Search results
26 wrz 2023 · Tropicamide, a non-selective muscarinic antagonist, suppresses the parasympathetic drive, relaxing both the iris sphincter (mydriasis) and ciliary muscles (cycloplegia).
3 lip 2014 · Pharmacologic mydriasis can be achieved using a number of different topical agents. Phenylephrine is an adrenergic stimulant that acts on the iris dilator muscle.
29 lut 2020 · This parasympathomimetic agent stimulates the muscarinic and nicotinic receptors on the iris sphincter muscle to create miosis, resulting in a smaller pupil aperture, which increases the depth of focus. 31 Unlike pilocarpine, it is a full agonist that also promotes acetylcholine release from parasympathetic nerve endings.
Phenylephrine is used to dilate the iris through α-adrenergic stimulation of the iris dilator muscle. Sympathetic stimulation of the ciliary muscle is believed to be inhibitory, decreasing accommodative amplitude.
15 maj 2021 · O p tometrists are well-acquainted with the two opposing muscles in the iris, the sphincter and the dilator, as we witness their effects daily in clinical practice. Pupil constriction (miosis) can either be stimulated by contraction of the iris sphincter or by relaxation of the iris dilator.
The iris dilator muscle is a smooth muscle located in the outer part of the iris that is responsible for dilating the pupil. It is primarily regulated by the sympathetic nervous system through adrenergic receptors, particularly the α1 receptors.
Tadpole pupil is a rare phenomenon in which segmental spasm of the iris dilator muscle results in a tadpole-shaped pupil. The pupillary distortion is usually unilateral, lasts several minutes, and can recur in clusters.
