Ophthalmology 422
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| Ectropion General Facts | - Mostly canines
- Breed related(Cocker Spaniel, Bloodhounds, Giant breeds)
- Age related (older dogs that have weakened eyelid muscles)
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| Ectropion - Secondary Problems | - Blepharospasm
- Epiphora
- Corneal ulceration
- Corneal melanosis
- Corneal vascularization
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| Ectropion - Treatment | - often not necessary
- lubrication
- Antibiotic/steroid ointment
- Wedge resection
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| 4 most common canine ocular neoplasias | - Meibomian adenoma (most common; age related)
- Papilloma (puppies only)
- melanoma(very old dogs)
- lymphoma (secondary metastasis to the eyelids)
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| Meibomian adenoma Clinical signs | - papilloma-like projection from eyelid margin
- swelling of the affected gland
- upper lid more commonly affected
- variable size
- blepharospasm if ulcerating
- rarely metastasizes
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| Meibomian adenoma Treatment | - Curettage and cryotherapy
- wedge resection
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| Most common feline ocular neoplasia | - squamous cell carcinoma (most common by far)
- fibrosarcoma
- mast cell tumor
- basal cell carcinoma
- lymphoma
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| Feline eyelid squamous cell carcinoma Clinical signs | - ulcerative lesion
- lower lid most common
- white or lightly pigmented cats are predisposed (exacerbated by UV exposure)
- metastasis occurs late
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| Feline eyelid squamous cell carcinoma Treatment | - Radiation is most effective
- Surgical excision (as an adjunct to radiation)
- cryotherapy
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| Equine ocular neoplasia | - squamous cell carcinoma (most common by far)
- melanoma
- sarcoid
- fibrosarcoma
- lymphoma
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| Equine eyelid squamous cell carcinoma 3 locations | - eyelid
- anterior surface of the third eyelid
- lateral aspect of the limbus
**equally distributed**
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| How is the equine eyelid squamous cell carcinoma different from the feline? | - more proliferative mass (can be palpated)
- non-ulcerative
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| Equine breeds predisposed to squamous cell carcinoma | - draft breeds
- appaloosas
- paints
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| Equine squamous cell carcinoma Treatment | - most difficult to treat (because usually not found until late stage)
- surgical debulking
- chemotherapy (cisplatin)
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| Bovine ocular neoplasia | - squamous cell carcinoma (most common)
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| Bovine squamous cell carcinoma 3 locations | - limbus (75%)
- eyelid and third eyelid (25%)
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| Stages of bovine eyelid squamous cell carcinoma | - thickening of eyelid skin
- proliferative mass (malignant form)
- Metastasis (to local salivary glands and lymph nodes)
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| Bovine eyelid squamous cell carcinoma Treatment | - may not treat
- economic decision
- not all precursors progress
- surgical debulking
- cryotherapy
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| Distichiasis general facts | - undifferentiated meibomian gland produces cilia
- the cilia emerges from the meibomian gland duct
- the cilia may contact the cornea or conjuntiva and cause irritation
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| Distichiasis breeds | - American cocker spaniels
- golden retrievers
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| Distichiasis Treatment | - manual epilation to confirm diagnosis
- remove cilia and wait to see if clinical signs resolve
- with confirmation of the diagnosis, cryotherapy
- warn O that it may depigment the area of treatment
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| Ectopic cilia General Facts | - failure of differentiation of meibomian gland --> cilia grows out of the gland and through palpebral conjunctiva
- usually happens in the upper lid at the 12 o'clock position
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| Ectopic cilia Clinical signs | - usually 8-12mo of age
- marked blepharospasm
- epiphora
- vertically linear superficial corneal ulcer
- raised papilla
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| Ectopic cilia Treatment | - excision
- cryotherapy (to remove cilia producing tissue)
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| Trichiasis General Facts | - hair from normal site in contact with cornea/conjunctiva
- most frequently in dogs
- brachycephalics
- yorkies, poodles, breeds with long facial hair
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| Trichiasis Clinical signs | - periocular hair touching ocular surface
- most often it doesn't cause irritation
- just wicks tears onto the face
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| Trichiasis most common origin of hair | - medial canthus
- nasal folds
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| Trichiasis Treatment | - usually not indicated
- cryotherapy
- lid surgery (to roll the lids out)
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| Traumatic eye injuries General facts | - abrasions --> first aid
- full thickness lacerations --> Sx repair
- lateral aspect of the upper lid is most frequently injured
- if injury is medial, need to check the nasolacrimal duct patency
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| Traumatic eye injuries causes | - Fight wounds
- Environmental objects
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| Traumatic eye injuries Treatment | - minimal debridement
- 2 layer closure
- orbicularis oculi m.
