Ocular Disease 3.1-3.4 Flashcards
What is sclerotic scatter and what is it used for?
a. Too look for corneal clarity
b. Illumination and ocular about 60 degrees apart. Focus light on temporal limbus (should create halo around iris) – creating total internal reflection. Look outside of oculars
What is a optic section used for?
a. Depth
b. Van herick angles
What is a conical beam used for?
a. Look for cells and flare (should be dark adapted)
What is specular reflection and what is it used for?
a. Idea of equal angles – incident and reflective angle. Focus light on purkinje image – endothelium and epithelium light up
b. Can also be used to look at posterior and anterior lens surface
What is indirect illumination used for?
a. Non- opaque corneal lesions – like those seen in EBMD
What are the lesions in EBMD called?
a. Map dot
b. Fingerprint
- What are you looking at when using the cobalt blue filter + NaFl?
a. Tear film and corneal integrity
b. NaFl stains defects
- What can you see with the cobalt blue filter, but no NaFl
a. Fleisher ring - will appear black
Decemets membrane
- What is the Fleisher ring?
a. Circular Iron deposit at base of cornea seen in keratoconus. In descemets
- Alkali vs acidic burn
a. Alkali – blanches = ichemia, more penetrate deeper and faster because of disruption of the fatty acids in the cell membrane due to increase in pH.
- What is the most common alkali agent causing burns?
a. CAOH
- Why does an abrasion cause a mitotic pupil?
a. An irritated cornea sends a signal to the iris via CN 5 = reflex
- How do you treat an abrasion and why?
a. Doxy – to inhibit MMP’s = enemies
- What causes a recurrent Corneal Erosion?
a. Abrasion
b. All corneal dystrophies
- You see a foreign body with a sterile infiltrate, what is the cause?
a. Vegetative or plant matter
b. NOTE: a sterile infiltrate is not always seen in plant or vegetative foreign bodies
- What does it mean if you see linear vertical corneal scratches?
a. Superior lid foreign body
- What causes a hyphema? What testing should you do?
a. Sickle cell – especially if have recurrent hyphema
b. Trauma
c. Clotting disorder – recurrent hyphemas
d. NSAIDs/ blood thinners
e. Idiopathic
i. Do sickle cell testing, CBC, PT/PTT
- What must you avoid if you have a hyphema or orbital fracture?
a. Gonio and scleral depression for 1 month minimum because it can cause rebleeds
- What is a positive seidel sign?
a. Leaky NaFL – indicates Aqueous leaking out of eye
b. Indicated an open globe wound – good to do it when see any corneal/ conj trauma
- When do you need a B scan?
a. To view post pole if unable to do BIO/78/90 – for RD
b. To differentiate between a melanoma ( optically empty) and a choroidal nevus
c. Optic nerve head drusen – lights up
- What are the different types of hyphema?
a. 8 ball hyphema – entire anterior chamber is filled with blood
b. Microhyphema – only see RBCs suspended with a slit lamp in the anterior chamber
- What is iridodialysis ?
a. The iris root is torn from the CB.
- What do you need to monitor for with a patient who has iridodialysis?
a. Angle recession glaucoma
- What is the thinnest and thickest part of the iris?
a. The iris root is the thinnest part of the iris
b. Collarette = thickest
- What is lens subluxation and what does it mean?
a. Means trauma has occurred
- You see a vossius ring and subluxation, what does this mean?
a. Trauma
- What is a vossius ring ?
a. Posterior pigments epithelium of iris hit the anterior lens surface
- What does the iris pigmented epithelium turn into?
a. Iris pigmented epithelium -> NPCE -> sensory retina
- What is corneal blood staining and what does it mean?
a. Cornea is stained with blood due to compromised in corneal endothelial cells.
b. Means that the patient had a hyphema
- What are you worried about when you see corneal blood staining and why does this occur? How do you resolve this?
a. High IOP because RBCs accumulate in the trabecular meshwork.
b. Have the patient elevate their head by 30 degrees.
