Ophthalmic Disease

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Ophthalmic Disease
2013-03-23 19:37:02
Animal Diseases Three

Animal Diseases
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  1. What area the three main categories of ophthalmic problems?
    • accessory structures
    • structures of the globe
    • retinal and neural pathway
  2. What are the accessory structures?
    • eyelids
    • conjunctiva
    • tear ducts
    • nictitating membrane
    • lacrimal glands
  3. What is conjunctivitis?
    inflammation of the conjunctiva
  4. Is conjunctivitis a primary disease?
  5. Is the conjunctiva highly vascular?
  6. What is hyerpemia?
    redness of the eyes
  7. What is chemosis?
    swelling of the eyes
  8. What are the different causes of conjunctivitis in cats?
    • Chelmydia felis
    • Mycoplasma felis
    • Bacillus spp
    • Staphylococcus spp
    • Feline herpes virus 1
    • Calici virus
    • eosinophilic
    • irritant conditions
    • trauma
    • accomplany other ocular disease
  9. What are the different causes of conjunctivitis in dogs?
    • canine distemper virus
    • immune mediated, atopy, pannus
    • irritant conditions
    • trauma
    • accompany other ocular disease
  10. What are the clinical signs of conjunctivitis?
    • chemosis
    • hyperemia
    • ocular discharge - serous or mucopurulent
    • epiphora
    • blepharospam
    • swelling of conjunctival lymph follicals (cobblestone)
  11. What is epiphora?
    overflow of tears
  12. How do you diagnose conjuncitivis?
    • complete physical exam
    • thorough visual exam of conjunctiva
    • conjunctival scraping, cytology, culture and sensitivity
    • Schirmer tear test
    • fluorescein stain
    • intraocular pressure
    • check lid for entropion, ectropion, trichiasis, distichiasis, ectopic cilia, foreign body
    • check behind the third eyelid
    • cornea - keratitis, ulcer
    • intraocular inflammation
  13. What is entropion?
    eyelids rolled inward toward cornea
  14. What is ectropion?
    eyelids rolled outwards away from cornea
  15. What is trichiasis?
    normal hairs that touch the cornea or conjunctiva
  16. What is distichiasis?
    hairs from the meibomian glands on the inner lid surface
  17. What is ectopic cilia?
    hair growing from an abnormal place
  18. How do we treat conjuncitivits?
    • treat underlying systemic disease if any
    • treat primary ocular disease
    • topical antibiotic ointments
  19. What are some different topical antibiotic ointments we can use?
    • neomycin
    • bacitracin
    • polymyxin B
    • Gentamicin ointment
    • may contain corticsone for follicular or atopic conjunctivitis
    • nonsteroidals - Ketorolac, Lodoxamide
  20. How do we treat viral conjunctivitis in cats?
    • idoxuridine (IDU)
    • adenine arabinoside (Vir-A)
