COST COST Anesthesia and Medications in Ophthalmic Surgery 1 — Questions and Answers
Question 1: Which topical anesthetic agent is most commonly used for ocular surface anesthesia during ophthalmic procedures?
- Lidocaine 2% injection
- Proparacaine 0.5% drops (Correct answer)
- Bupivacaine 0.75% injection
- Tetracaine 0.5% drops
Correct answer: Proparacaine 0.5% drops
Proparacaine 0.5% ophthalmic drops are the most widely used topical anesthetic for ocular surface procedures due to their rapid onset and minimal stinging.
Question 2: Which type of anesthesia involves injecting anesthetic behind the globe to anesthetize the entire eye and immobilize extraocular muscles?
- Topical anesthesia
- Peribulbar block
- Retrobulbar block (Correct answer)
- Sub-Tenon's block
Correct answer: Retrobulbar block
A retrobulbar block deposits anesthetic within the muscle cone behind the globe, providing complete anesthesia and akinesia for intraocular surgery.
Question 3: Malignant hyperthermia is a life-threatening reaction most commonly triggered by which agents used in general anesthesia?
- Propofol and midazolam
- Succinylcholine and volatile halogenated anesthetics (Correct answer)
- Fentanyl and morphine
- Vecuronium and rocuronium
Correct answer: Succinylcholine and volatile halogenated anesthetics
Malignant hyperthermia is triggered by succinylcholine (a depolarizing neuromuscular blocker) and volatile halogenated agents such as sevoflurane, causing uncontrolled skeletal muscle metabolism.
Question 4: Which mydriatic agent works by blocking muscarinic receptors to dilate the pupil and paralyze accommodation?
- Phenylephrine
- Epinephrine
- Atropine (Correct answer)
- Apraclonidine
Correct answer: Atropine
Atropine is an anticholinergic (antimuscarinic) agent that blocks muscarinic receptors in the iris sphincter and ciliary muscle, producing mydriasis and cycloplegia.
Question 5: Intracameral carbachol or acetylcholine is used during cataract surgery primarily for which purpose?
- To dilate the pupil for better visualization
- To constrict the pupil (miosis) after IOL implantation (Correct answer)
- To lower intraocular pressure postoperatively
- To prevent endophthalmitis
Correct answer: To constrict the pupil (miosis) after IOL implantation
Intracameral acetylcholine or carbachol is instilled to rapidly constrict the pupil after IOL insertion, reducing the risk of iris prolapse and confirming pupil function.
Question 6: Which viscoelastic material property is most important for protecting the corneal endothelium during cataract surgery?
- High viscosity and coating ability (cohesive OVD) (Correct answer)
- Low viscosity for easy removal
- Antibiotic properties
- Mydriatic effect
Correct answer: High viscosity and coating ability (cohesive OVD)
Cohesive ophthalmic viscosurgical devices (OVDs) with high viscosity coat and protect the corneal endothelium by creating a physical barrier against surgical trauma and ultrasonic energy.
COST COST Anesthesia and Medications in Ophthalmic Surgery 1
Which topical anesthetic agent is most commonly used for ocular surface anesthesia during ophthalmic procedures?