2. Chapter 4 Common Diseases of Companion Animals
Ophthalmic Diseases
Chapter 4
Common Diseases of Companion Animals

3. Ophthalmic Diseases
The cornea has no blood supply but has nerve endings. The outer layer is corneal epithelium which heals quickly when damaged. Descemet’s membrane is the innermost membrane of the cornea. The choroid contains blood vessels, lymph, and pigment. It stretches around to the ciliary bodies which make aqueous humor in the anterior chamber. The ciliary bodies have processes on them that attach to the lens that push or pull on the lens when focusing an image.

4. Conjunctivitis Causes of conjunctivitis Allergies
CONJUNCTIVA: pink tissue that lines the inner surface of the eyelids and covers the front portion of the eyeball except for the cornea
Causes of conjunctivitis
Allergies
Poor anatomy (ectropion, entropion)
Bacterial infection secondary to:
Injury
↓Tear production
Foreign body
Respiratory disease (Herpes virus, calicivirus, mycoplasma, chlamydia)

5. Redness, chemosis(congested/swollen),
painful, ocular discharge

6. Conjunctivitis Diagnosis Determine the primary disease:
Rule out a foreign body
Rule out ‘dry eye’ in chronic cases
Schirmer tear test
Numb the eye and explore the conjunctiva with a dry q-tip to look for FB
Below 10 on STT is indicative of decreased tear production

7. SCHIRMER TEAR TEST

8. Conjunctivitis Treatment Client info Topical antibiotic ointment
neomycin/bacitracin/polymyxin B (BNP or triple antibiotic)
Antibiotic ointment w/ cortisone (only if no corneal ulcer present)
Client info
Keep medial canthus of eye clean (warm water, clip hair)
Vaccinate kittens to prevent URI
Do not touch eye with applicator of eye ointment
Discard unused medication
Fluffy faced dogs and grooming

9. Epiphora EPIPHORA: excessive tearing Causes: Overproduction of tears
Ocular pain, irritation from hair, etc.
Faulty drainage of tears by lacrimal system
Blockage of duct
Blockage of puncta
Imperforate puncta (no opening)

11. Epiphora
Watery eyes
Staining of fur around eyes

12. Epiphora Diagnosis Physical exam
Fluorescein dye test for patency of duct
Dye draining at nose indicates duct is patent

13. EPIPHORA Treatment Treat primary cause Flush lacrimal ducts if blocked
Surgically open imperforate puncta
Topical antibiotic ointment for infection
Keep hair trimmed around eyes

14. EPIPHORA Client info Staining due to pigment in tears can be resolved
Some dogs have life-long problem
FLUSHING THE NASOLACRIMAL DUCT

15. EPIPHORA
Client info
Staining due to pigment in tears can be resolved with topical and/or medical management
Some dogs have life-long problem due to chronic infection or abnormal conformation

16. Entropion: eyelids that roll in against the cornea
Causes
Congenital
Trauma causing scarring and distortion of lid
Severe blepharospasm from pain
Signs
Epiphora
Chemosis
Conjunctivitis
Pain
Corneal ulceration (±)
Photophobia

18. Entropion Treatment Surgical correction is treatment of choice
Temporary mattress suture to evert eyelid (young animal)
Lateral canthoplasty to shorten eye lid
Hotz-Celsus: Remove elliptical piece of tissue from under eye

19. Hotz-celsus technique

20. Ectropion Causes Signs Treatment Congenital
Over-correction of entropion
Signs
Conjunctivitis
Epiphora
Keratitis (corneal inflammation/scarring)
Treatment
Surgery to shorten eye lid

21. Hypertrophy and Prolapse of 3rd eyelid gland

22. Prolapse of Nictitans Gland (Cherry Eye)
Nictitating membrane(3rd eyelid) is a protective structure and produces ~30% of tears
Signs
Young dog (<2 y)
Epiphora
Usually no pain
Diagnosis
Rule out tumor in older dogs and cats
Treatment
Sx to remove gland is an option , but not recommended
Suture back in place

23. Cherry eye surgery

24. Glaucoma
GLAUCOMA: increased intraocular pressure due to excess production or decreased drainage of aqueous humor
aqueous humor provides nourishment to lens and cornea
Normally, the amt of fluid produced = amt of fluid leaving eye
Normal intraocular pressure: Dog/Cat—12-22 mm Hg
Signs
Ocular pain
Corneal edema
Dilated pupil (unresponsive to light)
Blind (±)
Name of instrument used to measure intraocular pressure?