- What indicates that a patient has a metallic foreign body?
a. Rust ring surrounding the foreign body
- What must you not do if you believe patient has a metallic foreign body?
a. MRI
- What is the weakest bone in the orbit and what is the thinnest bone?
a. Weakest = maxillary
b. Thinnest = ethmoid
- What bones make up the floor?
a. My Pal ZZZ on the floor – maxillary, palatine, zygomatic
- What bones make up the roof of the orbit?
a. FrontLess – frontal and lesser wing of sphenoid
- What bones make up the lateral wall of the orbit?
a. Great Z – greater wing of the sphenoid and the zygomatic
- What bones make up the medial wall of the orbit?
a. SMEL – sphenoid, maxillary, ethmoid, lacimal
- What are the most common orbital fractures?
a. Blow out fracture = fracture to the floor
- Why does a blowout fracture occur?
a. Trauma leading to an increase in intra- orbital pressure
- What should you tell a patient to avoid doing if they have an orbital fracture and why?
a. Do not blow nose for 48 hours!
b. It can cause an orbital infection
- What are 3 unique symptoms a patient might complain of with a blow out fracture?
a. Diplopia
i. Why and what test do you do?
1. due to IR being caught (can’t look up) – (+) forced duction
b. Crepitus (crackling) during palpation of medial orbit or after nose blowing
c. Hypoesthesia of the cheeks
i. due to trapped infraorbital nerve – V2 branch
- What are some signs of a blowout fracture?
a. Step off fracture at rim– ie. bone poking
b. Enopthalmos
c. Sub conj heme
- Where is V1 located?
a. Above the orbit
- What are the branches of V2 and where is it located?
a. Located below the eye
b. Zygomatic and the infraorbital
- What is commito retinae? Symptoms? What are complications? How is it treated?
a. Vitreous hitting back of the eye – specifically hits the outer PR segments and RPE are affected
b. Aymptomatic
c. Permanent visual field loss
d. Usually self-limiting within 3-6 weeks, white will disappear 48-72 hours
- What is Berlin’s edema?
a. Commit retinae at the macula
- What UV range does the vitreous block?
a. 300-350
- What does the vitreous store?
a. Glucose
- Where is glucose stored in the eye?
a. Vitreous
b. Corneal epithelial cells
- What is purtscher’s retinopathy? What does it look like?
a. Think “purchest ret” – associated with acute chest compression trauma
b. Looks like CRVO – but less hemes and very large and lot of CWS
- What causes purtscher’s like retinopathy?
a. Acute pancreatitis
b. Renal failure
c. Long bone fractures
- Where are CWS located?
a. NFL
- What does a negative forced duction test indicate?
a. Cranial nerve palsy
- What is a choroidal rupture? What is it caused by? Complications?
a. Crescent shaped tears concentric to the ONH – usually temporal
b. Trauma
c. Complication – CNVM
- Why does a CNVM occur?
a. Break in Bruch’s
- What conditions cause a break in Bruch’s and why?
a. CHBALAS
i. Choroidal rupture – due to trauma
ii. Histoplasmosis – due to choroiditis
iii. Best’s disease – RPE degeneration
iv. Angioid streaks – decrease in elastin
v. Lacquer cracks – stretching
vi. AMD – drusen
vii. Scar
- How many layers are there in Bruch’s and what are they?
a. 5 layers
b. Basement membrane if RPE
c. Inner collagenous layer
d. Elastic layer
e. Outer collagenous layer
f. Choriocapillaris endothelium basement membrane
- What is eyelid ecchymosis
a. Black eye caused by blood leaking into the subcutaneous tissue
- How can a patient loose their vision with trauma? When do you see changes post trauma?
a. Can get a optic neuropathy – may not appear for weeks post trauma
- What is an optic neuropathies?
a. Pallor of the ONH
- Why do you get prolapsed orbital fat? What does it look like?
