Eyelids and the Third Eyelid Flashcards
Palpebral
refers to eyelid
Palpebral fissure
eyelid opening
Blepharo
refers to eyelids (blepharospasm, blepharoedema, blepharitis)
Canthus
where upper & lower eyelids meet: medial & lateral canthus
Cilia
eyelashes
Meibomian glands
tarsal glands = lipid secreting glands lining eyelid margins
proper conformation of the eyelid
The eyelids should conform to and rest against the cornea with the mucous membrane lining (palpebral conjunctiva) in contact with the cornea.
function of the eyelid
protect cornea, spread tear film, and reduce light stimulation for sleep; Any abnormality in this relationship may cause corneal irritation, pain, loss of corneal transparency and conjunctival inflammation.
What holds the eyelids open
The eyelids are held open by both sympathetic tone and by the levator muscle (Crn III).
What holds the eyelids shut?
They are closed by the obicularis oculi m. which encircles the eyelids and is innervated by Crn VII
Inability to close the eyelid is a dysfunction of what nerve?
CN VII or loss of sympathetic tone
sensory innervation to the eye
Sensory innervation to the eyelids is from Crn V (trigeminal n).
Blepharhospasm
the involuntary spasm or squinting of the eyelids caused by pain from disorders such as cilia contacting the cornea, dry eye, conjunctivitis, corneal ulcer, uveitis or glaucoma.
Blepharoedema
is swelling of the lids and is usually associated with an allergic reaction such as vaccine reaction or bee sting.
Treatment of belpharoedema
It can be treated with topical and/or systemic antihistamines or anti-inflammatory drugs based on the underlying cause.
Dermoid:
Skin and hair that develop in an abnormal place in the body is a dermoid. They commonly affect the cornea, but in some cases only the eyelid and/conjunctiva are
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affected. The hairs cause corneal irritation and may preclude normal eyelid closure.
Treatment of a demoid
They should be surgically removed with careful reconstruction of the affected eyelid margin.
Eyelind agenesis
This congenital defect usually affects the upper lateral eyelids in the cat, and is occasionally seen in the lower eyelids of dogs.
treatment for eyelid agenisis
Corrective, reconstructive surgery is indicated.
Ophthalmia Neonatorum (neonatal ophthalmia)
the result of an infection occurring prior to the natural lid opening at 10-14 days causing swelling behind the eyelids and purulent exudate.
Treatment for opthalmia neonatorum
The eyelids need to be gently opened, irrigated and treated topically with antibiotic ophthalmic ointment. The cornea needs to be kept moist.
Entropion
the rolling inward of the eyelid causing hair to rub on the cornea. It is a hereditary problem in many dog breeds and may have a later age of onset.
Genetic predisposition to entropion?
Brachycephalic cats and dogs generally have medial entropion and trichiasis.
Entropion is often seen in premature foals, lambs and Shar Pei puppies and alpacas.