Oculoplastics Flashcards
Which bones make up the medial orbital wall?
“SMEL”
• Sphenoid, lesser wing bone
• Maxillary bone
• Ethmoid bone
• Lacrimal bone
Which bones make up the orbital roof?
• Frontal bone
• Lesser wing of sphenoid bone
Which bones make up the orbital floor?
“Zip My Pants”
• Zygomatic
• Maxillary
• Palatine (thinnest)
Which bones make up the orbital lateral wall?
• Greater wing of sphenoid
• Zygomatic
What is a dermoid cyst?
• Lined by keratinizing epidermis with dermal
appendages
• Common pediatric periorbital mass
• Occurs when ectoderm tissue is pinched between
closing bony sutures during embryologic
development → trapped tissue forms cyst
• Type of choristoma
• 5% spontaneously rupture
• Most commonly at the frontozygomatic suture
(supratemporal)
• Second most commonly at the frontoethmoidal
suture (superomedially)
• Dumbbell appearance if they straddle across the
suture line with components inside and outside the orbit
• Treatment: Remove entire cyst with its capsule
because remnants left behind can induce severe
inflammation
What is the most common presentation and treatment of benign orbital tumor in adults?
• Cavernous hemangioma
○ Vascular tumor made of large endothelial-lined
vascular spaces enclosed within fibrous capsule
• Presents as painless progressive proptosis
• Treatment: Surgical removal is indicated if mass is
causing functional impairment (i.e. optic nerve
compression, diplopia, strabismus, substantial proptosis)
What is the most common benign orbital tumor in children and its presentation?
• Capillary hemangioma
○ Small endothelial-lined vascular spaces
contained within fibrous capsule
• Initially grows for several months then
spontaneously involutes or regresses
What is the definition and example of a choristoma?
Definition
• Histologically normal tissue in an abnormal location
Example
• Dermoid cyst
What are the diagnostic tests for myasthenia gravis (MG)?
• Ice pack testing
• Tensilon testing
• Anti-acetylcholine receptor antibodies (binding,
blocking, modulating) → present in 90% of systemic
MG and 70% of ocular MG
What are the clinical findings in blepharophimosis syndrome (BPES)?
Common clinical findings
• Blepharophimosis
• Telecanthus
• Severe ptosis → limited levator function
• Epicanthus inversus
• Deprivation, strabismic, or refractive amblyopia
• Type 1 BPES have early ovarian failure
Other less common clinical findings
• Hypertelorism
• Ectropion
• Hypoplasia of superior orbital rims
What is acute dacryoadenitis?
● Inflammation of lacrimal gland
● Most common cause overall is sterile inflammatory disease
○ Most common viral cause is EBV
What is the average volume of the adult orbit?
30 mL (cubic centimeters)
What is the most commonly injured extraocular muscle in cosmetic eyelid surgery?
● Inferior oblique
○ Inferior oblique divides central and medial fat
pads of lower eyelids
What is a sub-orbicularis oculi fat (SOOF) lift?
Suspends fat pad underneath orbicularis muscle in the
lower eyelid and anterior to orbital septum to improve
contour of lower eyelid, especially as part of midface lift.
What is the most common malignant lacrimal gland tumor and associated common findings?
• Adenoid cystic carcinoma
Associated with
• Lot of pain
• Swiss cheese pattern on pathology
What is the definition of epilation? What is the rate and chance of eyelash regrowth?
Definition
• Removing misdirected lashes with forceps
Rate of eyelash regrowth
• Occurs in 3-6 weeks
Chance of eyelash regrowth
• 100% chance of regrowth
How is radiofrequency ablation to eyelashes performed and what are its side effects?
• Uses a radiofrequency probe
• Slides down individual hair follicle shafts
• Energy delivered is concentrated to the hair follicle
and limits collateral damage
• If probe is moved during active treatment or several
closely clustered lashes are treated, could create a
notch in the lid margin
How is electrolysis to eyelashes performed and what are its side effects?
• Similar to radiofrequency ablation
• Fine wire is introduced into individual hair shaft
• High frequency electrical current is used to
coagulate the follicle
• Causes more scarring and has higher risk of notching
compared to radiofrequency ablation
How is argon laser treatment to eyelashes performed and what are its side effects?
