| Question |
Answer |
| Ectropion General Facts |
- Mostly canines
- Breed related(Cocker Spaniel, Bloodhounds, Giant breeds)
- Age related (older dogs that have weakened eyelid muscles) |
| Ectropion - Secondary Problems |
- Blepharospasm
- Epiphora
- Corneal ulceration
- Corneal melanosis
- Corneal vascularization |
| Ectropion - Treatment |
- often not necessary
- lubrication
- Antibiotic/steroid ointment
- Wedge resection |
| 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) |
| 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 |
| Meibomian adenoma
Treatment |
- Curettage and cryotherapy
- wedge resection |
| Most common feline ocular neoplasia |
- squamous cell carcinoma (most common by far)
- fibrosarcoma
- mast cell tumor
- basal cell carcinoma
- lymphoma |
| 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 |
| Feline eyelid squamous cell carcinoma
Treatment |
- Radiation is most effective
- Surgical excision (as an adjunct to radiation)
- cryotherapy
|
| Equine ocular neoplasia |
- squamous cell carcinoma (most common by far)
- melanoma
- sarcoid
- fibrosarcoma
- lymphoma |
| Equine eyelid squamous cell carcinoma
3 locations |
- eyelid
- anterior surface of the third eyelid
- lateral aspect of the limbus
**equally distributed**
|
| How is the equine eyelid squamous cell carcinoma different from the feline? |
- more proliferative mass (can be palpated)
- non-ulcerative |
| Equine breeds predisposed to squamous cell carcinoma |
- draft breeds
- appaloosas
- paints |
| Equine squamous cell carcinoma
Treatment |
- most difficult to treat (because usually not found until late stage)
- surgical debulking
- chemotherapy (cisplatin) |
| Bovine ocular neoplasia |
- squamous cell carcinoma (most common)
|
| Bovine squamous cell carcinoma
3 locations |
- limbus (75%)
- eyelid and third eyelid (25%)
|
| Stages of bovine eyelid squamous cell carcinoma |
- thickening of eyelid skin
- proliferative mass (malignant form)
- Metastasis (to local salivary glands and lymph nodes) |
| Bovine eyelid squamous cell carcinoma
Treatment |
- may not treat
- economic decision
- not all precursors progress
- surgical debulking
- cryotherapy |
| 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
|
| Distichiasis
breeds |
- American cocker spaniels
- golden retrievers
|
| 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
|
| 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 |
| Ectopic cilia
Clinical signs |
- usually 8-12mo of age
- marked blepharospasm
- epiphora
- vertically linear superficial corneal ulcer
- raised papilla |
| Ectopic cilia
Treatment |
- excision
- cryotherapy (to remove cilia producing tissue) |
| Trichiasis
General Facts |
- hair from normal site in contact with cornea/conjunctiva
- most frequently in dogs
- brachycephalics
- yorkies, poodles, breeds with long facial hair
|
| Trichiasis
Clinical signs |
- periocular hair touching ocular surface
- most often it doesn't cause irritation
- just wicks tears onto the face |
| Trichiasis
most common origin of hair |
- medial canthus
- nasal folds |
| Trichiasis
Treatment |
- usually not indicated
- cryotherapy
- lid surgery (to roll the lids out) |
| 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 |
| Traumatic eye injuries
causes |
- Fight wounds
- Environmental objects |
| Traumatic eye injuries
Treatment |
- minimal debridement
- 2 layer closure
- orbicularis oculi m.
