Cholinergic agonists are primarily used in glaucoma for which purposes?

• A. Angle closure glaucoma and pre-treatment before LPI
• B. Open-angle glaucoma management
• C. Diabetic retinopathy
• D. Macular degeneration

Answer: (A)

Cholinergic agonists in glaucoma work by stimulating muscarinic receptors in the eye to cause pupil constriction and ciliary muscle contraction. This dual action helps open the drainage angle and improve outflow of aqueous humor. In angle-closure glaucoma, a pupillary block narrows or closes the angle; forcing the pupil to constrict and pulling the iris off the trabecular meshwork reduces block and widens the angle, allowing better outflow and a rapid drop in pressure.

They are particularly useful as a pre-treatment before a laser peripheral iridotomy because the induced miosis and ciliary muscle activity help stabilize the iris configuration and make the laser procedure safer and easier to perform. In open-angle glaucoma, the underlying issue is outflow resistance within the trabecular meshwork rather than pupillary block, so the benefit of cholinergic agonists is limited and they’re not typically used as first-line long-term therapy. They don’t address diabetic retinopathy or macular degeneration, which are managed with other modalities such as anti-VEGF therapy or laser/photocoagulation.

So the primary use in glaucoma is to manage angle closure and to prepare for LPI.