Effect of Dual-Focus Soft Contact Lens Wear on Axial Myopia Progression in Children
Department of Optometry and Vision Science, New Zealand National Eye Centre, The University of Auckland, New Zealand. Ophthalmology
(Impact Factor: 6.14).
06/2011; 118(6):1152-61. DOI: 10.1016/j.ophtha.2010.10.035
To test the efficacy of an experimental Dual-Focus (DF) soft contact lens in reducing myopia progression.
Prospective, randomized, paired-eye control, investigator-masked trial with cross-over.
Forty children, 11-14 years old, with mean spherical equivalent refraction (SER) of -2.71 ± 1.10 diopters (D).
Dual-Focus lenses had a central zone that corrected refractive error and concentric treatment zones that created 2.00 D of simultaneous myopic retinal defocus during distance and near viewing. Control was a single vision distance (SVD) lens with the same parameters but without treatment zones. Children wore a DF lens in 1 randomly assigned eye and an SVD lens in the fellow eye for 10 months (period 1). Lens assignment was then swapped between eyes, and lenses were worn for a further 10 months (period 2).
Primary outcome was change in SER measured by cycloplegic autorefraction over 10 months. Secondary outcome was a change in axial eye length (AXL) measured by partial coherence interferometry over 10 months. Accommodation wearing DF lenses was assessed using an open-field autorefractor.
In period 1, the mean change in SER with DF lenses (-0.44 ± 0.33 D) was less than with SVD lenses (-0.69 ± 0.38 D; P < 0.001); mean increase in AXL was also less with DF lenses (0.11 ± 0.09 mm) than with SVD lenses (0.22 ± 0.10 mm; P < 0.001). In 70% of the children, myopia progression was reduced by 30% or more in the eye wearing the DF lens relative to that wearing the SVD lens. Similar reductions in myopia progression and axial eye elongation were also observed with DF lens wear during period 2. Visual acuity and contrast sensitivity with DF lenses were not significantly different than with SVD lenses. Accommodation to a target at 40 cm was driven through the central distance-correction zone of the DF lens.
Dual-Focus lenses provided normal acuity and contrast sensitivity and allowed accommodation to near targets. Myopia progression and eye elongation were reduced significantly in eyes wearing DF lenses. The data suggest that sustained myopic defocus, even when presented to the retina simultaneously with a clear image, can act to slow myopia progression without compromising visual function.
Proprietary or commercial disclosure may be found after the references.
Available from: Pauline Kang
- "Improvements in accommodation performance, i.e., reduced lags, have also been reported with orthokeratology , lending further support to the notion that reduction or elimination of accommodative lags contributes to the myopia control effects of such treatments. The notion that the peripheral retina plays a critical role in refractive error development and thus in myopia progression also has its origins in animal model studies      and is driving the development of some novel designs of spectacles   and soft contact lenses (SCLs)    for myopia control. The underlying premise is that by manipulating the defocus experience of the peripheral retina, one can either neutralise the optical defocus stimulus for excessive axial length elongation, i.e., by correcting peripheral (off-axis) hyperopia, or reverse it by imposing myopic defocus, thereby inhibiting eye growth. "
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To characterise the effects on accommodation and binocular vision in young adults of 2 distance centre multifocal soft contact lenses (MFSCLs), differing in add power.
Twenty-four young adult myopes (18-28 years; 20 females, 4 males) had baseline visual acuity, accommodation, near phoria, fixation disparity and stereopsis data collected with single vision (SV) SCLs. The same set of measurements was repeated immediately after subjects were fitted with each of two MFSCLs (with either +1.50 or +3.00 D add), and after 2 weeks of daily wear in each case. The order of testing was randomised and a one-week washout period was allowed between the first and second MFSCL trials.
Differences in distance and near acuities with MFSCLs compared to SVSCLs were small and clinically insignificant. Compared to responses with SVSCLs, MFSCLs increased accommodative lags with this change reaching statistical significance for the +1.50 D add lens. Furthermore, both MFSCLs induced significant shifts in near phorias in the exo direction. Finally, there were no significant differences in stereopsis and fixation disparity with MFSCLs compared to SVSCLs.