• Similar to radiofrequency
• Focused argon laser beam is used to thermally
destroy the individual hair follicle shafts
• Thick, dark hairs growing from pale skin have the
best uptake of energy and the highest success rates
• Concentrated energy helps limit collateral damage
• Result in notching if several closely clustered lashes are treated
How is cryotherapy to eyelashes performed and what are its side effects?
• Uses sub-zero temperature to freeze eyelid margin
• Prevents lashes regrowth by killing hair follicle cells
• Best for treating broad areas of clusters of lashes
(segmental trichiasis)
• Can lead to thinning of eyelid, loss of meibomian
glands and goblet cells, and skin depigmentation
What is the most common cause of necrotizing fasciitis and its treatment?
● Group A streptococcus
○ Tracks along the fascia
○ Spreads more quickly than typical bacteria and
causes more damage
● Treatment
○ Intravenous antibiotics and urgent surgical
debridement
Where does the levator aponeurosis attach in relation to the tarsal plate for Caucasian patients?
● Levator aponeurosis attaches to the lower one-half
of the anterior surface of tarsal plate
○ Sends projections to skin and orbicularis, which
help anchor the upper lid crease
What is the location and innervation of Muller’s muscle?
• Originates at the under-surface of the levator
muscle and extends a few millimeters down to the
anterior surface tarsus
• Inserts at superior border of tarsal plate
• Innervated by the sympathetic nervous system and
helps maintain the resting tone that holds the upper
eyelid open
What are the seven diagnostic criteria for neurofibromatosis type 1 (NF1) and how many criteria have to be met for diagnosis?
Criteria for NF1 diagnosis
• Six or more cafe-au lait spots
• Two or more axillary or inguinal freckles
• Two or more typical neurofibromas or one plexiform
neurofibroma
• Optic nerve glioma
• Two of more Lisch nodules or iris hamartomas
• Sphenoid dysplasia (causes pulsatile exophthalmos)
or long bone abnormalities
• First degree relative with NF1
Diagnosis
• Requires meeting 2 or more of the criteria above
What percentage of clinically symptomatic congenital nasolacrimal duct obstructions resolve in the first year of life?
By 1 year of age, 70-90% will resolve on their own
What are the most and least common locations for periocular basal cell carcinoma?
• Lower eyelid (50-60%)
• Medial canthus (25-30%)
• Upper eyelid (15%)
• Lateral Canthus (5%)
What are common causes of bilateral proptosis in children?
• Thyroid-associated ophthalmopathy
• Idiopathic orbital inflammation
• Metastatic neuroblastoma
• Leukemic infiltrates
What is a Fasanella-Servat procedure and when is it used?
• Tarsoconjunctival mullerectomy
• Treats mild amounts of ptosis (< 2 mm)
What are the indications for orbital decompression in thyroid eye disease?
• Exposure keratoconjunctivitis
• Compressive optic neuropathy
What is the function of the pretarsal portion of the orbicularis?
Reflex eyelid closure
What are the functions of the preseptal portion of the orbicularis?
Voluntary and reflex blinking
What is the function of the orbital portion of the orbicularis?
Voluntary eyelid closure
What are the classifications of eyelid melanoma and their descriptions?
Tumor thickness Breslow Depth:
1. Melanoma in situ: fully within epidermis
2. Thin/early melanoma: depth < 0.8 mm
3. Intermediate melanoma: depth 0.8 mm to 4 mm,
and/or ulceration. Higher risk of metastatic spread.
Lymph node biopsy recommended
4. Thick melanoma: > 4 mm. High risk of metastatic
spread. Obtain lymph node biopsy. < 50% survival at 5 years
5. Advanced melanoma: spread beyond original tumor site
How many millimeters does Muller’s muscle elevate the eyelid?
2 mm
How is Muller’s muscle innervated?
Sympathetic nervous system
What are the common causes, workup, and treatment of hemifacial spasm?
Most common cause
• Facial nerve compressed as it exits the brainstem by
ectatic vertebral artery or anterior inferior cerebellar artery
Other causes
• Stroke
• Multiple sclerosis
• Trauma
• Cerebellopontine tumor
Workup
• MRI/MRA of head and neck
Treatment
• Botox injections and Jannetta procedure to place
sponge between nerve and vessel
What is the etiology of afferent pupillary defect in orbital compartment syndrome?
Compression of posterior ciliary arteries which leads to
optic nerve ischemia
What is the description and treatment of keratoacanthoma?
