EPT6 Flashcards
What mechanism explains the iris color change sometimes noted in pts on topical ophthalmic latanoprost?
Increased pigmentation associated with INC of melanin within iridial melanocytes
Which is the MOST common cause of genetic visual impairment in infants and children?
Leber congenital amaurosis
What is sorsby dystrophy?
Peripheral choroidal and outer retinal disease that typically manifests in adulthood
When does choroideremia cause visual impairment?
Middle adulthood
Which technique for measuring aniseikonia is considered to be the MOST accurate?
Space eikonometer
Rare to have, most clinicians just estimate aniseikonia with the rule that for every 1.00D of power difference, there will be ~1% induced aniseikonia
If you add two soft CL’s how do you figure out the resultant power and axis?
- Resultant cyl axis is between the cylinder lens axis
- Resultant cyl axis is closer to the CL with more cyl power
- Sum of spherical equivalents of the 2 cyl lenses will equal the spherical equivalent of the resultant cyl lens
DEC synthesis of type 1 collagen is MOST likely result in which of the follow? Select 2
a. INC IOP
b. Corneal thinning
c. Blue sclera
d. Cataract formation
e. Vitreous syneresis
b. Corneal thinning
c. Blue sclera
NOTE: type 1 collagen is primarily located w/in the cornea and sclera. Thus, DEC synthesis of type 1 collagen is MOST likely to result in scleral thinning (noted as a blue sclera due to the visibility of the underlying uvea), as well as corneal thinning
Type I collagen is found in which part of the cornea?
Stroma (450 um)
Where is type IV collagen found in the cornea?
Basement membrane & Descemet’s Membrane
Where is Type II collagen found in the cornea?
Bowman’s membrane
What mucin types bind to goblet cells?
Mucin 1,4,6
EBMD and Meesan affects what part of the cornea?
Basement Membrane
NOTE: thcikens w age, 8-10 weeks for regeneration
Band Keratopathy, Pterygia, Reis-buckler dystrophy, and Keratoconus affects which part of the cornea?
Bowman’s Membrane
NOTE: strong barrier to injury, acellular, embryologically layed down (no regeneration)
Macular dystrophy, granular dystrophy, and lattic dystrophy affects which part of the cornea?
Stroma
NOTE: hydrophilic, nerves enter here and move anteriorly
What are the 2 effects of PTH?
- Stimulation of osteoclast activity in bone
2. Stimulation of calcium reabsorption by the kidney
The midbrain is involve in the control of which of the follow (select 3)?
a. Sensory innervation of the cornea
b. Innervation of the lateral rectus
c. Innervation of the Superior Oblique
d. Innervation of the levator palpebrae superioris
e. Motor activity to the muscles of facial expression
f. Pupillary constriction
c. Innervation of the Superior Oblique
d. Innervation of the levator palpebrae superioris
f. Pupillary constriction
NOTE: the midbrain contains nuclei for CN3/4, and the EW nucleus.
Autoimmune damage to the salivary glands is MOST likely associated with which of the following clinical findings?
a. 11mm wetting after 5 min on Schirmer 1 testing
b. 6 sec TBUT
c. 4mm wetting after 5min on Schirmer 2 testing
d. 11mm wetting after 15 sec on phenol red thread test
c. 4mm wetting after 5min on Schirmer 2 testing
NOTE: autoimmune damage to the salivary glands (including the lac gland) causes Sjogren’s syndrome which is associated with ADDE. <5mm of wetting after 5min on Schirmer 2 testing is suggestive of ADDE
What is the MOST common infectious cause of post-operative endophthalmitis?
Gram (+) bacteria
NOTE: our lids and lashes have gram (+)
What is the MOST common clinical finding in toxic anterior segment syndrome following cataract extraction is?
Corneal edema
NOTE: marked diffuse corneal edema with little to no post seg inflammation Dx w/in first 12-48 hours following cat extraction. PS & suppurative conjunctivitis are LESS common but possible.
Zeaxanthin and lutein are xanthophyll pigments that are PRIMARILY located where?
