Opthalmic and Dental Procedures Flashcards
Colored part of eye?
iris
Tough, fibrous, white outermost layer of eye?
sclera
Small, pink nodule in corner of eye; lacrimal duct?
caruncle
Keeps objects from sliding behind eyeball?
conjunctiva
Where topical opthalamic drugs are administered?
conjunctiva
Part of the eye that forms the optic sheath encircling the optic nerve?
sclera
3 out layers of the eye?
sclera, cornea, conjunctiva
Tough outer layer of eye that is transparent and is the anterior part of the sclera
cornea
Middle layers of eye?
uveal tract, (choroid, iris, ciliary body)
Innermost layer of eye?
retina
Layer that produces O2 for retina?
choroid
Are there capillaries in retina?
no
Part of eye that is a neurosensory membrane which converts light impulses to neural impulses via the optic nerve to the brain
retina
This thick fluid is attached to blood vessels and optic nerve?
vitreous gel
Major cause of vision loss?
retinal detachments from choroid layer
3 layers of tissue which provides most of the nutrients to the eye?
uveal tract
Part of the uveal tract which contains blood vessels, is posterior, and supports the retina?
choroid plexus
Part of the uveal tract which controls light entry with muscle fibers and changes the pupil size?
iris
Sympathetic nervous system control of the iris does what and parasympathetic does what?
SNS- dilate; PNS- constricts
2 functions of the ciliary body?
secretes aqueous fluid and controls shape of the lens
How do the ciliary muscles change the shape of the lens?
tension on the Zonule of Zinn
Where is aqueous humor drained?
Schlems Canal
Where is aqueous humor formed?
posterior chamber
The 3 chambers of the eye ball?
anterior, posterior, viterous
IOP is determined by? And what should it be?
rate of aqueous humor formation to outflow; 25 or less
Which chamber is blocked in glaucoma?
anterior chamber
Schlemms canal is in which chamber?
anterior
Balance between production and elimination of aqueous humor formation maintains an average volume of what?
250 mL
IOP is usually between what and what?
10-22
Part of eye that is fibrous connective tissue from corneal limbus to behind the eye orbit?
Tenon capsule
Main function of Tenon capsule?
serves as cavity in which eye moves
Term for near sighted and far sighted?
myopia; hyperopia
Which type vision is elongated and the focal point is nearer to the lens?
myopia
Which type of vision is where the eye is short and the focal point is further from the lens?
hyperopia
Which type of vision is a concern with a retrobulbar block? And why?
myopia; bc the globe is elongated and the sclera is stretched thin so it is easier to puncture with a needle
What part of the eye turns the image in to the correct perspective?
optic nerve
The optic nerve is a direct connection to what?
occipital lobe
Which type of vision requires glasses for most of life?
myopia
An elongated globe is longer than __mm?
24
A short globe is shorter than __mm?
22
How many muscles are in the eye?
6
The rectus muscles originate from where and how many are there?
annulus of Zin; 4
This nerve controls the superior, inferior, and medial rectus muscles? And is it SNS or PNS innervation?
oculomotor nerve (III); PNS
Which way do the rectus muscles pull the eye?
in the direction of their attachment
Which nerve controls the lateral rectus muscle?
abducens (VI)
How many cranial nerves control the eye?
3
How many oblique muscles of the eye are there?
2
Which nerve controls the superior oblique muscle?
trochlear (IV)
Which nerve controls the inferior oblique muscle?
oculomotor (III)
Which muscle rotates the eye towards the nose or intorts?
superior oblique/trochlear nerve
Which muscle rotates the eye sideways/extorts/vertical gaze action?
inferior oblique/oculomotor
Where is the annulus of Zin? And which muscles originate there?
orbital apex; all ocular muscles except the obliques
CN that conveys visional info from retina to occipital lobe?
optic/II
CN that controls tears and closes the eye lids?
facial/VII
CN that is the efferent pathway for oculocardiac reflex -bradycardia and dysrythmias?
X/vagus
Why is an injection in to the optic nerve sheath basically an injection in to the CNS?
it is covered by meninges
2 branches of the facial nerve (CN VII)?
temporal and zygomatic
Why do you sometimes block the facial nerve with an eye block?
because the branches control the opening and closing of the eye
How many bones and what are they that form the eye orbit?
7; frontal, sphenoid, lacrimal, ethmoid, maxillary, palatine, zygomatic
How is each eye orbit shaped?
like a pear and has 4 sided pyramid
Where is the blood supply to the rectus muscles from? And where is it primarily from?