    • lysine PO - arginine inhibitor - slows replication of herpes virus
    • keep eyes clear of discharge
  21. What kind of client education do we need to provide about conjuncitivis?
    • do not allow your dog to ride with his head out the car window
    • remove excess hair that may trap discharge
    • vaccinate kittens for upper respiratory disease
    • do not touch ointment tip to the eye
    • ointments provide longer contact time than solutions
    • need to be applied frequently to be effective
    • demonstrate proper technique of applying medications
  22. What is epiphora?
    overflow of tears
  23. What causes epiphora?
    • overproduction o ftears due to ocular pain or ocular irritation
    • faulty drainage - lacrimal system
    • brachycephalics
  24. What causes faulty drainage in the eye?
    • blockage of ducts by swelling or inflammation
    • imperforate puncta, trauma
    • entropion
    • ectropion
  25. Why do brachycephalics have a problem with epiphora?
    • large globes, shallow orbits
    • little room for accumulation of tears - tears spill out on face
    • accumulation in hair or face folds may wick the tears onto face
  26. What are the clinical signs of epiphora?
    • watering of the eye, acute or chronic
    • wet facial hair in medial canthus
    • secondary bacterial infection of periocular skin
    • discoloration of periocular skin and hair
  27. How do we diagnose epiphora?
    • eye exam - look for causes of pain
    • fluorescein stain - look for stain to exit through the nares
  28. How do we treat epiphora?
    • treat primary cause of pain or irritation
    • flush nasolacrimal ducts to remove obstructions
    • surgically open imperforate puncta
    • surgical correction of lids
    • keep facial hair trimmed away from eyes to prevent contact with cornea
  29. What is keratoconjunctivitis sicca (KCS)?
    • dry eye
    • deficiency of aqueous tear production
  30. What are the purpose of tears?
    • clean
    • lubricate
    • nourish
    • reduce bacteria
    • aid in healing
  31. What are the three tear layers?
    • aqueous
    • lipid
    • mucus
  32. What is the the aqueous layer?
    • produced by lacrimal gland
    • bulk of tear volume
    • immunoglobulins, enzymes, glucose, proteins, ions, salt
  33. What is the lipid layer?
    • secreted by the meibomian glands
    • aids in tear distribution
    • waxy - helps hold watery tears in the orbit
  34. What is the mucus layer?
    • secreted by conjunctival goblet cells
    • aids in tear adherence to the corneal surface
  35. How many lacrimal glands do dogs and cats have?  What are they?
    • 2
    • lateral orbit
    • nictitans gland
  36. What does the lateral orbit lacrimal gland do?
    produces 70% of tear volume
  37. What does the nictitans gland do?
    produces 30% of tear volume
  38. What does the loss of both lacrimal glands produce?
  39. What are the clinical signs of KCS?
    • recurrent conjunctivitis, corneal ulcers, and keratitis
    • cornea and conjunctiva appear dry, dull, and irregular
    • tenacious mucoid ocular discharge (mucopurulent)
    • discharge sticks to cornea and lid margins, conjunctival sacs
    • blepharospasm
    • crusty nares
    • corneal vascularization
    • corneal pigmentation
    • decreased vision
    • usually bilateral, may be unilateral
  40. How do we diagnose KCS?
    • schirmer tear test (STT)
    • base diagnosis on clinical signs and STT together
  41. What is the Schirmer Tear Test?
    • commercially available test strips
    • absorbable strips
    • use same brand each time animal is rechecked
    • remove excess corneal discharge
  42. How do you do the Schirmer Tear Test?
    • bend test strip at notch
    • place bent area into the conjunctival sac
    • close lids and leave in for one minute
    • measure tears on the strips in mm
  43. Should we use other medications and eye drops before doing the STT?
  44. How do we treat KCS?
    • tear stimulation
    • artifical tears
    • topical antibiotic ointment
    • parotid duct transposition
  45. How do we do tear stimulation?
    • cyclosporines (Optimmune)
    • cyclosporines in corn oil - can get compounded at most pharmacies
    • oral pilocarpine in food (salivation, vomiting, diarrhea, and bradycardia)
  46. What kind of client education do we need to provide for KCS?
    • prognosis for resolution is guarded
    • usually life long treatment
    • 15 - 20% may go into remission
    • failure to treat will result in blindness
  47. What is entropion?
    eyelids roll in towards cornea
  48. Which animal is entropion the most common in?
    • common in dogs
    • less common in cats
  49. What are the different types of entropion?
    • congenital (hereditary)
    • acquired non-spastic
    • acquired spastic
  50. How does acquired non-spastic entropion occur?
    • usually due to trauma or surgery
    • chronic inflammaion
    • scarring of the lid with contraction
    • lid turns inward towards globe
  51. How does acquired spastic entropion occur?
    • usually secondary to painful corneal lesions or conjunctival inflammaion
    • squinting
  52. What are the clinical signs of entropion?
    • range from absent to severe
    • blepharospasm, epiphora
    • hair rubbing on cornea
    • corneal pigmentation, vasculatization, ulceration
    • chemosis, pain, photophobia
    • rolling in of eyelid margins
  53. How do we treat entropioin?
    • medical: treat causes of spastic entropion, treat corneal ulceration
    • surgical:  temporary tacking, permanent
  54. What kind of client education do we need to provide about entropion?
    • avoid purchasing breeds known to have this defect
    • carefully examine puppies
    • dogs do not usually outgrow this condition
  55. What is ectropion?
    eyelid margins rolled away from eye
  56. Which eyelid does ectropion affect the most?
    lower lid
  57. What are the clinical signs of ectropion?
    • may be asymptomatic
    • vary with extent of the entropion
    • conjunctivitis
    • epiphora
    • debris accumulation (purulent)
    • keratitis if severe (exposure)
