Eyelids, eye abnormalities and conjunctiva Flashcards
What are the functions of the eyelids?
Protect eyeball
Spread tear film into lacrimal punctuae to remove foreign material and exclude late
What is the space between the eyelids called?
Palpebral fissure
What are the corners of the eye called?
Medial and lateral canthus
How are the canthus of the eye attached to the bone? Which species is the exception?
Canthal ligaments
Dog - poorly developed, replaced by retractor anguli oculi
Lid margins are hairless, however which lid has cilia and which way are they directed?
Upper
Directed away from the eyeball
What supports the eyelids? What does this contain?
Tarsal plate
Contains tarsal glands
Which species has a poorly developed tarsal plate?
Dog (compared to cat)
What is the term that describes the abnormal growth of hairs from the tarsal glands?
Distichiae
Do cats have dogs have more sclera visible? What about horses?
Dogs have more visible than cats
Horses have lots visible but often pigmented
Horses have a loose lid at the medial canthus. What do they have at the medial canthus?
Lacrimal caruncle
What is a sty an infection of?
Sebaceous and sweat glands at the base of eyelashes
What provides sensory innervation to the eyelids?
Trigeminal
Upper lid = ophthalmic
Lower lid = maxillary
Brachiocephalic breeds have protuberant eyes. What does this mean and what does it cause?
Eyeballs too large for orbit
Can’t close eyes when sleeping –> dry eye (keratoconjunctivitis) and keratitis
Why may fluroscein dye not appear in the nares of brachycephalic breeds?
Lacrimal duct drains into caudal nasal cavity then nasopharynx
What is entropion and what does it cause? (ectropion not as problematic)
Inwards turning of the eyelids
Hairs rub on eye and cause ulceration
