1. Ophthalmic anesthesia
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics-
PhD ( physiology), IDRA

2. History
The “Year 1884”
Carl Koller discovered cocaine hydrochloride as a topical anaesthetic agent for performing eye surgery
Herman Knapp used cocaine for retrobulbar injection and performed enucleation

3. Relevant anatomy Pyramid towards middle cranial fossa
Medial walls enclose nasal cavity
Lateral walls make an axis different from globe
4 – 5.5 cm

4. The globe occupies the anterior part of the Orbit
axial length of 20–25 mm
elongated in myopic individuals
Rectus muscle along with fibro tendinous sheath form a cone
SO4 , LR6. others 3 ( nerves)
Levator palpabrae – 3
Orbicularis oculi – facial nerve
Tenon’s capsule is a thin membrane, which covers the globe.

5. The sensory supply of the globe is via the long and short ciliary nerves, which are branches of the nasociliary nerve, itself a branch of the ophthalmic division of the trigeminal nerve.
Optic nerve – deep medial injection

6. Injections of fluid within the orbit will inevitably give rise to pressure on the globe and an increase in intraocular pressure
Mild proptosis
Not more than 30 mmHg pressure
Preblock scan of the globe

7. IV midazolam or / fentanyl
Three types of block
Retrobulbar block
Peribulbar block
Subtenon’s block
Preop assessment
IV midazolam or / fentanyl

8. Indications Cataract surgery, vitreoretinal surgery,
panretinal photocoagulation,
trabeculectomy,
optic nerve sheath fenestration,
delivery of drugs (steroids, neurolytic agents),
strabismus surgery in willing patients.
delivery of neurolytic agents for the treatment of chronic orbital pain.

9. Retrobulbar block Topical anesthesia of cornea (clouding ?)
Inferotemporal quadrant injection
Patient to view straight
Scleral or from the skin
Previous – superomedial gaze (atkinson)– optic nerve damage
Now modified straight gaze
10 – 15 mm , change go in , 4 – 5 ml
The best position for the patient is a semi-recumbent position (45°).

10. Technique

11. Skin or sclera

12. Drugs 2 % lignocaine or 0.5 % bupi or 0.75 % ropi
1 in 2 lakh adrenaline
+ 150 IU hyaluronidase
Akinesia is good , small volume , quick onset
26 G - one and half inch needle

13. Pressure Manual Thirty seconds-- Five second gap
The ocular compression device most commonly used is Honan’s balloon which is applied for min with the pressure set at 30 mmHg
If akinesia is incomplete , median peribulbar block supplementation

14. Complications
Hemorrhage in the very well-vascularized orbit, with a frequency of 0.7–1.7 % (known as “compartment syndrome”), can lead to blindness.
Chemosis
Perforation – esp. myopic patients
Injury to optic nerve
Subarachnoid
Intravascular
OCR
Myositis

15. Retro bulbar haemorhage
Steroids NSAIDS, aspirin, anticoagiulants
Proptosis, SCH , chemosis etc
If CRA pressure decreases , urgent decompression
Postpone surgery
But very mild no further bleeding outside,
Proceed with surgery 45 minutes later

16. Penetration ( one side )
Perforation( through & thro)
Both retrobulbar and peribulbar
Pain and loss of vision
prevention is the best

17. Myopathies
Muscle weakness
Corneal abrasion
( pressure)

18. Peribulbar block Inferotemporal Medial canthal Caruncular( Supplement)
Volume is slightly higher
Complications are less
Akinesia is more complete
Facial nerve block – not necessary

19. Pictures from the internet for closed academic circles only
25-G, 31-mm-long needle is inserted through the conjunctivaas far laterally as possible in the infero temporal quadrant.
Once the needle is under the globe, it is not
directed upward and inward, but it is directed along the orbital floor.
Five ml of LA
Medial canthal or caruncular as supplements – peribulbar blocks

20. So called safety of outside the cone
Volume higher
Akinesia OK
Can be late
Direct injury rates less ??
Why these sites
No direct injection into the muscle

21. Sub tenon’s block
Tenon’s capsule is a dense, fibrous layer of elastic tissue surrounding the eye and extra ocular muscles in the orbit
Potential space between posterior sclera and tenon’s capsule
Deposit LA

22. LA here --along the extraocular muscle sheaths,
diffusion into the retrobulbar space,
spread into the fascial planes around the lids,
as well as a direct action on the nerves supplying the globe that pass through this space.

23. LA topical
Lid retraction
Infero medial - Spring scissors – sclera incised
Cannula inserted to posterior part of the globe
4- 5 ml

24. Pictures from the internet for closed academic circles only
Infero medial
Cannula insertion

25. Subtenon’s block Little resistance usually
More resistance – some problem somewhere
Position better
Big conjunctival swelling – compress and take out
Mild protrusion is acceptable
7 – 10 mm from limbus is success
Excellent rapid analgesia
Post operative analgesia

26. Less volume – near by muscles are affected but distant LR may be spared
Advantageous in squint surgery
Scleral cautery is possible
Anticoagulants – OK
Chemosis and conjunctival haemorhage should be explained
No sharp needles !!

27. Facial nerve for orbicularis oculi
Atkinson

28. What is needed ? Cornea and conjunctiva – topical or blocks
Extraocular muscles – blocks ( peri or retobulbar )
Orbicularis oculi – facial nerve

29. You can”t do this after complete anesthesia
Check patient is correct
Check side is correct

30. Summary Thank you all Relevant anatomy Indications
Three types of block
Advantages and disadvantages
Facial nerve block
Thank you all