- skin
- ID and reconstruct inferior nasolacrimal system
- systemic and topical antibiotics |
| Traumatic eye injuries
what layer is the primary holding layer when surgically closing a laceration? |
- the orbicularis oculi m. |
| 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 |
| Bacterial blepharitis
Clinical Signs |
- eyelid swelling
- blepharospasm
- excoriation
- alopecia
- mucopurulent discharge
- granuloma formation
- usually bilateral (in dogs)
- recurrence is common |
| 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) |
| Chalazion
General facts |
- Older dogs
- Obstruction of the meibomian duct
- Accumulation of meibomian secretion
- Rupture of the meibomian gland
- Granulomatous reaction |
| Chalazion
Clinical Signs |
- nodular swelling within the eyelid
- No inflammation
- No pain
- Yellow white appearance through palpebral conjunctiva (viewed from underneath the eyelid) |
| Chalazion
Treatment |
- incision through the palpebral conjunctiva
- curettage of the glandular and granulomatous material
- topical antibiotic/steroid |
| Eyelid agenesis
General Facts |
- congenital condition
- most commonly in cats |
| 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 |
| 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)
|
| Neonatal ophthalmia
General facts |
- infection under eyelids before opening
- staph, strep, herpesvirus |
| Ankyloblepharon |
- adhesion of the ciliary edges of the upper and lower eyelids to each other
- normal in dogs and cats 10-14days old |
| neonatal ophthalmia
clinical signs |
- inflamed, distended eyelids
- purulent discharge
- conjunctival hyperemia
- chemosis
- (+/-) corneal ulceration |
| Neonatal ophthalmia
Treatment |
- open eyelids (digital manipulation, blunt probe)
- flush with dilute betadine solution
- topical antibiotics |
| Retained Spectacle
General Facts |
- in snakes
- fused eyelids = spectacle
- spectacle contains blood vessels and sheds regularly with skin (ecdysis)
- abnormal if retained (not shed) |
| Retained Spectacle
clinical signs |
- Dull, cloudy appearance
- NOT the cornea
|
| Retained Spectacle
Causes |
- dry environment
- systemic disease
- mite or tick infestation
- injury to the spectacle |
| Retained Spectacle
Treatment |
- conservative (don't peel if off)
- misting, soaking the spectacle
- increase humidity
- Add "furniture" to encourage normal shedding
- address systemic disease |
| 4 primary layers of the cornea |
- epithelium
- stroma
- Descemet's membrane
- endothelium |
| Corneal epithelium
general facts |
- 5-10cells thick
- constant turnover
- hydrophobic
- won't take up fluorescein dye
- mechanical barrier |
| 2 organisms that can directly infect the corneal epithelium |
- feline herpesvirus
- moraxella bovis |
| 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)
|
| 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
|
| Corneal endothelium |
- monolayer of epithelium ("posterior corneal epithelium")
- Na/K pump removes fluid from corneal stroma |
| 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) |
| 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
|
| 2 sources of nutrition for the cornea |
1. tears (for anterior cornea)
2. aqueous (for posterior cornea)
|
| 3 functions of the cornea |
1. transmission of light
2. refraction of light
3. fibrous outer layer of eye protection |
| Signs of corneal disease |
- edema
- cellular infiltrate
- lipid/mineral deposits
- fibrosis
- precipitates
- blood vessels
- melanin
- neoplasms |
| 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
|
| Corneal cellular infiltrate |
- infection present = stromal abscess
- specific sign
|
| Corneal lipid/mineral deposits |
- usually cholesterol, other lipids, or Ca++ salts
- non-specific sign |
| Corneal fibrosis |
- some past injury
- non-specific |
| 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 |
| 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 |
| Corneal melanosis |
- response to chronic irritation/inflammation
- varies by species
- non-specific sign |
| Corneal neoplasm |
- rare in cats and dogs
- common in horses and cattle |
| 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 |
| Uncomplicated corneal ulcer
Clinical signs |
- epithelium only, no stromal loss
- Heals within 7days
- No change in stromal character (stromal melting)
- No extensive vascularization |
| uncomplicated corneal ulcer
Treatment |
- ABSOLUTELY NO TOPICAL STEROIDS
- topical broad spectrum ABs
- topical atropine
- Ecollar
- recheck 2-3days, then 7 days |
| 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 |
| 2 signs of a complicated corneal ulcer that are specific for infection |
- stromal infiltrate
- change in stromal character (stromal melting) |
| 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 |
| Complicated corneal ulcer
Diagnosis of infection |
- cytology
- C&S |
| Complicated corneal ulcer
Treatment |
- referral is first choice
- vigorous AB's/antifungals (q2hr)
- topical serum
- Ecollar
- warm compresses
- cage rest |
| Complicated corneal ulcer
Exposure
Clinical signs |
- most frequent with brachycephalics
- centrally located
- round firm edges
|
| Complicated corneal ulcer
Treatment of exposure ulcer |
- frequent AB ointment
- (+/-) atropine
- possibly tarsorrhaphy (closure of eyelids) |
| 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 |
| 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
|
| 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 |
| 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 |
| Chronic superficial keratitis
clinical signs
acute |
- fibrovascular invasion just under the corneal epithelium in the ventrolateral cornea
- plasmoma = third eyelid thickening
|
| Chronic superficial keratitis
clinical signs
chronic |
- corneal melanosis
- blindness |
| Differential diagnoses for Chronic superficial keratitis
|
- KCS
- Corneal ulceration |
| Chronic superficial keratitis
Treatment |
- Topical steroids (neopolydex, prednisolone)
- topical cyclosporine
|
| 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
|
| Exposure keratitis
Clinical signs |
- corneal vessels and melanosis medially
- may lead to ulcers |
| Exposure keratitis
Causes |
- conformation, breed related
- eyelid agenesis
- age related weakening of the orbicularis oculi m.
