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
What are the components of the basic eye exam?
visual acuity, visual field, ocular motility, pupils, external exam (eyelids, conjunctiva, cornea), fundoscopic exam (red reflex, disc, retina)
What are possible implications of recurrent iritis?
ankylosing spondylitis, RA, Crohn’s, ulcerative colitis, Lupus, Sarcoidosis, Syphilis, TB
How does corneal abrasion present on exam?
possible presence of irregular epithelium and slightly cloudy cornea.
What is associated with contact lens use?
corneal ulcer (bacterial or protozoan). Risk = 10x higher for extended wear
What is a distinct characteristic of corneal ulcer?
White infiltrate in the cornea
What are common foreign bodies found in the cornea?
metal, glass, organic material
Describe herpetic keratitis
eye redness, pain, photophobia, decreased vision, and tearing.
Fluorescein on the ocular surface –> dendritic epithelial ulcer with branching pattern and terminal bulbs
Treatment of herpetic keratitis
watchful waiting (usually resolves in 3 weeks) or oral acyclovir/valacyclovir
What is the etiology of herpes zoster ophthalmicus?
reactivation of VZV. V1 dermatological involvement
How does herpes zoster ophthalmicus present?
prodromal fatigue; low-grade fever; unilateral rash on forehead, upper eyelid, and nose; unilateral eye pain, redness; decreased vision; photophobia
What are the risk factors for angle closure glaucoma?
Asian, geriatric, hyperopia
How does angle closure glaucoma present on exam?
sluggish mid-dilated pupil, conjunctival injection, hazy cornea and shallow anterior chamber
What is open angle glaucoma?
progressive disease of the optic nerve associated with elevated intraocular pressure. No symptoms
What are common symptoms of cataract development?
vision appears as though looking through a dirty window, color desaturation, night-time glare, halos
What are the indications for cataract surgery?
vision cannot be corrected with glasses, cataracts interfering with daily activities
dark red spot with visible overlying vasculature on fundoscopic exam
Subretinal hemorrhage
Dot-blot hemorrhage on fundoscopic exam
diabetes
Flame/splinter hemorrhage on fundoscopic exam
hypertension
Vitreous hemorrhage (obscured retina) on fundoscopic exam
diabetes
Hard, yellow exudate on fundoscopic exam
diabetes
Drusen (yellow subretinal deposits in macula) on fundoscopic exam
hallmark of macular degeneration
Hollenhorst plaque in arteriole bifurcation on fundoscopic exam
embolus from carotid atherosclerotic plaque
Cotton wool spots on fundoscopic exam
diabetes, hypertension
Choroidal nevus on fundoscopic exam
benign pigmented neoplasm
Macular scar on fundoscopic exam
old inflammation
What is the number 1 cause of blindness in working age adults?
diabetic retinopathy
Pathophysiology of diabetic retinopathy
microvascular injury –> retinal hemorrhage –> capillary leakage –> ischemia –> neovascularization
What is the more severe form of diabetic retinopathy
proliferative = vision threatening
What is the number one cause of vision loss in DM?
diabetic macular edema (non-proliferatic diabetic retinopathy)
How is diabetic retinopathy managed?
glycemic control, BP control, laser photocoagulation, Anti-VEGF injection, pars plana vitrectomy (tractional retinal detachment)
Characteristic hypertensive retinopathy findings
vasoconstriction, Arteriosclerosis (copper and silver wiring, aterio-venous nicking)
central retinal vein occlusion findings
dilated veins and extensive hemorrhage
central retinal artery occlusion findings
“stroke” to the eye. cherry red spot
what is the number one cause of blindness in people age 50+?
age-related macular degeneration
what are age-related macular degeneration risk factors?
> 75y, white, female smokers
What is the number one optic neuropathy?
glaucoma (nerve fiber layer and optic disc injury –> visual field loss)
glaucoma risk factors
age, elevated IOP, race, central corneal thickness, family hx, myopia
Papilledema
increased intracranial pressure –> bilateral optic disc swelling
Fundoscopic findings associated with papilledema
blurred disc margin (sometimes with surrounding hemorrhage)
What are the two types of anisocoria?
abnormal miosis, abnormal mydriasis
Describe abnormal miosis
Horner syndrome: sympathetic dysfunction –> poor “dark” response –> dilation lag, ptosis +/- anhidrosis
Mydriatic pupil with poor light response
abnormal structure = iris damage
Parasympathetic dysfunction –> Tonic pupil (tonic dilation, segmental palsy, light-near dissociation), CN3 palsy (ptosis, EOM paresis)
Pathway of neurologic pathway disturbances
optic nerve –> optic chiasm –> optic tract –> lateral geniculate nucleus –> optic radiations –> occipital cortex
Hallmarks of visual field loss from neurologic visual pathway disturbances
defect respects vertical and/or horizontal meridians
defect is homonymous (same area of visual field in each eye)
defect is a combination of homonymous + respects vertical median
Clinical features of optic neuritis
visual acuity loss, central visual field loss, pain with eye movements, younger patients, usually normal optic disc at onset, recovery by 6-10wks
Clinical features of anterior ischemic optic neuropathy (AION)
+/- Visual acuity loss, altitudinal/arcuate VF loss, older patients, edematous and hemorrhagic optic nerve, minimal recovery
clinical approach to complaints of diplopia
Is it binocular? (yes = ocular misalignment)
Horizontal or vertical?
Worse with any position of gaze?
worse at near or distance viewing?
Most common cause of oscillopsia
nystagmus
