Eye Surgery - Quiz 4 Flashcards

1
Q

What are the 3 Layers of the Eye?

A

Sclera - Outermost

Uveal Tract - middle

Retina - Innermost

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2
Q

Where does the most Focus Power of the eye come from?

A

Curvature of Cornea

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3
Q

What is the Uveal Tract made of?

A

Choroid

Ciliary Body

Iris

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4
Q

What is the Choroid?

A

Layer of Blood Vessels in the back of the Uveal Tract that supplies oxygen to the eye

Detachment = Vision Loss

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5
Q

What does the Ciliary Body do?

A

Sits behind Iris

Makes Aqueous Humor & Adjusts Focus by reducing tension on the Lens

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6
Q

What does the Retina contain?

A

Photoreceptors - neural signal

Pars Plana

NO Capillaries

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7
Q

Where is the Pars Plana of the Retina located?

A

Between Limbus of Cornea & End of Retina

(Area of Entry for Vitrectomies)

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8
Q

What is the Center of the Eye filled with?

A

Vitreous Gel

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9
Q

What does the Center of the Eye attach to?

A

Blood Vessels & Optic Nerve

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10
Q

What happens when there is Traction of the Vitreous on the Retina?

A

Detachment

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11
Q

What does the Superior Oblique muscle of the Eye do?

A

Rotates & Depresses Eye

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12
Q

What does the Inferior Oblique muscle of the Eye do?

A

Rotates Eye on Horizontal Axis

Extorts & Elevates Eyeball

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13
Q

Where do all Muscles of the Eye originate from with the exception of the Inferior Oblique?

A

Annulus of Zinn

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14
Q

What is the Ocular Cardiac Reflex (Five & Dime)?

A

Trigeminovagal Reflex that happens w/ Eye Manipulation (Especially Medial Rectus)

Bradycardia

AV Block

Ventricular Ectopy

Asystole

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15
Q

How does the Trigeminovagal Reflex work?

A

Afferent Impulses from Eyes –> Ciliary Ganglion –> Ophthalmic Trigeminal Nerve @ 4th Ventricle –> Trigeminal Sensory Nucleus –> Visceral Motor Neclei of Vagus –> Efferent Vagus –> Heart

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16
Q

With what type of Anesthesia does the Ocular Cardiac Reflex Occur?

A

Topical & General > Retrobulbar Blocks

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17
Q

What worsens the Ocular Cardiac Reflex?

A

Hypoxemia

&

Hypercarbia

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18
Q

How is Ocular Cardiac Reflex treated?

A

Stop Manipulation

Lidocaine Localization

Deepen Anesthetic

Atropine

Robinul

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19
Q

How is Intraocular Perfusion Pressure calculated?

A

MAP - IOP

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20
Q

What is the Normal IntraOcular Pressure?

A

10 - 22 mmHg

(> 25 mmHg is BAD)

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21
Q

The Globe is ________ with a _____ volume

A

The Globe is NON-COMPLIANT with a FIXED volume

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22
Q

What regulates IntraOcular Pressure?

A

Amount of Aqueous & Blood Volume

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23
Q

Production of Aqueous Humor is constant and is faciliated by _______

A

Production of Aqueous Humor is constant and is faciliated by CARBONIC ANHYDRASE

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24
Q

What can Increased IOP lead to?

A

Optic Disc Atrophy

Nerve Atrophy

Optic Artery Occlusion

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25
Q

What can Decreased IOP lead to?

A

Fluid Accumulation in the Eye

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26
Q

What happens to IOP with a Sudden BP Decrease of < 90 mmHg?

A

↓IOP

Los of Autoregulation

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27
Q

How does a Sudden BP Increase affect IOP

A

↑IOP, but normalizes d/t Drainage System

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28
Q

An Increase in CVP has a ______ effect than an Increase in BP regarding IntraOcular Pressure

A

An Increase in CVP has a GREATER effect than an Increase in BP regarding IntraOcular Pressure

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29
Q

How much can coughing increase IOP?

A

40x d/t Drainage Obstruction

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30
Q

How does Decreased PaCO2 affect IOP?

A

FAST drop in IOP d/t Choroidal Vasoconstriction

31
Q

How does Increased PaCO2 affect IOP?

A

SLOW increase in IOP

32
Q

How does Fast Breathing affect IOP?

A

INCREASE IOP d/t Insufficient Venous Drainage

33
Q

How does Metabolic Acidosis / Alkalosis affect IOP?

A

Alkalosis = ↑Choroid Volume & IOP

Acidosis = ↓Choroid Volume & IOP

34
Q

Blinking, Squinting, and Forced Lid Squeeze can increase IOP by _____, _____, and _____ respectively

A

Blinking, Squinting, and Forced Lid Squeeze can increase IOP by 5 mmHg, 25 mmHg, and 50 mmHg respectively

35
Q

Which muscle relaxant increases IOP?

A

Succinylcholine

36
Q

Which IV drugs can be given to Decrease IOP?

A

Acetazolamide - Carbonic Anyhydrase Inhibitor - Depletes Lytes

&

Mannitol - Osmotic Diuretic - Lasts 30-45 min, returning to baseline 5-6 hrs.

37
Q

What is Echothiophate?

A

Topical Anti-Cholinesterase used to maintain Miosis & treat Gluacoma

38
Q

What can happen if Echothiophate is systemically absorbed?

