How Do Antiglaucoma Miotics Work?

Reviewed on 5/13/2021

How Do Antiglaucoma Miotics Work?

Antiglaucoma miotics stimulate the parasympathetic nervous system to make pupils contract (miosis), which increases the outflow of aqueous humor and reduces the pressure inside the eye (intraocular pressure). Aqueous humor is a clear fluid that fills the space between the lens and the cornea in the eyes.

A part of the eye known as the ciliary body produces aqueous humor, which supplies oxygen and nutrients to the lens and cornea and removes waste products. Balancing the inflow and outflow of aqueous humor helps maintain optimum pressure in the eye and it is this pressure that keeps the eyeball roughly in a spherical shape.

Antiglaucoma miotics stimulate the contraction of the ciliary and the sphincter muscles, which make the pupils constrict, increasing the outflow of aqueous humor. Miotics work in two ways:

  • Mimic a chemical known as acetylcholine (neurotransmitter) that nerve endings in muscles secrete and stimulate proteins (cholinergic receptors) on eye muscles which respond to acetylcholine and activate muscle contraction.
  • Enhance acetylcholine activity by preventing its degradation.

Uses of antiglaucoma miotics

Antiglaucoma miotics are ophthalmic solutions that are topically administered or injected into the eyes. Antiglaucoma miotics are used to reduce intraocular pressure in the following conditions:

  • To treat glaucoma, a progressive disease that damages the optic nerve. Glaucoma is most often characterized by elevated intraocular pressure which can further damage the nerve. Reducing intraocular pressure is the primary treatment for glaucoma. Types of glaucoma treated with antiglaucoma miotics include:
    • Open-angle glaucoma: The most common type of glaucoma, in which the drainage angle through which the aqueous humor drains remains open, but the drainage channels are partially blocked.
    • Secondary glaucoma: Secondary glaucoma results from an injury or other conditions that lead to elevated intraocular pressure, or after cataract surgery.
  • To prevent an increase in intraocular pressure after eye surgery.

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Side effects of antiglaucoma miotics

The use of antiglaucoma miotics has declined since the development of newer antiglaucoma medications with fewer side effects. Side effects of antiglaucoma miotics may include the following:

Ocular side effects:

Systemic side effects:

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

What are names of some antiglaucoma miotics?

Generic and brand names of some antiglaucoma miotics include:

References
https://reference.medscape.com/drugs/antiglaucoma-miotics

https://www.medscape.com/answers/1206147-155140/

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