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47 Cards in this Set
- Front
- Back
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List the three components of natural tear production.
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Oily layer
Watery portion Mucous portion |
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Produces oily part of tears.
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Meibomian gland
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Produces watery part of tears (2 glands).
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Main lacrimal gland
Gland of 3rd eyelid |
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Produces mucous portion of tears.
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Goblet cells of bulbar, palpebral, and 3rd eyelid conjunctiva
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4 functions of precorneal tear film.
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Antimicrobial activity
Optical clarity (refractive surface) Carries oxygen Remove wastes and FB |
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Afferent stimulus for tearing from this nerve
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Ophthalmic branch of CN 5
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Ocular effects if CN 5 is damaged.
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Decreased tearing, no blink response, poor corneal healing (neurotropic keratitis)
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Neurotropic keratitis results when this cranial nerve is damages.
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CN 5 (ophthalmic branch of trigeminal nerve)
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Parasympathetic innervation to the lacrimal glands is provided by this cranial nerve
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CN 7
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External damage to the inner ear and damage to CN 7 can have this effect on the eye
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Decreased tearing
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Spillage of tears
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Epiphora
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This species has nasolacrimal ducts in the upper and lower palpebrae that pass thru the maxillary and lacrimal bones and exit in the lateral nasal vestibule.
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Dog (and cat)
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This species has nasolacrimal ducts in the upper and lower palpebrae that pass thru the maxillary and lacrimal bones and exit in the floor of the medial nasal canal.
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Horse
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Primary species affected by keratoconjunctivitis sicca
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Dog
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Normal tear production in a dog as measured by the Schirmer tear test
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15 mm/min
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Criteria for "definite" KCS on a Schirmer tear test in the dog.
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<5 mm/min
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Cutoff value for "satisfactory" tear production on a Schirmer tear test in the dog.
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10 mm/min, although may be more for bug-eyed breeds
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Problem with using Schirmer tear tests in the cat.
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Sympathetic innervation may shut down tear production to the eye when cat is excited.
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Four major clinical signs of keratoconjunctivitis sicca.
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Decreased aqueous tear film
Pain Thick mucous thread Corneal and conjuncival changes |
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How do the clinical signs for cats with KCS differ from dogs?
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Cats may show little in the way of CS besides mucous, mild keratitis, and repeated conjunctivitis.
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These breeds are predisposed to developing keratoconjunctivitis sicca.
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Brachycephalics
Small terriers Shelties Poodles Golden Retrievers Spaniels |
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Primary cause of keratoconjunctivitis sicca
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Immune-mediated aka. idiopathic
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Immune destruction of these two glands causes idiopathic KCS.
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Lacrimal gland
Gland of the 3rd eyelid |
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List two iatrogenic causes of KCS
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Removal of the 3rd eyelid gland
Post irradiation damage |
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These two drug classes, when used long-term, can cause KCS.
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Sulfonamides
Etodolac |
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How can otitis contribute to KCS?
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Desruction of nervous innervation to the lacrimal glands
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Primary drug used in treatment of KCS
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Cyclosporine A
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Cyclosporine A effectively treats KCS in these circumstances.
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Young, atopy stricken, or predisposed breeds of dogs.
Not useful in cats |
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T-cell suppressor used to treat KCS.
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Cyclosporine A
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Goal of medical therapy for KCS.
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Induce production of natural tears
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List some supportive measures that can help treat KCS.
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Lubrication
Anti-infectives Mucolytic agents Lacromimetics/parasympathomimetic drugs Corticosteroids Good periocular hygiene Oral interferon |
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Temporary surgical solution for KCS.
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Temporary tarsorraphy
3rd eyelid flap |
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Partial permanent tarsorraphies are used to treat this common disease.
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Keratoconjunctivitis sicca
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Last-resort surgery to treat keratoconjunctivitis sicca
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Parotid duct transposition
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What are some downsides to parotid duct transposition for the treatment of KCS?
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High mineral content
Little to no Ig's or Ab Flows according to stimuli of smell or eating |
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Causes of epiphora (2 major categories)
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Hypersecretion
Poor drainage |
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List some hypersecretory conditions that may lead to epiphora.
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Acute infections, ocular diseases
Irritations Foreign bodies or hairs |
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List some reasons for poor ocular drainage that may lead to epiphora.
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Congenital malformations (lack of puncta or nasolacrimal duct)
Lid deformities Acquired nasolacrimal duct obstruction |
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List some causes of "poodle epiphora"
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Foreign bodies
Lash anomalies Medial entropion Chronic conjunctivitis Ectropion Corneal ulcers Nasolacrimal duct malformation |
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What causes the brown staining of "poodle epiphora?"
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Porphyrin stain or periocular yeast/bacteria
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List three medical therapies for epiphora.
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Flush nasolacrimal ducts followed by antibiotic steroid drops
Treat any conjunctivitis Oral tetracycline to reduce staining |
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When is removal of the gland of the third eyelid an appropriate treatment for epiphora?
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NEVER
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Surgical treatments for epiphora.
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Pigtail probe and suture
Catheterize duct and leave a stent Dacycrocystorhinostomy |
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Infection of inflammation of the nasolacrimal duct system.
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Dacryocystitis
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Clinical signs of dacryocystitis
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Epiphora
Purulent discharge from medial canthus +/- pain |
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List some causes of dacryocystitis
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Congenital atresia of lower nasal punctum
FB obstruction Compression of nasolacrimal duct due to facial fractures |
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Therapy for dacryocystitis
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Frequent flushing of nasolacrimal duct with abx +/- corticosteroids
Nasolacrimal duct catheterization for 2-3 weeks (infuse with abx/steroids) Opening of a congenitally impatent nasal punctum |
