Evaluating the effect of 0.125% atropine on foveal microvasculature using optical coherence tomography angiography

Abstract

This study investigated alterations in the foveal microvasculature following the administration of 0.125% atropine in myopic children. In this prospective study, 63 eyes from 36 individuals aged 5-18 years with myopia were administered 0.125% atropine for myopia control. After administration, foveal microvascular parameters such as the area and perimeter of the foveal avascular zone (FAZ), the acircularity index (AI) of FAZ, and foveal vessel density were evaluated longitudinally. The effect of atropine on foveal microvasculature was analyzed using a linear mixed model. One month after atropine application, the area and perimeter of FAZ significantly decreased (p = 0.014 and 0.041). A significant decrease in vessel density within the 300-µm wide annulus around FAZ and an increase in the AI of the FAZ were observed in the initial 3-month period (p = 0.035 and p = 0.047, respectively). However, changes in the FAZ area, perimeter, AI and foveal vessel density throughout the follow-up were not significant. These findings suggest that 0.125% atropine may induce transient changes in FAZ size and foveal vessel density, but its overall safety in managing myopia is supported by the stability of foveal parameters over time.

Keywords: Atropine; Fovea; Myopia; Myopia control; OCT; Vasculature.

Fig. 1

The changes of estimated means of AL during longitudinal follow-up^a. AL in myopic children treated with 0.125% atropine changed significantly 1, 3, and 6 months after initiating atropine using a linear mixed model. ^aEstimated means of AL were adjusted by age. *Significant estimated mean compared with baseline. AL: axial length.

Fig. 2

The changes of estimated means of foveal parameters during longitudinal follow-up^a. The changes in FAZ area, FAZ perimeter, AI, and FD-300 in myopic children treated with 0.125% atropine. FAZ area (a) and perimeter (b) significantly reduced one month after the initiation of atropine but remained stable at baseline at other follow-up periods. The increase of AI (c) and reduction of FD-300 (d) were significant three months after the initiation of atropine but also remained stable to baseline at other follow-up periods. Significance was estimated with the linear mixed model. ^aEstimated means of foveal parameters were adjusted by AL. *Significant estimated mean compared with baseline. AL: axial length; FAZ: foveal avascular zone; AI: acircularity index; FD-300: foveal vessel density-300; F/U: follow-up.

Fig. 3

Illustration of foveal parameters. (a) The anatomy of the FAZ. Foveal area is the 1-mm circle centred on the fovea. The avascular area within the foveal area is the FAZ. FD-300 is the vessel density of the 300-µm circular annulus around FAZ. (b) The acircularity of FAZ. Our study demonstrated the acircularity of FAZ as the AI, which is the perimeter of FAZ to the perimeter of a circle with an equal area. (c) OCTA image in the left eye of a 9-year-old boy at baseline. The FAZ area, FAZ perimeter, AI, and FD-300 were measured using the automated calculation output from the ANGIOVUE software (version A2017.1.0.151, Optovue Inc., Fremont, CA, USA). FAZ: foveal avascular zone; FD-300: foveal vessel density-300; AI: acircularity index; OCTA: optical coherence tomography angiography.