- skin
- ID and reconstruct inferior nasolacrimal system
- systemic and topical antibiotics
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| Traumatic eye injuries what layer is the primary holding layer when surgically closing a laceration? | - the orbicularis oculi m.
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| Bacterial Blepharitis General Facts | - overgrowth of surface bacterial flora
- enters the eyelid via the meibomian gland ducts
- Staph and Strep most common bacteria
- Hypersensitivity to staph toxins
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| Bacterial blepharitis Clinical Signs | - eyelid swelling
- blepharospasm
- excoriation
- alopecia
- mucopurulent discharge
- granuloma formation
- usually bilateral (in dogs)
- recurrence is common
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| Bacterial blepharitis Treatment | - Topical antibiotic/steroid
- Oral antibiotics
- Oral prednisone (low anti-inflammatory dose for hypersensitivity component)
- Warm compresses (pain relief and reduction of swelling)
- Autogenous vaccines (recurrent/chronic cases)
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| Chalazion General facts | - Older dogs
- Obstruction of the meibomian duct
- Accumulation of meibomian secretion
- Rupture of the meibomian gland
- Granulomatous reaction
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| Chalazion Clinical Signs | - nodular swelling within the eyelid
- No inflammation
- No pain
- Yellow white appearance through palpebral conjunctiva (viewed from underneath the eyelid)
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| Chalazion Treatment | - incision through the palpebral conjunctiva
- curettage of the glandular and granulomatous material
- topical antibiotic/steroid
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| Eyelid agenesis General Facts | - congenital condition
- most commonly in cats
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| Eyelid agenesis Clinical signs | - Absence of lateral 1/2 to 2/3 of the upper eyelid
- always bilateral (but not symmetrical)
- secondary trichiasis and exposure keratitis
- (+/-) microphthalmos and persistent pupillary membrane
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| Eyelid agenesis Treatment | - lubricants (reduce trichiasis irritation, reduce exposure)
- cryotherapy (of trichiasis hairs)
- blepharoplastic procedures (transplant part of the lower lid to the upper lid)
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| Neonatal ophthalmia General facts | - infection under eyelids before opening
- staph, strep, herpesvirus
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| Ankyloblepharon | - adhesion of the ciliary edges of the upper and lower eyelids to each other
- normal in dogs and cats 10-14days old
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| neonatal ophthalmia clinical signs | - inflamed, distended eyelids
- purulent discharge
- conjunctival hyperemia
- chemosis
- (+/-) corneal ulceration
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| Neonatal ophthalmia Treatment | - open eyelids (digital manipulation, blunt probe)
- flush with dilute betadine solution
- topical antibiotics
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| Retained Spectacle General Facts | - in snakes
- fused eyelids = spectacle
- spectacle contains blood vessels and sheds regularly with skin (ecdysis)
- abnormal if retained (not shed)
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| Retained Spectacle clinical signs | - Dull, cloudy appearance
- NOT the cornea
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| Retained Spectacle Causes | - dry environment
- systemic disease
- mite or tick infestation
- injury to the spectacle
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| Retained Spectacle Treatment | - conservative (don't peel if off)
- misting, soaking the spectacle
- increase humidity
- Add "furniture" to encourage normal shedding
- address systemic disease
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| 4 primary layers of the cornea | - epithelium
- stroma
- Descemet's membrane
- endothelium
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| Corneal epithelium general facts | - 5-10cells thick
- constant turnover
- hydrophobic
- won't take up fluorescein dye
- mechanical barrier
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| 2 organisms that can directly infect the corneal epithelium | - feline herpesvirus
- moraxella bovis
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| Corneal stroma general facts | - 90% of the corneas thickness
- lamellar arrangement of collagen fibers
- hydrophilic
- takes up fluorescein dye
- readily susceptible to infection
- densely innervated by CN V (outer half is innervated; inner half is not)
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| Decemet's membrane General facts | - basement membrane of the corneal endothelium
- very elastic
- last barrier to perforation
- produced throughout life
