eyelids Flashcards
Size of palpebral or lid fissure
Dogs: 10-35mm Horses: 36-51
Tarsal plate
Dense connective tissue which gives rigidity to eyelids and serves as an insertion for levator and Muller’s muscles. Poorly developed in animals
Third eyelid
T-shaped cartilage covered with conjunctiva Produces 30-50% of tear film
Cilia
Upper lid only on dog Cats have no true eyelashes Horses have very few on lower lid
contain the openings of the meibomian or tarsal glands
Lid margin
Located in upper and lower lids, 2-4 mm from medial canthal angle in dog and 5-8 mm in horse
Lacrimal puncta
Orbicularis oculi
surrounds the palpebral fissure Attaches too orbital wall by medial and lateral palpebral ligaments
Orbicularis oculi innervation and function
VII closes the eyelids
Levator palpebra superioris
Dorsal to opitc canal between dorsal rectus and dorsal oblique muscles
Inserts into the tarsal plate of the upper lid
Levator palpebra superioris innervation and action
CN III
Elevate upper lid
Muller’s muscle
originates among fibers of levator muscle
inserts on tarsal plate with levator
Innervation and action of Muller’s muscle
Assist in elevation of eyelid
Innervated by sympathetic nerve fibers
Superciliaris muscle
originates from median line of frontal bone
Extends into the medial half of the upper eyelid
Innervation and action of superciliaris or corrugator supercilii
Elevate nasal portion of upper lid
Innervated by auriculopalpebral branch of VII
Retractor anguli oculi
comes form temporal fascia
extends to lateral palpebral angle
Retractor anguli oculi innervation and action
maintains normal size of the palpebral aperture
Innervation by auriculopalpebral branch of VII
*What is the sensory nerve supply to the upper eyelid*
Ophthalmic branch of V
*what is the sensory nerve supply to the lower eyelid*
Maxillary branch of V
*Muscles responsible for opening the eye*
Levator palpebrae superioris and Muller’s muscle
*muscle responsible for closing the eye*
Orbicularis oculi
*innervation of levator
CN III
* innervation of Muller’s
Sympathetic
*innervation of orbicularis oculi
CN VII
*Most common eyelid tumor in dog*
Meibomian gland adenoma
*Most common eyelid tumor in horse and cow*
Squamous cell carcinoma
Meibomian gland
Long sebaceous glands whos openings from a row posterior to the cilia
Close to or within tarsal plate
Purpose of meibomian gland
Secretion is oily and forms the outer layer of the precorneal tear film
Funciton of eyelids
Production, distribution, and removal of tears
What produces outer oily layer of tears
Meibomian glands
Atresia or agenesis of the eyelid
Most commonly seen in cats
Effects dorsolater upper lid
Ankyloblepharon
adhesion of the eyelid edges to each other
Physiologic in dogs and cats up to 10-15 days
Ophthalmia neonatorum
Eyelid must be opened and treated with antibiotics
infection associated with ankyloblepharon
Blepharophimosis
narrow palpebral fissure
usually incidental
Macroblepharon
Enlarged palpebral fissure
Brachycephalic breeds
Medial canthoplasty most effective fix
Distichiasis
Most common eyelash disease
Extra cilia arise from meibomian glands
Only those causing a problem need to be corrected
Corrections for distichiasis
Manual epilation: tempeorary effect, determine if hairs are causing clincial disease,
Electrolysis
Cryotherapy: Theryapy of choice for multiple distichia
Laser
Trichiasis
Normal placement of cilium, but grow in the wrong direction
Same treatements as distichiasis
Distichiasis
Ectopic cilium
Trichiasis
Ectopic cilia treatment
Surgical correction by partial thickness excision and/or cryoablation
Entropion treatment
Puppies less than 4-5 months: temporary eyelid tacking
Entropian
Rolling of the eyelids
Entropion treatment in older animals
Excision of skin parallel to the lid margin and full thickness eyelid rection
Temporary eyelid tacking may be utilized in adult animals that have significant corneal disease
When should the amount of correction for entropion surgery be estimated
Prior to anesthesia
Ectropion
Rolling out of the eyelid
may accompany entropion
Correction for ectropion
only if it’s causing corneal disease or excessive ocular discharge
Use V to Y correction
How to fix a lid laceration
Clean debris, prep with betadine
Minimal debridement
If not fresh/swollen: Furacin pack for 12-24 hrs
Suture wound in 2 layers
How to suture a lid laceration
2 layers
1: Edge of the eyelid to ensure accurate apposition in figure 8 pattern
2: Simple interrupted
Coloboma
Congenital notch like defect of eyelid
No therapy if mild
Excessive nasal folds
Brachycephalic breeds
surgical correction if they are causing secondary keratitis
Medial canthus entropion
Brachycephalic breeds
Correct with medial canthoplasty
Blepharitis
Inflimmation of the eyelids
Etiologies of blepharitis
*Bacterial: Staph. aureus*
Parasitic
Metabolic
actinic
fungal
…
Diagnosis and treamtent of blepharitis
Bacterial: systemic antibiotics and coticosteroids
Hordeolum
Inflmation of Zeis, Moll, or meibomian glands
Treat with drainage, topical antibiotics, and hotpacks
Uveodermatologic syndrome
Usually seen as depigmentation and/or ulceration of mucous membrane junctions and eyelid margins
When is full thickness eyelid rection indicated
When lesion involves less than 1/4 to 1/3 of the eyelid margin
What is an effective treatment for most canine eyelid masses
Cryotherapy
Dermoids
Congenital mass lesion
not neopllastic
Young animal/cattle
*Meibomian gland adenoma*
Most common eyelid tumor of dogs
nearly always benign
Papillomas
Superficial and associated with the skin
remove if increasing in size
Melanomas
superficial and benign
usually slow growing and multiple
Histocytomas
Raised, hairless, pink nodules
Rapid growing
Frequently regress
Primarily a tumor of young animals
Squamous cell carcinomas
Most frequent in Catlle, then horses, cats
Rapid, highly invasive, ulcerate early
Sarcoid
Locally invasive fibroblastic tumor of equine skin