Description
• Nodule with crater like center
• Low-grade tumor that originates in the
pilosebaceous glands
• Closely resembles squamous cell carcinoma
Treatment
• Complete excision
What is the definition of a nevus?
Undifferentiated melanocytes found at the epidermal-dermal border
What is a description of ephelides (freckle)?
• Flat pigmented skin change due to melanocytes
producing too much pigment
• Normal number of melanocyte cells → produce
increased number of melanosomes filled with melanin
Actinic keratosis is what type of lesion and can lead to which type of cancer?
• Premalignant lesion
• Leads to squamous cell cancer
What are common signs of thyroid-associated orbitopathy?
• Eyelid retraction (superior scleral show) in 90%
• Exophthalmos in 60%
• Lid lag in 50%
• Positive Von Graefe sign: eyelid is slow to go down
when patient looks down
What is the etiology, clinical findings, diagnosis, and treatment of “indirect” (dural) carotid-cavernous fistula?
Etiology
• Rupture of thin-walled dural arteries that normally
cross the cavernous sinus → form fistula between
branches of internal or external carotid and cavernous sinus
Clinical findings:
• Chronic red eye → corkscrew conjunctival and
episcleral vessels
• Lack history of trauma
Diagnosis
• Dilated superior ophthalmic vein and inferior
ophthalmic vein
• Enlarged or congested extraocular muscles
Treatment
• Endovascular placement of coils, glue, or occlusive
devices to close the fistula
What is the etiology, clinical findings, and treatment of “direct” carotid-cavernous fistula (CCF)?
Etiology
• Caused by trauma - more common in young males
• Fistula between internal carotid artery (ICA) and
cavernous sinus
Clinical findings
• More fulminant, explosive symptoms compared to
indirect CCF due to high blood flow between ICA and
cavernous sinus
• Very prominent proptosis
• Chemosis
• Ophthalmoplegia
• Orbital pain
• Vision loss
Treatment
• Endovascular placement of coils, glue or occlusive
devices to close the fistula
What is a common presentation and workup of sebaceous carcinoma?
Common presentation
• Recurrent chalazion in the same location
Workup
• Full thickness biopsy of lesion → Oil red O or Sudan
black stain on fresh tissue
• If biopsy positive, then obtain map biopsy of
surrounding conjunctiva
• Sentinel lymph node biopsy after mapping
• Commonly exhibits pagetoid spread
• If the carcinoma spreads from conjunctival epithelium
→ progress very rapidly
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What is the etiology, presentation, and causes of ankyloblepharon?
Etiology
• Normally eyelids are fused together from week 8 to
week 20 of gestation, they separate prior to birth
• In ankyloblepharon, upper and lower eyelids fail to
completely separate
Presentation
• Partial or complete fusion of upper and lower lids by webs of skin
Causes
• Congenital
• Acquired (trauma, inflammation)
What is the definition of epiblepharon?
Pretarsal skin and orbicularis override eyelid margin,
causing eyelashes to be pushed toward ocular surface.
What is the description and associations of euryblepharon?
Description
• Horizontal lengthening of lower eyelid, combined
with vertical shortening of lower eyelid skin → leads
to lateral lower lid being pulled away from ocular surface
Associations
• Blepharophimosis syndrome
• Isolated finding
What vascular structures are 8 mm medial to the medial canthal tendon?
Angular artery and vein
What are common post-op complications of a facelift?
• Post-op hematoma: Occurs first 12 hours after
surgery. Must be drained
• Skin flap necrosis: Risk factors are extensive cautery
to flap, stretching the skin tightly, hematoma
accumulation and poor patient vascularity. This
takes days before frank necrosis is apparent
• Nerve injury: Injury to sensory nerves (branches of
trigeminal). May cause numbness of overlying skin.
Self-limited and rarely painful
• Infections: Rare, occur < 1% of time, typically occur >
3 days after surgery
What are the measurements of various components of the nasolacrimal duct?
• Vertical portion of canaliculi: 2 mm
• Horizontal portion: 8 to 10 mm
• Nasolacrimal sac: 12 to 15 mm; extends 2 to 3 mm
above medial canthal tendon
• Nasolacrimal duct: 12 mm
• Average length from punctum to nose: 35 mm
How much more common is thyroid eye disease (TED) in women compared to men?
