
Purulent exudate
• Rx
– Surgery to shorten eye lid
– Other procedures
Hypertrophy and Prolapse of 3rd eyelid
gland
Hypertrophy and Prolapse of Nictitans Gland
(Cherry Eye)
Nictitating membrane is the 3rd eyelid; is a protective structure
Produces ~30% of tears
• Cause is unknown
– Bassets, Beagle, Bos. Terr, C. Span
• Signs
– Young dog (<2 y)
– Epiphora
– Usually no pain
• Dx
– r/o tumor in older dogs and cats
• Rx
– Sx to remove gland is an option , but not recommended
– Suture back in place
Glaucoma
Aqueous humor provides nourishment to lens and cornea
Increased intraocular pressure; → Blindness
Normally, the amt of fluid produced = amt of fluid leaving eye
Normal: Dog/Cat—12-22 mm Hg
• Causes
– Inherited (C Span, Basset, Chow)
– Secondary—obstruction of drainage angle
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Neoplasia
Luxation of lens
Hemorrhage
Uveitis (ciliary body,
iris, choroid)
• Signs
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Ocular pain
Episcleral injection
Corneal edema
Dilated pupil (unresponsive to light)
Blind (±)
Glaucoma
• Dx
– IOP>30 mm Hg
• Rx
– Acute (this is an emergency; prevent blindness)
• Latanoprost (Xalatan 0.005%)
– Facilitates aqueous outflow
• Dichlorphenamide (Daranide)
– Decreases aqueous production
• Surgical
– Cryosurgery or laser (destroys part of ciliary body)
» Decreases aqueous production
– Chronic
• Enucleation to relieve pain
Schiotz Tonometer
Tono-Pen
Ulcerative Keratitis
(Corneal Ulcers)
Ulcers usually heal within a few days
• Causes
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Trauma
Chemical burns
Foreign objects
KCS (Keratoconjunctivitis Sicca)
Conformational abnormalities
Herpes virus (cats)
• Signs
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Pain
Epiphora
Blepharospasm (eyelid spasm)
Hyperemia of conjunctiva
• Dx—Fluorescein dye to cornea
Herpes virus
Ulcerative Keratitis
(Corneal Ulcers)
• Rx
– Topical atropine (1%) ointment (Debate over benefits and how
long to use)
• Decrease pain, blepharospasm
– Topical broad-spectrum antibiotic ointment
– Viral ointments or solutions (Viroptic for cats with herpes virus)
– Surgery
• Eyelid flap, conjunctival flap
– Serum (autologous)
• Blocks proteases released from leukocytes and bacteria (helps
prevent continued collagen loss)
– keep in refrigerator (throw out after 72 hours)
Deep Corneal Ulcer
• Desmetocele – erosion to membrane
Ulcerative Keratitis
(Corneal Ulcers)
• Client info
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Most ulcers heal quickly with treatment
Avoid using old medications
Rx with cortisone will inhibit healing of ulcer
Do not touch eye with ointment applicator
Chronic Superficial Keratitis (Pannus)
Pannus—superficial corneal vascularization/scar tissue
Progressive, bilateral, can result in blindness
• Cause
– Thought to be immune-mediated
(Infiltration of cornea with lymphocytes, plasma cells)
– Increased ultraviolet light/high altitudes increases incidence
• Signs
– Opaque lesions that begin at limbus and extend into cornea
• Milky, pink, or tan
Chronic Superficial Keratitis (Pannus)
Chronic Superficial Keratitis (Pannus)
• Breeds
– Ger. Shep, B. Collie, greyhound, Sib. Husky
• Dx
– r/o KCS, corneal ulcers
• Rx
– Corticosteroids often lifelong
– Cyclosporine often lifelong
– Antibiotic eye ointment
• Client info
– No cure
– If Rx is stopped, disease will return and progress
– High altitudes and ↑sun predispose animals
DOGGLES!!!!
