ACE Review - Optho Flashcards
questions
anwers
what is the purpose of the gas bubble in the eye
to help with retinal adhesion and fibrosis
what is avoided when gas bubbles are used
nitrous oxide
why is nitrousoxide bad? moa
it expands and will cause compressive ischemia on the retina
when can nitrous oxide be used in patients who had gas bubble
after 3 months to allow all of gas bubbles to be absorbed
where is a retrobulbar block placed
muscular cone behind the globe
complications of retrobulbar block
intravasc injection..sz’s, subarach injection, retrobulbar bleeding, optic nerve injury
which block does not require a seperate facial block to prevent blinking
peribulbar block
how is a peribulbar block done
it is placed outside the muscular cone, thus anes to the orbicularis oculi
what is a subTenon block
anes is injected under the sclera
does KTP;Nd-YAG laser cause damage to cornea
no it passes cornea and then goes to retina
what does KTP;Nd-YAG laser burn retina
bc it is absorbed by pigmented tissue
what kind of filter does protective eye wear for KPT;Nd-YAG need
operators need red filter glasses
what do all lasers besides CO2 lasers have in common,
they conduct through glass very well, thus requiring special filters on glasswear
what color of filter is needed on glasses for krypton laser
amber colored filters
what laser has the highest infrared wavelength
co2 laser
what color is co2 laser
it is colorless, so a helping light is used to guide the operator
why does co2 laser cause corneal damage versus all the other lasers
because it is also absorbed by clear tissue and water.
what kind of filter is needed on eyewear when using co2 laser
since it is absorbed by clear tissue and water, all eyewear that is clear is protective enough
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what is the most common cause for perioperative vision loss
ischemic optic neuropathy
what are 2 general categories for periopterative visino loss
anterior and posterior ischemic optic neuropathy
what is a common associated symptom of both types of ischemic optic neuropathy
both are painless
what does anterior ischemic optic neuropathy mean
when the ischemic involves the optic disk
what does posterior ischemic optic neuropathy mean
when the retrobulbar portion of the optic nerve
what vessel is affected in anterior optic neuropathy
the watershed areas of the short posterior ciliary arteries
is anterior optic neuropathy unilateral or bilateral
45% unilateral, 55% bilateral
what kind of surgery is anterior optic neuropathy usually associated with
cardiac surgery
what do you see on fundoscopic exam of anterior ischemic optic neuropathy
pale optic disk edema
when does anterior optic neuropathy happen
24 - 48 hrs after surgery
what nerve is affected by the posterior ischemic optic neuropathy
intraorbital optic nerve
is posterior ischemic optic neuropathy unilateral or bilateral
bilateral 60-75% of cases
what surgery is posterior ischemic optic neuropathy associated with
spine surgery
what do you see on fundoscopic exam of posterior ischemic optic neuropathy
normal exam
when does posterior ischemic optic neuropathy manifest
right after surgery
what are subdivisions of both ant and post ischemic optic neuropathy
arteric vs non-arteric
what is temporal arteritis
is is a form of anterior ischemic optic neuropathy
what symptom does temporal arteritis have.
it is painful
what lab work is pathonomonic for temporal arteritis
temporal aa biopsy shows giant cells
what do you do to treat temporal arteritis
steriods
what is this…bilateral blindness, painless, normal fundoscopic exam
cortical blindness vs posterior ischemic optic neuropathy
how can you tell difference between posterior ischemic optic neuropathy and cortical blindness
cortical blindness has normal pupillary reflexes
what are 2 types of drug moa that is used for open angle glaucoma
beta blockers and parasympathomimetics
what is assoc with beta blockers used for open angle glaucoma
they can cause severe hypotension
does defasiculating dose of nmd help prevent increase intraoc pressure associated with succ
not reliabily
is the use of atropine strictly contraindicated in open angle glaucoma
no
what is the pathophys behind glaucoma
the increase in iop causes decrease blood to optic nerve
what is open angle glaucoma
it is the decrease filtration and drainage of aqueous fluid through the trabeculae tissue
how do beta blockers prevent glaucoma
it decrease aqueous humor production
what is apraclonidine and brimonidine for glaucoma
they are alpha 2 Agonist drugs used to decrease aqueous humor
what is acetazolamide and dichlorphenamide used in glaucoma
these are carbonic anhydrase inhibitors
what is prilocarpine and carbachol of glaucoma treatment
these constrict pupils and increase aqueous outflow
what is latanoprost and xalantan of glaucoma treatment
they are prostoglandins that increase aqueous outflow
what is physiostigmine and echothiophate and isofluorophate of glaucoma treatment
they are anticholinesterase inhibitors that decrease intraocular pressure
would the use of atropine be contraindicated in glaucoma
atropine is an anticholinergic….supposedly it causes pupil dilation….but the amount given is minimal and would not cause pupil dilation
can you give scopolamine to a glaucoma patient
scopolamine causes significant pupil dilation…it is contraindicated
iop. what is normal intraocular pressure
10 to 22 mmHg
iop. 3 determinants of iop
sclera compliance, extraocular pressure, and intraocular volume
iop. what is the intraveous agent that can cause increase in iop
ketamine
iop. of the introcular volume…what is the most important factor that increases iop
venous blood volume…anything that prevents venous return back to the heart may increase iop…like c collar or trendelenburg position
