miotics

miotics

Drugs that constrict the pupil. They may be used in the treatment of glaucoma and accommodative esotropia and, sometimes, after a mydriatic examination. Miotics are either parasympathomimetic (cholinergic-stimulating) drugs which have a direct muscarinic action, such as pilocarpine and carbachol, or anticholinesterase drugs which block the effect of acetylcholinesterase thus letting acetylcholine produce its effect, such as physostigmine, neostigmine, echothiophate and demecarium. There are also some miotics which act by blocking α-or β-adrenergic receptors. For example, dapiprazole and thymoxamine block the α-adrenergic receptors and propranolol blocks the β-adrenergic receptors. See adrenergic receptors; open-angle glaucoma; sphincter pupillae muscle; mydriatic; parasympathomimetic drug.