-
Cilia (ie. _______) originate just outside the ____________.
eyelashes; Meibomian gland openings
-
Which lids have cilia in horses, cows, sheep, pigs, dogs, and cats?
- Horses, cows, sheep: upper and lower
- Dogs, pigs: upper only
- Cats: neither
-
Tissue (collagen) sheet that encompasses the structures of the eyelid margin.
tarsus
-
What is the purpose of the tarsus? (2)
- gives eyelid rigidity
- provides surface for muscle attachment
-
What are the tarsal glands/ Meibomian glands?
row of sebaceous glands that lie along the eyelid margin, with ducts opening at the mucocutaneous junction and secrete lipid layer of the precorneal tear film
-
Eyelids are ________ vascularized with vessels _________ to eyelid margins.
well; parallel
-
What is the motor innervation to the eyelid? (2)
- CN III (oculomotor)--> levatory palpebrae superioris muscle
- CN VII (facial n)--> orbicularis oculi muscle, malaris muscle
-
What is the sensory innervation to the eyelid? (1)
CN V (trigeminal n)
-
Muller's muscle is innervated by the __________.
sympathetic nerve
-
What is the function and innervation of the orbicularis oculi muscle?
- sphincter muscle around the eye--> closes eyelid
- CN VII (facial n)
-
What is the function and innervation of the levator palpebrae superioris muscle?
- elevates upper eyelid
- CN III (oculomotor n)
-
What is the function and innervation of Muller's muscle?
- smooth m. that provides tone to the tarsus
- sympathetic n.
-
What is the function and innervation of the malaris muscle?
- lowers the inferior eyelid
- CN VII (facial n)
-
Define ptosis.
drooping of eyelids (often secondary to facial n. paralysis)
-
Describe the medial canthal ligament.
firm ligamentous band that anchors the medial canthus to the periosteum of the medial orbital rim
-
The __________ lies just deep and ventral to the medial canthal ligament; the __________ runs just medial to it.
lacrimal sac; anguli oculi vein
-
Describe the lateral canthal ligament.
- (aka retractor anguli muscle)
- anchors the lateral canthus
-
What is lateral canthal entropion?
when the lateral canthal ligament is weak, the lateral canthus moves medially when blinking, and the eyelid rolls inward
-
A portion of the periorbital fascia that extends from the orbital rim forward to attach to the tarsus, providing support to the eyelid and serves as a barrier b/w the orbit and the subQ space.
orbital septum
-
Mobile elastic mucous membrane that lines the inner eyelid and globe as one continuous sheet.
conjunctiva
-
What are the components of the conjunctiva and where is each located?
- Palpebral: lines eyelids
- Bulbar: lines exposed surfaces of globe
- Fornix: cul-de-sac; formed by reflections at transition from lid to globe and nictitans
- Nictitans: covers palpebral and bulbar surfaces
-
What are nasolacrimal puncta?
opening in the medial aspect of the upper and lower eyelids, which open into the lacrimal drainage system
-
What are vibrissae?
- "whiskers"
- large tactile hairs around the eyes and muzzle that are very responsive to change in position
-
What is the innervation to the vibrissae?
CN V (trigeminal n)
-
What are protective measures of the eyelids?
- blink reflex in response to stimuli (tactile, chemical, thermal, and sound stimuli)
- reflex blinking help to remove foreign bodies
- also squinting to protect yes from harsh light
-
What produces the different tear film components?
- Meibomian glands produce meibum/ lipid layer
- Conjunctival goblet cells produce mucus layer
-
What is macropalpebral fissure/ macroblepharon?
excessive eyelid length and wide palpebral fissure relative to the globe size, leading to excessive eyeball exposure and may cause secondary keratitis
-
What is lagophthalmus?
incomplete blink, causing secondary exposure keratitis and ulceration; common with macroblepharon
-
Macroblepharon is common in...
brachycephalic dogs, hounds (droopy face)
-
How is macroblepharon diagnosed? (3)
Clinical diagnosis: prominent globe, overly exposed bulbar conjunctiva, pigmentary keratitis
-
How is macroblepharon treated? (3)
medial canthoplasty, lateral canthoplasty, cyclosporine A (decreased corneal pigment and vessels)
-
What are clinical signs of entropion? (4)
- blepharospasm
- keratitis/ corneal ulceration
- epiphora
- moist dermatitis
-
Define trichiasis.
