Eyelids– Metzler Flashcards
What is the function of the tarsal plate?
- gives eyelid margin some degree of rigidity
- surface for muscular attachment
a) What type of glands are Meibomian glands?
b) Location
c) Function
a) sebaceous
b) Along eyelid margin at mucocutaneous junction in a row of evenly defined orifices (“gray line”)
c) secrete lipid layer of precorneal tear film
What muscle functions to close the eyelids? What is its innervation?
Obicularis oculi; innervated by palpebral branch of CN 7 (facial n.)
What muscle elevates the upper eyelid? What is its innervation?
Levator palpebrae superioris (slight contributions from levator anguli oculi medialis and frontalis); CN 3 (oculomotor n.)
What structures anchor the eyelids to the orbital rim?
- Medial canthal (palpebral) ligament- anchor medial canthus to medial orbital rim
- Lateral canthal (palpebral) ligament
- Orbital septum- anchor orbital rim forward to attach to the tarsus
What muscle provides “tone” to the upper eyelid? What is its innervation?
Muller’s muscle; innervated by the sympathetic nerve
What muscle lowers the lower eyelid? What is its innervation?
Malaris muscle; innervated by CN 7 (facial n.)
What are the differences between distichia, trichiasis, and ectopic cilia?
a) Distichia– cilium originating and exiting from tarsal/meibomian gland; often asymptomatic
b) Trichiasis– normal hairs around the eyes that irritate the globe because of abnormal direction of the hairs (hair in the medial canthus or nasal fold); often asymptomatic
c) Ectopic cilia– cilium originating from meibomian gland and exiting through palpebral conjunctiva; very painful
Entropion
a) clinical signs
b) breed predispositions
c) treatment
d) how is entropion repaired?
a) blepharospasm, periocular wetting/epiphora, corneal vascularization, corneal fibrosis, corneal (red) pigmentation, corneal ulceration, moist dermatitis
b)
- dog: shar pei, labrador retriever, bulldog, golden retriever, rottweiler
- cat: brachycephalic
c) + d)
- puppies < 3-4 months of age: temporary tacking
- dogs > 3-4 months: Permanent Lateral (or Medial) Canthoplasty + Modified Hotz-Celsus
- cats with unilateral entropion: prophylactic Lateral Canthoplasty
- topical lubricants (artificial tears ointment, viscous tear supplements such as Genteal gel)
- topical cyclosporine to decrease progression of pigmentation in pugs
- brow lift/”brow sling” if due to excessive forehead skin
Ectropion
a) clinical signs
b) breed predispositions
c) treatment
a) conjunctivitis (hyperemia, chemoses, mucoid discharge), macropalpebral fissure, weak lateral cantonal ligament, cicatricial (fibrosis/scarring), senile (sagging of obicularis oculi m.)
b) spaniels, hounds, great danes, st. bernards, bloodhounds
c)
- non-necessary in no secondary clinical signs of corneal disease or significant conjunctivitis
- tear supplements
- Full Thickness Wedge Resection of the lower eyelid and/or Permanent Lateral Canthoplasty
Most common eyelid tumors in:
a) dog
- Most common tumors in dogs that are benign or malignant
b) cat
c) horse
d) cow
a) dogs:
- usually benign
benign: meibomian gland (sebaceous) adenomas most common, squamous papilloma, melanoma, viral papilloma, histiocytoma
malignant: mast cell tumors, basal cell carcinoma, cutaneous squamous cell carcinoma
b) cats:
- usually malignant
- squamous cell carcinomas most common, basal cell carcinomas, mast cell tumors, fibrosarcomas, hidrocystomas, papillomas, adenomas
c) horses:
- usually malignant
- squamous cell carcinomas most common, sarcoid/fibrosarcoma, melanoma (usually benign)
d) squamous cell carcinomas most common, lymphoma
How are eyelid tumors excised?
En bloc (full thickness) excision, wedge-shaped, using a V-plasty technique, two layer closure
- can remove up to 33% of eyelid margin for 1º closure in dogs
- can remove up to 25% of eyelid margin for 1º closure in cats
In the horse, what are the best treatment options for squamous cell carcinoma of the eyelid or medial canthus?
- cryotherapy
- radiation (external beam)
- chemotherapy (cisplatin (intralesional), 5-fluorouracil (topical or intralesional)
- photodynamic therapy
What is a chalazion and how is it treated?
- meibomian granuloma(subnormal near lid margin or light-colored inside margin), usually resulting from obstruction or infection of the gland leading to distention from inspissated meibum and inflammatory cells
- treated with warm compresses BID for 5 minutes, topical +/- systemic antibiotics, +/- drainage or curettage
Blepharitis
a) what is it?
b) common causes in dogs and cats
a) inflammation of the eyelids
b)
- Ophthalmia neonatorum from Staph. infection in puppies, chalazion, allergic reaction (allergic blepharitis), staphylococcus sp. or streptococcus sp., immune-mediated (pyogranumatous blepharitis), parasites such as mites (demodex and sarcoptes most common)
