1. Diseases of the Eye Casey Conway Jeannie Stall , R.V.T. & ???
Credits : Clip Art graphics/Google images

2. The Eye 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

3. Anatomy Credits: ukvetsonline
Image credit: ukvetsonline.com

4. 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
Keratoconjunctivitis sicca – “Dry Eye “

5. Conjunctivitis Inflammation of the conjunctiva
Rarely a primary dz process
Canine: can be non-infectious or infectious
Feline : is primarily infectious
FHV – seen w/ Upper Resp. Tract symptoms
Calicivirus
Chlamydia psittaci
Mycoplasmas
Feline Herpes Virus

6. 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!

7. Epiphora Overflow of tears Clinical Signs
Overproduction (pain or irritation)
Faulty drainage: (lacrimal duct blocked by swelling or
trauma)
Clinical Signs
Watering of the eye
Wet facial hair
Secondary bacterial infection of facial skin
Discoloration of the facial hair

8. Epiphora cont’d……. Dx: Tx: Eye exam Fluorescein dye
Dacryocystorhinography ( Radiography of nasolacrimal duct )
Tx:
Resolve primary cause of pain & irritation /
Flush lacrimal ducts / Surgery / Topical abx/ Trim hairs

9. 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
The eyelid sebaceous gland is also known as : Meibomian or tarsal gland .
A “Chalazion “ is a plugged or blocked meibomian gland .

10. Blepharitis: Swelling of the eyelids Causes: Clinical signs Allergens
Nutritional Deficiencies
Viral
Dermatitis from any cause
Clinical signs
Generalized swelling of lid
Periocular pruritis (itchy eyes)
Periocular alopecia ( hairloss)
Rubbing of the eyes

11. Blepharitis Cont. Dx: Tx: warm compresses
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)

12. Blepharitis

13. 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

14. Entropion

15. Entropion Clinical Signs Rolling inward of the lid margin(s)
Epiphora (tear overflow)
Chemosis ( conjunctiva swelling )
Swelling
Conjunctivitis
Blepharospasm(eyelid muscle spasm)
Pain
+/- corneal ulceration
Photophobia

16. Entropion Con’t…… Dx: Tx: Surgical correction
Observe lids interaction with globe
Eye exam while awake
Tx: Surgical correction

17. 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
Lid eversion
Conjunctivitis
Epiphora
Keratitis
Purulent exudate

18. Ectropion Cont.
Dx:
Observe lids
Interaction with globe
Eye exam while awake
Tx: Surgical correction advised if clinical signs present

19. “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

20. 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

21. Cherry Eye continued….. Dx: Tx: W/O sx., corneal damage can occur &
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

22. Cherry Eye

23. 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: 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
IOP = Intra ocular pressure

24. 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

25. Corneal Ulcers Ulcerative Keratitis
Cornea:Window of the eye- has 4 layers
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

26. 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
Warn clients as orange dye turns green & exits via tear ducts/nose, causes green nasal discharge. When animal licks at it, gets a fluorescent green tongue!!

27. 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

28. Pannus

29. “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
Recurrent conjunctivitis
Corneal ulcers
Keratitis
Cornea & conj. appear dull, dry, & irregular
Ocular discharge
Blepharospasm
Crusty nares
a.k.a. “ Dry eye”

30. KCS cont’d ….. Dx: Tx: Failure to treat will result in blindness
Schirmer Tear Test <15mm/min on repeat testing (k , 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

31. 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 )

32. Cataracts cont’d Clinical signs Dx: 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

33. Cataracts cont’d…….. Pupillary light response is usually normal Tx:
Sx removal
Tx of any other dz

34. 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)

35. 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

36. 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 !)

37. “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

38. 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