a. When the orbital septum becomes weak
b. Swollen corners of eyes
- What is the orbital septum and its function?
a. Membrane sheath that is located anterior to the orbit (goes from the orbit rim to the eyelids
b. Divides the eyelids in half – separates the orbicularis from rest of the eyelid
- What is preseptal cellulitis?
a. An infection anterior to the orbital septum
- What causes preseptal cellulitis?
a. Ocular infections – hordeolum (focal), dacryocystitis
b. Skin trauma – insect bite, puncture wound
c. Systemic infections – middle ear infection/ upper respiratory infection
- What is a chalazion?
a. Scar tissue post hordeolum
b. No pain
- What are the symptoms of preseptal?
a. Eyelid ptosis, red, hot
- Which is more common preseptal cellulitis or orbital cellulitis?
a. preseptal cellulitis
- What is orbital cellulitis
a. An infection posterior to the septum
- What causes orbital cellulitis?
a. Sinus infection
i. Ethmoid sinusitis: because the ethmoid bone is the thinnest and the infection can spread easily through the thin lamina papyracea
b. Orbital infection
i. Dacyoadenitis, dacryocystitis, preseptal cellulitis spreading
c. Orbital fracture
d. Dental infection
- How do you differentiate preseptal cellulitis from orbital cellulitis?
a. Fever, EOM restriction/ pain, proptosis, decreased VA , don’t feel good, APD = orbital
- What is the leading cause of exophthalmos in kids?
a. Orbital cellulitis
- What are complications of orbital cellulitis if not treated early?
a. Meningitis
b. Mucormycosis in diabetics
- What is Mucormycosis?
a. A fungal infection that can occur in diabetics as a result of orbital cellulitis
b. This is life-threatening
- What is an indication that a patient has mucormycosis?
a. Black eschar
- What is black eschar?
a. Black necrotic tissue in the mouth and nose
- How can you diagnose orbital cellulitis?
a. CT
- Who gets TED?
a. 40 year old female
- What is the reason a patient may go to the doctor for TED?
a. Complain of heart palpitations, heat intolerance, hair loss and weight loss ie. too much sympathetic
- What is the grading system for TED?
a. NO SPECS
i. N – no signs or symptoms initially
ii. O – only signs no symptoms
1. Upper lid Retraction – caused my Mueller’s ( sympathetic control)
2. Dalrymple’s sign
3. Von Graefe’s sign
4. Kocher’s sign
iii. S – soft tissue involvement
1. Lid edema
2. Chemosis
iv. P – proptosis
1. Caused by muscles swollen behind the eye
v. E – EOM involvement
1. (+) FD test
vi. C – Corneal Involvement
1. SLK = superior limbic Keratoconjunctivitis
2. Punctate keratitis
3. Ulcers
vii. S – sight loss due to ONH Compression
1. Because swollen EOMs choke nerve –> leads to disc edema -> pallor
2. May see APD, low color vision, VF loss, Decreased VA
- What is Von Graefe’s sign?
a. Upper eyelid lag during down gaze
- What is Kocher’s sign?
a. The globe lag compared to lid movement when looking up
- Why does SLK occur in ted?
a. Due to friction caused by the new position of the lid
- What is SLK associated with?
a. TED
b. Cls
c. Dry eye n
- What EOM’s are first involved in TED?
a. I’M So Lazy
i. I = inferior rectus first
ii. M = medial rectus
iii. S = superior rectus
iv. L = lateral rectus
- is Dalrymple’s sign?
a. Looks like patient is staring due to upper lid retraction
- What is the pathyophys of TED?
a. The thyroid releases T3 and T4 normally to the brain
b. If there is not enough T3 and T4 then the brain releases TSH to the thyroid
c. This causes that thyroid to release more T3 and T4
d. TED = TSH mimic ( auto ab to TSH receptor) - this increases T4 and T3- the brain detects high T4 and T3 and inhibits the release of TSH via negative feedback
e. The thyroid stimulating antibodies go after the EOMs and orbital tissue – causing fibroblast proliferation + inflammation
i. EOMs inflamed and thickened
- How is ted diagnosed?