Differences in acuities, accommodation accuracy and binocular posture with MFSCLs compared to SVSCLs were clinically small and mostly not significant. These results predict good tolerance of MFSCLs in young patients fitted with them for myopia control.
Available from: Jaime Pauné
- "Soft multifocal contact lenses are advantageous compared to ophthalmic lenses because they move with the eye and thus the optical correction remains centered for all gaze positions. Previous studies of multifocal contact lenses have reported reductions in myopic progression ranging from 30% to 50% and about 30% in axial length (AL) depending on lens design     . Generally, all experimental lenses tested were designed with a central optic zone intended for distance vision and surrounded by one or more rings with plus addition powers. "
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ABSTRACT: Objective. To evaluate the degree of axial elongation with soft radial refractive gradient (SRRG) contact lenses, orthokeratology (OK), and single vision (SV) spectacle lenses (control) during a period of 1 year before treatment and 2 years after treatment. Methods. This was a prospective, longitudinal, nonrandomized study. The study groups consisted of 30, 29, and 41 children, respectively. The axial length (AL) was measured during 2 years after recruitment and lens fitting. Results. The baseline refractive sphere was correlated significantly (Spearman's Rho (í µí¼) correlation = 0.542; P < 0.0001) with the amount of myopia progression before baseline. After 2 years, the mean myopia progression values for the SRRG, OK, and SV groups were −0.56 ± 0.51, −0.32 ± 0.53, and −0.98 ± 0.58 diopter, respectively. The results represent reductions in myopic progression of 43% and 67% for the SRRG and OK groups, respectively, compared to the SV group. The AL increased 27% and 38% less in the SRRG and OK groups, respectively compared with the SV group at the 2-year visit (P < 0.05). Axial elongation was not significantly different between SRRG and OK (P = 0.430). Conclusion. The SRRG lens significantly decreased AL elongation compared to the SV control group. The SRRG lens was similarly effective to OK in preventing myopia progression in myopic children and adolescent.
- "Such lenses not only include the plethora of commercially available bi-and multifocal contact lenses but also novel lens designs, including the marketed myopia control contact lens MiSight, which features a large central distance zone surrounded by alternating concentric distant and near zones. Various commercial and novel multifocal contact lenses have been assessed for the capacity to retard myopia progression     , however, few studies have assessed the visual performance of multifocal contact lenses in non-presbyopic myopic eyes   . The accumulated evidence from these studies indicates some degradation of visual performance is likely to occur when contact lenses with multiple refractive zones are worn. "
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ABSTRACT: To assess visual performance of single vision and multifocal soft contact lenses.
At baseline, forty-four myopic participants (aged 18-35 years) were fitted bilaterally with a control lens (AirOptix Aqua). At the four follow-up visits, a total of 16 study lenses (5 single vision, 11 multifocal lenses) were fitted contralaterally. After 1h of lens wear, participants rated (scale 1-10) vision clarity (distance, intermediate and near), magnitude of ghosting at distance, comfort during head movement, and overall comfort. Distance high contrast visual acuity (HCVA), central refraction and higher order aberrations, and contact lens centration were measured.
For single vision lenses, vision ratings were not significantly different to the control (p>0.005). The control outperformed Acuvue Oasys, Clariti Monthly and Night and Day in HCVA (mean VA: -0.10±0.07 logMAR, p<0.005). Most refraction and higher order aberration measures were not different between lenses. The Night and Day lens showed greatest differences compared to the control, i.e., C[4, 0] was more positive (p<0.005) at distance (Δ=0.019μm) and near (Δ=0.028μm). For multifocal lenses, the majority of vision ratings (84%) were better with the control (p<0.005). HCVA was better with the control (p<0.005). Proclear Multifocal lenses showed greatest differences for M, C[3, -1] and C[4, 0] at distance and near, and were inferiorly de-centered (p<0.005).
Design differences between single vision lenses had a small impact on visual performance. Lenses featuring multifocality decreased visual performance, in particular when power variations across the optic zone were large and/or the lens was significantly de-centered.
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