Ophthalmology Flashcards
What is normal IOP pressure?
10-21 mm Hg
Ocular hypertension 22-25 mmHg
Concern for glaucoma >30 mmHg
*most people >40 mmHg have some degree of eye pain
How to organize an approach to the red eye?
Extra vs. intra-ocular
Painless vs. painful
What are extra-ocular causes of red eye?
blepharitis chalazion, hordeolum dacrocystitis periorbital cellulitis orbital cellulitis
What are intra-ocular causes of red eye?
conjunctivitis - viral, bacterial, fungal, irritant corneal abrasions corneal ulcers/erosions keratitis - infectious, chemical, inflammatory iritis/uveitis, radiation episcleritis scleritis subconjunctival hemorrhage hyphema endophthalmitis acute angle closure glaucoma
Where is aqueous humour produced
ciliary body
What is the path of aqueous humour in the eye
ciliary body - posterior chamber - pupillary aperture - anterior chamber - canal of schlemm - absorbed into episcleral vein
What are 6 causes of floaters
o Retinal break or detachment o Posterior vitreous detachment o Vitreous haemorrhage o Vitreous debris o Posterior uveitis o Corneal opacity / FB
What are causes of flashes
o Retinal break or detachment o Retinitis o Posterior vitreous detachment o Migraine o CNS disorder → occipital lobe pathology
What type of bacterial conjunctivitis requires IV antibiotics instead of topical?
Gonoccocal conjunctivitis
What are 5 historical points to ask on review of systems?
floaters/flashers vision loss blurry vision redness pain headache tearing itching scalp tenderness
What are 10 points on ocular physican exam to include?
visual acuity pupillary response RAPD extra-ocular movements other cranial nerves color/red desaturation ocular pressure lid/lacrimation/external exam lymphadenopathy *pre-auricular conjunctiva/sclera cornea anterior chamber iris lens vitreous fundus
What are 10 points on ocular physican exam to include?
visual acuity pupillary response RAPD extra-ocular movements other cranial nerves color/red desaturation ocular pressure lid/lacrimation/external exam lymphadenopathy *pre-auricular conjunctiva/sclera cornea anterior chamber iris lens vitreous fundus
What 2 muscles innervate the eyelids? What nerves innervate these muscles?
orbicularis oculi - CN VII
levator palpebra - CN III
What are the 3 chambers of the eye?
anterior chamber - cornea to iris
posterior chamber - iris to lens
vitreous chamber - lens to retina
What are the 5 layers of the cornea? (superficial to deep)
- epithelium
- bowman’s layer
- stroma
- descemet’s membrane
- endothelium
What innervates the sensation in the cornea?
CN V - trigeminal nerve
What are 5 ocular causes of red eye that need urgent ophthalmology referral?
acute angle closure glaucoma infectious keratitis hyphema hypopion iritis/uveitis corneal ulcer
What are 5 ocular causes of red eye that need urgent ophthalmology referral?
acute angle closure glaucoma infectious keratitis hyphema hypopion iritis/uveitis corneal ulcer
What is the physiology behind hyperopia? myopia?
hyperopia: visual axis length too short
myopia: visual axis length too long
What are 2 classes of mydriatic drugs?
- Anticholinergic (dilation by paralyzing iris sphincter)
- tropicamide, cyclopentolate, homatropine
* also cycloplegic, paralyze ciliary body, will affect accommodation - Adrenergic (dilation by stimulating pupillary dilator)
- phenylephrine
* not a cycloplegic
What are 2 classes of mydriatic drugs?
- Anticholinergic (dilation by paralyzing iris sphincter)
- tropicamide, cyclopentolate, homatropine
* also cycloplegic, paralyze ciliary body, will affect accommodation - Adrenergic (dilation by stimulating pupillary dilator)
- phenylephrine
* not a cycloplegic
What are 4 types of glaucoma topical medications?
- Beta blockers
- timolol, levobunolol - Cholinergic agonists
- pilocarpine - Alpha 2 agonists
- brimonidine, apraclonidine - adrenergic stimulating
- epinephrine - carbonic anhydrase inhibitors
- acetazolamide, brinzaolamide, etc.
