Made during lens session.

1. ANAESTHESIA FOR
CATARACT
SURGERYBipin Bista
Resident - Ophthalmology

2. Introduction
• Procedures and medications given to allow successful completion of lens removal with minimal
risk , pain and anxiety.
• Historically, surgery were done without any anaesthesia
• Koller used topical cocaine at limbus in late 1800s
• Retrobulbar anaesthesia was first described in 1884 by Knapp : 4% cocaine for anaesthesia
• Modern technique of retrobulbar anaesthesia described in 1945 by Atkinson.

3. Retrobulbar anaesthesia
• Aim is to block oculomotor nerves by
depositing the L.A into posterior intraconal
space.
• Reliable akinesia
• Quicker onset of the block
• Temporary visual loss more reliably than
peribulbar.

4. Complication of Retrobulbar anaesthesia
• Retrobulbar hemorrhage
• Ocular perforation (< 0.1% incidence, but 1 in 140 injections in
myopic eyes)[28]
•
Subarachnoid or intradural injection, leading to brainstem anesthesia
in 1 in 350–500 patients
• Respiratory depression or arrest (0.29% incidence)
• Optic nerve contusion and atrophy
• Retinal vascular occlusion
• Grand mal seizure
• Decreased visual acuity
• Hypotony (< 8 mmHg)
• Contralateral amaurosis
•
Muscle complications: ptosis from levator aponeurosis dehiscence,
entropion and diplopia following extraocular muscle injection
• Pulmonary edema
•
Oculocardiac reflex, usually produced by pressure on the globe
(vasovagal bradycardias are more common)

5. Peribulbar Block
• Outside the posterior muscle cone and
thereby preventing grievous injuries by
retrobulbar block.
• Utilises higher volume (6-10ml) with use of
pressure device.
• 25 mm needle is advanced parallel to the
plane of orbital floor either
transcutaneously or transconjunctivally.
• Assessment after 5 minutes for degree of
akinesia.
• Mediocanthal if akinesia isn’t seen.

6. Peribulbar Block

7. Sub tenon’s block
• First described by Turnbull in 1884 using open dissection of tenon’s layer followed by instillation
of cocaine.
• Later Stevens and Greenbaum made modifications.
• Tenon’s capsule :: Jacques René Tenon ( 1724-1826)
• Facial sheath enveloping the eyeball and separating from orbital fat.
• Conjunctiva anaesthesized by topical then via infranasal approach (3-5 mm from limbus) then a
simple incision is made in the sclera.
• Anterior technique : tip remains anterior to the globe equator ,less akinesia obtained than
posterior.

8. • Bevel is introduced
• Volume : 6.4 to 2.6 ml
• Complication : chemosis , inflammation,
scleral perforation, CV collapse, sight as
well as lifethreatening complication also
reported.
Sub tenon’s block

9. Topical anaesthesia
• More than 60% of surgery are performed in
united States.
• Oxybuprocaine is used (0.4%)
• proparacaine is less toxic for corneal
endothelium.
• Tetracaine 0.5-1%
• Lidocaine 1-4%
• Bupivacaine 0.5-0.75 %
• Lidocaine 2% jelly

10. Topical anaesthesia
ADVANTAGE DISADVANTAGE
• Distracting
• No akinesia
• Less effective than sub-Tenon’s block
• Unsuitabel for rookie surgeon.
• Epithelial and endothelial toxicity
• Surface keratopathy
• No risk with needle insertion
• Reduced risk of periocular haemorrhage
• Functional vision is maintained
• Reduced post-op diplopia and ptosis.

11. Local anaesthetic agent
• Most commonly used lidocaine 2% with hyaluronidase 15 iu/ml.
• Greater duration requires bupivacaine with lidocaine 50:50
• 2-chloroprocaine
• 2-3% mepivacaine
• Bupivacaine 0.25-0.75%
• Prilocaine 3%
• Ropivacaine 0.75%
• Articaine 2-4%

12. ADJUVANTS
• Epinephrine 5µg/ml : improve onset time, quality and duration of the block. Avoided in
atherosclerotic patients for optic artery thrombosis secondary to vasoconstriction
• Hyaluronidase : enzyme derived from rams testicles (previously cattle), hydrolyses C1-C4
bonds between glucoamine and glucoronic acid in connective tissue : thus penetrate tissue
effectively, also helps to prevent diplopia by preventing damage to rectus muscle.

13. Sedative Agents
• Midazolam : short acting bzd with T ½ of 2 hours, both amnesic and anxiolytic properties. 0.5-1
mg increment.
Overdose has reversed : flumanezil half-life is 1 hour so re-sedation can occur.
• Propofol : short acting phenol : rapid and clear headed recovery.
• Fentanyl : potent, short acting nacrcotic analgesic with DOA 30 minutes ; 25-50 µg :
anaesthesia with minimal sedation.
• Remifentanyl : Ultra-short acting

14. General anaesthesia
• Suitable for babies, children and the uncooperative .
• Intubate paralyse and ventilate.
• Laryngeal mask airway
• Avoid suxamethonium : rise in IOP

15. Specific conditions
• Ischaemic heart disease : avoid for 3 months
• Anticoagulants : risk of haemorrhage
• Diabetes mellitus

16. References
- Ophthalmology : Yanoff and Duker : 4th Edition
-American academy of ophthalmology : section 11 : 2014-2015

17. THANK YOU