Peripheral optical quality and myopia progression in children

Background: To investigate the peripheral optical quality and its relationship with axial elongation, myopic progression in Japanese children. Methods: Twenty-nine Japanese children, ages 10 to 12 years old, with baseline refraction from +0.75D to -5.5 D, were included and followed for 9 months. The central and peripheral point spread functions (PSFs; 0, 10, 20, 30 nasally) were obtained at 0.25 D steps around ±2.5 D of best-focus PSF (BF-PSF) using double-pass PSF system. Modulation transfer function (MTF) area of the BF-PSF was calculated from BF-PSF to represent the peripheral optical quality. Relative peripheral defocus (RPD), the refraction of anterior/posterior focal lines, MTF area, and their correlations with myopia progression were analyzed. Results: The average refractive change in 9 months was -0.5 ± 0.8 D. The change in axial length was significantly positively correlated with the amount of myopic progression (P = 0.0058) and RPD (P = 0.0007, 0.0036 and 0.0040, at 10, 20, 30 respectively) at the initial visit, but did not correlate with the peripheral MTF area. Myopic progression of more than 0.5 D with axial elongation was observed in seven children (MP group). The RPDs at 20 and 30 in the MP group were significantly more hyperopic than in the non-MP group (P = 0.002 and 0.007), whereas there was no significant difference in axial length, and central and peripheral MTF area between the MP and non-MP groups. MP group had more hyperopic focal lines compared with non-MP group at 20 and 30. Conclusion: These results suggest that the progression of axial myopia in children is associated with hyperopic RPD and refraction of focal lines, not with peripheral optical quality.