● TED 6x more common in women
○ TED in women - 86%
○ TED in men - 14%
● Peak incidence of TED in women follows bimodal
pattern at ages 40-44 years and 60-64 years
● Peak incidence of TED in men is 60-69 years
● Side note: Relative risk of developing TED is 7 times
higher in smokers compared to nonsmokers
Lateral pretarsal eyelid tissues drain into which vein?
Lateral pretarsal eyelid tissues drain into which vein?;
Medial pretarsal eyelid tissues drain into which vein?
Angular vein
Posterior tarsal eyelid tissues drain into which veins?
• Orbital veins
• Deeper branches of anterior facial vein
• Pterygoid plexus
The angular artery is an extension of which artery?
External carotid artery → facial artery → angular artery
What are the branches of the ophthalmic artery?
• Central retinal artery
• Short and long posterior ciliary arteries
• Extraocular muscle arteries
What is the most common pathogen responsible for preseptal cellulitis resulting from trauma and its treatment?
● Staphylococcus aureus
● Treatment
○ Broad spectrum → penicillin or cephalosporin
○ MRSA coverage → clindamycin or
trimethoprim-sulfamethoxazole
What is fibrous dysplasia?
● Benign disorder
● Normal bone is replaced with immature bone
○ Immature bone impinges on vital structures if it
occurs in facial skeleton or orbit
● CT scan shows ground glass bony opacities or
complete sclerosis of bone
What is an osteoma?
● Abnormal growth of normal bone onto other sites
○ Can grow on other bones (homoplastic)
○ Can grow on other tissues (heteroplastic)
What is a sphenoid wing meningioma and its radiologic findings?
• Hyperostosis of bone with sheet-like dural plaque
• CT scan shows hyperostotic bone enhancement with contrast
What is the most common site, type, and method of diagnosis of orbital lymphoma?
Most common site
• Superotemporal, lacrimal gland fossa
Type
• 90% are non-Hodgkin B cell → 40-60% of which are
MALT variety
Diagnosis
• Fresh biopsy not in fixation, enable flow cytometry
What are acute treatments for compressive optic neuropathy from thyroid associated ophthalmopathy?
• High dose steroids (intravenous or oral)
• Urgent orbital decompression
What is Crouzon syndrome?
• Most common type of craniosynostosis
• Autosomal dominant
• Branchial arch syndrome
• Occurs in 1.6 per 100,000
• Premature closure of one or more of metropic,
sagittal, or lambdoidal sutures
• Anatomically shallow orbits results in bilateral
congenital proptosis and midface hypoplasia
• Syndactyly absent
What is the mechanism of action of botulinum toxin?
Prevents release of acetylcholine from presynaptic
neuron from neuromuscular junction.
What is the cellular origin, cause, and association of Kaposi sarcoma?
Cellular origin
• Endothelial cells
Cause
• HHV-8 (human herpes-8) infection in
immunocompromised patients
Association
• AIDS-defining illness
• Mistaken for subconjunctival hemorrhage when they
occur in subconjunctiva
From where does orbital septum arise?
Extension of periosteum.
What is the normal configuration of the lateral canthal tendon insertion in relation to the medial canthal tendon insertion?
Lateral canthal tendon inserts 2 mm more superior than
medial canthal tendon.
What is epicanthus supraciliaris?
Medial eyelid skin fold that is more prominent from eyebrow to lacrimal sac
What is epicanthus tarsalis?
Medial eyelid skin fold that is more prominent in upper eyelid
What is epicanthus inversus?
Medial eyelid skin fold that is more prominent in the
lower eyelid
What is epicanthus palpebralis?
Medial eyelid skin fold that is equally prominent upper
and lower eyelid
What is rhabdomyosarcoma?
● Derived from undifferentiated pluripotent
mesenchymal cells
● FOXO1 gene translocation
● Clinical findings
○ Increased fullness of eyelids
○ Periocular ecchymosis
○ Proptosis
○ Ocular misalignment
○ Typical age of presentation is 8 to 10 years
● Types (“embryonal everyone; pleomorphic please;
alveolar awful)
○ Embryonal (80% cases, most common),
common in supranasal quad, good survival rate
Alveolar, most malignant, common in lower orbit
○ Pleomorphic, best prognosis
● Treatment
○ Radiation, chemotherapy
What conditions are comorbid with myasthenia gravis (MG)?
• Graves disease (5-10% of MG)
• Thymoma (10% of MG)
What is the most common pathogen, workup, and treatment of infectious canaliculitis?
