Lecture 9 2/18/25 Flashcards
Which mucous membrane is the most exposed?
conjunctiva
What are the three areas of the conjunctiva?
-palpebral conjunctiva
-conjunctival fornix
-bulbar conjunctiva
What are the two layers of the conjunctiva?
-superficial layer with non-keratinized epithelium and goblet cells
-deep layer with substantia propria and lymphocyte and fibrous tissue
What are the purposes of the conjunctiva?
-contribute to tear film
-provide immunity
-allow movement of the globe without compromising vision
What is tenon’s capsule?
parallel connective tissue fibers that insert obliquely onto the bulbar conjunctiva
What is important about tenon’s capsule?
dissecting it appropriately removes tension from conjunctival grafts
Why is the two-layered structure of the conjunctiva important?
-prevents corneal desiccation via mucous secretions from goblet cells
-protects ocular surface from pathogens, both as a barrier and as a source of inflammatory cells
What are the acute pathologic responses in conjunctivitis?
-hyperemia
-cellular exudates
-edema/chemosis
-ocular discharge
-blepharospasm
What are the chronic pathologic responses in conjunctivitis?
-goblet cell proliferation leading to increased mucus production
-keratinization
-follicle formation
What is bacterial conjunctivitis?
rare primary bacterial infection of the conjunctiva leading to purulent discharge and hyperemia
How is bacterial conjunctivitis diagnosed and treated?
diagnosed:
-culture
-cytology
-rule out KCS, dacryocystitis, and eyelid disease
treated:
-broad spectrum topical antibiotic to start
-systemic antibiotics if severe
What is chronic allergic conjunctivitis?
seasonal disease related to atopy, causing a mucoid discharge
How is chronic allergic conjunctivitis diagnosed and treated?
diagnosed:
-seasonal
-cytology showing lymphocytes, plasma cells, and eosinophils
treated:
-desensitization if appropriate
-topical or systemic antihistamines
-possible topical hydrocortisone temporarily
What is acute allergic conjunctivitis?
acute profuse chemosis and hyperemic eyelids, often secondary to a bee sting
How is acute allergic conjunctivitis diagnosed and treated?
diagnosed:
-history of bee sting or being outside prior to onset
treated:
-ensure open airway
-artificial tear ointment if blinking is inhibited
-one dose of systemic diphenhydramine and dexamethasone +/- topical steroid
What is viral conjunctivitis?
conjunctivitis caused by distemper virus in the early stage of disease
How is viral conjunctivitis diagnosed and treated?
diagnosed:
-general clinical signs
-history
treated:
-topical antibiotics for secondary infections
-checking for KCS and treating as needed
What is follicular conjunctivitis?
abnormal proliferation of lymphoid follicles on the conjunctiva secondary to antigenic stimulation
How is follicular conjunctivitis diagnosed and treated?
diagnosed:
-appearance of vesicles approx. 2mm in diameter
-cytology revealing lymphocytes
treated:
-topical dexamethasone first
-rub follicles with a 4x4 covered cotton tipped applicator to rupture them and continue corticosteroids
How is physical irritation from drugs, wind, dust, and eyelid disease handled?
-do a complete eye exam
-identify any disease states resulting from irritation
-treat disease states as needed
What is fungal conjunctival disease?
granulomas that occur on the conjunctiva caused by blasto, histo, or crypto
What is conjunctival hemorrhage?
diffuse, petechial, or ecchymotic hemorrhages
What are the etiologies of conjunctival hemorrhage?
-trauma
-rocky mountain spotted fever
-choke collars
-blood dyscrasias
What are the diagnostics and treatment steps for conjunctival hemorrhage?
diagnostics:
-history
-physical exam
-CBC/chem/coag panel
treatment:
-treat primary disease
-treat eye as needed; not often indicated
What is conjunctival neoplasia?
rare occurrence in which a mass is seen within the conjunctiva; nodular granulomatous episcleritis is most common
What is the anatomy of the nictitans?
-conjunctiva lines both sides
-T shaped cartilage with its base towards the medial fornix and its top along the leading edge
-lacrimal gland on bulbar side
What are the functions of the nictitans?
-protection of cornea
-production of 35% of aqueous tear film
-reticuloendothelial/lymphoid activity
What is a cherry eye?
prolapse of the nictitans gland toward the leading edge of the nictitans
What is the pocket technique for correcting cherry eye?
an incision is made on either side of the gland and the conjunctiva is sutured over top of the gland
What is the tack down technique for correcting cherry eye?
gland is tacked to either the periosteum of the orbital rim or the ventral rectus muscle
What is pannus/plasmoma of the nictitans?
-considered to be related to pannus of the cornea
-immune-mediated and related to UV exposure
-appears as depigmented mass-like areas on leading margin of nictitans
What is the treatment for pannus/plasmoma of the nictitans?
-topical dexamethasone or prednisone to start; taper to control dose
-cyclosporine or tacrolimus for maintenance
-monitor lesions based on pigment
-goal is to control; cannot cure
What are the characteristics of scrolled cartilage of the nictitans?
-base of T cartilage is bent and flips out of the leading edge of the third eyelid
-seen in young, giant breed dogs; remains unless repaired
-bent part of cartilage is excised; no sutures placed, heals via second intention
