Orbit Exam 2

Which species have an incomplete bony orbit?

-dog

-cat

What species have a complete bony orbit?

-horses

-ruminants

Where is soft tissue access to the retrobulbar space?

behind last molar

T or F: incomplete bony orbits have no bony floor

True

What are the soft issue borders of the orbit?

-temporalis

-masseter

-pterygoid

-zygomatic salivary gland

How to evaluate the orbit?

-assess symmetry

-palpation

-retropulsion

-ocular motility

-aspirate for culture/cytology

-US

-radiographs

-CT/MRI

-exploratory

What is proptosis?

eye prolapse

What is proptosis typically caused by?

trauma

Describe the signalment and prognosis of proptosis?

-common in brachycephalics

-dolicephalic and cats have poor prognosis

What is the treatment for proptosis?

-stabilize patient

-replace globe as soon as possible

-enucleation if rupture of optic nerve or globe

-topical antibiotics

-systemic antibiotics or steroids

What is a tarsorrhaphy?

suturing together of the eyelids

T or F: pupil size and response can be used to tell if enucleation is necessary

False

What are the prognostic factors of proptosis?

-breed

-chronicity/time

-# of muscles affected

T or F: the globe is connected to the optic nerve

True

T or F: proptosis can pull on chiasm and contralateral optic nerve

True, especially in cats

What is phthisis bulbi?

shrinkage of eye secondary to decreased aqueous production or chronically low IOP

What are the traits of phthisis bulbi?

-chronic inflammatory process

-fibrinous disorganization of intraocular contents

-non-functional eye

What is buphthalmos?

enlargement of the globe

What is microphthalmos?

congenitally small globe

With orbital disease, what is important to differeniate?

-exophthalmos

-buphthalmia

Which orbital disease has increased IOP and corneal diameters, exophthalmia or buphthalmia?

buphthalmia

What is exophthalmos?

forward displacement of globe form orbit

If a mass is outside of the muscle cone, what is displaced?

-globe

-orbital contents including third eyelid and conjunctiva

If a mass is in the muscle cone, what is displaced?

globe only

What are common causes of orbital abscess or cellulitis?

-stick chewing

-tooth rot abscess

How to diagnose orbital abscess and cellulitis?

-mouth exam

-painful retropulsion

-painful opening mouth

-ocular ultrasounds

-aspirate of retrobulbar space

-typically unilateral

What is the treatment for orbital abscess or cellulitis?

-oral antibiotics and anti-inflammatories

-drain behind last molar if not resolution from medication

-advanced imaging if recurrent

What are the traits of orbital tumors?

-slow onset

-usually non-painful

-usually older dogs

-typically unilateral

How to diagnose orbital tumors?

-imaging

-aspirate

-biopsy

What is the typical treatment for orbital tumors?

exenteration

Is prognosis for tumors typically worse in cats or dogs?

cats

What are the traits of extraocular myositis?

-only extraocular muscle affected

-young animals

-bilateral exophthalmos

-frontal gaze

-scleral showing

-common in golden retirevers

-painful

-acute

What are the traits of masticatory myositis?

-recurrent acute attacks

-pain when opening mouth

-can be chronic with atrophy and enophthalmos

What is the treatment for myositis?

systemic glucocorticoids

What is enophthalmos?

sinking of globe secondary to loss of orbital tissue, ocular pain, small globe, or horner's

What does enophthalmos put a patient at risk for?

entropion

What is the treatment for blind painful eyes?

enucleation

What is an evisceration?

remove contents of globe, leaving coneal scleral shell

What are the contraindication of evisceration?

-uveitis

-tumor

-hyphema

What is exenteration?

removal of the eye and all orbital contents

What is the indication for exenteration?

orbital neoplasia