stains Flashcards
(42 cards)
what are the 5 diagnostic stains?
fluorescein rose bengal indocyanine green* lissamine green fluramene**
Which diagnostic stain is NOT used by optometrists, but is used often by ophthalmologists?
indocyanine green (IGGY)
Which diagnostic stain is a COMBINATION stain; it contains 2 products.
fluramene
which is NOT a property of diagnostic stains?
a. serve to enhance contrast
b. has special affinity for ocular tissues and cells.
c. acidic, basic, or neutral
d. chromatic differentiation depends on distinct absorption and emission spectrums.
acidic, basic, or neutral.
this is wrong! stains are only acidic or basic. they are NOT neutral!!!
T/F: Diagnostic stains are not neutral, therefore they can irritate the patient’s eye. light which is not absorbed is reflected, and we see what is reflected.
true!!!!
T/F: fluorescein absorbs 465nm (cobalt blue) and 493 nm in blood.
false!! 493 = cobalt blue and 465 in blood.
T/F: fluorescein is ionized in tears, is not lipophilic, therefore it does not readily enter the cornea.
true
fluorescein is a natural pigment found in organisms, such as _________. we are worried about this because it can drill a hole through CL’s.
pseudomonas
in what case can fluorescein enter the cornea?
when the cornea is NOT completely intact, ie. when the cornea is dry. Tight junctions are broken and fluroscein can leak between the gaps, staining the cornea.
T/F: Aqueous humor has basic pH.
true
When fluorescein on the surface of the eye appears as a different color over a lesion (ie. when aqueous humor leaks out) this is a “positive ______ sign”.
positive seidel sign
What is the order of least quenching to most quenching anesthetic?
a. Benzoalkonium chloride (BAC), benoxinate < proparacaine < tetracaine.
b. tetracaine < proparacaine < BAC/benoxinate.
benzoalkonium chloride (BAC) benoxinate < proparacaine < tetracaine
BB<p><T
T/F: quenching refers to any process that increases the fluorescence intensity of a substance.
false. any process that DECREASES fluorescence intensity.
what kind if filter should you use to filter out 520nm light? and where do you put it?
Wratten filter. You should put the filter in front of the receiving lens, so that it allows you to see fluorescein in great contrast. DO NOT PUT FILTER IN FRONT OF THE COBALT BLUE FILTER!!!!!!!!
T/F: quenching can be problematic because it affects how well we’re able to see contrast. if anesthetic is on the eye, it can cause excited fluorescein to go back to ground state without emitting 493 nm.
true
T/F: due to quenching, fluorescence intensity is diminished and false positives may result
false!!
false negatives may result.
what is punctate keratitis?
dry eye!
RGP lenses may block UV from a burton lamp, thus a wratten 47 filter is required over the light source.
true
if you see fluroscein, that means it is trapped under the lens, and that the lens is NOT in contact with the eye. the lens has great EDGE LIFT
true
what is methyl violet?
aniline dye used in indelible pencils. it is toxic!
what does a sodium fluorescein stain evaluate??
can distinguish herpes simplex virus (HSV) vs. herpes zoster virus.
if you see bulb-like ends on a fern-like filament, what kind of viral keratitis is this?
herpes simplex virus (not zoster)
Quenching causes an ___________ of intraocular pressure evaluation with applanation tonometry.
a. overestimation
b. underestimation
underestimation
stargardt’s disease is a genetically inherited juvenile macular degeneration that develops between what ages?
6-12 years old
leads to buildup of lipofuscin
