Experimental Myopia Results in Peripapillary Ganglion Cell and Astrocyte Reorganization with No Functional Implications During Early Development

Myopic eye growth induces mechanical stretch, which can lead to structural and functional retinal alterations. Here, we investigated the effect of lens-induced myopic growth on the distribution of retinal ganglion cells (RGCs), glial fibrillary acidic protein (GFAP) expression and intensity, and peripapillary retinal nerve fiber layer (ppRNFL) thickness in common marmosets (Callithrix jacchus) induced with myopia continuously for six months, using immunohistochemistry and spectral-domain optical coherence tomography. We also explored the relationship between cellular structural parameters and the photopic negative response (PhNR) using full-field electroretinography. Marmosets induced with myopia for six months developed axial myopia, had a thinner ppRNFL, reduced peripapillary ganglion cell (approximate to 20%) and astrocyte density (approximate to 42%), increased panretinal GFAP expression (approximate to 42%) and nasal mid-periphery staining intensity (approximate to 81%) compared to age-matched controls. Greater degrees of myopia and vitreous elongation were associated with reduced peripapillary RGCs and astrocyte density, and increased GFAP expression and intensity. These cellular structural changes did not show a significant relationship with the features of the PhNR, which remained unchanged. The outcomes of this study suggest that myopia induces a reorganization of the peripapillary inner retina at the cellular level that may not result in measurable functional repercussions at this stage of myopia development.