- eyelid injury
|
| 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
|
| 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 |
| Corneal degeneration
Clinical signs |
- roughened surface of cornea
- blepharospasm
- recurrent ulceration (from chalky deposits flaking off)
|
| Corneal degeneration
Causes |
- aberrant healing response
- secondary to trauma, irritation, inflammation
|
| Corneal degeneration
Treatment |
- ABs for relief
- keratectomy for permanent resolution
|
| Corneal Dystrophy
General facts |
- primary heritable defect
- resembles corneal degeneration |
| 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)
|
| Corneal Dystrophy
Treatment |
- not indicated
- no pain
- no vision defect |
| Feline herpesvirus
General facts |
- FHV-1 infects corneal epithelial cells and conjunctival cells
- May result in
- corneal sequestrum
- eosinophilic keratitis
|
| Feline herpesvirus
clinical signs |
- blepharospasm
- epiphora
- conjunctival hyperemia
- chemosis
- corneal vessels
- Dendritic ulcers
- focal pinpoint cellular infiltrate |
| What clinical sign is pathognomonic for FHV-1 |
- dendritic ulcers |
| 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. |
| 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 |
| Corneal sequestrum
General facts |
- unique to domestic cats |
| Corneal sequestrum
Clinical signs |
- distinctive dark brown plaque
- necrotic stroma
- NOT MELANIN
- painful
- can lead to rupture
|
| Corneal sequestrum
Causes |
- Herpesvirus plays a role, but is not the only factor
- chronic exposure
- as in brachycephalics |
| 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
|
| Eosinophilic keratitis
General facts |
- most frequently in cats
- also seen in horses
- associated with herpesvirus |
| Eosinophilic keratitis
Clinical signs |
- fibrovascular infiltrate with white "caseous" islands
- nests of eosinophils
|
| Eosinophilic keratitis
diagnosis |
- clinical signs
- fibrovascular infiltrate
- caseous plaques
- cytology
- scrape white plaque and stain for eosinophils |
| Eosinophilic keratitis
Treatment |
- Topical steroids and antivirals
or
- megesterol acetate
|
| Infectious Bovine Keratitis
General facts |
- common
- economically significant
- caused by moraxella bovis predominantly
- Herefords are most affected breed
- younger affected more than older |
| Infectious Bovine Keratitis
Clinical signs |
- variable severity
- initially unilateral
- blepharospasm
- epiphora
- central stromal infiltrate
- vigorous vascular response
- perforation, phthisis bulbi possible |
| Infectious Bovine Keratitis
Treatment |
- Can run its course without Tx
- may rupture cornea and scar in
- Penicillin
- Ampicillin
- Oxytetracycline (Tx of choice) |
| 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 |
| 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 |
| Corneal hemoangioma/sarcoma
Clinical signs |
- blood blisters
- lateral aspect of the limbus |
| Corneal lymphoma
Clinical signs |
- bilateral
- 360 degree corneal vessels and white creamy infiltrate
- eyelids swollen |
| Treatment of corneal neoplasms
Limbal melanoma, hemangioma/hemangiosarcoma, SCC |
- require excision and adjunctive Tx
- cryotherapy
- radiation |
| Treatment of corneal neoplasms
Recurrent hemangiosarcoma |
- enucleation |
| Treatment of corneal neoplasms
Lymphosarcoma |
- treat symptomatically |
| Corneal neoplasia in cats
General facts |
- limbal melanoma/cytoma most common
- still rare
- Dx and Tx same as dog |
| corneal neoplasia in horses |
- limbal scc most common
|
| 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
|
| primary causes of limbal SCC in horses |
- UV light
- breed predisposition
- draft horses
- appaloosas |
| Equine limbal SCC
Treatment |
- keratectomy (cytoreductive)
- adjunctive
- cryotherapy
- radiation
- high success rate
|
| Corneal neoplasia in cows
General facts |
- SCC by far the most common
- important economic loss
|
| 2 locations of bovine SCC |
- limbus (75%)
- bulbar conjunctiva
|
| Bovine corneal SCC
Clinical signs |
- starts as a plaque and progresses
- metastasis late to regional lymph nodes and parotid salivary gland
|
| Bovine corneal SCC
causes |
- increasing age
- females may be predisposed
- breed
- Herefords (have light periocular pigmentation)
- UV exposure
- nutritional status |
| Bovine corneal SCC
Treatment |
- same as horse, but may elect for enucleation for economic reasons |
| 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) |
| Corneal dermoid
clinical signs |
- choristoma
- located laterally
- at the lateral limbus
- can involve the lateral canthus |
