Transcript Diseases of the Eye CC

Diseases of the Eye
Casey Conway
Jeannie Stall , R.V.T. & ???
Credits : Clip Art graphics/Google images
The Eye
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CDCA has great picture of a cross section.(hint)
Most highly developed of all senses
Most pets can live quality lives with a vision loss
Proper diagnosis, quick treatment – Essential!
3 main categories of eye diseases:
▫ Accessory structures
▫ The globe
▫ The retina and the neural pathways
Anatomy
Credits: ukvetsonline
Diseases of the Accessory
Structures
• Eyelids, conjunctiva, tear ducts,
third eyelid, lacrimal glands
• Red eyes, blepharospasm (squinting),
ocular discharge
• Common causes: Trauma & infection
• Conjunctivitis/Epiphora(overflow of tears)/
KCS (Keratoconjunctivitis sicca)/Cherry Eye
Conjunctivitis
• Inflammation of the conjunctiva
• Rarely a primary dz process
• Canine: can be non-infectious or infectious
Feline : is primarily infectious
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FHV – seen w/ Upper Resp. Tract symptoms
Calicivirus
Chlamydia psittaci
Mycoplasmas
Conjunctivitis cont’d
• Clinical signs
▫ Chemosis (swelling)
▫ Hyperemia (redness)
▫ Ocular discharge
▫ +/- signs of URT dz
• Dx
▫ PE (thorough exam of conjunctiva/foreign body)
▫ Schirmer Tear Test, conj. scraping (cytology, c & s)
• Tx:
▫ Resolve underlying systemic dz.
▫ Topical antibiotic ointments/drops
▫ Nonsteroidal oint/drops may be needed
▫ Keep eyes clean and clear
• Prevent eye issues – riding out car window!
Epiphora
• Overflow of tears
▫ Overproduction (pain or irritation)
▫ Faulty drainage: (lacrimal duct blocked by swelling or
trauma)
• Clinical Signs
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Watering of the eye
Wet facial hair
Secondary bacterial infection of facial skin
Discoloration of the facial hair
Epiphora cont’d…….
• Dx:
▫ Eye exam
▫ Fluorescein dye
▫ Dacryocystorhinography ( Radiography of nasolacrimal
duct )
• Tx:
Resolve primary cause of pain & irritation /
Flush lacrimal ducts / Surgery / Topical abx/ Trim hairs
Eyelid Diseases
• At the base of each eyelash is a sebaceous gland
Hordeolum: Meibomian gland abscess, usually
caused by a staph. infection
Chalazion: When inflammation involves
meibomian glands & granulation occurs
• Eyelid neoplasms : Older animals/
most are benign (cat usually malignant),
Squamous cell carcinoma most common tumor
Blepharitis:
Swelling of the eyelids
• Causes:
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Allergens
Nutritional Deficiencies
Viral
Dermatitis from any cause
• Clinical signs
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Generalized swelling of lid
Periocular pruritis (itchy eyes)
Periocular alopecia ( hairloss)
Rubbing of the eyes
Blepharitis Cont.
• Dx:
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Eye exam
Skin scrape
Fungal culture
Bacterial cultures
• Tx: warm compresses
▫ Express hordeolum(staph infection)
▫ Surg. removal of chalazion (granulation tissue)
▫ Topical abx or systemic abx
▫ Corticosteroids ( Prednisolone)
▫ Antifungals ( Conofite or Tresaderm)
Blepharitis
Entropion
• Eyelids roll in against the cornea
• Common in dogs, not in cats
• 3 main forms:
▫ Congenital: breeds have large orbits with deep-set
eyes, inadequate lid support, lid droops over the lower
orbital rim and inverts – Collies, Great Danes, Irish
Setters, Dobes, Goldens, Rotts, Weim (primary lid
deformities, poor ocular muscle development)
▫ Acquired nonspastic: surgical or traumatic – scarring
of the lid with contraction – lid turns inward
▫ Acquired spastic – most common in cats – secondary
to painful corneal lesions, conj. inflam. or both
Entropion
Entropion
• Clinical Signs
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Rolling inward of the lid margin(s)
Epiphora (tear overflow)
Chemosis ( conjunctiva swelling )
Swelling
Conjunctivitis
Blepharospasm(eyelid muscle spasm)
Pain
+/- corneal ulceration
Photophobia
Entropion Con’t……
• Dx:
▫ Observe lids interaction with globe
▫ Eye exam while awake
• Tx: Surgical correction
Ectropion:
Eyelids that roll outward, exposing the cornea
• Excessive lid droops outward
• Natural breed characteristic for:
Basset hounds, bloodhounds, cocker span, clumber span,
Eng. bulldogs, St. Bernards – usually asymptomatic
• All breeds: Secondary to muscular dz in senile dogs/
Dogs w/ surgical overcorrection of entropion
• Clinical signs
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Lid eversion
Conjunctivitis
Epiphora
Keratitis
Purulent exudate
Ectropion Cont.
