OKAP practice
What are some OTHER causes of neuroretinitis?
#1) Bartonella - cat-scratch disease in 2/3 of all cases Other infectious: Syphilis! DUSN, Toxo (both) and Lyme Non infectious: Sarcoid
Retinal Astrocytomas / Astrocytic hamartomas are found in which two phakomatoses?
1) Tuberous Sclerosis 2) NF1
Microcornea is a horizontal diameter less than:
10 mm - Most have high hyperopia - risk for seconday angle closure.
How much astigmatic power is lost for misaligning a toric IOL axis?
10% for every 3 degrees. So off by 30degrees = no astigmatic power.
Which mutation has highest rate of spontaneous recovery in Leber Hereditary optic neuropathy?
14484 (11778) - worst prognosis 3460 - the other one
When does a traumatic hyphema rebleed occur?
3-7 days
What is the triad for measles?
Cough, coryza and follicular conjunctivitis
What is the most common ocuar complication of tamoxifen?
Crystalline retinopathy
What is the SRK formula?
D=A-2.5(L)-0.9(K)
What are the secondary and tertiary actions of the SO, respectively?
Depression, abduction
most common benign orbital mass in kids
Dermoid cyst
What is the treatment for neuroretinitis (cat scratch disease)
Doxycycline or azithromycin
Which lipid mediator is associated with CME in anterior segment surgery?
Eicosanoids
Schlemm's canal is what kind of tissue?
Endothelial lining
What is the characteristic pattern of inflammatory cells in sarcoidosis?
Epitheloid histiocytes forming nodules (NON CASEATING)
Black sunburst in sickle cell retinopathy is due to what?
Intraretinal and subretinal hemorrhaging and resultant RPE hypertrophy and hyperplasia
What feature distinguishes Fuch's iridocyclitis from HSV?
Lack of PAS/PS in Fuch's
The greater superficial petrosal nerve innervates which organ?
Lacrimal gland, and so excision causs dry eye.
Keplerian/astronomical lenses
Larger focal lengths. The eyepiece and and objective are both positive and SUM of their focal lengths
Faermer/rancher with fever, headache, diarrhea, myalgias with NGAU and hypopyon, vitiritis and vasculitis
Leptospirosis (gram negative spirochete)
which heart medication can cause angioedema?
Lisinopril
What are some features of ICE syndrome?
Middle age women Unilateral Spontaneously acquired
How is aqueous humor produced?
Mostly via active secretion: 1. CO2 + H20 -> Carbonic Acid 2. Epithelial cells produce Bicarbonate (HCO3-) and protons (H+) from CO2 (via carbonic anhydrase) 3. HCO3- and H+ move from the non-pigmented area to the pigmented area 3. HCO3- and H+ transported in exchange for chloride (Cl-) and Na(+) out into the Pigmented Epithelium 4. Na+ and Cl- then are transported and diffuse into the aqueous humour (water follows) 5. Aqueous humor leads to increased liquid and increased pressure ***Carbonic anhydrase inhibitors block this process
inferolateral displacement of globe can be caused by what?
Mucocele (mucous filled epithelial cysts filled with mucous or pus, that come from the ethmoid or frontal sinus) and can push through walls.
Positive defocus represents which lower-aberration refractive error?
Myopia
What pigmented lesion is associated with an elevated risk for uveal melanoma?
Nevus of ota, ie. Congenital melanosis, ie. ocular melanocytosis. 1/400 life time risk of uveal melanoma. Which is much higher than 1/6000. PAM has increased risk for conjunctival melanoma, not uveal melanoma.
The simultaneous prism and cover test measures which component of the ocular motility disturbance?
Only the latent deviation (ie. only the tropia). The alternating cover test does measures both latent (phoria) and manifest (tropic) portions, and cannot differentiate from each other.
Most frequent path of intraocular spread for retinoblastoma?
Optic nerve
What can vitamin A derivatives do to the eye?
Papilledema (bilateral optic nerve edema) by causing increased ICP. Tetracyclines, lithium and steroids can also do it
Where is the Lockwood ligament found and what does it form?
Part of the suspensory ligaments that hammocks the globe. -- medial to the medial canthal tendon -- Laterally to the lateral canthal tendon -- anteriorly -- uses with capsulopalpebral tendon -- Posteriorly -- to tenons capsule
Which class of medications causes deposits on anterior lens epithelium?
Phenothiazines (chlorpromazine)
What are the effects of aphakic glasses?
Pincushion Jack in the box ring scotoma magnification
What are the 4 stages of syphilis?
Primary - painless chancre 4-6 weeks after inoculation Secondary - 4-10 weeks later, non specific fever, malaise and maculopaplar rash of hands and feet Latent Tertiary - Neuro syphilis or ocular syphilis many months or years after
What is the most common malignant tumor of the conjunctiva?
