Peripheral Eye Length Evaluation in Myopic Children Undergoing Orthokeratology Treatment for 12 Months Using MRI

Figures & data

Table 1 Demographic Data of the Subjects

Baseline Parameters	Eccentricity	Ortho K (n = 45)	SVS (n = 25)	p-value
Age (y)		8.38 ± 0.49	8.2 ± 0.41	0.110
Male/Female*		20/25	15/10	0.289
Best Corrected VA (logMAR)		−0.01 ± 0.08	0 ± 0.05	0.378
SER (D)		−2.92 ± 1.07	−2.51 ± 1.12	0.529
Cornea Curvature FK (D)		43.6 ± 1.27	43.12 ± 1.03	0.116
Axial Length (mm)		23.85 ± 0.71	23.49 ± 0.95	0.082
Peripheral Eye Length, PEL (D)	N30	20.68 ± 0.89	20.74 ± 1.25	0.818
	N20	21.83 ± 0.91	21.75 ± 1.06	0.746
	N10	23.08 ± 0.76	22.75 ± 0.74	0.082
	C	23.85 ± 0.71	23.45 ± 0.97	0.082
	T10	23.09 ± 0.59	22.8 ± 0.75	0.088
	T20	21.91 ± 0.89	21.89 ± 1.11	0.934
	T30	20.88 ± 0.85	20.99 ± 1.15	0.659
Peripheral Refraction, PR (D)	N30	−1.92 ± 1.01	−1.89 ± 0.93	0.906
	N20	−2.45 ± 1.06	−2.30 ± 1.16	0.588
	N10	−2.95 ± 1.06	−2.72 ± 1.35	0.440
	C	−3.22 ± 1.11	−3.03 ± 1.35	0.529
	T10	−2.92 ± 1.11	−2.76 ± 1.30	0.592
	T20	−2.50 ± 1.08	−2.47 ± 1.21	0.899
	T30	−2.02 ± 1.11	−1.95 ± 1.18	0.781

Notes: Statistical tests: Independent t-test; *Pearson Chi-Square test.

Abbreviations: Ortho-K, orthokeratology; SVS, single-vision spectacles; SER, Spherical Equivalent Refraction; D, diopter; PR, peripheral refraction; PEL, peripheral eye length; C, central cornea; FK, flat keratometry; N, nasal retina; T, temporal retina.

Table 2 Mean and Standard Deviation (±SD) of Ocular Parameters at Baseline and 12 Months

Parameters	Ortho-K (n = 45)			SVS (n= 25)
	Baseline	12 Months	p-value	Baseline	12 Months	p-value
SER (D)	−2.92 ± 1.07	−0.06 ± 0.12	<0.001	−2.51 ± 1.12	−3.77 ± 1.23	<0.001
BCVA	−0.01 ± 0.08	−0.02 ± 0.08	0.058	0.00 ± 0.05	0.01 ± 0.05	0.425
Cornea FK (D)	43.6 ± 1.27	40.69 ± 2.54	<0.001	43.12 ± 1.03	43.47 ± 1.10	0.019
AL (mm)	23.85 ± 0.71	23.64 ± 0.59	0.002	23.49 ± 0.95	23.97 ± 0.59	<0.001
PEL -N30	20.68 ± 0.89	20.80 ± 0.97	0.008	20.74 ± 1.25	21.09 ± 1.08	0.134
PEL-N20	21.83 ± 0.91	21.95 ± 1.02	0.013	21.75 ± 1.06	22.2 ± 0.89	<0.001
PEL-N10	23.08 ± 0.76	23.15 ± 0.83	0.116	22.75 ± 0.74	23.23 ± 0.87	<0.001
LAL- Centre	23.85 ± 0.71	23.64 ± 0.59	0.003	23.45 ± 0.97	23.97 ± 0.59	<0.001
PEL -T10	23.09 ± 0.59	23.15 ± 0.69	0.148	22.8 ± 0.75	23.39 ± 0.74	<0.001
PEL-T20	21.91 ± 0.89	22.04 ± 0.89	<0.001	21.89 ± 1.11	22.36 ± 1.08	<0.001
PEL-T30	20.88 ± 0.85	20.98 ± 0.85	<0.001	20.99 ± 1.15	21.39 ± 1.03	0.003

Abbreviations: SER, Spherical Equivalent Refraction; Ortho-K, orthokeratology; SVS, single-vision spectacles; D, diopter; BCVA= Best Corrected Visual Acuity; FK, flat keratometry; AL, Axial length using A-scan; LAL, Longitudinal Axial length; PEL, peripheral eye length; C, central cornea; N, nasal retina; T, temporal retina.

Figure 1 Peripheral eye length (PEL) at the baseline and 12 months in single vision (SVS) wearers.

Figure 2 Peripheral eye length (PEL) at the baseline and 12 months in Orthokeratology (Ortho-K) wearers.

Table 3 Mean Relative Peripheral Refraction (RPR) in the Orthokeratology (Ortho-K) and Single Vision (SVS) Wearers at the Baseline and 12 Months

Eccentricities	Ortho-K (n = 45)			SVS (n = 25)
	Baseline	12 Months	p-value	Baseline	12 Months	p-value
RPR-30N	1.3 ± 0.55	−1.38 ± 0.64	<0.001	1.14 ± 0.92	2.58 ± 1.33	0.001
RPR-20N	0.76 ± 0.45	−0.71 ± 0.54	<0.001	0.72 ± 0.57	1.94 ± 1.06	<0.001
RPR-10N	0.27 ± 0.30	−0.19 ± 0.53	<0.001	0.31 ± 0.33	0.76 ± 0.75	0.013
RPR-10T	0.3 ± 0.24	−0.20 ± 0.46	<0.001	0.27 ± 0.33	0.72 ± 0.60	0.003
RPR-20T	0.72 ± 0.42	−0.80 ± 0.44	<0.001	0.56 ± 0.74	1.73 ± 0.99	<0.001
RPR-30T	1.19 ± 0.49	−1.40 ± 0.58	<0.001	1.08 ± 1.02	2.25 ± 0.94	<0.001

Abbreviations: RPR, Relative Peripheral Refraction; Ortho-K, orthokeratology; SVS, single-vision spectacles; D, diopter; N, nasal retina; T, temporal retina.

Table 4 Linear Regression Between Changes in SER at 12 Months for a Given Peripheral Eccentric Location [(M Nasal + M Temporal)/2] and the SER at Baseline

Eccentricity	Linear Regression (r²)	p-value
10	−0.874	<0.001
20	−0.886	<0.001
30	−0.941	<0.001

Abbreviations: SER, Spherical Equivalent Refraction; M, mean spherical equivalent.