• Dx:
▫ Observe lids
▫ Interaction with globe
▫ Eye exam while awake
• Tx: Surgical correction advised if clinical signs present
“Cherry Eye” or
Hypertrophy of Nictitans Gland
• Third eyelid:
▫ Protective structure/Spreads pre-corneal tear film
Covers eye to protect from injury/ Produces ~50%
of lacrimal fluid
• Prolapse of 3rd eyelid/gland: “passive forward
displacement when eye withdrawn into orbit”
Hypertrophy of gland ONLY occurs in K9’s
• Etiology: Unknown cause
• Breeds: Basset, beagle, Boston, cocker
Cherry Eye
• Usually seen in young dogs (< 2 yrs. old)
-usually neoplasia if seen in old K9’s & cats
• Medial canthus is filled with red, swollen, third
eyelid, resembles a small cherry
• Clinical signs
▫ Reddened enlargement of tissue
in the medial canthus of the eye
▫ Mild irritation
▫ Usually no pain
▫ Epiphora ( tears)
▫ +/- conj. irritation
Cherry Eye continued…..
• Dx:
▫ Clinical signs
▫ Predisposed breed
▫ Rule out tumor (usually older dogs & cats)
• Tx:
▫ Surgical replacement of the gland, Tuck sutured
▫ Avoid excision – predisposes to KCS
– only excise in cases of neoplasia
• W/O sx., corneal damage can occur &
may affect vision
Cherry Eye
Glaucoma:
• In healthy eye:
Aqueous fluid production =‘s aq. fluid amt. leaving eye,
so IOP(intraocular pressure) remains fairly constant
• More aqueous fluid produced than leaves = glaucoma
• Normal k9/fel IOP range: 12-22 mm Hg w/ Tono-pen
• Most K9’s have decreased outflow, not increased prod.
• Primary – inherited defect (cocker, basset, chow)
• Secondary –drainage angle obstruction secondary to
another dz.– ie: Neoplasia, uveitis,
lens luxation, hemorrhage
Glaucoma cont’d
• Acute – elevated IOP (> 60 mm Hg ) can produce
blindness within hours
Clin. signs: Ocular pain, vascular congestion, diffuse
corneal edema, dilated pupil, sluggish or unresp to light,
+/- blind
• Chronic – painful, blind eye which is unresponsive to
med. therapy. Make pet comfy w/salvage procedures
Clin. Signs: Enlarged lobe, corneal striae, optic disk
cupping, pain, blindness
• Dx: IOP > 30 mm Hg,/ clin. signs/ r/o luxated lens
• Tx: Acute – true emergency – decrease IOP rapidly, sx
Chronic – sx – enucleation
• Bilateral disease – even if one eye is asymptomatic
Corneal Ulcers
Ulcerative Keratitis
• Cornea:Window of the eye- has 4 layers
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Epithelium
Stroma
Descemet’s membrane
Endothelium
• Full-thickness loss of corneal epithelium exposing stroma
• Etiology: Trauma, chemicals, foreign body, prev. dz. ie:
KCS/ Herpes in cats, conformation issues,
distichiasis (tiny, inwardly –facing meibomian gland hairs)
• Clinical signs
▫ Pain
▫ Epiphora
▫ Blepharospasm
▫ Conjunctival hyperemia
Corneal Ulcers
• Dx:
▫ Fluorescein dye- absorbed by stroma,
not by epithelium (green uptake of dye)
WARN client about fluorescent green dye !!
