Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Advanced Princples Of Anesthesia Study Supplements > Eye Anesthesia + Blocks > Flashcards

Eye Anesthesia + Blocks Flashcards

(78 cards)

Start Studying
1
Q

What is a common ocular anesthesia technique used in cataract surgery?

A

Topical / Intraocular Anesthesia

Example: 2% lidocaine drops or gel, often supplemented with intracameral injection of preservative-free 1% lidocaine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the advantages of Topical / Intraocular Anesthesia?

A

Safe, simple; preserves motor function; rapid recovery.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the disadvantages of Topical / Intraocular Anesthesia?

A

No akinesia (eye or eyelid movement not blocked); variable pain relief.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the Sub-Tenon Block?

A

Provides deeper analgesia than topical anesthesia and is performed between rectus muscles of the globe.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the procedure for a Sub-Tenon Block?

A

Conjunctiva is incised; Tenon’s capsule is lifted and incised; blunt cannula inserted into the sub-Tenon space; local anesthetic (3–4 mL typical; up to 10 mL reported) is injected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the advantages of the Sub-Tenon Block?

A

Good analgesia; safer than sharp needle blocks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the limitations of the Sub-Tenon Block?

A

Variable akinesia (some globe movement may persist); requires more skill and time than topical.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the most common and effective way to produce profound analgesia and akinesia?

A

Ocular Regional needle block.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What blocks are involved in the Ocular Regional anesthesia?

A

Retrobulbar and peribulbar blocks.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which cranial nerves are affected by Ocular Regional anesthesia?

A

CN III (oculomotor), IV (trochlear), V (trigeminal), VI (abducens), VII (facial).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do the affected cranial nerves control?

A

Extraocular muscles, sensation, and eyelid motion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is the Ocular Regional anesthesia procedure performed?

A

In the orbital epidural space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of needle is used for a retrobulbar block?

A

23-gauge dull needle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where is the insertion site for a retrobulbar block?

A

Infratemporal quadrant, just above the inferior orbital rim

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the needle trajectory for a retrobulbar block?

A

Advanced toward the orbital apex, 35 mm deep

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the anesthetic volume injected in a retrobulbar block?

A

2–4 mL injected into the muscle cone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What should be done post-injection in a retrobulbar block?

A

Digital pressure applied over the closed eyelid; globe is inspected for akinesia after a few minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the complications of a retrobulbar block?

A

Trauma to optic nerve, vessels, globe → possible permanent vision loss; Seizures → from inadvertent intravascular injection; Respiratory arrest → anesthetic enters CSF via optic nerve sheath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What gaze direction should be used to avoid risk during procedures?

A

Use primary gaze (straight ahead) or down-and-out gaze to shift vital structures away.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the recommended needle depth to reduce optic nerve trauma?

A

Recommended depth: 19–25 mm – just posterior to globe, reduces optic nerve trauma.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What type of needles should be used for safer navigation?

A

Use dull/flat-grind needles, curved-tip, or pinhead needles for safer navigation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How can patient comfort be improved during procedures?

A

Sedation or topical anesthetic may improve tolerance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the current understanding of orbital anatomy?

A

Newer anatomical understanding emphasizes 360° fascial septa and open orbital communication.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the needle angle in the original Atkinson technique?