- becomes thickened as animal ages
- hydrophobic
- won't take up flourescein dye
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| Corneal endothelium | - monolayer of epithelium ("posterior corneal epithelium")
- Na/K pump removes fluid from corneal stroma
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| 2 layers that control the hydration state of the cornea | - epithelium (hydrophobicity restricts tears from entering the stroma)
- endothelium (Na/K pump actively transports fluid from stroma)
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| 5 factors that contribute to corneal transparency | 1. avascularity
2. relative dehydration
3. orderly arrangement of stromal collagen fibrils
4. lack of pigment
5. non-keratinized epithelium
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| 2 sources of nutrition for the cornea | 1. tears (for anterior cornea)
2. aqueous (for posterior cornea)
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| 3 functions of the cornea | 1. transmission of light
2. refraction of light
3. fibrous outer layer of eye protection
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| Signs of corneal disease | - edema
- cellular infiltrate
- lipid/mineral deposits
- fibrosis
- precipitates
- blood vessels
- melanin
- neoplasms
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| corneal edema | - need to ID layer allowing edema (epithelium or endothelium)
- entire cornea (diffuse) or sectional
- epithelium affected --> sectional
- endothelium affecthed --> diffuse, more severe
- non-specific sign
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| Corneal cellular infiltrate | - infection present = stromal abscess
- specific sign
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| Corneal lipid/mineral deposits | - usually cholesterol, other lipids, or Ca++ salts
- non-specific sign
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| Corneal fibrosis | - some past injury
- non-specific
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| Corneal precipitates | - accumulations of inflammatory cells and debris on the endothelial surface
- always ssecondary to past or present anterior uveitis
- specific sign
- can cause corneal edema
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| Corneal blood vessels | - always pathologic (response to injury)
- diffuse or sectional?
- tree-like with fine branching = superficial corneal vascularization
- short non branching = deep corneal vascularization
- takes 2-3days to initiate, then 1mm/day
- non-specific sign
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| Corneal melanosis | - response to chronic irritation/inflammation
- varies by species
- non-specific sign
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| Corneal neoplasm | - rare in cats and dogs
- common in horses and cattle
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| Normal corneal ulcer healing | "slide and divide"
- sliding (migration) of epithelial cells to cover the exposed stroma
- formation of basement membrane between epithelium and stroma
- mitosis to restore normal # of layers of the corneal epithelium
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| Uncomplicated corneal ulcer Clinical signs | - epithelium only, no stromal loss
- Heals within 7days
- No change in stromal character (stromal melting)
- No extensive vascularization
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| uncomplicated corneal ulcer Treatment | - ABSOLUTELY NO TOPICAL STEROIDS
- topical broad spectrum ABs
- topical atropine
- Ecollar
- recheck 2-3days, then 7 days
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| Complicated corneal ulcer Clinical signs | - increasing depth
- stromal infiltrate (specific sign)
- change in stromal character (specific sign)
- corneal vascularization
- hasn't healed in 7-10 days
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| 2 signs of a complicated corneal ulcer that are specific for infection | - stromal infiltrate
- change in stromal character (stromal melting)
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| Complicated corneal ulcer Common causes | - infection (bacterial, fungal, viral)
- foreign bodies
- exposure
- entropion
- ectopic cilia
- persistent ulcer syndrome ("boxer" ulcer)
- very common in SA practice
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| Complicated corneal ulcer Diagnosis of infection | - cytology
- C&S
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| Complicated corneal ulcer Treatment | - referral is first choice
- vigorous AB's/antifungals (q2hr)
- topical serum
- Ecollar
- warm compresses
- cage rest
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| Complicated corneal ulcer Exposure Clinical signs | - most frequent with brachycephalics
- centrally located
- round firm edges
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| Complicated corneal ulcer Treatment of exposure ulcer | - frequent AB ointment
- (+/-) atropine
- possibly tarsorrhaphy (closure of eyelids)
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| Complicated corneal ulcer Persistent ulcer syndrome clinical signs | - middle aged or older
- redundant epithelium around periphery
- forms a sheet that floats in the tear film
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| Complicated corneal ulcer Persistent ulcer syndrome Treatment | - corneal debridement with Q-tip
- grid keratotomy
- only in dogs
- never in cats and horses
- Medical Tx as uncomplicated
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| why would you never do a grid keratotomy in a cat or horse with persistent ulcer syndrome? | because, in addition to stimulating basement membrane deposition, scoring the cornea will embed infectious material
Cats - prone to herpes
Horses - prone to infectious ulcers
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| Chronic superficial keratitis general facts | - immune mediated
- affects young adults
- German shepherds predisposed
- UV light alters stromal proteins and causes an immune response
- lymphocyte migration --> cytokines --> inflammation
- AKA pannus
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| Chronic superficial keratitis clinical signs acute | - fibrovascular invasion just under the corneal epithelium in the ventrolateral cornea
- plasmoma = third eyelid thickening
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| Chronic superficial keratitis clinical signs chronic | - corneal melanosis
- blindness
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| Differential diagnoses for Chronic superficial keratitis | - KCS
- Corneal ulceration
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| Chronic superficial keratitis Treatment | - Topical steroids (neopolydex, prednisolone)
- topical cyclosporine
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| Exposure keratitis General facts | - usually brachycephalic dogs
- eyelids don't meet fully in medial aspect
- age related
- weakening of the orbicularis oculi m.
- Cats with eyelid agenesis
- secondary to eyelid injury
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| Exposure keratitis Clinical signs | - corneal vessels and melanosis medially
- may lead to ulcers
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| Exposure keratitis Causes | - conformation, breed related
- eyelid agenesis
- age related weakening of the orbicularis oculi m.
- eyelid injury
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| Exposure keratitis Treatment | - refer if ulcerated
- treat underlying prob (agenesis, lid conformation problem)
- topical AB/steroid ointment until keratitis controlled, then reduce
- topical lubricating ointment long term
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| Corneal degeneration General facts | - secondary to injury or inflammation
- crystalline or chalky deposits under epithelium (Very superficial)
- lipid and Ca salts
- unilateral or bilateral
- Painful/inflammatory
- can lead to chronic recurrent ulceration
- exclusively older pati
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| Corneal degeneration Clinical signs | - roughened surface of cornea
- blepharospasm
- recurrent ulceration (from chalky deposits flaking off)
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| Corneal degeneration Causes | - aberrant healing response
- secondary to trauma, irritation, inflammation
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| Corneal degeneration Treatment | - ABs for relief
- keratectomy for permanent resolution
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| Corneal Dystrophy General facts | - primary heritable defect
- resembles corneal degeneration
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| Corneal Dystrophy Clinical signs | - crystalline, ground-glass deposits
- under corneal epithelium
- bilateral, but not symmetric
- no pain, no inflammation
- no vision defect
- seen in young patients (1-2yrs)
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| Corneal Dystrophy Treatment | - not indicated
- no pain
- no vision defect
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| Feline herpesvirus General facts | - FHV-1 infects corneal epithelial cells and conjunctival cells
- May result in
- corneal sequestrum
- eosinophilic keratitis
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| Feline herpesvirus clinical signs | - blepharospasm
- epiphora
- conjunctival hyperemia
- chemosis
- corneal vessels
- Dendritic ulcers
- focal pinpoint cellular infiltrate
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| What clinical sign is pathognomonic for FHV-1 | - dendritic ulcers
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| How are cats most commonly infected with FHV-1? Did an adult cat with an outbreak get FHV-1 from the new kitten in the household? | - in utero
- No, the adult cat probably was infected with FHV-1 in utero and just had an outbreak in response to the stress of a new kitten in the household.