A

Total Cholinesterase Inhibition & Prolonged Post-Sux Paralysis

39
Q

What drug is used to Dilate the Pupil?

A

Phenylephrine

40
Q

What drugs are used to Constrict the Pupil?

A

Pilocarpine & Acetylcholine

May cause Bradycardia & Brochospasm

41
Q

What is Timolol used for?

A

Beta Blocker used to treat Glaucoma

42
Q

What can occur if Timolol is Systemically Absorbed?

A

Bradycardia

Bronchospasm

CHF

43
Q

How does Flomax affect Cataract Surgery?

A

Binds Iris Dilator Muscles

&

Makes Iris Floppy 7-28 days off therapy

44
Q

How should Pre-Op Severe HTN (Stage 3 > 180/110) be handled before Eye Surgery?

A

Reschedule surgery until two weeks of Anti-HTN Treatment

45
Q

What is the Blood Glucose goal for diabetics regarding Eye Surgery?

A

BS: 150-250

46
Q

What Urea Nitrogen level is considered Critical for eye surgery?

A

> 104 mg/dL

47
Q

What should be done if a patient came in for Cataract Surgery and was on Coumadin?

A

Continue with Surgery - safe to do w/ patient on warfarin

48
Q

What are Eye Surgery Requirements?

A

Eye Immobility & Lots of Anesthetic at the Site

49
Q

When should Versed & Fentanyl be avoided for Eye Surgery?

A

In patients w/ limited cognitive reserve

50
Q

What kind of Facial Nerve Blocks are typically used prevent eyes from Squeezing & Squinting?

A

Van Lint

Atkinson

O’Brien

51
Q

What is a Major Complication from Van Lint, Atkinson, or O’Brien blocks?

A

Subcantaneous Hemorrhage

52
Q

What kind of block affects the entire trunk of Facial Nerve and causes Lower Facial Droop for hours post-op?

A

Nadbath Rehman Block

53
Q

What are complications related to Nadbath Rehman Blocks?

A

Vocal Cord Paralysis

Laryngospasm

Dysphagia

Respiratory Distress

54
Q

How is a Retrobulbar Block done?

A

Inject 1:1 Bupiv 0.75% + Lidocaine 2% at the Inferior Temporal Margi of the Orbit

55
Q

What are the effects of a Retrobulbar Block?

A

Anesthesia of the Globe

Extraocular Akinesia

Hypotony - ↓IOP & ↓Aqueous Humor

56
Q

What indicates that the Superior Rectus muscle is not affected by the Retrobulbar Block since its outside the muscle cone?

A

Intorsion on Downward Gaze

57
Q

What are the complications from a Retrobulbar Block?

A

Hemorrhage

Proptosis (Downward Displacement)

Subconjuctival Ecchymosis

Optic Nerve Damage

Ocular Perf

Post-Op Strabismus (Cross Eyed)

58
Q

What happens with Intravascular Injection during a Retrobulbar Block?

A

Intravenous: Nothing

Arterial: CNS Excitation & Seizure

59
Q

What can happen when local is injected into the Optic Nerve Sheath/Subarachnoid during a Retrobulbar Block?

A

Contralateral Amaurosis (Vision Loss)

Obtundation

Respiratory Arrest w/in 20 min

Total Spinal & Vascular Collapse

60
Q

What are contraindications to a Retrobulbar Block?

A

Bleeding Disorders

Extreme Myopia (Nearsightedness)

Open Eye Injury

61
Q

How does a Peribulbar Block compare to a Retrobulbar Block?

A

Safer

Multiple Injections around Eye

Doesn’t Enter Muscle Cone

Longer Onset

Less Complete Akinesia

Increased Risk of Ecchymosis

62
Q

What makes a Sub-Tenon’s Block safer than a Peri/Retrobulbar Block?

A

No sharp needle & Less complications

63
Q

When is Topical appropriate for Eye Surgery?

A

Small Incision Surgeries & Phacoemulsion

64
Q

What are the Disadvantages to using Topical?

A

Patient Movement

Increased Pt. Anxiety & Discomfort

65
Q

What is used in Topicals for Eye Surgery?

A

Tetracaine 0.5%

&

Lidocaine 4%

66
Q

What meds can be given to limit IOP response to Intubation?

A

Lidocaine

&

Opioids

67
Q

What symptom may indicate IO Hypertension, Corneal Abrasion, or other complications?

A

Severe Pain

68
Q

What is done to tamponade a detached retina to the globe during certain vitreoretinal procedures?

A

Inject air bubble into eye

69
Q

When should N2O be stopped when air bubbles are use to tamponade detacehd retinas?

A

15 min before Sulfur Hexaflouride & avoid for 7-10 days after to avoid increased IOP

70
Q

How long should N2O be avoided after the use of Perfluoropropane (C3F6)?

A

1 Month

71
Q

How is Lacrimal Surgery done for kids?

A

Probe & Irrigation - suction well

72
Q

How is Lacrimal surgery done for Adults?

A

Dacrocystorhinostomy - Suction well

73
Q

Which anesthetic is avoided d/t nystagmus?

A

Ketamine

74
Q

What type of Anesthesia is used for Retinal Detachment & Vitreal Surgery?

A

General

or

Retrobulbar BLock