Pathogen
• Actinomyces israelii, filamentous gram positive rods
→ stone formation within canalicular system
Workup
• Culture purulent material manually expressed from
punctum
Treatment
• Warm compresses, lid massages, broad spectrum
topical antibiotics
• If unresponsive or if stone is present →
canaliculotomy from conjunctival side and allow for
healing by second intention. Stones protect
microbes from antibiotics, therefore stones need to
be surgically removed
What are the types, advantages, and disadvantages of non-porous ocular implants?
Types of non-porous ocular implants
• Glass
• Silicone
• Acrylic
Advantages
• Less expensive
• Faster surgery
Disadvantages
• Higher risk of exposure or extrusion
○ Decrease risk of exposure by wrapping the
implant in autogenous or donor sclera, or coat
the implant with absorbable material
What are the types, advantages, and disadvantages of porous ocular implant?
Types of porous ocular implants
• Hydroxyapatite
• Porous polyethylene
• Aluminum oxide
Advantages
• Tiny pores that vascularize with surrounding orbital
soft tissue
• Allow for better implant motility
• Less risk of implant migration
• Lower infection rate
Disadvantages
• High risk of exposure or extrusion through
conjunctiva
What does solar lentigo look like and what is it associated with?
• Seen in older patients
• Sun exposed skin
• Flat, regular pigmentation resembling freckles but
larger in size
What is lentigo maligna and what is it associated with?
• Similar to solar lentigo except irregular pigmentation
• 30-50% of these lesions progress to melanoma
What is lentigo simplex?
• Resembles freckles but larger
• Not related to sun exposure or age
In relation to superficial musculoaponeurotic system (SMAS), what is an appropriate plan for dissection to minimize risk of injury to the facial nerve?
● Stay deep to SMAS in upper face, superficial to SMAS
in lower face
○ In upper face, facial nerve lies superficial to
SMAS
○ In lower face, facial nerve lies deep to SMAS
What is a description of caruncular oncocytoma and its clinical findings?
Description
• Transformed salivary-type epithelial cells with
increased mitochondria
• Benign tumors
• Mimic conjunctival melanoma
Clinical findings
• Pigmented conjunctival lesion
• Smooth cystic appearance
• Slow growth
What are adrenochrome deposits?
• Hyperpigmented spots
• Occur on conjunctiva
• Seen after chronic exposure to topical epinephrine
or its analogues (dipivefrin)
What skin condition characterized by rough “sandpaper” texture with round and scaly appearance can progress to squamous cell cancer?
Actinic keratosis
• Premalignant lesion
• Caused by UV damage
• Most common premalignant skin lesion that
progresses to squamous cell carcinoma occurring in
2% of cases at 4 years
What structures are innervated by the superior branch of cranial nerve 3?
• Superior rectus
• Levator palpebrae
What is the management of indirect traumatic optic neuropathy?
• No good evidence based surgical or medical options available
• Conservative management
What is the most common location and source of sebaceous gland carcinoma?
• Location: Upper eyelid
• Source: meibomian and Zeis glands
What are the Garcia-Harris guidelines?
As a general recommendation, observation with
intravenous antibiotics only is indicated when:
• Under 9 years of age (likely to be culture negative or
no more than one aerobic bacterial species)
• No intracranial involvement
• Medial wall abscess of moderate size
• No vision loss or afferent pupillary defect (no signs
of optic neuropathy)
• No front sinus involvement
• No dental abscess
What structures are located superior to the annulus of Zinn?
“LFTs”
• Lacrimal nerve of cranial nerve V1
• Frontal nerve of cranial nerve V1
• Trochlear cranial nerve IV
• Superior ophthalmic vein
What structures are within the annulus of Zinn?
• Superior and inferior divisions of cranial nerve III
• Nasociliary branch of cranial nerve V1
• Sympathetic roots of ciliary ganglion
• Cranial nerve VI
Which vascular structure is inferior to annulus of Zinn?
Inferior ophthalmic vein
What is the step ladder management approach to congenital nasolacrimal duct obstruction?
Crigler massage, topical antibiotics, and/or observation
↓
Probe and irrigate
↓
Repeat probe +/- inferior turbinate fracture, balloon dacryoplasty, intubating with silicone stents
↓
DCR, if canaliculi are imperforate or obliterated → conjunctivodacryocystorhinostomy (cDCR)