ingrowth or introversion of eyelashes
-
What are causes of developmental/ anatomic entropion? (3)
macropalpebral fissue, abnormal development of lateral canthal ligament, relative enophthalmia
-
How is developmental/ anatomic entropian diagnosed? (3)
- see inturned eyelid
- wet palpebral hair
- keratitis
-
What kind of entropion do brachycephalic cats get?
medial inherited/ conformational entropion
-
Medial canthal entropion is most common in __________ and it causes __________; may cause ___________.
brachycephalics (dogs and cats); pigmentary keratitis in pugs; corneal sequestrum in cats
-
What is the treatment of medial canthal entropion? (2)
- cyclosporine
- medial canthoplasty
-
How is congenital (present at birth) entropion treatment? (3)
- artificial lubricants
- temporary tacking procedure
- treat underlying illness
-
What is the pathogenesis of spastic entropion?
chronic blepharospasm (involuntary tight closure of the eyelid)
-
Describe spastic entropion.
chronic blepharospasm--> acquired entropion--> can become permanent if the underlying cause is not corrected
-
How is spastic entropion diagnosed?
topical anesthesia will alleviate the discomfort and allow the eyelid to roll back to its normal position
-
How is spastic entropion treated?
correct underlying problem
-
What is the pathogenesis of cicatrical entropion?
spastic entropion with resulting fibrosis of the orbicularis oculi muscle; due to trauma or burns and overcorrection ectropion
-
His is cicatrical entropion diagnosed and treated?
- dx based on hx
- treatment is same as for developmental entropion (cathoplasty, cyclosporine)
-
What is lateral canthal laxity/ rolling?
causes notching of eyelid near the lateral canthus; common in dog with entropion
-
What are indications for permanent lateral canthoplasty? (2)
macroblepharon, lateral canthal rolling/laxity
-
Describe permanent lateral canthoplasty procedure.
- full-thickness excision of crescent including upper and lower eyelid margin (1-2mm removed) and two layer closure
- always follow with Hotz-celcus procedure
-
What is the modified Hotz-celcus procedure?
- done AFTER lateral canthoplasty
- crescent skin incision of lower lid at lateral edge (do not exceed 1-2mm from eyelid margin with parallel incision!!)
-
What are potential complications with entropion repair?
- overcorrection resulting in ectropion (its better to err on the side of undercorrection than to overcorrect)
- recurrence of entropion (large breeds with heavy brow, cats)- often recur if lateral canthoplasty not done
-
Describe ectropion.
outward turning of the eyelid margins and loss of contact of eyelid to cornea--> inadequate distribution of tear film
-
What is the pathogenesis of developmental ectropion?
weak lateral canthal ligament, macropalpebral fissures
-
What are clinical signs of developmental ectropion? (3)
- chronic conjunctivitis
- ocular d/c
- occasionally secondary keratitis
-
What is Pagoda lid?
central ectropion and canthal entropion
-
What is ectropion associated with?
multiple eyelid defects in Great Danes, St. Bernards, and bloodhounds
-
What is the treatment for ectropion that has clinical signs associated with it?
full thickness wedge resection of the lower eyelid and/or a permanent lateral canthoplasty
-
What is the treatment for Pagoda lid?
- (central ectropion + canthal entropion)
- permanent lateral canthoplasty +/- wedge resection of notches of the eyelids + modified Hotz Celsus
-
What are the possible pathogeneses of acquired ectropion? (3)
- Senile: orbicularis oculi muscle sags with age
- Cicatricial: trauma or overcorrection of entropion
-
What 2 factor predispose to entropion?
macroblepharon, lateral canthal laxity
-
What is the most important sequela of entropion or ectropion?
corneal ulceration
-
Cilium originating and exiting from the meibomian gland opening(s) and rubbing on the cornea.
Distichiasis
-
What are clinical signs of distichiasis?
