Abstract
Purpose:
To investigate short-term changes in choroidal thickness and other ocular biometrics to imposed myopic defocus in Chinese myopic children.
Methods:
Ocular biometrics of twenty myopic children (9 boys and 11 girls; SE range: -1.25 to -5.50 D) aged 11 to 15 years old were measured before and after 30 minutes of exposure to +5 D of monocular defocus (right eye) while watching movies on a 5.5 m distant screen. Choroidal and retinal thicknesses were measured by means of SD-OCT (Heidelberg Spectralis OCT; Heidelberg Engineering, Heidelberg, Germany) and axial length by Lenstar LS 900 optical biometer (Lenstar LS 900; Haag Streit AG, Koeniz, Switzerland). The fellow eye was optimally corrected for distance (no defocus).
Results:
After 30 minutes, choroidal thickness of the right eye exhibited a significant increase for +5 D defocus conditions (mean change: +5.00 ± 5.07 mm; t = 4.408, p < 0.001). Retinal thickness exhibited no significant change (mean change: -0.60 ± 1.59 mm; t = -1.693, p = 0.107). Optical axial length decreased significantly after +5 D defocus condition (mean change: -6.4 ±10.6 mm, t = -2.691, p = 0.014). Choroidal thickness, retinal thickness and axial length of the left eye showed no significant change (p > 0.05).
Conclusions:
Significant increase in choroidal thickness and significant decrease in optical axial length occurred in myopic children after 30 minutes of myopic defocus of +5 D. Amplitudes of biometric changes were comparable to those previously observed in adults.