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| Feline herpesvirus Treatment | - Topical antivirals (idoxuridine, cidofovir)
- Oral L-lysine
- TOPICAL STEROIDS ARE ABSOLUTELY CONTRAINDICATED!
- treatment isn't curative, just shortens the course of the episode
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| Corneal sequestrum General facts | - unique to domestic cats
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| Corneal sequestrum Clinical signs | - distinctive dark brown plaque
- necrotic stroma
- NOT MELANIN
- painful
- can lead to rupture
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| Corneal sequestrum Causes | - Herpesvirus plays a role, but is not the only factor
- chronic exposure
- as in brachycephalics
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| Corneal sequestrum Treatment | - if there is a vascular response
- will slough on its own
- if no vascular response
- keratectomy
- conjunctival graft to the stromal bed
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| Eosinophilic keratitis General facts | - most frequently in cats
- also seen in horses
- associated with herpesvirus
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| Eosinophilic keratitis Clinical signs | - fibrovascular infiltrate with white "caseous" islands
- nests of eosinophils
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| Eosinophilic keratitis diagnosis | - clinical signs
- fibrovascular infiltrate
- caseous plaques
- cytology
- scrape white plaque and stain for eosinophils
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| Eosinophilic keratitis Treatment | - Topical steroids and antivirals
or
- megesterol acetate
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| Infectious Bovine Keratitis General facts | - common
- economically significant
- caused by moraxella bovis predominantly
- Herefords are most affected breed
- younger affected more than older
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| Infectious Bovine Keratitis Clinical signs | - variable severity
- initially unilateral
- blepharospasm
- epiphora
- central stromal infiltrate
- vigorous vascular response
- perforation, phthisis bulbi possible
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| Infectious Bovine Keratitis Treatment | - Can run its course without Tx
- may rupture cornea and scar in
- Penicillin
- Ampicillin
- Oxytetracycline (Tx of choice)
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| Corneal neoplasia in dogs Genneral facts | - relatively rare compared to horses and cattle
- limbal melanoma most common
- hemangioma/sarcoma
- lymphoma manifesting in corneal
- squamous cell CA very rare
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| Limbal melanoma Clinical signs | - Dark mass centered on limbus
- extends to the sclera and cornea
- unilateral
- more aggressive in younger dogs
- German shepherds predisposed
- have to distinguish from anterior corneal melanoma growing into the sclera
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| Corneal hemoangioma/sarcoma Clinical signs | - blood blisters
- lateral aspect of the limbus
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| Corneal lymphoma Clinical signs | - bilateral
- 360 degree corneal vessels and white creamy infiltrate
- eyelids swollen
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| Treatment of corneal neoplasms Limbal melanoma, hemangioma/hemangiosarcoma, SCC | - require excision and adjunctive Tx
- cryotherapy
- radiation
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| Treatment of corneal neoplasms Recurrent hemangiosarcoma | - enucleation
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| Treatment of corneal neoplasms Lymphosarcoma | - treat symptomatically
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| Corneal neoplasia in cats General facts | - limbal melanoma/cytoma most common
- still rare
- Dx and Tx same as dog
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| corneal neoplasia in horses | - limbal scc most common
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| Three common locations for equine limbal squamous cell carcinoma | 1. eyelids
2. anterior surface of the third eyelid
3. overlying the lateral aspect of the limbus
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| primary causes of limbal SCC in horses | - UV light
- breed predisposition
- draft horses
- appaloosas
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| Equine limbal SCC Treatment | - keratectomy (cytoreductive)
- adjunctive
- cryotherapy
- radiation
- high success rate
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| Corneal neoplasia in cows General facts | - SCC by far the most common
- important economic loss
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| 2 locations of bovine SCC | - limbus (75%)
- bulbar conjunctiva
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| Bovine corneal SCC Clinical signs | - starts as a plaque and progresses
- metastasis late to regional lymph nodes and parotid salivary gland
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| Bovine corneal SCC causes | - increasing age
- females may be predisposed
- breed