a. High T3,T4
b. Low TSH
c. CT/MRI to look for enlargement of EOMs ONLY
d. Exophthalmometry
e. VF for ONH defects
- What are Exophthalmometry norms? What are abnormal findings?
a. White people: 12-33 mm
b. Asian: 12 – 18 mm
c. Black: 12-24 mm
d. NOTE IF VALES AND HIGHER AND IF GREATER THAN 3 MM DIFFERENCE = ABNORMAL
- What is the strongest risk factor for the development of TED?
a. Cigarette smoking
- 40 - 50 year old patient presents with unilateral/bilateral proptosis, what are your differentials?
a. Orbital pseudotumor
b. TED
c. Cavernous hemangioma – if unilateral
- What differentiates TED from Orbital pseudotumor?
a. In orbital pseudotumor both the EOMs and the tendons are enlarged
b. In TED only the EOMs enlarged
- What is a capillary hemangioma?
a. Benign orbital tumor in kids
b. “ think – capillaries = small, so seen in kid”
- What are complications of capillary hemangiomas?
a. Deprivation amblyopia if the visual axis is blocked
- What is the treatment of capillary hemangiomas?
a. No treatment, usually shrink by age 7
- What is a cavernous hemangioma?
a. Benign orbital tumor in adults
- Who gets a Carotid Cavernous Fistula?
a. 20 yo M usually by a motor accident-causing trauma to the cavernous sinus
- What is a Carotid Cavernous Fistula?
a. An abnormal communication between the arterial and venous systems
b. When the blood entering the cavernous sinus cannot drain due to high pressure in the ICA, this leads to a back flow of venous blood to the eye leading to the triad
- What is the triad of the cavernous sinus fistula?
a. Chemosis
i. NOTE: not associated with itching
b. Pulsatile proptosis
c. Ocular bruit = abnormal sound of blood flowing through an artery that is partly/ completely obstructed
- What other signs may you notice in cavernous sinus fistula besides the triad?
a. Because the cavernous sinus contains CN 3,4,6, V1, V2, sympathetic fibers + ICA
i. CN palsy, loss of sensation in CN V ( above and below eye)
b. High IOP
c. Red eye – due to blood flowing back into eye
- What is chemosis + itching mean?
a. Allergy
- Explain the venous drainage system of the eye
a. The eye drains by 2 veins
i. Inferior ophthalmic veins
ii. Superior ophthalmic veins
b. Both veins empty into the cavernous sinus
c. The cavernous sinus drains into the sigmoid sinus
d. Goes into the internal jugular vein
e. Goes to the heart
f. Aorta -> common carotid -> ICA -> ophthalmic artery -> CL MS LSE
- What are the branches of the aorta?
a. ABCS. (R-> L )
i. Aorta
ii. Brachiocephalic
iii. Common carotid
iv. Subclavian
- What are the branches of the Subclavian?
a. Vertebral artery
- What do the vertebral arteries join to form?
a. Basilar artery which becomes the Posterior cerebral artery
- What are the branches of the common carotid?
a. ICA
b. ECA
- What are the branches of the ICA?
OPAM
a. Ophthalmic artery
b. Posterior communicating artery
c. Anterior cerebral artery
d. Middle cerebral artery
- What are the branches of the ophthalmic artery?
a. CL MS LSE
i. CRA
ii. Lacrimal artery
iii. Muscular artery
iv. SPCA
v. LPCA
vi. Supraorbital artery
vii. Ethmoid artery
- Where is a dermoid cyst found?
a. Superior temporal quadrant
Who gets dermoid cysts?
diagnosed in early childhood- first decade of life
what is a dermoid cyst?
well-defined mass seen on CT.
what are symptoms of a dermoid cyst?
proptosis