Abstract
Purpose :
Earlier studies report an association of refractive error (RE) with retinal and choroidal thickness (RT and ChT respectively). However, it is not known whether these differences are present before the development of RE in children or develop as a consequence of the RE. We evaluated longitudinal changes in RT and ChT in young children who are at high or low risk of developing myopia as part of the Preventing myopia: Investigating Contributing factors to Nearsightedness In Children (PICNIC) study.
Methods :
Children (n=23, age=7.6±0.9 years) were categorized as low risk (LR) (n=12, age=7.9±0.8 years, axial length, AXL=22.8±0.3mm, RE=1.1±0.3D) and high risk (HR) (n=11, age=7.4±1.0 years, AXL=22.5±0.8mm, RE=0.8±0.5D) for myopia, based on parental history and cycloplegic autorefraction at baseline. Wide-field SD-OCT (Spectralis, Heidelberg) radial scans centered on the fovea (55°, 12 lines) were collected at 3 points in time: baseline, 6 and 12 months. Images were processed in a custom Matlab program and corrected for lateral magnification using biometric data (Lenstar). RT and ChT were evaluated for retinal eccentricities of 1, 3, 5, 8 and 12 mm.
Results :
At 12 months, AXL increased and RE decreased (less hyperopic) in the HR group (p<0.05 both) while only AXL increased in the LR group (p<0.05). At baseline, RT and ChT were not significantly different between the two groups at any eccentricity, although there was a trend for thicker choroid in the LR compared to the HR group at all eccentricities. There was also a significant increase in RT for the HR group at 1, 3 and 5 mm eccentricities, while RT increased at the central 1 mm only for the LR group (p<0.05 all). ChT increased significantly at all eccentricities for both groups, greatest superiorly (27.9±29.0 µm) and smallest nasally (19.9±20.7 µm) (p<0.05 both). Subfoveal ChT at 12 months increased significantly only in the LR group (26.2±27.8 µm, p<0.01).
Conclusions :
At 12 months, there was greater ocular elongation and decreased hyperopia in children for HR of myopia, as predicted. Additionally, there were significant increase in RT and ChT, with different patterns of thickening for the HR and LR groups, which suggests differences in ocular growth patterns prior to myopia development. We will continue to follow up these children for 3 years, which will provide an understanding of changes associated with myopia development.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.