The orientation of choroidal macrophage polarization significantly influences the development of myopia in murine models

Myopia is a primary contributor to visual impairment and has emerged as a global public health concern. Evidence indicates that one of the main structural features of myopia is the corresponding decrease in choroidal thickness, and choroidal macrophages play an important role in maintaining the choroidal thickness. Nevertheless, the effect of choroidal macrophages on myopia remains unclear. Here, we discovered that the continuous intraperitoneal injection of clodronate liposomes depleted choroidal macrophages and leads to myopia, which confirmed that the presence of choroidal macrophages plays an important role in myopia development. Subsequently, based on the phenotypic characteristics of macrophages, experiments were designed to study the effects of different polarization directions of macrophages on myopia development. We found that lipopolysaccharides (LPS) injection can induce the polarization of choroidal M1 macrophages, thinning the choroidal thickness and resulting in myopia. Conversely, IL-4 or IL-13 injection causes choroidal M2 macrophage polarization, thickens the choroid, and suppresses the progression of myopia. Additionally, we demonstrated that the opposite effects of M1 and M2 macrophages on myopia development may be related to their impacts on choroidal thickness, inflammation, and oxidative stress response. These findings establish that choroidal macrophages are critically important in the development of myopia and provide new strategies for the development of myopic therapies.