Orbit and eyelids

Question 1

Boney Orbit

Answer 1

a part of the adnexa, the conical boney structure that contains the eyeball and periorbital cone

Question 2

Periorbital cone

Answer 2

Supportive cone like structure that contains the eyeball, extraocular muscles, fat, vessels, nerves, and fascia that reside within the orbit

Question 3

Orbital ligament

Answer 3

ligamentous structure that forms the lateral boundary of the boney orbit in cats and dogs

Question 4

Exophthalmos

Answer 4

abnormal protrusion of the eye from the orbit. The position is abnormal. The globe size is normal

Question 5

Buphthalmos

Answer 5

Literally means “cows eye” but refers to the abnormal enlargement of the eyeball. For practical purposes, buphthalmosis only caused by glaucoma. The size is abnormal, the position is normal.

Question 6

Enophthalmos

Answer 6

abnormal recession of the eye within the orbit

Question 7

Strabismus

Answer 7

deviation of one or both eyes, so that both eyes are not directed at the same object

Question 8

Horner’s syndrome

Answer 8

sympathetic denervation to the eye and ocular adnexa. There are 4 classic clinical signs

Enophthalmos

Ptosis –drooping of the eyelid

Miosis

Protrusion of the third eyelid

Question 9

Microphthalmos

Answer 9

congenitally small and malformed globe

Question 10

Phthisis bulbi

Answer 10

an acquired shrunken globe, most often from severe or chronic inflammation

Question 11

Proptosis

Answer 11

Anterior displacement of the globe such that the eyelids are caught behind the equator of the globe.

Question 12

Tarsus

Answer 12

The fibrocartilagenouslayer of the eyelid that contains the meibomonianglands (aka tarsal glands). This is the holding layer surgical eyelid closures.

Question 13

Meibomian glands

Answer 13

These are glands within the tarsal layer of the eyelid that produce lipid, or, sebum, to the tear film. This is the outermost, or most external layer of the three-layered tear film

Question 14

Lateral canthus

Answer 14

the lateral, or, temporal convergence of the upper and lower eyelids

Question 15

Medial canthus

Answer 15

the medial, or, nasal convergence of the upper and lower eyelids

Question 16

Palpebral fissure

Answer 16

the area outlined by the upper and lower eyelid margins.

Question 17

Lagophthalmos

Answer 17

incomplete eyelid closure/coverage of the eyeball

Question 18

Eyelid margin

Answer 18

identified by the ‘grey line’ of Meibomian gland orifices. This is an important landmark to identify when closing the eyelid surgically

Question 19

Entropion

Answer 19

rolling in of the eyelid margin such that hairs are touching the ocular surface

Question 20

Ectropion

Answer 20

The outward rolling of the eyelids. Animals will often develop exposure keratitis or conjunctivitis due to the poor ability of the eyelids to completely close over the ocular surface

Question 21

Blepharospasm

Answer 21

Spasm of the orbicularis oculi muscle resulting in eyelid closure. AKA squinting

Question 22

Tarsorrhaphy

Answer 22

A surgical procedure in which the eyelids are sutured together. This can be temporary or permanent, and can be partial (closing only a portion of the eyelid) or complete (closing the entire eyelid).

Question 23

Lagophthalmos

Answer 23

incomplete eyelid closure and globe coverage

Question 24

Trichiasis

Answer 24

Hairs growing from normal skin reach the corneal and/or conjunctival surface. Technically speaking, entropion causes trichiasis, however, trichiasisis most often used to describe hairs from the nasal folds (nasal fold trichiasis) that are directed toward the eye in brachycephalic dog breeds.

Question 25

Distichia

Answer 25

cilia (eyelashes) which emerge from the Meibomian (tarsal) glands.

Question 26

Ectopic cilia

Answer 26

cilia (eyelashes) protruding through the palpebral conjunctiva. These hairs typically cause severe, intermittent pain and often cause corneal ulceration. They most commonly arise from the 12 o’clock eyelid position