This single-masked randomized clinical trial aimed to evaluate the effectiveness of orthokeratology (ortho-k) for myopic control.
A total of 102 eligible subjects, ranging in age from 6 to 10 years, with myopia between 0.50 and 4.00 diopters (D) and astigmatism not more than 1.25D, were randomly assigned to wear ortho-k lenses or single-vision glasses for a period of 2 years. Axial length was measured by intraocular lens calculation by a masked examiner and was performed at the baseline and every 6 months. This study was registered at ClinicalTrials.gov, number NCT00962208.
In all, 78 subjects (37 in ortho-k group and 41 in control group) completed the study. The average axial elongation, at the end of 2 years, were 0.36 ± 0.24 and 0.63 ± 0.26 mm in the ortho-k and control groups, respectively, and were significantly slower in the ortho-k group (P < 0.01). Axial elongation was not correlated with the initial myopia (P > 0.54) but was correlated with the initial age of the subjects (P < 0.001). The percentages of subjects with fast myopic progression (>1.00D per year) were 65% and 13% in younger (age range: 7-8 years) and older (age range: 9-10 years) children, respectively, in the control group and were 20% and 9%, respectively, in the ortho-k group. Five subjects discontinued ortho-k treatment due to adverse events.
On average, subjects wearing ortho-k lenses had a slower increase in axial elongation by 43% compared with that of subjects wearing single-vision glasses. Younger children tended to have faster axial elongation and may benefit from early ortho-k treatment. (ClinicalTrials.gov number, NCT00962208.).
"Two studies were randomized controlled trials (RCTs)  , and the remaining 6 were cohort trials [16–18, 20, 21, 23]. Six of the eight studies used common OK as treatment      , while the remaining two used partial reduction orthokeratology (PRok) and toric orthokeratology (Tok), respectively  . In the control group, seven studies used single vision spectacles (SV) [16, 18–23] and one employed soft contact (SC) lenses . "
[Show abstract][Hide abstract] ABSTRACT: Background. To evaluate the efficacy and acceptability of orthokeratology for slowing myopic progression in children with a well conducted evidence-based analysis. Design. Meta-analysis. Participants. Children from previously reported comparative studies were treated by orthokeratology versus control. Methods. A systematic literature retrieval was conducted in MEDLINE, EMBASE, Cochrane Library, World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. The included studies were subjected to meta-analysis using Stata version 10.1. Main Outcome Measures. Axial length change (efficacy) and dropout rates (acceptability) during 2-year follow-up. Results. Eight studies involving 769 subjects were included. At 2-year follow-up, a statistically significant difference was observed in axial length change between the orthokeratology and control groups, with a weighted mean difference (WMD) of −0.25 mm (95% CI, −0.30 to −0.21). The pooled myopic control rate declined with time, with 55, 51, 51, and 41% obtained after 6, 12, 18, and 24 months of treatment, respectively. No statistically significant difference was obtained for dropout rates between the orthokeratology and control groups at 2-year follow-up (OR, 0.79; 95% CI, 0.52 to 1.22). Conclusions. Orthokeratology is effective and acceptable for slowing myopic progression in children with careful education and monitoring.
Journal of Ophthalmology 07/2015; 2015:1-12. DOI:10.1155/2015/360806 · 1.43 Impact Factor
"Considering the evidence that orthokeratology slows myopia progression       and that this treatment induces a substantial change in the peripheral refractive error  of the myopic eye toward high degrees of peripheral myopic defocus and astigmatism , a link has been suggested between relative peripheral hyperopic defocus and myopia progression in humans  . Some ophthalmic lenses  and contact lenses  have been designed specifically to arrest myopia progression based on this hypothetical mechanism. "
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To evaluate the impact of eye and head rotation in the measurement of peripheral refraction with an open-field autorefractometer in myopic eyes wearing two different center-distance designs of multifocal contact lenses (MFCLs).
Nineteen right eyes from 19 myopic patients (average central M ± SD = -2.67 ± 1.66 D) aged 20-27 years (mean ± SD = 23.2 ± 3.3 years) were evaluated using a Grand-Seiko autorefractometer. Patients were fitted with one multifocal aspheric center-distance contact lens (Biofinity Multifocal D(®)) and with one multi-concentric MFCL (Acuvue Oasys for Presbyopia). Axial and peripheral refraction were evaluated by eye rotation and by head rotation under naked eye condition and with each MFCL fitted randomly and in independent sessions.
For the naked eye, refractive pattern (M, J0 and J45) across the central 60° of the horizontal visual field values did not show significant changes measured by rotating the eye or rotating the head (p > 0.05). Similar results were obtained wearing the Biofinity D, for both testing methods, no obtaining significant differences to M, J0 and J45 values (p > 0.05). For Acuvue Oasys for presbyopia, also no differences were found when comparing measurements obtained by eye and head rotation (p > 0.05). Multivariate analysis did not showed a significant interaction between testing method and lens type neither with measuring locations (MANOVA, p > 0.05). There were significant differences in M and J0 values between naked eyes and each MFCL.
Measurements of peripheral refraction by rotating the eye or rotating the head in myopic patients wearing dominant design or multi-concentric multifocal silicone hydrogel contact lens are comparable.
"Progressive addition lenses (PALs) have shown insignificant effect on myopia control,6–11 and bifocal spectacle lenses have shown promising effect on children with fast myopia progression.12 Orthokeratology has showed certain effect on retarding axial elongation,13
14 but children need to sleep with lenses overnight to maintain appropriate corneal curvature and clear vision. "
[Show abstract][Hide abstract] ABSTRACT: To determine if 'Defocus Incorporated Soft Contact' (DISC) lens wear slows childhood myopia progression.
A 2-year double-blind randomised controlled trial was carried out in 221 children aged 8-13 years, with myopia between -1.00 and -5.00 Dioptres (D) and astigmatism ≤1.00 D. Subjects were randomly assigned to the DISC (n=111) or single vision (SV; n=110) contact lens group. DISC lenses incorporated concentric rings, which provided an addition of +2.50 D, alternating with the normal distance correction. Refractive error (cycloplegic autorefraction) and axial length were measured at 6-month intervals. Differences between groups were analysed using unpaired t test.
In total, 128 children completed the study, n=65 in the DISC group and n=63 in the SV group. Myopia progressed 25% more slowly for children in the DISC group compared with those in the control group (0.30 D/year; 95% CI -0.71 to -0.47 vs 0.4 D/year; 95% CI -0.93 to -0.65, p=0.031). Likewise, there was less axial elongation for children in the DISC versus SV groups (0.13 mm/year; 95% CI 0.20 to 0.31 vs 0.18 mm/year; 95% CI 0.30 to 0.43, p=0.009). Treatment effect correlated positively with DISC lens wearing time (r=0.342; p=0.005). Indeed, myopia in children who wore the DISC lenses for five or more hours/day progressed 46% (mean difference=-0.382 D, p=0.001; 95% CI -0.59 to -0.17) less than those in the SV group.
The daily wearing of DISC lens significantly slowed myopia progression and axial elongation in Hong Kong schoolchildren. The findings demonstrated that simultaneous clear vision with constant myopic defocus can retard myopia progression.
The British journal of ophthalmology 10/2013; 98(1). DOI:10.1136/bjophthalmol-2013-303914 · 2.98 Impact Factor
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