• Tx:
▫ Topical Atropine
▫ Topical abx
▫ Sx
• Meds. w/ cortisone slow healing & makes
condition worse
• Frequent re-evaluations needed to monitor
progress/healing
Pannus:
Chronic Superficial Keratitis
• Superficial corneal vascularization & infiltration of
granulation tissue (lymphocytes & plasma cells)
• Progressive, bilateral, degenerative, can result in
blindness
• Cause – immune-mediated, animals at > 5000 ft most
susceptible (G.shep, B. Terv, B. Collie, Greyh, SibHusky)
• C/S: breed predisposed with opaque lesion – pink or tan
• Dx: corneal scraping – infiltrate, eye exam
• Tx: Antiinflam. for life of patient, +/- subconj. inj.,
cryosurgery, superficial keratectomy
• No cure
Treatment to maintain regression of lesion is life-long
Pannus
“KCS”:
Keratoconjunctivitis Sicca
• Loss of both lacrimal glands
• Viral inf., drug-related toxicities, Imm-mediated dz,
inflamm, breed predisp., congenital abn
• Most cases idiopathic, older >7 yr. – neutered
• Clinical signs
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Recurrent conjunctivitis
Corneal ulcers
Keratitis
Cornea & conj. appear dull, dry, & irregular
Ocular discharge
Blepharospasm
Crusty nares
KCS cont’d …..
• Dx:
▫ Schirmer Tear Test <15mm/min on repeat testing (k9 1525, fel 11-23) NOTE: Perform this test 1st
▫ 2nd: Fluorescein dye –assess ulcer presence
• Tx:
▫ Stimulate tear prod. w/meds (cyclosporine)
▫ Topical art. tears
▫ Surgery if medical tx are unsuccessful
(parotid duct transposition)
• Failure to treat will result in blindness
Cataracts :
• Most common dz. involving the lens
• An opacity of the lens sufficient enough to cause a
reduction in visual function – aging cells w/in lens
become dehydrated & overlap each other, producing
a central change in the reflection of light- lens may
appear grey and opaque
• Freq. cause of blindness in dog, occas. seen in cat
• Etiology: Inherited, secondary to diabetes mel.,
hypocalcemia, trauma, nutritional deficiency,
electric shock, uveitis, or lens luxation
(Photo Credits: dog-health-handbook.com )
Cataracts cont’d
• Clinical signs
▫ Progressive loss of vision
▫ Opaque pupillary opening
▫ Signs related to systemic dz. (diabetes mellitus or
hypocalcemia)
• Dx:
▫ Complete eye exam/Assess via obstacle course/
Lack of menace /Failure to track visual responses
Photo Credits: petdig.com
Cataracts cont’d……..
• Pupillary light response is usually normal
• Tx:
▫ Sx removal
▫ Tx of any other dz
Anterior Uveitis
• Inflammation of the uvea (iris, ciliary body, choriod)
• Trauma, extension of local infx, foreign body,
neoplasm, thermal trauma, parasites, protozoa
(bact, viral, mycotic dz – hematogenous spread)
• C/S: epiphora, photophobia, blepharospasm, +/vision defects, corneal edema, chemosis, prolapsed
3rd eyelid, pain, change in iris color
• Dx: c/s, hx, labs, x-ray, ultrasound, tonometry
• Tx: I.D. & elim. cause, control inflamm w/topical
steroids (w/o tx, vision will eventually be lost)
Progressive Retinal Atrophy
• Group of hereditary retinal disorders seen in
many breeds of dogs
(can occur in cats, but not as frequently)
• Toy poodles, min poodles, goldens, Irish sett,
cockers, min sch, collies, samoyed, gordon sett,
Norw. Elkhound
• C/S: defective night vision, slowly progressive
loss of day vision, cataract formation
• Dx: labs, eye exam of retina
• No Tx. currently exists
Horses
• Entropion
• Conjunctivitis – Summer/
dry, dusty condition /flies
• Corneal ulcers
• Cataracts – Sx. prognosis is good in foals
• Many blind horses can still be ridden
safely, if owner doesn’t exceed horse’s ability &
comfort level … (or the owner’s !)
“Moon Blindness”
Periodic Opthalmia, Recurrent Uveitis
• Comes & goes/ exact cause undetermined
• Many animals have high Lepto antibody titer
• Signs: cloudy eye, blepharospasm, excessive
tears
• Dx: visualization of protein flare in fluid of
anterior chamber, affected eye may be smaller,
corneal stain, Lepto titer
• Tx: topical corticosteroids, atropine, banamine
or Subconjunctival long-acting steroid injections
Sheep and Goats
• Entropion – most common ocular abnormality
in neonatal lambs
• Infectious Conjunctivitis (Pinkeye) –
responds well to medication – herd management
• Cataracts – most common lens abnormality in
sheep and goats