Purpose: To elucidate the development of the choroid and retina in children, and to explore changes in these during myopic shift.
Methods: A total of 118 children aged 7 to 12 years participated in this 1-year longitudinal study. Children underwent several examinations at baseline and follow-up, including cycloplegic refraction, axial length measurement, and swept-source optical coherence tomography. Thickness changes in the choroid and retina were compared among children with or without myopic shift.
Results: Eighty-eight children (74.6%) developed a myopic shift after 1 year, and their central foveal choroid was significantly attenuated (P < 0.01). No significant change was observed in choroids of children without myopic shift (P = 0.83). Choroidal thickness decreased in all subfields during myopic shift, whereas the thickness of the retinal layers increased or were unchanged in most subfields. Axial length increase and central foveal choroidal thinning were associated with myopic shift (R = 0.157, P < 0.01), but axial length increase was not significantly related to choroidal thinning (P > 0.05).
Conclusion: Choroidal thinning occurs early in myopic progression. Axial length increase and choroidal thinning are independently associated with myopic shift.