Myopia onset and role of peripheral refraction

Figures & data

Table 1 Central and peripheral refraction in all study visits and in each study group

Group	Field of peripheral refraction	Baseline	12 months	18 months
All eyes	−30	0.12±1.44 (−2.25 to 5.13)	0.4±1.27 (−1.63 to 5.63)	0.21±1.26 (−1.5 to 5.5)
	−20	0.11±1.26 (−2.38 to 5.13)	0.37±1.27 (−2 to 5.38)	0.20±1.27 (−1.75 to 5.25)
	−10	0.32±1.18 (−1.25 to 6)	0.4±1.25 (−2.38 to 5.63)	0.32±1.34 (−2.63 to 5.88)
	0	0.53±1.17 (−1.25 to 5.63)	0.40±1.28 (−2.75 to 5.63)	0.41±1.38 (−2.63 to 6)
	10	0.32±1.09 (−1.5 to 5.13)	0.42±1.28 (−2.75 to 6)	0.31±1.31 (−2.75 to 6.13)
	20	0.28±1.14 (−1.63 to 5.5)	0.31±1.36 (−3.25 to 6.25)	0.34±1.34 (−3.5 to 6.13)
	30	0.19±1.21 (−1.75 to 5.63)	0.31±1.33 (−3.00 to 6.00)	0.27±1.36 (−3.13 to 6.38)
nMi-nMf	−30	0.43±1.38 (−2.25 to 5.13)	0.69±1.28 (−1.00 to 5.63)	0.53±1.26 (−1.38 to 5.5)
	−20	0.40±1.20 (−1.13 to 5.13)	0.66±1.26 (−1.25 to 5.38)	0.52±1.27 (−1.25 to 5.25)
	−10	0.54±1.23 (−1.25 to 6.00)	0.71±1.20 (−0.63 to 5.63)	0.63±1.33 (−0.75 to 5.88)
	0	0.84±1.15 (−0.38 to 5.63)	0.73±1.23 (−0.63 to 5.63)	0.76±1.30 (−0.38 to 6.00)
	10	0.53±1.15 (−0.88 to 5.13)	0.69±1.26 (−0.75 to 6.00)	0.61±1.28 (−0.63 to 6.13)
	20	0.53±1.17 (−1.50 to 5.50)	0.61±1.31 (−1.25 to 6.25)	0.65±1.30 (−0.63 to 6.13)
	30	0.42±1.25 (−1.25 to 5.63)	0.64±1.28 (−1.5 to 6.00)	0.57±1.35 (−0.75 to 6.38)
nMi-Mf	−30	−0.33±2.08 (−2.25 to 1.88)	−0.79±0.76 (−1.63 to −0.13)	−0.54±0.31 (−0.88 to −0.25)
	−20	−0.13±1.42 (−1.13 to 1.5)	−0.17±0.95 (−1 to 0.88)	−0.75±0.66 (−1.5 to −0.25)
	−10	0.33±0.40 (−0.13 to 0.63)	−0.67±0.19 (−0.88 to −0.50)	−0.25±0.25 (−0.50 to 0.00)
	0	0.21±0.14 (0.13 to 0.38)	−0.17±0.14 (−0.25 to 0.00)	−0.63±0.13 (−0.75 to −0.50)
	10	−0.08±0.29 (−0.25 to 0.25)	−0.04±0.31 (−0.38 to 0.25)	−0.42±0.19 (−0.63 to −0.25)
	20	−0.29±0.38 (−0.63 to 0.13)	−0.83±0.29 (−1.00 to −0.50)	−0.21±0.38 (−0.63 to 0.13)
	30	−0.25±0.33 (−0.63 to 0.00)	−0.79±0.40 (−1.25 to −0.50)	−0.42±0.44 (−0.88 to 0.00)
Mi-Mf	−30	−0.79±0.89 (−1.75 to 0.63)	−0.58±0.75 (−1.50 to 0.25)	−1.10±0.43 (−1.50 to −0.38)
	−20	−0.83±0.75 (−1.88 to 0.25)	−1.02±0.70 (−2.00 to −0.25)	−1.10±0.52 (−1.75 to −0.38)
	−10	−0.67±0.37 (−1.00 to 0.00)	−0.90±0.91 (−2.38 to −0.13)	−1.19±0.79 (−2.63 to −0.38)
	0	−0.79±0.30 (−1.25 to −0.50)	−1.17±0.84 (−2.75 to −0.50)	−1.27±0.75 (−2.63 to −0.50)
	10	−0.52±0.53 (−1.50 to 0.00)	−0.94±0.95 (−2.75 to −0.25)	−1.08±1.02 (−2.75 to 0.13)
	20	−0.71±0.73 (−1.63 to 0.50)	−0.96±1.28 (−3.25 to 0.00)	−1.08±1.26 (−3.5 to 0.13)
	30	−0.85±0.81 (−1.75 to 0.25)	−0.90±1.18 (−3.00 to 0.38)	−1.06±1.13 (−3.13 to 0.00)

Note: Data presented as mean ± SD (95% CI).

Abbreviations: Mi-Mf, myopic during the 18 months; nMi-Mf, non-myopic at baseline and developed myopia after 18 months; nMi-nMf, non-myopic after 18 months.

Figure 1 Peripheral refraction (A) and relative peripheral refraction (B) for the children in the “nonmyopia, myopia” classification at baseline (left), at 12 months (middle), and at 18 months (right).