Keratoconjunctivitis Sicca (KCS)
Lack of tear production; tears lubricate, nourish, ↓bacteria, aid in healing
Tears from 2 glands: 70%--Lacrimal gland; 30%--Nictitans gland
• Signs
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Recurrent conjunctivitis, corneal ulcers, keratitis
Dull, dry, irregular cornea, conjunctiva
Tenacious, mucoid ocular discharge
Blepharospasm
Crusty nares
• Rx
– Tear stimulation—cyclosporine, pilocarpine
– Artificial tears
• Client info
– Px is guarded for resolution
– Failure to treat → blindness
KCS
Cataracts
Opacity of lens that causes reduced vision; most common disease of lens
• Cause
– Genetic
– 2º to:
• Diabetes mellitus (bilat; within 1 y of disease; ↑glucose → ↑fluid in lens)
– Most common cause
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Trauma (unilateral; HBC, thorn penetration, shotgun pellet)
Lens luxation
Nutritional deficiency
Uveitis
Hypocalcemia
Electrical shock
• Rx
– Surgical removal of lens
– Treat underlying cause (e.g., Diabetes)
• Client info
– Most cataracts are inherited, so don’t breed affected dogs
– Dogs can live quality lives even with bilat. cataracts
Cataracts
• Signs
– Progressive loss of vision
– Opaque pupillary opening
• Dx
– Must be distinguished from senile nuclear sclerosis
• Normal old age change; graying of lens; bilat; usually does not affect
sight
CATARACTS
Progressive Retinal Atrophy
• A group of hereditary disorders causing loss of rods,
cones, and/or blood supply
– Breeds
• Toy/min. Poodle, G. Ret, I. Set, C. Span, Schnauzer, Collie, Samoyed,
N. Elkhound
• Recessive gene isolated in some breeds
• Signs—slow onset of blindness
– Loss of night vision (rods) → loss of day vision (cones)
→ cataracts (±)
• Dx
– r/o metabolic disorders that could cause cataracts
– Ophth exam
• gray, granular appearance of retina
• Hyperreflective retina
• Vascular attenuation, optic nerve atrophy
PROGRESSIVE RETINAL ATROPHY
Normal canine retina
PRA, optic nerve atropy and vessel
attenuation
Progressive Retinal Atrophy
• Rx
– None
• Client info
– This is an inherited disease
– Avoid buying affected breeds
• Have ophth exam by board certified ophth to r/o PRA
– Blind animals adapt well
• Have trouble in strange surroundings
– Cats need well balanced diet
• Taurine deficiency can lead to PRA
Anterior Uveitis
• Inflammation of uvea: ciliary body, iris,
choroid
• Causes
– Inflammation/infection – FeLV/FIP, fungal,
bacterial
– Neoplasia
– Trauma
Uveitis – Clinical Signs
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Blepharospasm
Aqueous flare – increased turbidity of aqueous humor
Miosis of affected eye
Iridal swelling or congestion
Keratic precipitates
Ciliary flush in limbal region
+/- Corneal edema
+/- hyphema
Anterior Uveitis – hyphema
Anterior Uveitis
Anterior Uveitis – keratic precipitates
Anterior Uveitis – Treatment
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Topical steroids or
Topical Anti-inflmmatory drugs (ocufen)
Or systemic steroids
Atropine – dilates eye, decreases pain
Antibiotics – topically +/- systemically
Anterior Uveitis – Client Info
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Recheck within 3 days
Secondary glaucoma is frequent complication
Prognosis depends on cause
Treat for 2 months regardless of cause – bloodaqueous barrier disrupted for 6 weeks
Proptosed Globe
• Cause
– Trauma
– Conformation
– Retrobulbar abscess or neoplasia
• Clinical Signs
– Protrusion of the globe,
– Eyelids unable to close, may be trapped behind
globe
Prognosis
• Favorable
– brachycephalic dog,
– positive direct or
consensual pupillary
light response
– normal findings on
posterior segment exam
– proptosed eye with
vision on initial
presentation
• Unfavorable indicators
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non-brachycephalic
cat breed
hyphema,
no visible pupil
facial fractures
optic nerve damage and
avulsion of 3 or more
extraocular muscles
Proptosed Globe
Proptosed Globe – Treatment
• Lubricate immediately
• Reduce the globe into the socket ASAP to
reduce trauma to optic nerve
• Enucleation if optic nerve severed
• Systemic and topical antibitics
• +/- Steroids
Proptosed Globe
References
• http://www.vetmed.ucdavis.edu/courses/vet_ey
es/
• Alleice Summers, Common Diseases of
Companion Animals
• http://www.vetmed.wisc.edu/Data/CourseMate
rial/Miller/Emergencies.pdf