Effects of Orthokeratology on Axial Length Elongation in Anisometropes

Abstract

<b><i>Introduction:</i></b> This study aimed to investigate the therapeutic effects of overnight orthokeratology (OK) lenses on anisometropes. <b><i>Methods:</i></b> We enrolled 178 anisometropes from August 2015 to August 2017. We then divided these patients into 2 parts depending on them wearing either monocular or binocular OK lenses. In part one, 47 monocular myopic subjects (25 males and 22 females) were treated with OK lenses in the myopic eyes only. We also labeled the myopic eyes as the OK group and the contralateral nonmyopic eyes as the control group. The initial average wearing age of the subjects was 12.35 ± 2.37 years (8–16 years). The mean follow-up duration was 15.43 ± 4.88 months (7–25 months). The average spherical equivalent refraction (SER) was −2.31 ± 1.16 diopter (D) in the OK group and 0.15 ± 0.49 D in the control group (<i>p</i> < 0.001). In part 2, 131 binocular myopic anisometropes (56 males and 75 females) were involved in the study. The eyes with more severe myopia were assigned to the G group and the contralateral eyes to the L group. The initial average wearing age of the subjects was 12.92 ± 2.60 years ( 8–16 years). The mean follow-up duration was 17.83 ± 5.02 months (7–26 months). The average SER was −4.79 ± 1.90 D in the G group and −3.14 ± 1.88 D in the L group (<i>p</i> < 0.001). We calculated the axial length (AL) difference and AL elongation as our primary outcome measures. <b><i>Results:</i></b> In part one, the AL elongation in the OK group (0.21 ± 0.09 mm) was significantly lower than that in the control group (0.70 ± 0.17 mm) at 24 months (<i>p</i> < 0.001). Meanwhile, the AL difference exhibited a decrease of 0.50 ± 0.29 mm from a baseline of 1.08 ± 0.35 to 0.58 ± 0.25 mm at 24 months (<i>F</i> = 24.539, <i>p</i> < 0.001). In part 2, the AL had increased by 0.17 ± 0.13 mm in the G group and 0.24 ± 0.18 mm in the L group after 24-month follow-up, respectively (<i>p</i> < 0.001). While the AL difference decreased from 0.55 ± 0.11 mm at the baseline, to 0.48 ± 0.08 mm at 24 months, eliciting a decrement in AL difference of 0.07 ± 0.09 mm (<i>F</i> = 3.884, <i>p</i> = 0.030). <b><i>Conclusions:</i></b> OK lenses can slow down AL growth in anisometropes and has a greater effect on reducing AL elongation in the more severely affected myopic eyes of anisometropic patients.

Effect of Overnight Orthokeratology Lens Wear on Sleep and Quality of Life in Children Aged 8-12 Years and Relationship Between Corneal Morphology and Visual Function

“…In this experiment, uncorrected visual acuity and refraction were higher, while axial length was reduced 1 to 6 months after overnight orthokeratology lens wear treatment than in children treated with spectacles. When overnight orthokeratology lens wear is used to correct visual acuity, the main reason for its success depends on the equivalent refraction, while the change of equivalent refraction is determined by the change of curvature [20]. In this experiment, the uncorrected visual acuity and refraction of children 1 ~ 6 months after overnight orthokeratology lens wear treatment showed a gradually improving trend, which was in line with the characteristics of continuous uctuation of keratometry.Therefore, overnight orthokeratology lens wear can improve uncorrected visual acuity and refraction, and reduce axial length in the treatment of myopic children, which is conducive to the recovery of children.…”

Topical Review: Studies on Management of Myopia Progression from 2019 to 2021

“…In a 2-year retrospective study, orthokeratology lenses reduced myopia progression by 0.85 D and axial length by 0.19 mm in Japanese children 30 . In another 2-year retrospective study, orthokeratology lenses reduced axial length progression by 0.50 mm in Chinese children 31 . The axial length growth was significantly reduced in bilateral myopic anisometropia with greater effects in the more myopic eye (difference of 0.07 mm).…”

“…30 In another 2-year retrospective study, orthokeratology lenses reduced axial length progression by 0.50 mm in Chinese children. 31 The axial length growth was significantly reduced in bilateral myopic anisometropia with greater effects in the more myopic eye (difference of 0.07 mm).…”

“…17 In recent studies, orthokeratology lenses have been shown to reduce axial length elongation in White (randomized controlled trials) and Asian (study with retrospective design) children (Table 2). [29][30][31] In a 1.5-year randomized controlled trial, the average elongation in the orthokeratology group was 0.24 mm smaller than the control group in Danish children. 29 In this randomized controlled trial, there were no fast myopia progressors in the orthokeratology group, and no vision-threatening adverse events were reported.…”

Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology

“…However, the effectiveness of OK varies greatly among different studies, 3 and its mechanism for myopia control remains unclear. 4 Recent studies indicated that increments of choroidal thickness occurred after OK application. 5,6 Then it is speculated that the underlying mechanism of myopia control using OK could be associated with the change in choroidal thickness.…”