- usually asymptomatic
- may cause blepharospasm, tearing, keratitis, ulceration
-
What are the treatment options for symptomatic distichiasis? (4)
- Medical: topical lubricants, epilating (plucking)
- Surgical: crysurgery (sx of choice), other options include electroepilation
- AVOID lid splitting techniques
-
Cilia or hair from a normal location contacting the cornea due to abnormal direction of hair growth.
trichiasis
-
What are the etiologies of trichiasis? (2)
-
What are clinical signs of trichiasis? (4)
- frequently asymptomatic
- blepharospam
- keratitis
- ulceration
-
What are the common types of trichiasis? (3)
ciliated caruncle/ medial canthus, misdirected hairs (as in the case of dogs with many nasal folds)
-
What is the treatment for trichiasis due to ciliated caruncle/ medial canthus?
medial canthoplasty
-
What is the treatment of trichiasis due to misdirected hairs?
cryosurgery
-
If prominent nasal folds are causing keratitis/ tear wicking, what are the consequences of not treating?
pigmentary keratitis and scarring--> decreased vision
-
Cilium originating from the meibomian gland but exiting through the palpebral conjunctiva.
ectopic cilia
-
What re clinical signs of ectopic cilia? (4)
- keratitis
- ulceration
- blepharospasm
- PAIN
-
What is the treatment for ectopic cilia?
- topical lubricants
- en bloc excision of the conjunctiva and tarsal gland +/- cryotherapy
-
In what animals does eyelid agenesis commonly occur? What is it?
- cats
- portion of upper lateral eyelid unformed, usually bilateral
-
Eyelid agenesis in cats is frequently associated with...
lens and optic nerve coloboma (congenital malformation)
-
What are the sequela of eyelid agenesis in cats? (2)
exposure keratitis and trichiasis
-
What is the treatment for eyelid agensis in cats? (2)
- crysurgery
- eyelid reconstruction
-
What is ankyloblepharon?
physiological adhesion of the eyelids, delayed eyelid opening after birth (normally occurs b/w 10-14 days of life)
-
Delayed eyelid opening results in _____________, which is...
ophthalmia neonatorum; infection under the eyelids
-
Ophthalmia nenatorum is caused by _________ in puppies and _________ in kittens;which is ultimately caused by ___________ in both species.
- Staph spp.- dogs
- Feline Herpesvirus-1- cats
- uterine or vaginal infection from bitch/queen
-
What is the treatment for ophthalmia neonatorum? (3)
- warm compresses
- gentle manual opening of eyelids
- topical antibiotics
- DO NOT INCISE
-
What is the usual outcome of ophthalmia neonatorum?
- usually no blindness
- symblepharon (abnormal adhesions of the conjunctiva) in cats sometimes
-
90% of eyelid neoplasms in dogs are ________.
benign meibomian gland adenomas
-
Usually, eyelid neoplasms in cats, horses, and cows are...
malignants squamous cel carcinoma
-
What are the 3 most common eyelid neoplasms in dogs?
meibomian gland adenoma, papilloma (viral), melanoma
-
You see a red, hairless swelling along the eyelid margin in a young dog; what is your top differential?
histiocytoma, which is self-limiting and should be gone in 3-6 weeks
-
When assessing an eyelid mass, you should always...
evert the eyelid to assess the extent of the mass.
-
Describe eyelid mass resection.
- full-thickness wedge excision through skin and tarsal plate; complete excision with Stevens tenotomy scissors; two-layer closure
- can remove up to 33% of eyelid in dogs and still get primary closure (25% in cats and horses)
-
What are associations of SCC in cats? (3)
- white cats
- UV exposure
- high elevation
-
What are clinical signs of SCC?
slightly raised or ulcerated lesion at or adjacent to eyelid margin
-
Describe the treatment of SCC in cats. (5)
- wide surgical excision + blepharoplasty
- cryosurgery
- hyperthermia
- radiation
- chemotherapy
-
Describe the type of radiation used as adjunctive therapy for SCC.
- linear accelerator- high energy
- brachytherapy intralesionally
-
Describe the chemotherapeutic agents used as adjunctive therapy for SCC.
Cisplatin (NOT IN CATS) or carboplatin
-
What is the prognosis for SCC?
- well-differentiated tumors treated early have good prognosis
- extensive or poorly differentiated tumors have guarded prognosis
- [you only know this by staging and histopathology]
-
Basal cell carcinomas are ___________.
Mast cell tumors around the eyelids are usually _________.
Fibrosarcomas around the eyelids are __________.
