Influence of Overnight Orthokeratology on Corneal Surface Shape and Optical Quality

Sun, Yuan; Wang, Lin; Gao, Jing; Yang, Mei; Zhao, Qi

doi:10.1155/2017/3279821

Cited by 17 publications

(12 citation statements)

References 30 publications

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“…The sample size was calculated with G*Power (version 3.1.9.2; Kiel University, Kiel, Germany) based on the average apical corneal power difference anticipated between the two eyes during orthokeratology treatment. A minimum interocular difference of 0.50 D was expected with a within-subject standard deviation of 0.70 D. 18 Therefore, a minimum of 18 subjects were required to provide 80 per cent power to detect a significant difference with an alpha level of 0.05.…”

Section: Sample Size Determinationmentioning

confidence: 99%

mentioning

confidence: 99%

“…As the corneal shape is altered during orthokeratology treatment, both corneal and ocular aberrations, primarily spherical and comatic aberrations, significantly increase. [15][16][17][18][19][20][21] Hiraoka et al 22 investigated the correlations between ocular aberrations and axial elongation in 55 children (mean age: 10.3 AE 1.4 years) undergoing orthokeratology treatment for one year and showed that children with greater increases in the root-mean-square (RMS) error values for spherical, comatic, and total higherorder aberrations (HOAs) exhibited slower axial eye growth. Theoretically, a greater change in HOAs should be induced during orthokeratology treatment when the amount of myopia corrected is higher, as a greater change in corneal shape is necessary to achieve the desired refractive correction (that is, more reduction in corneal sphericity).…”

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confidence: 99%

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The influence of orthokeratology compression factor on ocular higher‐order aberrations

Lau

Vincent

Cheung

et al. 2020

Clinical and Experimental Optometry

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Background To investigate the influence of compression factor upon changes in ocular higher‐order aberrations (HOAs) in young myopic children undergoing orthokeratology treatment. Methods Subjects aged between six and < 11 years, with low myopia (0.50–4.00 D inclusive), low astigmatism (≤ 1.25 D), and anisometropia (≤ 1.00 D), were randomly assigned to wear orthokeratology lenses of different compression factors in each eye (one eye 0.75 D and the fellow eye 1.75 D). HOAs were measured weekly over one month of lens wear. Wavefront analysis was conducted over a 5‐mm pupil using a sixth order Zernike polynomial expansion. Linear mixed models were used to examine the individual Zernike co‐efficients and specific root‐mean‐square (RMS) error (spherical, comatic, total HOAs) metrics and their changes between the two eyes during the study period. Results Twenty‐eight myopic (mean manifest spherical equivalent refraction: −2.10 ± 0.58 D) children (median [range] age: 9.3 [7.8–11.0] years) were analysed. Significant interocular differences in HOAs at baseline were observed for Z6−6 and Z6−4 only (both p < 0.05). During the lens wear period, eyes fitted with the increased compression factor showed greater changes in primary spherical aberration (Z40, p = 0.04) and RMS values for spherical and total HOAs (both p < 0.01). Considering data from both eyes together, after adjusting for the paired nature of the data, some other Zernike terms (Z31 and Z60, both p < 0.01) and the RMS value of comatic aberrations (p < 0.001) significantly increased after one month of orthokeratology treatment. The increase in primary spherical aberration (Z40) was positively correlated with the reduction in spherical equivalent refractive error, but only in eyes fitted with the increased compression factor (r = 0.69, p < 0.001). Conclusions Increasing the orthokeratology compression factor by 1.00 D significantly altered some HOAs, particularly spherical aberration. Given the association between positive spherical aberration and eye growth in children, further research investigating the influence of orthokeratology compression factor on axial eye growth is warranted.

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Section: Sample Size Determinationmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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The influence of orthokeratology compression factor on ocular higher‐order aberrations

Lau

Vincent

Cheung

et al. 2020

Clinical and Experimental Optometry

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“…[11] Sun et al have recently reported increased corneal irregularity and ocular HOA (spherical aberrations and comas) with OK lenses, despite improvements in refractive error. [24] No significant lens decentration was seen in our patients.…”

Section: Discussionmentioning

confidence: 42%

Orthokeratology in Moderate Myopia: A Study of Predictability and Safety

Singh

Bhattacharyya

Goel

et al. 2020

JOVR

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Purpose: Literature is relatively silent on safety profile and predictability of orthokeratology lenses in terms of myopia correction and prevention of further progression, especially in semi-tropical countries; this study was designed to fill this gap. Methods: This prospective, intervention case series enrolled 30 eyes of 30 patients with myopia up to –5.5 diopters (D). Patients were randomized into two groups of 15 each; the study group was prescribed overnight orthokeratology (OK) lenses, while the control group used daily wear conventional soft contact lenses. Follow-up examinations were performed after 1 h and 6 h, and then at 1, 7, 15, 30 days, and 4 months post lens wear. Uncorrected visual acuity (UCVA), contrast sensitivity, keratometry, central corneal thickness (CCT), and tear film break up time (TBUT) were evaluated at each follow-up examination. Results: All patients attained a visual acuity of 0.00 Logarithm of the Minimum Angle of Resolution (logMAR) after one week of lens use, which was maintained throughout the study period. While patients allotted to the study group had a gain of 8.1 Snellen lines (UCVA), those in the control group gained 8.9 lines (BCVA) at the end of follow-up period. In the OK group, cornea showed a flattening of 0.8 D (mean keratometry) after single overnight usage of OK lens and overall flattening of 1.2 D compared to baseline, at the end of four months. The change in contrast sensitivity, corneal endothelial specular count, axial length and tear film status was not significant in either group. Conclusion: Orthokeratology is an effective and safe modality to correct moderate myopia in motivated young adults. No side effects were encountered after a short-term follow-up in participants who resided in semi-tropical environments.

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“…Regarding OK, the change in corneal geometry causes an increase in ocular aberrations [64,65]. Chen et al [61] described a statistically significant rise in spherical aberrations (0.05 ± 0.6 to 0.19 ± 0.13 µm) and coma aberrations (0.12 ± 0.19 to 0.36 ± 0.23 µm).…”

Section: Orthokeratologymentioning

confidence: 99%

The Combined Effect of Low-dose Atropine with Orthokeratology in Pediatric Myopia Control: Review of the Current Treatment Status for Myopia

Sánchez‐González

De-Hita-Cantalejo

Baustita-Llamas

et al. 2020

JCM

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Pediatric myopia has become a major international public health concern. The prevalence of myopia has undergone a significant increase worldwide. The purpose of this review of the current literature was to evaluate the peer-reviewed scientific literature on the efficacy and safety of low-dose atropine treatment combined with overnight orthokeratology for myopia control. A search was conducted in Pubmed and Web of Science with the following search strategy: (atropine OR low-dose atropine OR 0.01% atropine) AND (orthokeratology OR ortho-k) AND (myopia control OR myopia progression). All included studies improved myopia control by the synergistic effect of orthokeratology with low-dose atropine, compared with orthokeratology treatment alone. All studies included a short or medium follow-up period; therefore longer-term studies are necessary to validate these results.

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Influence of Overnight Orthokeratology on Corneal Surface Shape and Optical Quality

Cited by 17 publications

References 30 publications

The influence of orthokeratology compression factor on ocular higher‐order aberrations

The influence of orthokeratology compression factor on ocular higher‐order aberrations

Orthokeratology in Moderate Myopia: A Study of Predictability and Safety

The Combined Effect of Low-dose Atropine with Orthokeratology in Pediatric Myopia Control: Review of the Current Treatment Status for Myopia

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