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Ophthalmic Diseases

Ophthalmic Diseases. Pupil Iris Sclera Conjunctiva. Chapter 4 Common Diseases of Companion Animals. Conjunctivitis . Causes (in dogs, usually not caused by infectious agent) Allergy (atopy) Anatomic (ectropion, entropion) Bacterial infection (predisposed by): Injury

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Ophthalmic Diseases

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  1. Ophthalmic Diseases Pupil Iris Sclera Conjunctiva Chapter 4 Common Diseases of Companion Animals

  2. Conjunctivitis • Causes (in dogs, usually not caused by infectious agent) • Allergy (atopy) • Anatomic (ectropion, entropion) • Bacterial infection (predisposed by): • Injury • ↓Tear production • Foreign body • Causes(in cats, it is usually infectious) • Feline herpes virus (most common cause of bilateral conjunctivitis) • Calicivirus • Chlamydia psittaci bacteria • Mycoplasma

  3. Conjunctivitis • Signs • Redness • Chemosis (swelling of conjunctiva) • Ocular discharge (tears, mucus) • Dx • Determine 1º disease, if any • r/o FB • r/o ‘dry eye’ in recurrent cases • Schirmer tear test • 1 min; tears show as blue dye

  4. Conjunctivitis • Rx • Topical antibiotic ointment • neomycin/bacitracin/polymyxin B • Gentamicin ophthalmic ointment • Antibiotic w/ cortisone (if cornea is intact) • Client info • 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

  5. Epiphora Excess 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

  6. Epiphora • Signs • Watering of eye • Discoloration of hair • Dx • Fluorescein dye test • Dye at nose shows duct is open • Rx • Treat 1º cause • Flush lacrimal ducts • Surgically open imperforate puncta • Topical antibiotic ointment • Keep hair trimmed around eyes • Client info • Hair acts as wick • Staining due to pigment in tears, not blood • Some dogs have life-long problem

  7. Entropion Eye lids rub against cornea; common in dogs, not in cats • 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 (also congenital) • Chesapeake, Labs, Chow, Sam • Trauma → scarring with distortion of lid • 2º to painful corneal lesion, conjunctiva inflammation (most common cause in cats) • Signs • Epiphora (tearing) • Chemosis (swelling of conjunctiva) • Conjunctivitis • Pain • Corneal ulceration (±) • Photophobia

  8. Entropion • Rx • Surgical correction is TOC • Temporary mattress suture to evert eye (young animal) • Lateral canthoplasty (to shorten eye lid) • Remove elliptical piece of tissue from under eye

  9. Ectropion • Causes • Congenital • Bassets, Blood, C Span, E Bull, St Bern • Signs • Conjunctivitis • Epiphora • Keratitis (corneal inflammation/scarring), usually from exposure • Purulent exudate • Rx • Surgery to shorten eye lid • Other procedures

  10. Hypertrophy of Nictitans Gland (Cherry Eye) Nictitating membrane is the 3rd eyelid; is a protective structure Produces ~30% of tears • Cause is unknown • Bassets, Beagle, B Terr, C Span • Signs • Young dog (<2 y) • Epiphora • Usually no pain • Dx • r/o tumor • Rx • Sx remove gland • Stitch back in place

  11. 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 • Neoplasia • Luxation of lens • Hemorrhage • Uveitis • Signs • Ocular pain • Episcleral injection • Corneal edema • Dilated pupil (unresponsive to light) • Blind (±)

  12. 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

  13. Ulcerative Keratitis(Corneal Ulcers) Ulcers usually heal within a few days • Causes • Trauma • Chemical burns • Foreign objects • KCS (Keratoconjunctivitis Sicca) • Conformational abnormalities • Herpes virus (cats) • Signs • Pain • Epiphora • Blepharospasm (eyelid spasm) • Hyperemia of conjunctiva • Dx—Fluorescein dye to cornea Herpes virus

  14. 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) • 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)

  15. Ulcerative Keratitis(Corneal Ulcers) • Client info • Most ulcers heal quickly with treatment • Avoid using old medications • Rx with cortisone will retard healing of ulcer • Do not touch eye with ointment applicator

  16. Chronic Superficial Keratitis (Pannus) 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) • Animals living above 5000 ft elevation most susceptible • Increased ultraviolet light increases incidence • Signs • Opaque lesions that begin at limbus and extend into cornea • Milky, pink, or tan

  17. Chronic Superficial Keratitis (Pannus) • Breeds • G Shep, B Collie, greyhound, S Huskie • Dx • r/o KCS, corneal ulcers • Rx • Corticosteroids for life • Client info • No cure • If Rx is stopped, disease will return and progress • High altitudes and ↑sun predispose animals

  18. Deep Corneal Ulcer • Desmetocele – erosion to membrane

  19. Keratoconjunctivitis Sicca (KCS) Lack of tear production; tears clean, lubricate, nourish, ↓bacteria, aid in healing Tears from 2 glands: 70%--Lacrimal gland; 30%--Nictitans gland • Signs • 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

  20. 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 • 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

  21. 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; usu does not affect sight

  22. Progressive Retinal Atrophy A group of hereditary disorders causing loss of rods, cones, and/or blood supply • Breeds • T/min Pood, G Ret, I Set, C Span, Schnauz, Collie, Sam, N Elk • Recessive gene isolated in some breeds • Signs—slow onset of blindness • Loss of night vision → loss of day vision → cataracts (±) • Dx • r/o metabolic disorders that could cause cataracts • Ophth exam • gray, granular appearance of retina • Hyperreflective retina • Vascular attenuation, optic nerve atrophy

  23. 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 taurine supplemented food to avoid retinal degeneration

  24. Anterior Uveitis • Inflammation of uvea • Causes • Inflammation/infection – FeLV/FIP, fungal, bacterial • Neoplasia • Trauma

  25. Uveitis – Clinical Signs • 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

  26. Anterior Uveitis – hyphema

  27. Anterior Uveitis

  28. Anterior Uveitis – keratic precipitates

  29. Anterior Uveitis – Treatment • Topical steroids • Topical Antiinflmmatory drugs (ocufen) • Subconjunctival steroids • Systemic steroids • Atropine – dilates eye, decreases pain • Antibiotics – topically +/- systemically

  30. Anterior Uveitis – Client Info • Recheck within 3 days • Secondary glaucoma is frequent complication • Prognosis depends on cause • Treat for 2 months regardless of cause – blood-aqueous barrier disrupted for 6 weeks

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

  32. Proptosed Globe

  33. Proptosed Globe

  34. 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

  35. Proptosed Globe

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