- benign
- benign
- common and malignant
-
What are associations with SCC in horses? (3)
- white eyelids (appaloosa, belgian)
- UV exposure
- on eyelid, lateral corneal limbus, third eyelid
-
What are rule outs when diagnosing equine SCC on the eyelid? (2)
- [pink proliferative and ulcerative mass]
- r/o Habronemiasis, orbital fat prolapse
-
What are common eyelid masses in horses? (3)
- SCC
- Sarcoid (fibrosarcoma)
- Melanoma
-
What is treatment for SCC in horses? (6)
- surgical excision/ debulking
- cryotherapy
- hyperthermia (superficial lesions)
- radiation therapy (best but expensive)
- chemotherapy (intralesional cisplatin or 5-FU)
- photodynamic therapy (photosensitive drug injected systemically and preferentially absorbed by tumor)
- [high rate of recurrence without adjunctive therapy]
-
What are the different forms of sarcoid in horses? (3)
- nodular/ fibroblastic
- verrucous (flat, scaly)
- mixed
-
Describe the treatment options for periocular sarcoids in horses. (3)
- difficult to manage surgically
- Medical txt- intratumoral BCG, cisplatin, or 5-FU (chemo); radiation; cryosurgery
- electron treatment (surgical debulking immediately followed by electron radiation--> can spare eye...but need multiple treatments)
-
What are characteristics of melanoma in horses? (5)
- older gray horses
- benign
- tumors around abdomen, tail base, etc
- locally extensive
- may cause keratitis
-
Describe the pathogenesis of bovine SCC.
- lack of periocular pigment
- UV radiation/ exposure
- mechanical irritants
- papilloma virus infection
- [also has to do with breed predisposition (Herefords)]
-
Describe strategic prevent of SCC in bovine herds.
periodic examination of herd detects most lesions in the precancerous stage for early treatment
-
What is chalazion?
meibomian granuloma, usually a result of obstruction and infection of the gland
-
What are clinical signs of chalazion?
subdermal nodule near lid margin or light colored nodule inside margin
-
What is the treatment of chalazion? (3)
- warm compresses 2xday for 5 minutes each
- topical antibiotics
- drain if needed
-
What are clinical signs of allergic blepharitis? (3)
- eyelid swelling, hyperemia
- rubbing eyes
-
What is the treatment for allergic blepharitis? (3)
- address primary cause
- topical and systemic corticosteroids
- antihistamines
-
What are clinical signs of pyogranulomatous blepharitis? How is it diagnosed?
- eyelid nodular swelling, hyperemia +/- ulceration
- diagnosed based on cytology
-
What is the etiology of pyogranulomatous blepharitis?
immune-medaited
-
How do you treat pyogranulomatous blepharitis? (3)
- systemic antibiotics
- systemic corticosteroids
- warm compresses
-
Infection of the meibomian glands or eyelid interstitium is usually caused by __(2)__; clinical signs include...(3)
Treatment is....(2)
- Staph or Strep
- brownish exudate, diffuse swelling of eyelid margins or abscesses
- Txt: systemic antibiotics and corticosteroids
-
Describe the clinical signs, diagnosis, and treatment of habronemiasis in horses.
- Signs: medial canthal ulceration, granular proliferation, d/c, pruritus
- Dx: cytology, biopsy (r/o SCC)
- Txt: cutterage of necrotic sites, topical atb, intralesional steroids, organophosphates, systemic NSAIDs, fly control
-
What immune-mediated disorders can affect the eyelids? What is the treatment?
- pemphigus complex at the mucocutaneous junctions
- immunosuppressive therapy
-
What is lagophthalmos?
- age-related degenerative inadequate eyelid closure; can also be due to facial nerve paralysis
- Clinical signs include absent blink response, ptosis, keratitis
- Treatment is artificial tears and address primary cause
-
- C- orbicularis oculi m.
- D- malaris m.
- E-levator palpebrae superioris m.
-
Meibomian glands are ___________.
sebaceous glands
-
What are the most common causes of blepharitis in dogs (4) and cats (3)?
- Dogs: Demodex, Sarcoptes, immune-mediated (pyogranulomatous), Staph
- Cats: FHV-1, allergic, Sarcoptes
-
How are eyelid lacerations managed clinically?
- debride very conservatively
- repair using a 2-layer closure
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