What is the mechanism of action of the different anti-glaucoma medications? (lower IOP)
- Beta blockers
reduce formation of aqueous humour by ciliary body - Cholinergic agonists
increase aqueous outflow through trabecular network - alpha 2 agonists
decrease aqueous production, increased uveoscleral (non trabecular meshwork) aqueous outflow - carbonic anhydrase inhibitors
aqueous humor suppression
What are 3 common causes of bacterial conjunctivitis?
non typeable H. influenza
S. aureus
S. pneumonia
What is EKC?
Epidemic keratoconjuncitvitis
caused by adenovirus, highly contagious
spectrum of conjunctivitis to keratitis, can have prolonged course
What are clinical features of EKC?
preauricular lymphadenopathy (ipsilateral) follicular conjunctivitis watery discharge hyperemia/chemosis corneal opacities
What is a chalazion and where is it located?
Granulomatous inflammation of the meibomion glands
occur when the meibomion pores get clogged, undernear the tarsal plate
seen best when eyelid everted
What is the difference between a corneal abrasion and corneal ulcer?
Corneal ulcer has associated inflammatory infiltrate/opacity - appears white on plain exam
What are differentiating features between preseptal and septal (orbital cellulitis)
Orbital cellulitis is associated with: painful extraocular movements limited extraocular movements RAPD Proptosis Chemosis
What is the most common opportunistic ocular infection with HIV/AIDS?
CMV retinitis
associated with CD4 counts
What are 3 predictors of vision loss in hyphema?
large hyphema
sickle cell disease or trait
bleeding diatheses
What are 5 etiologies of spontaneous hyphema?
Diabetes mellitus
Iris melanoma, retinoblastoma, and other eye tumors
Juvenile xanthogranuloma
Clotting disorders (eg, thrombocytopenia, hemophilia, Von Willebrand disease)
Medications that inhibit platelet function (ASA, warfarin)
What 3 diagnoses should you consider in traumatic hyphema?
globe rupture
posterior segment injury
intraocular foreign body
What are 5 physical exam findings associated with hyphema?
Photophobia Decreased visual acuity Aniscoria Elevated IOP Corneal blood staining
What are 8 findings of globe rupture?
Markedly decreased visual acuity
Eccentric pupil
Increased anterior chamber depth
Low intraocular pressure
Extrusion of vitreous
External prolapse of the uvea or other internal ocular structures
Tenting of the cornea or sclera at the site of globe puncture
Seidel’s sign, fluorescein streaming in a tear drop pattern away from the puncture site
What are 3 types of retinal detachment?
rhegmatogenous (from PVD or trauma)
exudative (from infection)
traction
What are risk factors for retinal detachment
posterior vitreous detachment
myopia
cataract surgery
fluroquinolone use (rare)
What are symptoms of retinal detachment
floaters/cobwebs (PVD)
photopsia (flasher’s, from mechanical tug on retina stimulating photoreceptors)
shower of black spots (vitreous hemorrhage)
curtain vision loss
What should you instruct your patients with orbital floor fractures to avoid?
blowing nose
valsalva
=> reduce chance of ocular emphysema
What are 8 major diagnostic considerations in ocular trauma?
ruptured globe retinal detachment hyphema traumatic iritis traumatic mydriasis/miosis iridodialysis corneal abrasion/foreign bodies intraocular foreign body orbital fractures (blowout, entrapment)
What are 4 complications of hyphema
increased IOP corneal blood staining chronic glaucoma anterior/posterior synechia formation *rebleed
Where do ocular ruptures usually occur? (2)
insertion of intraocular muscles
limbus
(sclera is thinnest)
What features of blunt globe injuries are associated with poor prognosis and higher rates of enucleation? (4)
afferent pupillary defect
retinal detachment
poor initial visual acuity
absent red reflex
What is the sensitivity/specificity of CT for open globe injuries?
sens 75%
spec 93%
What are 4 causes of vitreous hemorrhage?
diabetic retinopathy
posterior vitreous detachment
retinal vein occlusion
trauma (shaken baby syndrome)
Which lid lacerations should be referred to oculoplastics? (5)
- involving lid margin
- involving canalicular system (medial)
- involving the levator or canthal tendons
- through the orbital septum (orbital fat confirms diagnosis)
- with significant tissue loss
What are causes of conjunctivitis?
viral bacterial mechanical allergic toxic radiation
What is a pterygium?
