Myopia alters the structural organization of the retinal astrocyte template, associated vasculature and ganglion layer thickness.

PurposeTo describe the effect of myopic eye growth on the structure and distribution of astrocytes, vasculature and ganglion cell thickness, critical for inner retinal tissue homeostasis and survival. MethodsAstrocyte and capillary distribution, retinal nerve fiber (RNFL) and ganglion cell layer (GCL) thicknesses were assessed using immunochemistry and spectral domain optical coherence tomography on eleven retinas of juvenile common marmosets (Callithrix Jacchus), six of which were induced with lens-induced myopia (refraction, Rx: -7.01{+/-}1.8D). Five untreated age-matched juvenile marmoset retinas were used as controls (Rx: -0.74{+/-}0.4D). ResultsAs control marmoset eyes grew normally, there was an age-related increase in astrocyte numbers associated with RNFL thickening. Marmosets with induced myopia did not show this trend and, on the contrary, had reduced astrocyte numbers, increased positive GFAP immunopositive staining, thinner RNFL, lower peripheral capillary branching, and increased numbers of string vessels. ConclusionThe myopic changes in retinal astrocytes, vasculature, and ganglion cell layer thickness suggest a reorganization of the astrocyte and vascular templates during myopia development and progression. Whether these adaptations are beneficial or harmful to the retina remains to be investigated. Summary StatementThis article provides new information on how progressive myopia affects key elements of the retinal neurovascular unit.