A

Oblique—directed toward orbital apex

Higher risk of trauma to optic nerve, vessels, and globe.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is the needle angle in the modified Gills & Lloyd technique?
Parallel—along lateral limbic margin, entering muscle cone posterior to globe ## Footnote Lower risk to posterior structures.
26
What is a key tip for the modified technique?
The needle passes lateral and parallel to the optic nerve, staying safer than in Atkinson’s original deep oblique path.
27
What is the original needle depth in the Atkinson technique?
~35 mm (1.38 in) → higher risk
28
What is the modified needle depth?
~25 mm (1 in) → places needle just behind globe, avoiding deep orbital structures.
29
What is the safe needle depth range?
19–31 mm (0.75–1.25 in), accounting for orbital and globe size variability.
30
What is the new approach for needle placement?
Use axial length to calculate globe’s equator to safely redirect needle cephalad into the retrobulbar space.
31
What eye position increases risk in the Atkinson technique?
Upward & inward gaze ## Footnote Increases tension on optic nerve & vessels—higher risk.
32
What eye position is recommended to reduce risk?
Primary gaze or down-and-out ## Footnote Maintains S-shaped optic nerve; reduces risk of trauma.
33
What is a Peribulbar Block?
Needle inserted outside the muscle cone (extraconal) to create positive pressure and spread anesthetic into the cone.
34
What is the typical volume used for a Peribulbar Block?
Larger volume of 8–12 mL.
35
Which cranial nerves are targeted in a Peribulbar Block?
Anesthesia of CN III–VII.
36
What are the common injection sites for a Peribulbar Block?
Inferotemporal (most common), medial, or superior-temporal.
37
What is the safety advantage of a Peribulbar Block?
Lower risk of optic nerve injury; safer for patients with high myopia, enophthalmos, staphyloma, or scleral buckle history.
38
What is a note regarding Peribulbar blocks?
They may require repeat injections due to poor spread into the cone from extraconal sites.
39
How does axial length of the globe relate to needle insertion?
Typically ~12.5 mm insertion reaches the equator; past this point, cephalad redirection into the muscle cone is considered safer.
40
What geometric method allows calculation of safe redirection point?
The geometric method by Harvey (OAS 23rd meeting) based on orbital-globe relationship.
41
What is the least vascular injection zone for retrobulbar and peribulbar blocks?
Inferotemporal zone (most common, safest).
42
What is the least vascular injection zone for extraconal peribulbar?
Superior orbital (just lateral to 12-o’clock).
43
What is an alternative extraconal access injection zone?
Medial conjunctival (via caruncle).
44
What are key safety practices for Peribulbar Block?
Use primary gaze or down-and-out positions, insert needle to ~25 mm depth, favor parallel approach, consider block in high-risk anatomies, calculate equator distance based on axial length, avoid deep needle paths unless necessary.
45
What is the purpose of the Gills-Lloyd Modified Retrobulbar Block?
Provides deep orbital anesthesia and akinesia with improved safety over the original Atkinson technique.
46
What is the needle insertion site for the Gills-Lloyd Modified Retrobulbar Block?
Transconjunctival, inferotemporal approach, parallel to lateral limbic margin (corneoscleral junction).
47
What is the depth of needle insertion for the Gills-Lloyd Modified Retrobulbar Block?
Insert needle to 25 mm (1 inch) and redirect cephalad between lateral and inferior rectus muscles after passing globe equator (~12.5 mm).
48
What is the volume/dose for the Gills-Lloyd Modified Retrobulbar Block?
Inject 1–1.5 mL of 1–2% lidocaine after negative aspiration, total ~6 mL for orbital filling.
49
What are the technique highlights for the Gills-Lloyd Modified Retrobulbar Block?
Start with a small volume peribulbar injection to reduce discomfort. Second insertion enters the muscle cone after crossing equator. Inject slowly (1 mL/10 sec). Use digital pressure after injection. Monitor for pressure sensation (orbital tension = full block).
50
What are the advantages of the Gills-Lloyd Modified Retrobulbar Block?
Avoids optic nerve and vessels, safer than traditional retrobulbar, can provide globe and eyelid akinesia without need for separate CN VII block.
51
What is the purpose of Peribulbar Extraconal Block Techniques?
Safer block option for high-risk patients (e.g., long axial length, staphylomas, previous scleral surgery).
52
Where are the injection sites for Peribulbar Extraconal Block?
Inferotemporal and/or supraorbital regions for better anesthetic spread. ## Footnote Medial peribulbar block for eyelid akinesia or missed muscle targets.
53
What is the needle insertion technique for Peribulbar Extraconal Block?
Insert 25 mm (1 inch) needle outside the muscle cone. ## Footnote Direct needle parallel to or angled away from visual axis.
54
What is the recommended volume for the Peribulbar Extraconal Block?
Large volume 10–12 mL (e.g., 6 mL inferior, 4–6 mL superior).
55
What is the technique summary for the Infraorbital injection?
Inject lateral to limbic margin, bevel toward globe.
56
What is the technique summary for the Supraorbital injection?
Insert just inferior to supraorbital rim (12 o'clock).
57
What should be done after the block for drug spread and IOP control?
Apply positive pressure after block.
58
How long should you wait for anesthesia to set in after the block?
Wait 10 minutes for anesthesia to set in.
59
What are the limitations of the Peribulbar Extraconal Block?
May not achieve full akinesia due to septal barriers. ## Footnote Requires multiple injection sites or repeat blocks.
60
What is the purpose of the Medial Peribulbar Block?
Primary or supplemental block, especially useful for eyelid akinesia (CN VII).
61
Where should the needle be inserted for the Medial Peribulbar Block?
Insert through caruncle conjunctiva, angled toward lacrimal bone.
62
What is the recommended needle length for the Medial Peribulbar Block?
Use a 0.5-inch (12 mm) needle.
63
What structures should be avoided during the Medial Peribulbar Block?
Avoid the puncta, canaliculi, and medial rectus muscle.
64
What is the recommended volume to inject for the Medial Peribulbar Block?
Inject ~3 mL or more after negative aspiration.
65
What are the advantages of the Medial Peribulbar Block?
Provides eyelid akinesia with less discomfort than Van Lint or Nadbath blocks. Can be used alone or to supplement incomplete globe akinesia. Avoids deep injection and globe trauma.
66
How is akinesia of the globe evaluated after a retrobulbar block?
Evaluated ~2 minutes post-injection.
67
How is akinesia of the globe evaluated after a peribulbar block?
Evaluated ~10 minutes post-injection.
68
What should be assessed after the Medial Peribulbar Block?
Globe movement in all four quadrants should be assessed.
69
What should be done if the orbicular muscle is still active after the block?
Supplement with medial peribulbar block.
70
What is the purpose of the Orbicularis Oculi Block?
It is a supplemental block when eyelid movement remains after retrobulbar or peribulbar anesthesia.
71
How is the Inferotemporal injection performed for the Orbicularis Oculi Block?
Insert a 30-gauge, 0.5-in needle bevel down, tangential to the skin. Inject 1–2 mL of local anesthetic subcutaneously. Digitally spread to medial and lateral canthi—do not run the needle across the lid.
72
How is the Supranasal injection performed for the Orbicularis Oculi Block?
Use the same needle placement, applying finger pressure to depress the globe. Inject 1–2 mL, bevel down and tangential to the lid. Digitally spread, followed by light pressure to prevent bleeding.
73
What is the Van Lint Technique?
It provides akinesia of the orbicular muscle (eyelids) via facial nerve (CN VII) branches.
74
When is the Van Lint Technique used?
It is an alternative to the medial peribulbar block when additional eyelid akinesia is needed.
75
What type of needle is used in the Van Lint Technique?
A 25–27 gauge, 1.5-in needle.
76
What are the steps for the first injection in the Van Lint Technique?
Inject 1–2 mL along the lower orbital rim, then withdraw.
77
What are the steps for the second injection in the Van Lint Technique?
Redirect supratemporally along the upper orbital rim with 1–2 mL.
78
What should be done post-injection in the Van Lint Technique?
Apply light pressure post-injection to reduce ecchymosis.

Advanced Princples Of Anesthesia Study Supplements (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions