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25 Cards in this Set
- Front
- Back
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What is the main blood supply to the eye? |
Maxillary aa. -> external opthalmic a. To globe |
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What nerves are in the orbital fissure ? |
Oculomotor (3), trochlear, abduscens (6), opthalmic branch of trigeminal nerve (4) |
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State 1° orbital diseases signs |
Exopthalmus, enophthalmos , strabismus |
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State 2° orbital disease sign |
Discharge , swelling , lagophthalmos, corneal dzz- decrease tears and increase exposure, decreased vision, 3rd eyelid protrusion, optic nerve involvement , retinal abnormalities |
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State ddx for exopthalmus |
Buthalamos, enlarged globe, increased IOP, breed |
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What are the causes of exopthalmus in order? |
1. Orbital cellulitis /abscesses (<5yr) 2. " neoplasia especially middle-aged to old 3. " edema / haemorrage 4. Masticatory myositis 5. Cystic orbital dzz |
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Describe clinical signs of exopthalmus from orbital cellulitis /abscesses |
Sudden/ overnight, 3rd eyelid protrusion , periorbital swelling , pain opening mouth, epiphora +/- leukocytosis, strabismus |
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State causes of orbital cellulitis / abscesses |
Penetration wound or FB, tooth abscess or paranasal sinus infection |
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State dx aids used when exopthalmus presents |
History , signalment , diagnostic imaging (xray, CT, US, magnetic resonance) , cytology, culture and sensitivity, surgical exploration and biopsy |
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Describe clinical signs of exopthalmus from neoplasia |
Slow progression , unilaterally , 3rd eyelid protrusion , no pain opening mouth +/- scleral indentation on fundus, blindness, strabismus |
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What is the prognosis of orbital neoplasia ? |
>90% malignant and 60-75% primary in dogs over 8 years. Not usually 1° in cat (14%) instead invasion, SCC , LSA, OSA, melanoma LSA and SCC in cattle |
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State usual treatment for orbital neoplasia |
Exentration + chemo/radiotherapy Lateral orbitotomy if benign and circumcscribe |
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State causes of orbital haemorrage |
Trauma or bleeding disorders |
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Describe clinical signs of exopthalmus from masticatory myositis |
Acute, bilateral , immune mediated, responsive to prednisolone with recurrances , pain opening mouth , enlarged mandibular lymph nodes |
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Describe clinical signs of exopthalmus from cystic orbital dzz and dx and tx |
Due to fluid accumulation after development of a zygomatic salivary mucocele. Dx: FNA (clear-golden tenacious fluid) Tx: surgical resection |
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What is strabismus? What is it associated with ? |
Deviation of the line of sight of 1 or both eyes when in primary gaze Associated with space occupying lesions , extra ocular muscle damage , cranial nerve to muscles lesion |
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State ddx for enophthalmos |
Microphtalmos, Phthisis bulbi |
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State aetiologies of enophthalmos |
Dehydration , severe cachexia, fat atropy after head trauma Component of horners syndrome in cats |
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How do you differentiate between exopthalmus and proptosis |
In proptosis the eyelid gets trapped behind the globe |
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State causes of proptosis |
Breed (large paloebral fissure and shallow orbit), fights, trauma, restraint |
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How would you approach proptosis ? |
Evaluate entire animal Determine if acute or chronic (periorbital swelling ) If acute pull eyelid over eye If chronic then sx cirrection + sterile ocular lube to decrease exposure keratitis |
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What is the prognosis for proptosis ? |
Gaurded to poor for vision. Positive indicators include PLR and myotic pupil size (normal pain response ). Intact globe , relatively clear cornea , absence of hyphema, globe pressed tightly against lids and orbit rim Worse in cats and dolcephalic dogs |
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How do you treat orbital abscesses ? |
Uncomplicated : BS antibiotics systemically and topically , hot compress Complicated : betadine prep of mouth and drain fluid pockets into oral cavity via small incision posterior to last upper molar and blunt dissect into orbit. C/S the exudate Caution : maxillary artery |
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What surgeries are used for proptosis ? |
Lateral canthotomy then check for ulcers -> temporary tarrsoraphy with partial thicknesssutuers to close kids and to protect globe-> leave space on nasal aspect for medical administration -> remove tarrsoraphy in 2weeks or more Medicines used: antibiotics , atropine , systemic ccs, hot compress |
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What complications would you look for after surgical correction of proptosis ? |
1. Dorsolateral ocular strabismus - tears in medial rectus and inferior oblique muscle tears (self-limiting in 4-6m). 2. Phthisis bulbi if trauma to globe is severe |
