Atropine is a non-selective muscarinic receptor blocker. The exact mechanism of atropine in retarding myopia progression is not known. It is believed that atropine acts directly or indirectly on the muscarinic receptors of the retina or sclera, causing thickening of scleral tissue and inhibiting thinning or elongation of the eyeball during growth.
Low dose atropine eyedrops, in concentrations ranging from 0.01% to 0.05%, has been proven to be effective and safe to slow down the progression of myopia. It is instilled once daily in both eyes.
A meta-analysis in 2020 by Zhao and colleagues, looking at high quality clinical trials comparing atropine treatment with placebo in myopic children in Asia and Europe, concluded that myopia progression was significantly less in children on atropine treatment compared to those who were not. Children who used atropine eyedrops had smaller increase in spectacles power and less eyeball elongation.
A report by the American Academy of Ophthalmology in 2017 also concluded that there is level 1 evidence that supports the use of atropine to prevent myopia progression.
The World Society of Paediatric Ophthalmology and Strabismus released a Myopia Consensus Statement which concluded that atropine 0.01% appears to offer an appropriate risk-benefit ratio, with no clinically significant visual side effects balanced against a reasonable and clinically significant 50% reduction in myopia progression.
Clinical studies have also shown that low dose atropine eyedrops are well tolerated by children. A small percentage may experience minor side effects including glare, sensitivity to bright light or reduced accommodation with blur near vision. If significant, treatment can include photochromatic (tinted) lenses or near addition with progressive lenses. Allergic reactions to the eyedrops are uncommon but are reversible with cessation of treatment.