According to this study, if one uses 1.0% eye drops daily over a period of 24 months, the progression of myopia can be slowed by 77% [1]. The atropine eye drops dilate the pupils and temporarily paralyzes the focusing muscle. Hence, it relaxes the eye's focusing mechanisms.
With that, there are currently 2 theories to explain this.
Firstly, the atropine may act on some retinal receptors to inhibit eyeball elongation. The other theory is that it possibly acts on scleral fibroblasts by inhibiting glycosaminoglycans synthesis, and so prevents eyeball elongation.
References:
1. Galvis V, Tello A, Parra MM, et al. Topical Atropine in the Control of Myopia. Medical hypothesis, discovery & innovation ophthalmology journal. 2016;5(3):78-88. Accessed April 1, 2020.