Inner segments of PR
A posterior vitreous detachment is MOST commonly the result of:
a. INC type 2 collagen content of the vitreous
b. Formation of lacunae and inward collapse of the vitreal cortex
c. Loss of Weiger’s ligament in the anterior vitreous
d. Separation of the vitreous base from the retina
b. Formation of lacunae and inward collapse of the vitreal cortex
NOTE: result of INC vitreal liquefaction, which results in lacunae formation and inward collapse of the cortex.
When does separation of the vitreous base from the retina most often occur?
Trauma and is NOT a cause of PVD
What is the DIRECT role of RPE in the visual cycle?
Converting All-trans-Retinol to 11-cis retinol –> then oxidized to 11-cis retinal**
NOTE: RPE transports All-trans retinol into its cytoplasm via cellular retinol binding protein, where it is sequentially converted into 11-cis retinal. Many rod-cone dystrophies occur as a result of interruptions to this pathway
Using a high powered add will have all of the following effects EXCEPT:
a. DEC WD
b. DEC FOV
c. DEC lateral magnification
d. INC relative distance magnification
c. DEC lateral magnification
What is duane syndrome exactly?
A group of EOM disorders characterized by abduction and/or adduction deficits due to misrouting of CN6 & irregular innervation of a branch of CN3
What is the index of refraction for an ideal thin film that minimizes reflections for an anterior chamber IOL (n=1.45) w/in the aqueous humor?
1.392
nf = (nLnm)^0.5
nf=(1.451.336)^0.5=1.392
nf=index of film
nL=index of IOL
nm=index of aqueous
For aquired and asymmetric color vision defects, which eye should you test monocularly first?
The POORER seeing eye!!!
Which layers are absent at the foveola and why?
No bipolar cells No ganglion cells No INL No IPL No NFL
in order to minimize light scattering as light travels to the cone PR
Which group of vessels exits the outer wall of schlemm’s canal?
External collector channels (aka aqueous veins of Ascher) –> Episcleral plexus –> Anterior ciliary veins –> muscular veins –> S/I ophthalmic veins –> CS
Which of the following is NOT an association of an acute, unilateral, non-granulomatous uveitis (SELECT 3):
a. Juvenile rheumatoid arthritis
b. Behcet’s disease
c. Fuchs’ heterochromic iridocyclitis
d. Ankylosing spondylitis
e. Reactive arthritis
f. Tuberculosis
a. Juvenile rheumatoid arthritis
c. Fuchs’ heterochromic iridocyclitis
f. Tuberculosis
(a) and (c) are both chronic non-granulomatous uveitis, most often uni in Fuch’s and bilateral in JRA
(f) is associated with chronic, bilateral, granulomatous uveitis that may be anterior, posterior, or panuveitis
What is the MOA of Spironolactone?
It inhibits the actions of aldosterone in the late distal convoluted tubule (DCT) & the collecting duct of the nephron, leading to DEC absorption of NaCl & DEC excretion of K+
Furosemide inhibits which cotransporter?
Na+/2Cl-/K+ cotransporter in the thick ascending loop of Henle
If a bacterium were susceptible to both penicillin and erythromycin, then it would NOT be appropriate to Tx the pt w both antibiotics at the same time bc?
Penicillin is ONLY effective against growing cells
Bc erythromycin inhibits cell growth, it will DEC the effectivity of penicillin if both medications are administered at the same time
Which wavelengths are we most easily able to distinguish?
495nm and 590nm
Which of the following CORRECTLY pairs the pt’s age w the MOST appropriate VA test?
a. 24 month old toddler who sits too close to the TV; broken wheel testing
b. 11-month old infant w/o vision concerns; Allen symbols
c. 9 month old infant w a suspected RET; ooptokinetic drum
d. 30 month old toddler who squints; teller acuity cards
a. 24 month old toddler who sits too close to the TV; broken wheel testing
Broken wheel testing is a forced choice test that is MOST appropriate for toddlers or children of pre-school age. Teller acuity cards, another forced choice method, are most appropriate for infants ages 6-18 months.
Allen symbols are most appropriate for pre-school children (3 years of age or older) rather than an infant
The OKN drum only assesses activity within the visual cortex & is not appropriate for determining the presence of strab or the risk of amblyopia
Your pt w a Hx of RA presents w a complaint of redness OD w/o associated pain. You note focal blue-gray areas of the sclera w mild conjunctival injection and no associated keratitis. What is the MOST likely Dx?