Squamos cell carcinoma
In children under 8, why should doxycycline be avoided and what should it be replaced with?
Stains teeth. - Should be replaced with erythromycin PO
The PPD is dependent on which cell type?
T cell
Best MRI Sequence to analyize an intraorbital lesion compressing the optic nerve?
T1 fat suppression with gado
In craniosynostosis why is there a V pattern?
The globes and orbits are excyclotorted, this converts MR into an elevator in adduction. On elevation the SR pulls laterally.
Which antifungal drug has highest bioavailability intraocularly when taken PO
Voriconazole
What is the histopathological pattern of granulomatous inflammation in phacoantigenetic uveitis?
Zonal Zone 1: PMNS Zone 2: Granulomatous = epitheloid histiocytes Zone 3: Plasma cells and granulation tissue
Segmental optic nerve hypoplasia in an infant is related to what?
maternal gestational diabetes
How do you reduce surge during phaco?
more rigid tubing
What is chromatic aberration in material indicated by?
the LOWER the ABBE number = the higher the chromatic aberration (Polycarbonate lenses have lowest abbe number and highest CA)
Vitamin A deficiency is common after what procedure?
bariatric surgery (malabsorption)
Yellow laser vs. green laser for retina
- Yellow has less scatter through cataracts -- low xanthophyll absorption vs. green -- little potential damage to adjacent pigmented tissues
enlarged corneal nerve ddx
-- MEN2b (Medullary carcinoma of the thyroid) -- Refsum disease -- Familial dysuatonomia: Riley Day -- Leprosy -- Keratoconus -- Acanthomaeba -- HSK / IK -- NF1 -- PPMD
Which condition is most commonly associated with chronic anterior uveitis and erythema nodosum?
-- Sarcoidosis -- Behcets (also has uveitis and erytheme nodosum)
Abnormal vessels in the AC can be distinguished how?
-- They are fine -- No radial or circumferential pattern (as normal vessels are radially oriented) -- They branch -- They cross the scleral spur
What are some diseases associated with purtscher, purtscher-like retinopathy?
-- Trauma, head trauma, chest compression, long bone fracture -- Acute pancreatitis -- Renal failure -- Autoimmune disease (SLE, TTP, scleroderma) -- Amniotic fluid emboli -- Child birth
What are the 3 types of CMV retinitis?
-- classic/fulminant: pizza pie large areas of retinal heme against a background of whitened, edematous necrotic retina emanating from the disc follow arcades -- granular: periphery, little retinal edema, but active retinitis -- Frosted branch angiitis - more common in kids most common manifestation of CMV in immunocompromised (HIV, hepatitis, cancer, or transplant patient)
Keratoconus pathology features
-- thinned cornea stromal centrally -- dehiscence to bowman's layer -- irregular epithelium and compensatory epithelium -- DM healed breaks, thinned, or frank ruptured -- Iron deposition (stains blue) in epithelium -- in low mag, cornea looks wavey
Takayasu arteritis
AKA "pulseless disease" Granulomatous inflammation of the aortic arch
What is the most effective treatment for orbital mucor?
Amphotericin B (though mortality is high)
Majority of the metabolic activity of the lens comes from?
Anaerobic glycolysis
Malignant glaucoma is most likely to form after which type of glaucoma?
Angle closure
Xanthelasma palpebrarum
Associated with hyperlipidemeia -- not the same as a xanthogranulomatous lesion!
Unilateral 3D myopic shift ddx?
Asymmetric "oil-drop" nuclear sclerotic cataract
The uveal tract is attached to the sclera where?
At the vortex veins Scleral spur (anteriorly) Optic disc
How does botox work at the neuromuscular junction?
Binds to pre-synaptic axons to prevent release of Acetylcholine from the motor neuron into the synaptic cleft
histopath of cavernous hemangioma
Blood-filled spaces separated by thick septa
Where does one and a half syndrome locate to?
Brainstem
Which gene is most commonly associated with AMD?
CFH and ARMS2
Most common cause of CRAO in 65 year old?
Carotid atheroma -- GCA is 1-2% of all CRAo cases
What are the side effects of brimonidine, alpha agonist
Children under 8: respiratory depression, apnea and somnolence. IN adults: fatigue, lethargy, hypotension
Most common organism causing post-cataract acute endophthalmitis?
Coag-negative staph. species (like. Staph Epidermidis)
What is mechanism of action of purtscher retinopathy
Complement mediated leukoembolization
What is an "Isopter"
Connected contour line representing points of equal retinal threshold (light sensitivity) on a visual field (island of vision)
Which laser has the shortest wavelength?