Notes: Plotted after univariate analysis of variance. (A) Central and peripheral refraction: statistically significant differences were found between groups (F₂=73.21; P<0.01). However, there were nonsignificant differences between visits (F₂=0.08; P=0.92) and visual field angle (F₆=0.47; P=0.83) in refraction. (B) RPR: statistically significant differences were found between groups (F₂=13.61; P<0.01), visits (F₂=3.92; P=0.02), and visual field angle (F₆=2.86; P=0.01). However, the interaction between visits and RPR was statistically nonsignificant between groups (F₃₆=0.79; P=0.80).
Abbreviations: RPR, relative peripheral refraction; nMi-nMf, non-myopic after 18 months; nMi-Mf, non-myopic at baseline and developed myopia after 18 months; Mi-Mf, myopic during the 18 months.

Table 2 Relative peripheral refraction in all study visits and in each study group

Group	Field of peripheral refraction	Baseline	12 months	18 months
All eyes	−30	−0.41±0.78 (−2.63 to 1.5)	−0.01±0.56 (−1.63 to 1.25)	−0.2±0.53 (−1.5 to 1.13)
	−20	−0.42±0.59 (−1.88 to 1.13)	−0.03±0.49 (−1.88 to 0.88)	−0.21±0.48 (−1.38 to 0.88)
	−10	−0.21±0.42 (−1.25 to 0.5)	−0.01±0.5 (−1.25 to 2)	−0.08±0.39 (−1.5 to 0.63)
	10	−0.21±0.53 (−1.25 to 0.88)	0.02±0.45 (−1 to 1)	−0.1±0.45 (−1.38 to 1.13)
	20	−0.25±0.55 (−2 to 1)	−0.09±0.54 (−1.13 to 1.13)	−0.07±0.5 (−1.5 to 1.13)
	30	−0.34±0.6 (−2.13 to 0.88)	−0.1±0.58 (−1.63 to 1.38)	−0.14±0.54 (−1.63 to 1)
nMi-nMf	−30	−0.41±0.68 (−2.63 to 0.75)	−0.04±0.51 (−1.63 to 1.13)	−0.23±0.52 (−1.5 to 0.63)
	−20	−0.44±0.5 (−1.5 to 0.63)	−0.07±0.49 (−1.88 to 0.63)	−0.24±0.46 (−1.38 to 0.75)
	−10	−0.3±0.41 (−1.25 to 0.38)	−0.02±0.51 (−1.25 to 2)	−0.13±0.41 (−1.5 to 0.63)
	10	−0.31±0.51 (−1.25 to 0.88)	−0.04±0.46 (−1 to 1)	−0.15±0.43 (−1.38 to 0.75)
	20	−0.32±0.54 (−2 to 1)	−0.12±0.52 (−1.13 to 1.13)	−0.12±0.41 (−1.5 to 0.5)
	30	−0.42±0.59 (−2.13 to 0.88)	−0.09±0.57 (−1.63 to 1)	−0.2±0.49 (−1.63 to 1)
nMi-Mf	−30	−0.54±1.95 (−2.38 to 1.5)	−0.63±0.75 (−1.38 to 0.13)	0.08±0.19 (−0.13 to 0.25)
	−20	−0.33±1.28 (−1.25 to 1.13)	0±0.82 (−0.75 to 0.88)	−0.13±0.54 (−0.75 to 0.25)
	−10	0.13±0.38 (−0.25 to 0.5)	−0.5±0.22 (−0.63 to −0.25)	0.38±0.13 (0.25 to 0.5)
	10	−0.29±0.38 (−0.63 to 0.13)	0.13±0.33 (−0.13 to 0.5)	0.21±0.26 (0 to 0.5)
	20	−0.5±0.5 (−1 to 0)	−0.67±0.38 (−1 to −0.25)	0.42±0.36 (0 to 0.63)
	30	−0.46±0.47 (−1 to −0.13)	−0.63±0.54 (−1.25 to −0.25)	0.21±0.4 (−0.25 to 0.5)
Mi-Mf	−30	0±0.66 (−0.75 to 1.13)	0.58±0.52 (−0.25 to 1.25)	0.17±0.55 (−0.5 to 1.13)
	−20	−0.04±0.54 (−0.88 to 0.75)	0.15±0.46 (−0.63 to 0.75)	0.17±0.45 (−0.5 to 0.88)
	−10	0.13±0.38 (−0.5 to 0.5)	0.27±0.38 (−0.25 to 0.88)	0.08±0.19 (−0.25 to 0.25)
	10	0.27±0.43 (−0.5 to 0.63)	0.23±0.32 (0 to 0.75)	0.19±0.57 (−0.5 to 1.13)
	20	0.08±0.55 (−0.63 to 1)	0.21±0.56 (−0.5 to 1)	0.19±0.74 (−0.88 to 1.13)
	30	−0.06±0.62 (−0.75 to 0.75)	0.27±0.57 (−0.25 to 1.38)	0.21±0.68 (−0.75 to 1)

Note: Data presented as mean ± SD (95% CI).

Abbreviations: Mi-Mf, myopic during the 18 months; nMi-Mf, non-myopic at baseline and developed myopia after 18 months; nMi-nMf, non-myopic after 18 months.

Figure 2 Axial length in all study visits and in each study group.

Abbreviations: nMi-nMf, non-myopic after 18 months; nMi-Mf, non-myopic at baseline and developed myopia after 18 months; Mi-Mf, myopic during the 18 months.