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Anesthetics in Ophthalmic practice

 reversible blockage of nerve fiber conduction (block sodium channels) Anesthetics in Ophthalmic Practice

 PH dependent for Anesthetics in Ophthalmic Practice: 

(less effective at low pH like inflamed tissue)

Classes ( esters and amides)

 Ester for Anesthetics in Ophthalmic Practice:

 hydrolyzed by plasma cholinesterase
 metabolized in liver

Examples
 cocaine
 tetracaine (amethocaine)
 proparacaine
 procaine
 benoxinate

 Amide Anesthetics in Ophthalmic Practice:

 longer duration and less systemic toxicity
 metabolized in liver

Examples

lidocaine
mepivacaine
bupivacaine

Routes of administration

 Topical Anesthetics in Ophthalmic Practice:

Disturb intercellular junction of corneal epithelium (increase permeability)

Examples

 Proparacaine (Ophthaine)
• 10- to 30-minute duration
• cause allergic dermatitis

Tetracaine (Pontocaine)
•similar to proparacaine but longer duration
• more toxic to corneal epithelium

 Benoxinate
• similar to proparacaine
• can be combined with fluorescein (Fluress) for tonometry

 Cocaine
• greatest epithelial toxicity
• excellent anesthesia
• sympathomimetic effect (test for Horner’s syndrome)

 Parenteral( injectables) for Anesthetics in Ophthalmic Practice:

May be used with epinephrine (1:100,000) to increase duration by preventing systemic absorption and decreases bleeding

Hyaluronidase (Wydase) 150 IU increases tissue penetration, but decreases duration.

Side effect of retrobulbar anesthesia 1⁄4 respiratory depression, bradycardia

 Toxicity: hypotension, convulsions, nausea, vomiting

Examples

 Lidocaine (Xylocaine)
• 1 hour duration (2 hours with epinephrine)
• used for local anesthesia and akinesia

 Procaine (Novocain)
• 30 to 45 minute duration

 Mepivacaine (Carbocaine)
• 2 hours duration

 Bupivacaine (Marcaine)
• 6 hours duration

 General Anesthetics in Ophthalmic Practice:

 All agents decrease intraocular pressure (IOP)except ketamine, chloral hydrate, N2O, and ether

 Malignant hyperthermia (Major complication)

 Rare anesthetics in Ophthalmic Practice

 autosomal dominant 

 Occurs after exposure to inhalation agents (most commonly halothane, also succinylcholine, haloperidol

More common in children and males

 Due to calcium-binding disorder with increased intracellular calcium, which stimulates muscle contraction and interference with oxidative phosphorylation causes hypermetabolic crisis

Most have defect in ryanidine receptor (RYR-1 gene on chromosome 19q13.1)

Anesthetics in Ophthalmic practice power point presentations:

Ophthalmic anesthesia:

Anesthetics in ophthalmic practice videos

Ophthalmic anesthesia towards a better block video

Regional anesthesia video

Anesthetics in Ophthalmic practice