1st branch of internal carotid artery, primarily from opthalmic artery
Medial muscular branch is?
medial rectus, inferior rectus, inferior oblique (MII)
The lateral muscular branch is?
lateral rectus, superior rectus, and superior oblique (LSS)
Ciliary artery branches in to (2)?
short posterior and long posterior
This artery supplies the globe, choroid, optic nerve head, and external part of retina?
short posterior
This artery of the ciliary artery gives rise to the 7 anterior ciliary vessels and supplies the anterior eye?
long posterior
Each rectus muscles has __ anterior ciliary vessels except the ______ rectus muscle has 1?
2; lateral
Topical opthalmic medications can have systemic absorption thru (2)?
conjunctiva and lacrimal duct because it goes in to the nasal mucosa
If a block or GA not used for cataract, what 4 things are given?
tetracaine, dilator, steroid, abx
How quickly are eye drops absorbed?
slower than IV, but faster than SQ
Suxxs contraindicated with taking with what eye drop? Why?
echothipate- may prolong the effects of Suxxs w plasma cholinesterase 3-7 weeks after d/c
What class of drug is echothiopate?
IRREVERSIBLE cholinesterase inhibitor
What does echothipate produce in the eye?
miosis
How do carbonic anhydrase inhibitors work as eye drops?
reduce aqueous humor production (glaucoma)
What does miosis do to the pupils?
constricts
Mydriasis does what to pupils?
dilates
Central anticholinergic syndrome is and which drug do you have to be careful about that with?
mad as a hatter, hot as a hare, dry as a bone; atropine
Why is atropine used as an eye drop?
it dilates the pupils; mydriasis; opthalmic capillary decongestion
What do phenylephrine and epinephrine do to the pupil?
mydriasis
What gas do you have to avoid with sulfur hexafluoride (SF6)?
N20
Metallic taste after eye drop can be a sign of toxicity but is often d/t?
LA passing thru nasal mucosa
What can you do after eye drop administration to reduce systemic absorption (3)?
close eyes for 60 seconds, avoid blinking, block tear outflow canal with index finger (with eye closed)
This topical anesthetic med stings on administration?
tetracaine
What does alkalizing a solution with sodium bicarb do to the absorption?
decreases the onset time
A protein enzyme that speeds onset of eye drops by promoting the even spread of the local anesthetic, especially in the peribulbar technique?
hyaluronidase
This type of anesthesia is used for ocular procedures if need suppresion of oculocardio reflex, akinsia, and analgesia?
regional
3 types of regional anesthesia for ocular procedures?
retrobulbar block, peribulbar techniques, sub tenon block
A synonym for retrobulbar block?
intraconal block
Which block is not very common any more?
sub tenons
Why is a sub tenons block contraindicated in glaucoma?
it raises the IOP
This block is better for anticoagulated patients at risk for retrobulbar hemorrhage?
sub tenons
Volume of orbit and volume of globe in mL?
30 mL, 7mL
In this type of block, the tip of the needle is inserted behind the globe?
retrobulbar
What type of block is sometimes required to go along with retrobulbar block?
facial
This type of block limits eyelid squinting?
orbicularis occuli
2 types of approaches for retrobulbar block?
transcutaneously or transconjunctivally
This type of eye block includes an injection outside of the cone?
peribulbar block
Some differences between retrobulbar and peribulbar blocks (5)?
retro: intraconal, deep needle placement w/in orbit, small volume 2-4 mL, fast onset 2 min, may need facial nerve block or eye lid block; extraconal: extraconal, needle away from optic nerve, larger volume 10-12 mL, latency of onset-10 minutes
Even pressure should be placed on the eye post block in order to (3)?
diffuse LA, reduce IOP, soften the eye
Honan device applies how much pressure and for how long?
30-40 mm Hg; 5 minutes
How should a digital massage after an eye block be done?
30 sec on, 5 sec off
Best block as far as pain on injection goes?
peribulbar
Best block for blocking surgical pain?
sub tenons
Best block to cause eye akinesia?
retrobulbar
Most frequent complication from eye block?
retrobulbar hemorrhage (and maybe superficial hemorrhage too-it’s not clear)
Which anesthetic should you avoid if a patient is allergic to esther anesthetics?
tetracaine
3 symptoms of retrobulbar hemorrhage?
subconjunctival hemorrhage, proptosis (bulging of eye), increased IOP
What does occlusion of retinal artery do to loss of vision? And when can this occur?
partial to complete loss of vision; with increased IOP
2 types of treatment for retrobulbar hemorrhage?
digital pressure and lateral canthotomy
2 ways in which a lateral canthotomy works?
increases the orbital space; reduces the orbital pressure that results from hemorrhage
The contralateral pupil should be constricted/dilated prior to the ocular block and if it constricts/dilates after the block that means it’s a subarachnoid or subdural injection?
constricted; dilated
How soon after injection does it occur that it was injected in to the subarachnoid/subdural space?
