Chapter 59 - Intraocular surgery Flashcards
What is equine recurrent uveitis (ERU) commonly referred to as?
Moon blindness.
What percentage of horses with ERU lose vision according to studies?
28%.
What are the three components of the uveal tract?
Iris, ciliary body, and choroid.
What does the breakdown of the blood-aqueous barrier cause?
Vascular dilation and increased permeability
What phenomenon represents the hallmark of uveitis?
Aqueous flare, visible as scattered light due to increased protein.
What can extensive posterior synechia lead to in ERU cases?
Complete blockage of the pupil, resulting in vision loss.
What effect do prostaglandins have on intraocular pressure?
They cause hypotony (reduced intraocular pressure).
Which inflammatory mediators primarily contribute to ERU?
Prostaglandins and leukotrienes.
What is iris bombé?
Anterior bowing of the iris due to trapped fluid behind it.
What is a definitive diagnosis of ERU based on?
Multiple recurrent episodes of ocular inflammation.
What role does Leptospira interrogans play in ERU?
It is the most frequently implicated infectious cause.
What percentage of vitreous samples from ERU horses tested positive for leptospires in one German study?
75%.
What ocular condition can mimic uveitis?
Corneal ulceration.
What is essential before applying topical corticosteroids in uveitis cases?
Exclusion of corneal ulceration.
What must be evaluated to determine if cataracts have formed due to uveitis?
The lens, ideally after pupillary dilation.
What clinical sign may indicate hypotony during an eye examination?
Low intraocular pressure (IOP).
What diagnostic procedure can be used to culture pathogens in uveitis?
Aqueous paracentesis.
What is a significant risk associated with retrobulbar anesthesia?
Potential trauma to the globe.
What is the purpose of using corticosteroids in ERU treatment?
To reduce inflammation and stabilize the blood-aqueous barrier.
Which topical corticosteroids achieve therapeutic concentrations in the aqueous humor?
Prednisolone acetate 1% and dexamethasone 0.1%.
What is the recommended treatment if a horse tests positive for Leptospira spp. in endemic areas?
Systemic antibiotic therapy.
What percentage of normal horses can have elevated serum antibody titers for Leptospira spp.?
19%.
What can happen to the lens zonules due to chronic inflammation?
They may be lysed, leading to lens luxation.
Why is careful management of general anesthesia critical in ocular surgery?
To prevent further trauma to the globe and reduce postoperative complications.
What is the typical postoperative recovery strategy after intraocular surgery?
Smooth recovery from anesthesia.
What is the significance of the Tyndall effect in diagnosing uveitis?
It indicates increased protein levels in the aqueous humor.
What may be indicated for horses with severe inflammatory responses in the anterior chamber?
Intracameral injection of tissue plasminogen activator.
What condition can occur due to secondary glaucoma from ERU?
Increased intraocular pressure leading to vision loss.
What must be meticulously preserved if an HA orbital implant is planned?
Conjunctival fornices and extraocular muscles.
What should be done if an infected globe ruptures during surgery?
Extensive irrigation of the orbit and broad-spectrum antibiotics.
What are the implications of the presence of fibrin in the anterior chamber?
It indicates severe inflammation and can obstruct aqueous humor flow.
What might indicate a chronic inflammatory response in the eye?
Cataract formation and retinal scarring.
What is the role of mydriatics in ERU management?
To dilate the pupil and alleviate pain.
What is a common cause of hyphema in uveitis cases?
Severe intraocular inflammation.