    • lid eversion
  58. How do we treat ectropion?
    • medical:  clean accumulated discharge daily, topical lubricant
    • surgical:  wedge resection lateral canthus, technique to shorten lower lid
  59. What is another name for a prolapsed third eyelid?
    Cherry eye
  60. What is the third eyelid and what is its purpose?
    • nictitating membrane
    • is a protective structure
    • assists in spreading tears
    • covers the eye to protect it from injury
    • produces tears
  61. How does a patient get a cherry eye?
    • Gland embedded in the third eyelid 
    • gland slips forward but remains underneath the conjunctiva
    • exposure results in swelling and inflammation of the gland
  62. Which animals typically get a cherry eye?
    Young dogs less than 2years old
  63. Describe what a cherry eye looks like.
    • Round, reddened soft mass in the media, canthus
    • possible mucous discharge
    • unilateral or bilateral
    • may be irritated
    • usually not painful
  64. How do we treat cherry eyes?
    Surgical restoration of normal gland pposition surgical removal is a last resort-cancer
  65. What are the two surgical restoration techniques for fixing cherry eyes?
    • Pocket technique
    • orbital rim tracking
  66. What are the different problems with the structure of the globe?
    • Corneal ulcers 
    • cataracts
    • glaucoma
    • uveitis
    • pigmentary keratitis
    • lens luxation
  67. What is another name for a corneal ulcer?
    Ulcerative keratitis
  68. What are the 5 ayers of the cornea?
    • Epithelium (outer)
    • bowman's membrane
    • stoma
    • descemet's membrane 
    • endothelium (inner)
  69. What is a superficial corneal ulcer?
    Loss of epithelium only
  70. What is a stomal ulcer?
    Loss of epithelium and some stoma
  71. What is a desmetocele?
    Stroma lost down to descemets membrane
  72. What is perforation in descemets membrane?
    Loss of aqueous humor, may have iris prolapse
  73. What are the different causes of corneal ulcers?
    • Trauma, chemicals, foreign bodies, KCS
    • conformational abnormalities
    • bacterial, fungal, viral
    • immune mediated
    • distichia, trichiasis, ectopic cilia
  74. What are the clinical signs of corneal ulcers?
    • Pain, blepharospasm, epiphora
    • hyperemic conjunctiva
    • ocular discharge (purulent)
    • fluid leakage from wound
    • upper respiratory infection in cats
  75. How do we diagnose corneal ulcers?
    • Thorough exam
    • fluorescein stain-detects corneal ulcers and abrasions
    • descemet's membrane will not stain
  76. How do we treat corneal ulcers?
    • Topical antibiotics
    • topical atropine
    • NSAIDs for uveitis
    • systemic antibiotics
    • contact lense protection 
    • oral lysine for cats
    • surgery -grid keratectomy, third eye lid flaps, eyelid flaps, conjunctival flaps
  77. What does topical atropine do?
    • Decreases pain
    • dilates pupil to prevent adhesions of iris to cornea
  78. Does the corneal epithelium heal fast or slow?
    Heals rapidly
  79. How long does it take for superficial ulcers heal?
    Several days
  80. Do infected ulcers heal fast or slow?
  81. How long does it take for indolent ulcers to heal?
    Fail to heal after weeks of therapy
  82. Should we use products containing cortisone for corneal ulcers?  Why or why not?
    No because cortisone delays wound healing and can make ulcers worse
  83. How often should a patient with corneal ul era get rechecked?
    Every 2-3days
  84. What is glaucoma?
    Increased intraocular pressure (IOP) beyond what is compatible with the health of the eye
  85. What can glaucoma result in?
    Permanent blindness
  86. What is primary glaucoma?
  87. What is secondary glaucoma?
    Due to another disease affecting the drainage of the eye (uveitis, lens luxation, neoplasia, trauma)