15 seconds
S/s of intravascular injection and optic nerve sheath penetration?
painless vision loss, disorientation, vomiting, aphasia, hemiplegia, unconsciousness, convulsions, respiratory or cardiac arrest a few minutes after!
This type of complication from a block is not always noticeable and may be delayed for days?
globe puncture
Globe puncture is easy to do in patients with ?
long eye/severely mioptic
Most devastating injury d/t anesthetic injection?
globe injury so if there is resistance stop!
Treatment of globe puncture?
it depends but if severe it’s a vitreoretinal
S/s globe puncture?
increased resistance to injection, immediate dilation and paralysis of pupil, rapid increase in IOP, edematous cornea, subconjunctival hemorrhage, pain and agitation, hypotony of globe (IOP
Measures to reduce likelihood of complications from nerve block?
use 1 1/4 in needle, caution in patients with longer axial lengths (miopia/near sighted), avoid supranasal position of gaze, direct needle away from axis of globe, observe globe movement with needle insertion, insert needle slowly, do not force injection, use modified retrobulbar or peribulbar techniques
S/s of persistent extraocular muscle paralysis and ptosis?
verticle diplopia (double vision)
Treatment of persistent extraocular muscle paralysis and ptosis?
surgical correction of injury to EOM
2 causes of facial nerve trauma (Bell’s Palsy)?
direct nerve trauma caused by needle or neurotoxicity of LA
Normal IOP range?
10-22
IOP follows what BP?
arterial
Increased IOP means what to the intraocular volume?
decreased intraocular volume
Open globe is permanet or reversible eye damage?
permanent
2 parts of acid base system that decrease IOP?
hypoxia and hypercarbia
Anesthetic drug that decreases IOP and 2 that increase IOP?
volatile gasses; ketamine, anectine
Afferent and efferent pathways for oculocardiac reflex involve which cranial nerves?
afferent-trigeminal; efferent-vagal
3 causes of oculocardiac reflex?
traction of extraocular muscles, pressure on globe, ocular manipulation
4 rhythms that can occur d/t OCR?
bradycardia, junctional rhythm, ventricular ectopy, asystole
2 ways to block OCR?
ocular block or deep sedation
Treatment for OCR?
atropine
Most common pediatric ocular operation?
strabismus
Why should you avoid Suxxs for strabismus surgery?
strabismus is more likely to reflect underlying myopathy so MH is more likely to occur
A surgery that is high risk for OCR?
strabismus
Strabismus surgery has as high as what percentage of N/V?
80%
Avoid what gas with SF6 and perfluorocarbons? And why? And how long?
N2O; can tamponade the retina; 10 days after injection N20 should be avoided
Difference between closed and open angle glaucoma?
closed angle is acute and where outflow is obstructed; closed is chronic and because of impaired aqueous drainage
What is treatment for glaucoma?
miotic drugs
Avoid what 2 drugs in glaucoma patients?
scopolamine and atropine drops
Main goal in patients with glaucoma?
prevent increases in IOP
What is unique about open eye procedures as far as anesthesia is concerned?
treat as full stomach
2 contraindications regarding open eye surgeries?
retrobulbar block and awake intubation with suxxs
Most common cause of postoperative eye pain after general anesthesia?
corneal abrasion
Treatment of corneal abrasion?
antibiotic ointment and patching for about 2 days
Treatment for acute glaucoma?
IV Mannitol or Acetazolamide and consult opthmologist
2 surgeries that put pt at risk for post op vision loss?
spine surgery in prone position and cardiac surgery
4 risk factors for post op vision loss?
hypotension, anemia, increased IOP, prone and head down position
Dental specialty that involves treating diseases and supporting and surrounding tissue of the teeth?
Periodonics
Dental specialty that encompasses pulp and root of tooth?
endodontics
Dental specialty encompassing rehab and maintenance of oral function and appearance of the
prosthodontics/orthodontist
Dental specialty for defects and esthetic aspects of maxilofacial region?
oral and maxilofacial surgery
What anatomical features place the dental patient at risk for severe pain?
maxillary and mandibular divisions of trigeminal nerve
Is it easier to numb the upper or lower teeth and why?
upper because bone is thinner
What are the main nerves you’re numbing on mandible for dental procedure?
lingual nerve and inferior alveolar nerve
Most common cause of postoperative eye pain after general anesthesia?
corneal abrasion
Treatment of corneal abrasion?
antibiotic ointment and patching for about 2 days
Treatment for acute glaucoma?
IV Mannitol or Acetazolamide and consult opthmologist
2 surgeries that put pt at risk for post op vision loss?
spine surgery in prone position and cardiac surgery
4 risk factors for post op vision loss?
hypotension, anemia, increased IOP, prone and head down position
Why do you not want to get a lot of Afrin spray in the nose?
it can increase the BP
What kind of intubation is usually used for dental procedures?
nasal