- Herefords (have light periocular pigmentation)
- UV exposure
- nutritional status
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| Bovine corneal SCC Treatment | - same as horse, but may elect for enucleation for economic reasons
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| Corneal dermoid General facts | - congenital
- Choristoma = normal tissue in an abnormal location
- mostly in dogs but also seen in cats, horses, cattle
- breed predisposition (GSD, St. Bernard, Dachshund)
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| Corneal dermoid clinical signs | - choristoma
- located laterally
- at the lateral limbus
- can involve the lateral canthus
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| Corneal dermoid Treatment | - keratectomy
- reconstruct lateral canthus
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| Components of the lacrimal system | - lacrimal gland
- gland of the third eyelid
- meibomian glands
- goblet cells
- lacrimal drainage apparatus
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| Components of the lacrimal system that are responsible for production of the tear film | - lacrimal gland
- gland of the third eyelid
- meibomian glands
- goblet cells
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| Lacrimal glands and ducts - position - innervation - function | - dorsolateral in orbit
- innervated by lacrimal nerve (parasympathetic)
- produces aqueous portion of tear film (nutrition and immunologic agents)
-
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| parasympathomimmetic drugs _________ tear production | increase
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| parasympatholytic drugs __________tear production | decrease
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| Gland of the third eyelid -position -innervation -function | - located on posterior surface of the third eyelid
- parasympathetically innervated
- produces aqueous portion of the tear film
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| Meibomian glands -location -function | - located in radial fashion within eyelids
- ducts are landmark of eyelid margin
- produce lipid portion of tear film
- prevents evaporation
- provides film like quality to tears
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| Three layers of tear film, where they are produced, and what function they serve | 1.superficial- lipid
-meibomian gland
-prevents evaporation; film like quality
2.middle- aqueous
-gland of the third eyelid
-lacrimal glands
-nutrition; immunological
3.inner- mucous
-Goblet cells
-anchors tear film
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| Goblet cells of the lacrimal system - location - function | - located in conjunctiva, (most numerous in the fornix)
- produces mucous portion of tear film
- anchors tear film to corneal epithelium
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| Nasolacrimal drainage apparatus | - lacrimal puncta (superior and inferior)
- canaliculi
- nasolacrimal duct
- nasal puncta
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| Which species only has inferior lacrimal puncta | rabbits
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| Functions of the lacrimal system | - provide nutrition to the ocular surface
- remove metabolic wastes and debris
- provide lubrication to ocular surface
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| General signs of disease of the lacrimal system | - tear production problems
- quantitative
- qualitative
- tear drainage problems
- epiphora
- discharge
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| Lacrimal system diagnostics | - schirmer tear test
- fluoroscein dye
- nasolacrimal flush
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| Schirmer tear test | - measures aqueous tear production
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| Fluoroscein dye passage | - tests patency of nasolacrimal duct
- potential for false negatives (animal may swallow the flush; especially brachycephalics)
- if + test, duct is patent
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| Nasolacrimal flush | - can locate and relieve obstructions
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| Keratoconjunctivitis sicca General facts | - reduction aqueous portion of tear film
- most common in dogs
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| Keratoconjunctivitis sicca Clinical signs | - mucoid discharge
- blepharospasm
- conjunctival hyperemia
- 360 degree corneal vessels (cornea trying to get nutrition elsewhere)
- corneal melanosis
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| Keratoconjunctivitis sicca Causes | - immune mediated (75% in dogs)
- drug therapy
- TMS
- atropine
- general anesthesia
- etodolac (severe and permanent)
- iatrogenic (removal of gland of third eyeld)
- trauma to lacrimal nerve
- infectious (CDV)
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| Keratoconjunctivitis sicca Diagnosis | - clinical signs
- confirm with schirmer tear test
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| Keratoconjunctivitis sicca Treatment | knowing underlying cause doesn't affect how you treat, just how long...
