Cholinergic effect on the eye involves which of the following?

Cholinergic effect on the eye involves which of the following?

• A. Mydriasis and increased intraocular pressure
• B. Nystagmus
• C. Cycloplegia
• D. Miosis and decreased intraocular pressure

Answer: (D)

Cholinergic stimulation in the eye drives the parasympathetic actions: the pupil constricts and the drainage of aqueous humor increases, lowering intraocular pressure. The sphincter pupillae contracts to produce miosis, and the ciliary muscle contracts to facilitate drainage through the trabecular meshwork, which reduces intraocular pressure. That combination—miosis with decreased IOP—is the classic cholinergic effect in the eye. Nystagmus isn’t a direct result of cholinergic action in the eye; and cycloplegia is caused by blocking acetylcholine’s action (anticholinergic effects) rather than by stimulating it. Conversely, mydriasis (pupil dilation) typically results from sympathetic stimulation or anticholinergic drugs, not from cholinergic activation. An example of a cholinergic agent with these effects is pilocarpine, used to lower intraocular pressure by promoting miosis and increasing aqueous humor outflow.

Cholinergic stimulation in the eye drives the parasympathetic actions: the pupil constricts and the drainage of aqueous humor increases, lowering intraocular pressure. The sphincter pupillae contracts to produce miosis, and the ciliary muscle contracts to facilitate drainage through the trabecular meshwork, which reduces intraocular pressure. That combination—miosis with decreased IOP—is the classic cholinergic effect in the eye.

Nystagmus isn’t a direct result of cholinergic action in the eye; and cycloplegia is caused by blocking acetylcholine’s action (anticholinergic effects) rather than by stimulating it. Conversely, mydriasis (pupil dilation) typically results from sympathetic stimulation or anticholinergic drugs, not from cholinergic activation. An example of a cholinergic agent with these effects is pilocarpine, used to lower intraocular pressure by promoting miosis and increasing aqueous humor outflow.