5 eye signs due to ketamine inj
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The textbook sources confirm all five signs clearly. Here is the complete, textbook-backed answer:
5 Eye Signs Due to Ketamine
Ketamine produces a characteristic cataleptic/dissociative state via NMDA receptor antagonism with indirect sympathomimetic activity. The ocular manifestations are:
| # | Sign | Mechanism |
|---|---|---|
| 1 | Nystagmus (lateral gaze) | Dissociative CNS effect - the most classic and consistent sign; ketamine causes a characteristic lateral gaze nystagmus |
| 2 | Mydriasis (pupillary dilation) | Indirect sympathomimetic activity - inhibition of catecholamine reuptake causes sympathetic stimulation |
| 3 | Lacrimation (excessive tearing) | Increased secretions from sympathetic/cholinergic stimulation; occurs alongside hypersalivation |
| 4 | Increased intraocular pressure (IOP) | Raised due to sympathetic stimulation and increased extraocular muscle tone; makes ketamine relatively contraindicated in open globe injuries and glaucoma |
| 5 | Roving / random eye movements (ocular divergence) | Dissociation of eye movement coordination; patients appear conscious with open eyes but cannot process sensory input |
Bonus - Blepharospasm: Ketamine also causes blepharospasm (involuntary eyelid spasm), which, together with nystagmus, makes it a poor choice for ophthalmic surgery.
Key exam points:
- Nystagmus + pupillary dilation + lacrimation + salivation together form the classic ketamine triad of secretion signs
- Ketamine is contraindicated in open globe injury and glaucoma because of raised IOP
- Eyes remain open during ketamine anesthesia (dissociative state) - this is unique compared to most other anesthetic agents
Sources: Goodman & Gilman's Pharmacological Basis of Therapeutics; Barash Clinical Anesthesia, 9e; Morgan & Mikhail Clinical Anesthesiology, 7e
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