Scleromalacia perforans
NOTE: also known as necrotizing scleritis w/o inflammation. It is a common form of scleritis in pts with severe RA. Pts present w a bluish-gray hue of the sclera due to thinning that results from rearrangement of the scleral collagen fibers after resolution of the inflammation. Pts ofte have minimal hyperemia & pain.
Nodula
A 45 year old female complains of bilateral ocular burning, tearing, and a FB sensation that progressively worsens throughout the day. She also reports a Hx of chronic dry mouth. Which of the following is MOST appropriate to further evaluate this pt’s symptoms?
Salivary gland biopsy
R/O sjogren’s
What is the MOA of ophthalmic trifluridine?
It prevents viral DNA replication by inhibiting thymidine synthetase
A pt who has experiences a TBI complains of difficulty finding the start of the next line when he finishes reading a line of text. Which of the following is MOST likely cause of his complaints?
a. Bitemporal hemianopsia
b. Left homonymous hemianopsia
c. Right homonymous hemianopsia
d. Binasal hemianopsia
b. Left homonymous hemianopsia
A pt who smokes cigarettes notices a gradual onset of labored breathing and shortness of breath. He has a reduced FEV1/FVC ratio. Which of the following is the MOST likley Dx?
Pulmonary emphysema
Enlarged air spaces & decreased elastic recoil
- Dyspnea
- Tachycardia
- REDUCED FEV1/FVC ratio
Which of the following wavelengths of light is MOST likely to damage the retina of a phakic elderly adult?
a. 285 nm
b. 370 nm
c. 310 nm
d. 210 nm
b. 370 nm
Recall:
UVA 400-315
UVB 315-280
UVC 280-100
UVC is absorbed by tears, cornea, and aq humor
UVA and UVB will be transmitted by the lens to the retina in a young pt
With age UVB is absorbed and almost all of UVA light
What is Kearns-Sayre Syndrome? What are some ocular features?
Kearns-Sayre syndrome is considered a mitochondrial myopathy in which mitochondrial DNA deletions result in a clinical triad of signs.
These signs include ocular features such as progressive external ophthalmoplegia (CPEO) and “salt and pepper” pigmented retinopathy (with predilection for the macula), as well as one or more systemic complications which can include heart block, cerebellar ataxia, or abnormally elevated cerebrospinal fluid protein.
Which of these statements are FALSE about a sphero-cylindrical lens OR for a SCL?
a. If the axis of the OR is the same as the axis of the spectacle Rx, INC cyl power in the soft toric CL
b. If the axis of the OR is 090 degrees from the axis of the spectacle Rx, DEC the cyl power in the SCL
c. For every 5 degrees of misalignment btwn the soft toric CL and the axis of the spectacle Rx, 1/4th of the original cyl power will manifest in the OR
d. If the axis of the OR is oblique compared to the axis of the spectacle Rx, the soft toric CL has rotated
c. For every 5 degrees of misalignment btwn the soft toric CL and the axis of the spectacle Rx, 1/4th of the original cyl power will manifest in the OR
NOTE: for every 5 degrees of misaligment btwn the soft toric CL position & the spectacle Rx, approx 1/6th of the original cyl power in the spectacle Rx will manifest in the sphero cylindrical OR.
If the axis of the OR and spectacle lens Rx are the same, the soft toric CL is under-correcting the pt’s astig; thus, the cyl power in the soft toric CL should be increased.
If the axis of the OR is 090 away then subtract the OR from the pts astig
If the axis of the OR and spec Rx are oblique, the axis of the soft toric CL is incorrect or the CL rotated on the eye
All of the following may occur as a result of an aneurysm of the posterior communicating artery EXCEPT:
a. impaired accommodation
b. Limited abduction
c. Limited supraduction
d. Mydriasis
e. Ptosis
b. Limited abduction
A PCA aneurysm is the MOST common cause of a pupil-involved CN3 palsy.
Impaired CN3 innervation results in Mydriasis (impaired iris sphincter), Ptosis (impaired levator), Poor accommodation (impaired ciliary muscle), & limited adduction, supraduction, and infraduction (poor innervation of the MR, SR, IO, and IR)