Eserine is widely used in ophthalmology for its ability to inhibit acetylcholinesterase, an enzyme that breaks down acetylcholine. This inhibition increases the levels of acetylcholine in the synapses, leading to improved muscle contraction and nerve signal transmission. As a result, eserine is commonly applied in the treatment of glaucoma, where it helps reduce intraocular pressure by facilitating the drainage of aqueous humor from the eye. Additionally, it is used diagnostically to confirm myasthenia gravis, a neuromuscular disorder, by temporarily improving muscle strength in affected individuals. Eserine also finds application in research settings to study cholinergic systems and their role in various physiological processes.