Feline Ophthalmology Flashcards
Eyelid Agenesis
- Absence a portion of the eyelid
– Secondary trichiasis and exposure keratoconjunctivitis
– Most common in cats and horses
– Cats upper temporal eyelid (also commonly associated with other ocular abnormalities, PPM, retinal dysplasia, cataracts…)
– Horses upper nasal eyelid
Surgical Repair of Eyelid Agenesis
Corneal Sequestrum
- what
- signs
- Area of corneal degeneration with amber to brown discoloration
- Usually in the central/paracentral cornea
- Variable vascularization
- Variable ocular pain
Corneal Sequestrum
- who
- treatment
- Unique to cats
- More common
- Persians
- Himalayans
- DSH with corneal irritation
- Ulcer, entropion, FHV 1
- Surgery required for removal…referral
Corneal Sequestrum
- surgery
- Surgical removal - keratectomy +/- conjunctival graft, cornealconjunctival transpostion, cyanoacrylate glue, lamellar or penetrating corneal transplant
- Recurrence is always possible!!!
Penetrating Keratoplasty
Eosinophilic Conjunctivitis/Keratoconjunctivitis
- what
- signs
Eosinophilic Conjunctivitis/Keratoconjunctivitis
- diagnosis
- treatment
- Diagnosis
– Eosinophils on cytology - Treatment
- Topical
- Prednisolone acetate 0.1% T-QID
- Dexamethasone 0.1% T-QID
- BID
- Optimmune 0.2% cyclosporine BID
- Cyclosporine 1 or 2% BID
- Tacrolimus 0.02 or 0.03% BID
- Topical megestrol acetate TID
- Systemic
- Prednisolone
- Topical
Eosinophilic Conjunctivitis/Keratoconjunctivitis
- Topical megestrol acetate TID 3 weeks
Eosinophilic Keratitis
- Prognosis:
Prognosis: usually favorable…but treatment may be long term
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Feline Herpesvirus 1
- cause what in eyes
Corneal ulcers
– Geographic
– Dendritic
– Stromal keratitis
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Diagnosis of FHV-1
- CLINICAL SIGNS!!!!
- If it is a cat and it has a corneal ulcer….
- Conjunctival cytology
- Intranuclear inclusions, neutrophils
- PCR – sensitive and specific
- IFA - insensitive
- Fluoroescein stain may cause false positive
- Serology (serum neutralization titer) - insensitive
- Virus isolation
- Definitive dx for acute infection
- Insensitive for chronic infection
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Feline Herpesvirus Topical Treatment
- Cidofovir 0.5% solution
- Compounding pharmacy
- 2 times daily
- Idoxuridine 0.1% solution
- Compounding pharmacy
- 4-6 times daily
- Trifluridine 1% solution
- Viroptic® and generic
- Refrigerated
- Topically irritating to most patients
- Topical antibiotic- to prevent bacterial infection
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FHV Systemic Treatment
- Famciclovir
- 250 mg or 125 mg tablets (Famvir ®)
- 30-40 mg/kg B-TID po
- Do NOT use valacyclovir
- Lysine
- 250 mg po BID in kittens
- 500 mg po BID adult cats
- Give with food
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Complications of FHV-1
- Globe rupture
- Symblepharon
Feline Glaucoma
- Primary glaucoma in cats is very very rare
- Secondary glaucoma
– Uveitis
– Intraocular neoplasia
– Feline aqueous misdirection syndrome - Treatment
– Topical carbonic anhydrase inhibitors (dorzolamide 2%)
– Beta blockers (0.25%)
– Latanoprost ineffective in cats
– Do not use oral carbonic anhydrase inhibitors
Feline Aqueous Humor Misdirection Syndrome
- who
- what
- signs
▪ Generally older cats
▪ AH shunted into the vitreous
– Shifts the lens & iris anteriorly
▪ Anisocoria
▪ Shallow anterior chamber
▪ IOP often not elevated initially…
Feline Aqueous Humor Misdirection Syndrome
- Treatment
- Topical carbonic anhydrase inhibitors B-TID
- Monitor IOP q1-3 months (both eyes)
- Refer for surgery if unresponsive to medications
Feline Cataracts
- Primary inherited cataracts are rare
- Most cataracts are secondary
– Anterior uveitis
– Trauma
– Lens luxation
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Systemic Hypertension
Generally older cats (>10years)
Present with dilated pupils or vision loss
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Hypertensive Retinopathy
- signs
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Hypertensive Retinopathy
- etiology
- Idiopathic
– 20% - Chronic kidney disease
– 19% to 65%of cats - Hyperthyroidism
– 10% to 20% - Diabetes mellitus
- Primary aldosteronism
- Pheochromocytoma
- Chronic anemia
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Hypertensive Retinopathy
- diagnostics
- treatment
- Diagnostics
– Systolic blood pressure
> 160 mmHg
– CBC/chemistry panel/UA/T4 - Treatment
– Treat underlying condition
– Antihypertensive medication - Amlodipine (0.18-0.22mg/kg PO SID, 0.625mg PO SID)
- Goal BP < 150 mmHg
- Prognosis for vision?
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Enrofloxacin Retinal Toxicity
- Acute retinal degeneration
- 1997 label dosing changed from 2.5mg/kg BID to 5-20mg/kg as a split or single dose
- May occur even at recommended dose (2.5mg/kg BID)
- Especially in cats with impaired drug metabolism (renal/hepatic dz.)
- IV administration of enrofloxacin may increase risk of retinal toxicity
- May occur even at recommended dose (2.5mg/kg BID)
- In most cases the blindness is permanent
- Use enrofloxacin if no other alternative
- Use only the lowest dose/shortest amount of time
Safety of Other Fluoroquinolones?
- Prudent precaution to consider that ALL fluoroquinolones may have the potential to induce ocular lesions in cats and that all fluoroquinolones should be used with caution in cats
- Pradofloxacin Veraflox®
- Oral suspension for cats
Polymyxin B and Anaphylaxis
- 61 cats
- Anaphylactic event within 4 hours
- BNP or Terramycin ophthalmic ointment
- Highlights the importance of reporting adverse drug events to the FDA or drug manufacturer
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Diffuse Iris Melanoma
- Most common feline primary intraocular tumor
- Malignant melanocytic neoplasm
- Slow, progressive, often multifocal areas of pigmentation of the iris
- Secondary glaucoma from involvement of the iridocorneal angle
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Distinguish DIM from Iris Nevus
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Diffuse Iris Melanoma
- prognosis
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Treatment Options for DIM
- Monitor for progression
– Photos or drawings in the medical record
– Recheck at 2-4 months intervals - Diode laser ablation???
- Enculeation
– Thoracic radiographs
– Abdominal US