  88. What are the acute clinical signs of glaucoma?
    • Ocular pain -rubbing eyes, hiding, personality changes
    • ocular redness
    • vision loss
    • dilated pupil -slow to absent pupillary light reflex
  89. What are the chronic clinical signs of glaucoma?
    • Any acute sign
    • buphthalmos -abnormal enlargement of the eye
    • linear streaks in the cornea
    • lens luxation
    • pain, blindness
  90. How do we diagnose glaucoma?
    • Tonometry
    • measure both eyes for comparison 
    • gonioscopy
  91. What are the two devices for tonometry?
    • Schiotz tonometer
    • tono-pen
  92. What is gonioscopy?
    checks filtration angle
  93. How do we treat glaucoma?
    • Reduction of IOP
    • may be able to preserve vision
    • no known cure
    • a true emergency 
    • mannitol - hyperosmotic
    • medications
  94. How do medications treat glaucoma?
    • decrease aqueous humor production
    • increase aqueous outflow
  95. What are the different types of surgery for glaucoma?
    • Gonioimplants
    • cyclophotocoagulation
    • cyclocryotherapy
    • salvage surgery
  96. What are gonioimplants?
    Aqueous shunting
  97. What is cyclophotocoagulation?
    Laser ablation of ciliary bodies
  98. What is cyclocryotherapy?
    Cold applied to the globe over the area of the ciliary body- partial destruction
  99. What is salvage surgery?
    • Enucleation
    • orbit implant
    • Evisceration with implant
    • intravitreal gentamicin injection - only on blind eyes - toxic to structures in the vitreous and the ciliary body
  100. What are cataracts?
    Opacity of the lens
  101. What is the most common disease involving the lens?
  102. What color does the lens change to with cataracts?
    From clear to white or blue
  103. What is the frequent cause of blindness in dogs?
  104. What could cataracts be secondary to?
    • Diabetes mellitus 
    • trauma
    • nutritional deficiencies
    • electric shock
    • uveitis
    • lens luxation
  105. What is senile nuclear (lenticular) sclerosis?
    • Normal change in aging animals
    • lens may appear gray or opaque
    • vision is maintained
    • can visualize fundus
    • begins at around 7 years old
  106. What are the clinical signs of cataracts?
    • Progressive vision loss
    • opaque pupil opening
    • other systemic disease
  107. How do we diagnose cataracts?
    • Ophthalmic exam
    • assess vision loss - obstacle course, lack of menace reflex, failure to track
    • PLR - pupillary light reflex - normal
    • serum profile for primary disease
  108. How do we treat cataracts?
    • Stabilize primary cause if any
    • surgical removal if necessary
    • treat uveitis or other inflammation in the eye
    • if surgery is not an option, monitor yearly
    • phacoemulsification
  109. What is phacoemulsification?
    • Ultrasound - breaks up lens
    • aspirate lens out with needle
    • preferred technique for removing most cataracts
    • can replace lens with intraocular lens prosthesis
    • success rate about 95%
    • usually a unilateral surgery
  110. What do we need to educate clients on about cataracts?
    • Cataracts are usually progressive
    • most cataracts are inherited - do not use animal for breeding
    • quality of life can be maintained
    • do not move furniture around if animal is blind
  111. What is anterior uveitis?
    Inflammation of the iris, ciliary body, or choroid
  112. What causes anterior uveitis?
    • Bacterial, viral, mycotic, parasites, immune mediated
    • lens induced - lens proteins
    • trauma, systemic disease, rickettsial
    • cats - FeLV, FIP, herpes
    • idiopathic
  113. What are the clinical signs of anterior uveitis?
    • epiphora, blepharospasm
    • photophobia
    • corneal edema (gray, white)
    • chemosis, scleral injection
    • cherry eye
    • pain
    • change in color of iris
  114. How do we diagnose anterior uveitis?
    • clinical signs
    • blood work for systemic disease
    • immunology screening panel (FeLV, FIP, FIV, mycosis panels)
    • ultrasound of the eye
    • tonometry - eye is usually soft
  115. How do we treat anterior uveitis?
    • treat underlying disease
    • control inflammation
  116. How do we control inflammation with anterior uvetitis?
    • Banamine or aspirin
    • topical opthalmic steroids and NSAIDs
    • atropine - for pain and to prevent adhesions
    • enucleation
  117. What is PRA?
    progressive retinal atrophy
  118. What is the retina?
    where the visual pathway begins
  119. What does the retina consist of?
    • photoreceptor cells - rods and cones
    • arteries and veins which connect to the optic disc
    • the optic disc connects to the optic nerve which connects to the brain
  120. What are photoreceptors cells?
    • sense light
    • rods:  black/white, low light
    • cones:  color, bright light
  121. Does the retina have to be functioning normally for vision to occur?
  122. What does PRA result in?
    loss of vision
  123. When do we start to see signs of PRA?
    • as early as 6 months of age
    • usually starts at middle age
  124. What type of vision is lost first with PRA?
    • loss of night/low light vision
    • progresses to affecting day vision
  125. What are the clinical signs of PRA?
    • most cases - complete blindness
    • cataracts often develop
  126. Is there a cure for PRA?
  127. Is there a treatment for PRA?
  128. How do we diagnose PRA?
    • retinal exam
    • electroretinogram is abnormal
    • DNA testing in some breeds
  129. How do we treat PRA?
    • no treatment
    • instruct owners on ow to care for a blind pet
    • do not breed animals with PRA
    • CERF exams
  130. What are CERF exams?
    • Canine Eye Registration Foundation
    • certifies dog free of heritable eye disease
    • board certified veterinary ophthalmologist
    • exam done yearly