Purpose The purpose of this study was to investigate the acute effect of atropine to better understand atropine’s mechanism of action in myopia prevention. The present study investigates whether atropine’s effect on the AxL comes forth from an increase in choroidal thickness (ChT) using SS-OCTa (swept source optical coherence tomography angiography).
Methods Twenty-five myopic children (25 eyes) (9 male and 16 females; mean age 11.8 years, range 7-15 years) were enrolled following documented myopia progression and AxL increase in the preceding 6 months. Using SS-OCTa, ChT and CSV (choroidal stromal volume) were measured at baseline and after 1 month of daily Atropine 0.1% use. AxL measurements were taken on the same days.
Results Following one month of daily instillation with atropine 0.1%, ChT increased by 22.41 ± 4.20 μm (p < 0,01), CSV increased by 1.08 ± 1.02 mm3 (p < 0,01) and AxL decreased by 0.044 ± 0.016 mm (p < 0,05), shown by mean ± standard error (SE). The CSV and ChT increase show a negative correlation with the AxL decrease of -0.462 and -0.374 respectively, demonstrating a weak to moderate correlation.
Conclusions Administration of atropine 0.1% eye drops daily over one month demonstrated an acute decrease in AxL concurrent with an increase in ChT and CSV. A direct cause-and-effect relationship between these two parameters is plausible, supporting a differentiated effect in the immediate and long-term effects of atropine eye drops.