25. Glaucoma Causes Inherited Secondary - obstruction of drainage angle
Neoplasia
Luxation of lens
Hemorrhage
Uveitis (inflammation of ciliary body, iris, choroid)

26. Glaucoma

27. Glaucoma
Diagnosis
IOP >30 mm Hg
Schiotz Tonometer
Tono-Pen

28. Glaucoma Treatment Acute - EMERGENCY
Latanoprost (Xalatan 0.005%)- Facilitates aqueous outflow
Dichlorphenamide (Daranide) - Decreases aqueous production
Surgical
Cryosurgery or laser -destroys part of ciliary body to decrease aqueous production
Chronic
Enucleation to relieve pain

30. Ulcerative Keratitis(Corneal Ulcers)
Causes
Trauma
KCS (Keratoconjunctivitis Sicca)
Herpesvirus (cats)
Signs
Pain
Epiphora
Blepharospasm (eyelid spasm)

31. Corneal Ulcers
Diagnosis: Fluorescein Dye Test

32. Corneal Ulcers Treatment
Topical atropine (1%) ointment – pupil dilation
Decrease pain, blepharospasm
antibiotic or antiviral ointments or solutions
Surgery
Eyelid flap, conjunctival flap
Serum (autologous/autogenous)
Blocks proteases released from leukocytes and bacteria
keep in refrigerator (throw out after 72 hours)

34. Deep Corneal Ulcer
Desmetocele – erosion to membrane

35. Corneal Ulcers Client info Most ulcers heal quickly with treatment
Avoid using old medications
No ointment w/cortisone! will inhibit healing of ulcer
Do not touch eye with ointment applicator

37. Chronic Superficial Keratitis (Pannus)
Definition: 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)
ultraviolet light/high altitudes increases incidence
Signs
Opaque lesions that begin at limbus and extend into cornea
Milky, pink, or tan

38. Chronic Superficial Keratitis (Pannus)

39. Chronic Superficial Keratitis (Pannus)
Diagnosis
Rule out KCS, corneal ulcers
Treatment
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

40. DOGGLES!!!!

41. Keratoconjunctivitis Sicca (KCS)
Definition: Lack of tear production
tears lubricate, nourish, ↓bacteria, aid in healing
Tears from 2 glands: 70%:Lacrimal gland; 30%:Nictitans gland
Signs of KCS
Recurrent conjunctivitis, corneal ulcers, keratitis
Dull, dry, irregular cornea, conjunctiva
mucoid ocular discharge
Blepharospasm
Crusty nares

42. KCS

43. KCS Treatment Tear stimulation Artificial tears Client info
Drugs: cyclosporine, pilocarpine
Artificial tears
Client info
Prognosis is guarded for resolution
Failure to treat → blindness
Parotid duct (salivary gland) transposition

44. Cataracts
Definition: Opacity of lens that causes reduced vision; most common disease of lens
NOT NUCLEAR SCLEROSIS!!
Cause
Genetic
2º to:
Diabetes mellitus (bilateral; within 1 y of disease; ↑glucose → ↑fluid in lens)
Trauma Lens luxation

45. Cataracts Signs Diagnosis Progressive loss of vision
Opaque pupillary opening
Diagnosis
Must be distinguished from senile nuclear sclerosis
Normal old age change; graying of lens; bilateral; usually does not affect sight

47. Cataracts Treatment Client info Surgical removal of lens
Treat underlying cause
Client info
Most cataracts are inherited, so don’t breed affected dogs
Dogs can live quality lives even with bilateral cataracts

48. Progressive Retinal Atrophy
A group of hereditary disorders causing loss of rods, cones, and/or blood supply to the retina
Signs - slow onset of blindness
Loss of night vision (rods) → loss of day vision (cones) Dx
Ophthalmic exam
gray, granular appearance of retina
Hyperreflective retina
Narrow blood vessels, optic nerve atrophy

50. PROGRESSIVE RETINAL ATROPHY
optic nerve atropy and vessel
attenuation
Normal canine retina

51. Progressive Retinal Atrophy
No Treatment
Client info
This is an inherited disease
Avoid buying affected dogs
Have ocular exam by board certified ophthalmologist
Blind animals adapt well, but may have trouble in strange surroundings
Cats need well balanced diet
Taurine deficiency can lead to PRA

52. Detached retina Usually related to trauma
Retina will look “folded” down from back of the eye
Animal will appear blind (no PLR) in affected eye
No treatment

53. Proptosed Globe Cause Clinical Signs Trauma Conformation
Retrobulbar abscess or neoplasia
Clinical Signs
Protrusion of the globe,
Eyelids unable to close, may be trapped behind globe

54. Proptosed Globe

55. Proptosed Globe – Treatment
Lubricate immediately
Reduce the globe into the socket ASAP to reduce trauma to optic nerve, if the eye is viable
Enucleation if optic nerve severed
Systemic and topical antibiotics

56. Proptosed Globe

57. Prognosis Favorable prognosis Unfavorable prognosis non-brachycephalic
brachycephalic dog,
Normal PLRs
normal findings on ophthalmic exam
proptosed eye with vision on initial presentation
Unfavorable prognosis
non-brachycephalic
cat
blood in the anterior chamber
no visible pupil
facial fractures
optic nerve damage and/or torn extraocular muscles

58. References http://www.vetmed.ucdavis.edu/courses/vet_eyes/
Alleice Summers, Common Diseases of Companion Animals
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