Myopia ‐ biological mechanisms and unresolved questions

Summary Research in animal models has consistently demonstrated that the retina extracts magnitude and sign of defocus in the projected image. Focussing errors trigger changes in axial eye growth, initiated by the retina, to reduce these error signals. Growth control occurs at each position in the retina, but the fovea, although very important in sharp vision, covers only a small fraction of the visual field and has therefore little input. Instead, the fovea controls accommodation, shifting the image plane similarly in the center and periphery. At the end, only a complete description of the focus error signals all over the visual field and over time will finally explain the development of myopia. Myopia is tightly linked to education, with 0.5 D more myopia per year of studies. Since extensive education is mandatory in our societies, its development can only be delayed and slowed down. Three evidence‐based approaches are promising at present to slow myopia progression: (1) increasing exposure to outdoor lighting, preferentially before myopia starts later at school, (2) “fooling” the retina about the true plane of focus (i.e. by multifocal contact lenses) and (3) low dose (0.01% or less) atropine eye drops.