Ophthalmology Flashcards
Which bones make up the orbital floor?
PaM-Z: Palatine, Maxillary, Zygomatic
Which bones make up the medial wall of the orbit?
SMEL: Sphenoid (lesser wing), Maxillary, Ethmoid, Lacrimal
Which bones make up the orbital roof?
Frontal, Sphenoid (lesser wing)
Which bones make up the lateral wall of the orbit?
Sphenoid (greater wing) and zygomatic
Which area of the orbit is the weakest part?
orbital floor
Which area of the orbit is the thinnest?
Medial wall
Which muscles in the orbit are innervated by CN 3?
Superior branch: superior rectus muscle, levator muscle
Inferior branch: inferior rectus muscle, inferior oblique, medial rectus muscle
Which muscle is innervated by CN 4?
superior oblique
Which muscle is innervated by CN 6?
lateral rectus
Where is the infraorbital nerve?
Branch of Maxillary branch of trigeminal. Exits the skull through infraorbital foramen. Trauma –> cheek and upper lip hypesthesia
What are the two types of cellulitis involving the orbit?
Orbital cellulitis and preseptal cellulitis
Describe orbital cellulitis
Sub-periosteal abscess –> proptosis (eye pushed out)
Presents with pain, erythematous lid swelling, TTP, EOM restriction, proptosis
How is orbital cellulitis managed?
Broad spectrum antibiotics. Drain and incise abscess if present
What is a concerning sequelae of orbital cellulitis?
Cavernous sinus thrombosis. Can lead to stenosis of internal carotid artery
Describe preseptal cellulitis
Infection superficial to the septum. Able to open eye; no proptosis; no vision loss
How is preseptal cellulitis treated?
Drain pus
what is a chalazion?
Plugged Meibomian oil glands in the tarsus –> inflammation. Treatment = warm compress
What is the concern regarding an eyelid laceration that disturbs the septum?
Potential for disturbed levator aponeurosis –> ptosis
What is the algorithm for eyelid avulsion repair?
Reconnect levator aponeurosis to tarsus, reappose tarsus, reappose eyelid margins, reappose skin and orbicularis
What are the most common sites of orbital fracture?
floor and medial wall
What are indications for repair of fractured orbit?
Enophthalmos (eye sunken in), trapping of muscles/orbital tissues, fracture involving more than 50% of the wall
What is dacryocystitis?
Infection caused by obstructed nasolacrimal duct
How is dacryocystitis treated?
antibiotics to treat infection. Surgical bypass of the obstructed nasolacrimal duct
What is the most common malignant tumor of the lacrimal gland?
Adenoid cystic carcinoma
What is the treatment for adenoid cystic carcinoma?
radiation, chemo, exenteration (take out entire orbit)
What is the differential diagnosis of unilateral red eye?
Viral or bacterial conjunctivitis, iritis, corneal abrasion, corneal ulcer, herpes simplex, herpes zoster ophthalmicus, subconjunctival hemorrhage
What is the differential diagnosis for bilateral red eye?
Dry eyes, allergic conjunctivitis
What is the presentation of conjunctivits?
Pink eye, eye pain, discharge, blurred vision, mattering of eyelids in the morning
What is the most common type of conjunctivitis?
Viral (adenovirus) –> watery discharge
post-URI
Describe iritis
inflammation of the iris.
Ocular/periorbital pain, photophobia, blurred/cloudy vision, redness. May have irregularly shaped pupil
Iritis treatment
Topical steroid eyedrops, dilating eyedrops