Excimer (UV - mix of gases and Fl - ArFl - 100 nm) Argon/Krypton lasers in the 400's nm ND YAg = 1064nm
What is the Riddoch Phenomenom and where does it stem from?
From damage to the occipital lobe. Patients can perceive moving targets but not static ones.
Which paranasal sinus pneumatizes last?
Frontal
Most common cause of thyrotoxicosis
Graves
The long posterior ciliary arteries course anteriorly in proximity to which muscles?
Horizontal rectus muscles
Asteroid hyalosis poses what risk during PPV?
INcrease rate of retinal break formation during surgery due to abnormal vit adhesions
Post-op mydriasis (damage to parasympethetic fibers) can occur operating on which muscle?
IO or IR -- parasympethetic fibers follow the inferior division of the oculomotor nerve via the ciliary ganglion and travel with the IR.
How do you diagnose MMP?
Immunofluorescent staining of basement membrane (BMZ) - from conjunctival biopsy.
According to ONTT, why is PO steroids contraindicated?
Increases risk of recurrence of optic neuritis vs. compared to high dose IV
Gyrate Atrophy
Progressive, bilateral retinal degeneration (AR) with well circumscribed, scalloped areas of chorioretinal atrophy that enlarge and coalesce -begins anterior (periphery) and moves posteriorly -S&S began around 10yo: nyctalopia, constricted VF, progressive myopia, decreased VA in first decade of life; *well-defined scalloped areas of peripheral chorioretinal atrophy* --atrophy lesions begin mid-periphery and coalesce to engulf most of the posterior pole (macula spared until 4th-7th decade) -Associated with PSC cataracts and high myopia/astigmatism -*Due to deficiency of mitochondrial enzyme and ornithine aminotransferase (OAT)* -Lab testings: hypolysinemia, hyperornithinuria, and *increased urine and plasma ornithine levels* -TX: --->restricted dietary arginine (precursor of ornithine) and protein
Which glaucoma medication causes sunken eye appearance?
Prostaglandins
EOG generates signals from which cells?
RPE
PORN and ARN clinical findings
Rapidly progressive retinal whitening and necrosis. -- Retinal vasculitis -- Retinal hemorrhages -- PORN lacks vitritis or AC cells. -- PORN is found in immunocompromised state. (HIV) -- Typical culprit is VZV, then HSV
What are the major diagnostic criteria for Behcet's?
Recurrent oral aphthous ulcers Recurrent genital ucers Uveitis Erythema nodosum (skin findings)
What bifocal type minimizes image displacement for a patient who is hyperopic?
Round top
What is this?
Schnabel's Cavernous ATrophy
Thioradazine causes what type of eye disease?
Thioadazine (Mellaril) is a phenothiazine. It is an antipsychotic medication. It is related to chlorpromazine. It causes pigmentary retinopathy. Salt and pepper fundus (macular pigmentary changes). Optic nerve atrophy and destruction of both the RPE/Choriocapillaris.
Pathophysiology of congenital glaucoma is due to?
Trabecular meshwork impermeability (it's a problem at the TM and angle), NOT schlemm canal dysgenesis
What is foster kennedy syndrome?
True Foster Kennedy: - Compressive optic neuropathy in one eye - Papilledema from ICP in the other eye presents with central field loss in one eye and enlarged blind spot in the fellow eye
Wavelength of excimer laser in PRK?
UV (100nm).
histopath of conjunctival follicles
aggregates of lymphocytes with germinal centers
In pediatric PKP, do you remove sutures earlier or later?
earlier; https://eyewiki.aao.org/Pediatric_penetrating_keratoplasty
Retinal cavernous hemangioma on FA
grape like clusters half filled with air and blood on IVFA. Can be associated with systemic cavernous hemangiomas, including within the brain, which if ruptured, can results in seizures, bleeds and death.
Stickler Syndrome
most common identifiable cause of cleft palate (57%), 1/7500-9000 births, autosomal dominant. Characteristics include cleft palate, SNHL, progressive myopia, retinal detachment and cataracts, progressive arthropathic (joint disease). Craniofacial features include maxillary and mandibular hypoplasia, flat midface impression, prominent eyes, long philtrum, depressed nasal bridge with epicanthal folds, cleft palate. Co-occur with pierre robin sequence
Transient vision loss in one or both eyes and lasts a few seconds can be caused by what?
papilledema (transient, binocular, has to be post chiasmal)
The central retinal artery supplies which part of the optic nerve?
prelaminar
benign essential blepharospasm vs. hemifacial spasm
severe spasm of the lids resulting in functional impairment. Disappears during sleep. Hemifacial spasm: CN7 compression from CPA tumor resulting in tonic/clonic contractions of one side of face. Present during sleep