| Corneal dermoid
Treatment |
- keratectomy
- reconstruct lateral canthus |
| Components of the lacrimal system |
- lacrimal gland
- gland of the third eyelid
- meibomian glands
- goblet cells
- lacrimal drainage apparatus |
| 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 |
| 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)
- |
| parasympathomimmetic drugs _________ tear production |
increase
|
| parasympatholytic drugs __________tear production |
decrease
|
| 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 |
| 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
|
| 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 |
| 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 |
| Nasolacrimal drainage apparatus |
- lacrimal puncta (superior and inferior)
- canaliculi
- nasolacrimal duct
- nasal puncta |
| Which species only has inferior lacrimal puncta |
rabbits |
| Functions of the lacrimal system |
- provide nutrition to the ocular surface
- remove metabolic wastes and debris
- provide lubrication to ocular surface
|
| General signs of disease of the lacrimal system |
- tear production problems
- quantitative
- qualitative
- tear drainage problems
- epiphora
- discharge |
| Lacrimal system diagnostics |
- schirmer tear test
- fluoroscein dye
- nasolacrimal flush |
| Schirmer tear test |
- measures aqueous tear production |
| Fluoroscein dye passage |
- tests patency of nasolacrimal duct
- potential for false negatives (animal may swallow the flush; especially brachycephalics)
- if + test, duct is patent |
| Nasolacrimal flush |
- can locate and relieve obstructions |
| Keratoconjunctivitis sicca
General facts |
- reduction aqueous portion of tear film
- most common in dogs |
| Keratoconjunctivitis sicca
Clinical signs |
- mucoid discharge
- blepharospasm
- conjunctival hyperemia
- 360 degree corneal vessels (cornea trying to get nutrition elsewhere)
- corneal melanosis |
| 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) |
| Keratoconjunctivitis sicca
Diagnosis |
- clinical signs
- confirm with schirmer tear test |
| Keratoconjunctivitis sicca
Treatment |
knowing underlying cause doesn't affect how you treat, just how long...
- topical cyclosporine
- topical AB/steroid
- client education |
| 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 |
| 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
|
| 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
|
| Foreign body obstruction of lacrimal drainage
General facts
|
- plant awns (foxtails)
- sand
- seasonal variation
|
| Foreign body obstruction of lacrimal drainage
Clincal signs |
- Painful
- Blepharospasm
- mucopurulent discharge
- medial canthal swelling
- negative fluoroscein dye passage
- NL flush diminished or negative
|
| 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
|
| Inflammatory obstruction of lacrimal drainage
General facts |
- inflammatory debris without foreign body
- descending infection
- stagnant tear drainage |
| 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 |
| Inflammatory obstruction of lacrimal drainage
Causes |
- infection of the most proximal lacrimal drainage apparatus |
| Inflammatory obstruction of lacrimal drainage
Treatment |
- NL flush (+/- betadine solution)
- topical AB/steroid |
| Anatomy of the iris |
Anterior border layer
Stroma
Posterior epithelial layer
Corpora nigra |
| Anterior border layer of the iris |
- fibroblasts
- melanocytes
- no continuous epithelial layer
|
| Stroma of the iris |
- blood vessels
- collagen fibers
- fibroblasts
- chromatophores
- melanocytes |
| 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 |
| Posterior epithelial layer of the iris |
- densely pigmented (melanin)
- continuous with inner, non-pigmented, ciliary epithelium |
| Corpora nigra |
- found in most herbivores
- cystic dilation of the posterior iris epithelium |
| 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 |
| Blood-aqueous barrier |
- ciliary body vessels (epithelial portion)
- iridal vessels (endothelial portion)
- prostaglandins |
| Ciliary body vessels |
- located in iridal stroma
- fenestrated, leak plasma
- junctional complexes along the lateral borders of the NPE
|
| Iridal vessels |
- non-fenestrated capillaries |
| 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 |
| Functions of the anterior uvea |
- regulate light entry by changing pupil size
- accomodation
- production of aqueous |
| General signs of disease of the anterior uvea |
- change in appearance of the iris
- change in aqueous
- secondary effects on the cornea and lens |
Spanish 3
