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Ocular Disease 4 > Lecture 1/2 - Diagnostics > Flashcards

Lecture 1/2 - Diagnostics Flashcards

1
Q

What is red light/filter used for?

A

travels the furthest - pigmentary disturbances, choroidal ruptures, choroidal nevi, choroidal melanomas

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2
Q

What is blue light/filter used for?

A

NFL, ILM, ERM, retinal folds, cysts

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3
Q

What is green light/filter used for?

A

retinal vasculature, hemorrhages, drusen, exudates

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4
Q

what are the 4 parts to the early phase in FA?

A

choroidal flush, arterial phase, arteriovenous phase, and venous phase

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5
Q

when is the choroidal flush?

A

10-15 seconds after injection, dye in choriocapillaries

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6
Q

when is the arterial phase?

A

1-2 seconds after choroid - about 12 seconds

a delay may indicate injection or circulatory problems = heart or peripheral disease

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7
Q

when is the venous phase?

A

about 30 seconds after injection - maximum vessel filing

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8
Q

what are the 3 main phases of FA?

A

early phase, mid phase (recirculation phase) and late phase

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9
Q

when does the mid phase occur?

A

2-4 minutes - veins and arteries remain roughly equal in brightness

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10
Q

when does the late phase occur?

A

7-15 minutes - gradual elimination of dye from retinal and choroidal vasculature (late staining of optic disc is normal)

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11
Q

what are the 2 main causes of hypofluorescence?

A

vascular filling defect or blockage

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12
Q

if you use a red-free filter to view a dark spot on the retina and it disappears, what was it?

A

choroidal nevus (CHRPE will remain with red-free)

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13
Q

what 2 conditions can cause autofluorescence (or preinjection fluorescence)?

A

optic nerve drusen and optic nerve hemartoma

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14
Q

what causes pseudofluorescence?

A

poorly matched filters

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15
Q

what can cause early hyperflorescence in the retina?

A

abnormal vessels = tortuosity, dilation, anastomosis, neo, aneurysms, telangiectasia, tumor vessels

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16
Q

what can cause early hyperflorescence in the choroid?

A

PE window defect = atrophy or congenital

Abnormal vessels = subretinal neo, inflammation, tumor vessels

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17
Q

what can cause late hyperflorescence in the vitreous?

A

neo, inflammation, tumors

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18
Q

what can cause late hyperflorescence in the retina?

A

cystoid edema or non-cystic edema

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19
Q

what can cause late hyperflorescence in the choroid?

A

pooling or staining

20
Q

what is leakage hyperfluorescence?

A

seepage of NaFl, increases in intensity and margins blur in late phase (Ex: CNVM, DME, Neo)

21
Q

what is staining hyperfluorescence?

A

dye enters tissue and it retains it - intensity increases during transit but then stays the same, margins are distinct (Ex: scar, drusen, optic nerve tissue or sclera)

22
Q

what is pooling hyperfluorescence?

A

accumulation of dye in a fluid-filled space in the retina or choroid, margins are distinct (Ex: RPE detachment in CSR)

23
Q

what is transmission/window defect hyperfluorescence?

A

increased normal choroidal fluorescence through RPE defects or loss of pigment - dye stays in choroid, does not enter retina (Ex: macular hole or RPE loss)

24
Q

how is ICG different than NaFl?

A

higher molecular weight, remains in larger blood vessels (cannot pass through choriocapillaris fenestrations) and is not blocked by melanin/xanthophyll

25
Q

what are the contraindications for ICG?

A

caution with history of iodine or shellfish allergy and contraindicated in liver disease or DM on Metformin

26
Q

what is OCT used for?

A

lamellar vs. pseudo/full thickness macular holes, VMT, DME, CSR, AMD

27
Q

what structures in the eye normally autofluoresce?

A

corneal epithelium/endothelium, lens, macular and RPE pigments

28
Q

why is autofluorescence useful in Bests Disease?

A

RPE cells are eating up dye and appear hyper (lipofuscin) and RPE cells are dead are hypo

29
Q

what is near infrared reflectance imaging used for?

A

better resolution of outer retina - RPE, bruch’s, and choroidal vessels are more detectable (uses melanin)

30
Q

what is adaptive optics?

A

uses very high transverse resolution (2um) and capable of visualizing rod photoreceptors

31
Q

what frequency B-scan do we normally use in clinic?

A

7-10 MHZ (medium) = retina, vitreous, optic nerve

32
Q

when do you use increase gain on a B-scan?

A

increased tissue penetration and sensitivity but decreased resolution = hemorrhage, syneresis, posterior hyaloid, inflammatory cells

33
Q

when do you use low gain on a B-scan?

A

good resolution but poor sensitivity = layers or membranes, hyaloid, retina, choroid, retinal break/tear, tumor, macular edema, holes

34
Q

what is an electroretinogram (ERG) and what are the 3 waves?

A

mass response evoked from the entire retina = A wave is late receptor potential, B wave is on-bipolar potential and C wave is inner retinal potentials

35
Q

when are the inner retinal potentials/C wave (oscillatory potentials) reduced in an ERG?

A

retinal ischemic states and in some forms of congenital stationary night blindness

36
Q

what do focal and multifocal ERG test?

A

foveal or parafoveal cones (topographic ERG map of the retina is produced) = plaquenil toxicity

37
Q

what does a bright flash ERG test?

A

performed pre-op for severely traumatized globes with a brighter than usual stimulus - un-recordable response is a poor prognosis (moderate signal suggests some salvageable retina)

38
Q

what is a pattern ERG?

A

alternating checkerboard presented to central retina - integrity of optic nerve, ganglion cells and their retinal interactions (early recognition of glaucoma)

39
Q

what conditions have an abnormal ERG?

A

foveal disease, RP, CRAO

40
Q

what is an elector-oculogram (EOG)?

A

measures a response from the RPE (+ corneal end and - retinal end)

41
Q

what disease is the EOG severely reduced?

A

Best disease

42
Q

what is a visually evoked cortical potential (VEP)?

A

electrical signals generated by occipital visual cortex in response to stimulation of the retina

43
Q

what does the VEP response look like?

A

2 (N) negative and 2 (P) positive peaks

44
Q

when is VEP used?

A

assessing misprojection, estimating VA, detecting/localizing VF defects, visual potential, amblyopia/optic neuritis prognosis

45
Q

what is a sub-normal, severely abnormal and nearly extinguished Arden ratio in EOG?

A

less than 1.86 and less than 1.30

Ocular Disease 4 (6 decks)

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