- topical cyclosporine
- topical AB/steroid
- client education
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| Developmental drainage obstruction General facts | - imperforate punctum and micropunctum (most common)
- canalicular atresia rare
- most common in dogs
- nasal imperforate punctum is seen in horses
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| Developmental drainage obstruction Clinical signs | - depends on if obstruction is complete or not
- dogs have epiphora from birth
- poor passage of fluoroscein dye
- NL flush
- nothing from inferior punctum (dogs)
- nothing from nasal punctum (horses)
- horses have chronic purulent discharge
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| Developmental drainage obstruction Treatment | Easy and effective Sx
Dogs
- flush superior punctum and look for bleb where inferior punctum should be
- incise conjunctiva over imperforate punctum
- topical AB/steroid
Horses
- place cannula and thread down
- excise skin covering nasal punctum
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| Foreign body obstruction of lacrimal drainage General facts | - plant awns (foxtails)
- sand
- seasonal variation
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|
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| Foreign body obstruction of lacrimal drainage Clincal signs | - Painful
- Blepharospasm
- mucopurulent discharge
- medial canthal swelling
- negative fluoroscein dye passage
- NL flush diminished or negative
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|
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| Foreign body obstruction of lacrimal drainage Treatment | - vigorous flushing (+/-) anesthesia
- dislodge/retrieve foreign body
- cannulate NL system and leave in place for 3-4wks
- topical AB/steroid
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|
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| Inflammatory obstruction of lacrimal drainage General facts | - inflammatory debris without foreign body
- descending infection
- stagnant tear drainage
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|
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| Inflammatory obstruction of lacrimal drainage Clinical signs | - mucopurulent discharge
- no medial canthal swelling
- not painful
- negative fluoroscein dye passage
- NL flush easy and often produces mucoid or mucopurulent plug
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|
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| Inflammatory obstruction of lacrimal drainage Causes | - infection of the most proximal lacrimal drainage apparatus
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|
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| Inflammatory obstruction of lacrimal drainage Treatment | - NL flush (+/- betadine solution)
- topical AB/steroid
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|
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| Anatomy of the iris | Anterior border layer
Stroma
Posterior epithelial layer
Corpora nigra
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|
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| Anterior border layer of the iris | - fibroblasts
- melanocytes
- no continuous epithelial layer
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|
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| Stroma of the iris | - blood vessels
- collagen fibers
- fibroblasts
- chromatophores
- melanocytes
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|
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| Muscles of the iris | sphincter muscle
- smooth muscle
- stronger than dilator
- innervated by CNIII
- parasympathetic innervation
Dilator muscle
- smooth muscle
- sypathetic innervation
- continuous with outer, pigmented, ciliary body epithelium
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|
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| Posterior epithelial layer of the iris | - densely pigmented (melanin)
- continuous with inner, non-pigmented, ciliary epithelium
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|
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| Corpora nigra | - found in most herbivores
- cystic dilation of the posterior iris epithelium
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|
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| Ciliary body epithelium | Inner, non-pigmented (NPE)
- extension of sensory retina
- junctions of these cells make up the Blood Aqueous Barrier (BAB)
Outer, pigmented epithelium
- extension of retinal pigmented epithelium
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|
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| Blood-aqueous barrier | - ciliary body vessels (epithelial portion)
- iridal vessels (endothelial portion)
- prostaglandins
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|
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| Ciliary body vessels | - located in iridal stroma
- fenestrated, leak plasma
- junctional complexes along the lateral borders of the NPE
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|
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| Iridal vessels | - non-fenestrated capillaries
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|
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| Prostaglandins of the BAB | - released after initiating event of anterior uveitis
- interfers with the junctional complexes at the lateral borders of the NPE
- compromises the BAB
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|
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| Functions of the anterior uvea | - regulate light entry by changing pupil size
- accomodation
- production of aqueous
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|
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| General signs of disease of the anterior uvea | - change in appearance of the iris
- change in aqueous
- secondary effects on the cornea and lens
🗑
|
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