Wedge shaped area of conjunctival fibrovascular tissue that grows from nasal side of sclera and extends ONTO cornea
*associated with increased exposure to UV light
What is a pingecula?
Raised yellow or white tissue on the conjunctiva, raised but NOT on cornea
*also associated with UV light exposure or dryness
What is the difference between a corneal ulcer vs. infiltrate?
Ulcer is associated with an overlying corneal epithelial defect (fluroscein uptake), infiltrate has an intact corneal epithelium
What are 8 causes of transient monocular vision loss?
amaurosis fugax - embolic ischemia to retinal artery (usually from carotids) giant cell arteritis nonarteritic anterior ischemic optic neuropathy retinal vein occlusion retinal migraine/vasospasm optic neuropathy papilledema optic nerve compression angle closure glaucoma spontaneous hyphema vitreous floaters
Where is the lesion in monocular vision loss?
anterior to the optic chiasm
anterior chamber, lens, vitreous, retina, ocular arteries/veins, optic nerve
Where is the lesion in binocular vision loss
posterior to the optic chiasm (chiasm, optic radiations, temporal/parietal lobes, occipital lobes)
What are 3 causes of transient binocular vision loss?
migraine
seizure
vertebrobasilar ischemia
What are 5 causes of retinal artery occlusion in children?
sickle cell disease vasculitis (HSP, SLE) hypercoagulable/thrombotic states IVDU pregnancy congenital heart disease with R->L shunt ocular trauma
What are 3 physical exam findings in CRAO?
pale retina (white)
cherry red macula
RAPD
(decreased VA, somtimes can see retinal emboli)
What are 4 physical exam findings in CRVO?
retinal hemorrhages cotton wool spots retinal edema dilated retinal veins \+/- RAPD if complete
What are 3 causes of unilateral proptosis?
retro-orbital tumor
retro-orbital abscess
retro-orbital hematoma
What part of the visual field does a lesion in the temporal radiations affect? (Meyer Loop)
superior quadrantanopsia
What part of the visual field does a lesion in the parietal radiations affect?
inferior quadrantnopsia
What systemic disease is CRVO associated with?
Hypertension
What are 4 critical causes of diplopia?
basilar artery thrombosis (posterior CVA)
botulism
basilar meningitis
intracranial aneurysm with CN III palsy
What are 4 emergent causes of diplopia?
myasthenia gravis
verterbral artery dissection
Wernicke’s encephalopathy
orbital apex syndrome (cavernous sinus disease)
How do you distinguish diplopia from orbital myositis vs. cranial nerve abnormality?
Ocular myositis can be distinguished from a neuro- genic palsy in that it abruptly restricts eye movement away from the muscle, whereas a CN palsy smoothly and progressively impairs movement toward the weakened muscle
How do vascular vs. compressive CN III palsies classically present?
Vascular - pupillary sparing
Compressive - pupillary involvement
Parasympathetic fibres run superficially on the external portion of the nerve, affected sooner in compressive neuropathies
Where is the lesion in internuclear opthalmoplegia (INO)?
medial longitudinal fasciculus
What are the basic elements of an ocular exam
VA IOP Slit lamp fundoscopy pupils/CN exam
Describe the Snellen chart and interpretation
Measured at 6 m or 20 feet, 10 feet
20/20 = what one sees at 20 feet, what a normal eye sees at 20 feet
vs. 20/50, what one sees at 20 feet a normal eye sees at 50 feet
*use pinhole for best corrected VA
What medication should you avoid for pupillary dilation in the ED?
Atropine
lasts 2 weeks
Which eyelid lacerations require ophtho referral?
involving lid margin
deep to tarsal plate
involving cannalicular system
What sutures and technique to repair non margin involving eyelid laceration?
6-0 prolene (or gut)
vertical simple interrupted
What options to remove crazy glue to eyelids
Very rare to have true EYE involvement
Warm water compresses, tea tree oil safe
Pry apart lashes, usually just need time
Which orbital floor fractures require repair?
Enophthalmos
Diplopia >2 weeks
Large (2x2cm)
How does conjunctiva heal?
Similar to mucous membrane
Sliding and proliferatio of epithelial cells, 1-2 days to heal
What layers of corneal contribute to healing?
epithelium - normal turnover 5-7 days
stroma
endothelium
*heal from limbus inward
Management of UV radiation corneal injury?
Usually only invades to epithelium/stroma
Analgesia, sunglasses, protective glasses, lubrication
Why are alkali injuries worse than acid injuries to cornea?
Alkali - saponification of tissues, liquifaction necrosis
Can penetrate to anterior chamber causing diffuse inflammation
Worst cornea chemical injuries?
extensive limbal epithelial damage - limits ability to heal
white limbus = dead limbus
What happens with acid injuries to cornea?
denatures and precipitates proteins
coagulation necrosis
limits depth of damage
What does ophtho use to treat chemical corneal injuries?
Abx drops (tetracyclines)
Topical steroids
lubricants
+/- Vitamin C
What can cause toxic corneal injuries?
topical anesthetic topical preservatives (benzalkonium chloride)
What are 5 causes of subconjunctival hemorrhage
spontaneous valsalva anticoagulants trauma bleeding diatheses
How does traumatic iritis present
anterior cells, photophobia, pain, decreased VA, ciliary flush
What are traumatic hyphemas often associated with?
traumatic iris tear
other anterior chamber injuries, open globe, retinal damage, vitreous
When do rebleeds occur with hyphema?
typically days 2-5
Suggestions for antibiotics in corneal abrasions
Moxifloxacin - contact lens wearer, organic material
Polysporin - non-contact lens, most material
definition of penetrating and perforating
penetration: wound passes into structure
perforating: wound passes through structure
What is the immediate management of ruptured globe?
Call ophtho Shield eye IV Ancef Tetanus Analgesia NPO
What is commotio retinae?
intracellular edema secondary to shock waves from trauma and disruption of photoreceptor layer
Examines as retinal whitening
(appears like CRVO)
self resolving
What is chorioretinitis sclopetaria?
high velocity missle in orbit without globe disruption (often GSW)
diffuse chorioretinal injury
What retinal injury is classically associated with CPR?
Purtscher retinopathy
Optic nerve edema, cotton wool spots, retinal hemorrhages (like diabetic retinopathy)
How does traumatic optic neuropathy typically present?
RAPD with relatively normal eye exam otherwise
What are typical symptoms of blepharitis
dry eye symptoms, morning crusting
What are 4 classic symptoms of orbital cellulitis
EOM restriction/pain
red eye
poor pupil reaction
decreased VA
What are 5 common bacterial causes of conjunctivitis?
S. aureus S. epidermidis S. pneumoniae H. influenza Gonoccocal
What SLE findings are associated with HSV, HZV?
HSV: dendrites
HZV: pseudodendrites (often “sloppy” looking)
How to differentiate epislceritis vs. scleritis? (other than phenylephrine test)
Episcleritis more superficial, not painful to touch
Scleritis usually has a rheumatologic undertone, tender on palpation
What are 4 causes of iritis? (major categories)
Rheumatologic
Infectious - TB, syphilis, HSV, HZV, adenovirus
Traumatic
Postop
What are 4 key symptoms of optic neuritis?
decreased VA
decreased color vision
RAPD
pain on EOM
What is the definitive treatment for angle closure glaucoma?
laser peripheral iridotomy
what options to dilate the eyes in ED?
mydriacyl or phenylephrine
