Monovision slows juvenile myopia progression unilaterally. Br J Ophthalmol

Department of Optometry and Vision Science, University of Auckland, Private Bag 92019, Auckland, New Zealand.
British Journal of Ophthalmology (Impact Factor: 2.98). 09/2005; 89(9):1196-200. DOI: 10.1136/bjo.2004.064212
Source: PubMed


To evaluate the acceptability, effectivity, and side effects of a monovision spectacle correction designed to reduce accommodation and myopia progression in schoolchildren.
Dominant eyes of 11 year old children with myopia (-1.00 to -3.00 D mean spherical equivalent) were corrected for distance; fellow eyes were uncorrected or corrected to keep the refractive imbalance <or=2.00 D. Myopia progression was followed with cycloplegic autorefraction and A-scan ultrasonography measures of vitreous chamber depth (VCD) for up to 30 months. Dynamic retinoscopy was used to assess accommodation while reading.
All children accommodated to read with the distance corrected (dominant) eye. Thus, the near corrected eye experienced myopic defocus at all levels of accommodation. Myopia progression in the near corrected eyes was significantly slower than in the distance corrected eyes (inter-eye difference=0.36 D/year (95% CI: 0.54 to 0.19, p=0.0015, n=13); difference in VCD elongation=0.13 mm/year (95% CI: 0.18 to 0.08, p=0.0003, n=13)). After refitting with conventional spectacles, the resultant anisometropia returned to baseline levels after 9-18 months.
Monovision is not effective in reducing accommodation in juvenile myopia. However, myopia progression was significantly reduced in the near corrected eye, suggesting that sustained myopic defocus slows axial elongation of the human eye.

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    • "In this case by a change in the dioptric environment that an eye is exposed to. After early studies showed relatively small impact of spectacle lenses on eye growth (Gwiazda et al., 2003), there is now more convincing evidence of that retinal defocus can affect the growth of the human eye (Phillips, 2005). Such findings strengthen the possibility that dioptric structure of the world and the dioptric demands of specific tasks such as reading may influence eye growth (Flitcroft, 2012). "
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    ABSTRACT: This review examines the hypothesis that human myopia is primarily a failure of homeostasis (i.e. regulated growth) and also considers the implications this has for research into refractive errors. There is ample evidence for homeostatic mechanisms in early life. During the first few years of life the eye grows toward emmetropia, a process called emmetropization. The key statistical features of this process are a shift of the mean population refraction toward emmetropia and a reduction in variability. Refractive errors result when either this process fails (primary homeostatic failure) or when an eye that becomes emmetropic fails to remain so during subsequent years (secondary homeostatic failure). A failure of homeostasis should increase variability as well as causing a possible shift in mean refraction. Increased variability is indeed seen in both animal models of myopia such as form deprivation and in human populations from the age of 5 or 6 onwards. Considering ametropia as a homeostatic failure also fits with the growing body of evidence that a wide range of factors and events can influence eye growth and refraction from gestation, through infancy, childhood and into adulthood. It is very important to recognize that the refraction of an eye is not a simple trait like eye colour but the consequence of the complex process of eye growth throughout life. To understand how an eye ends up with a specific refraction it is essential to understand all the factors that may promote the attainment and maintenance of emmetropia. Equally important are the factors that may either disrupt early emmetropization or lead to a loss of emmetropia during later development. Therefore, perhaps the most important single implication of a homeostatic view of myopia is that this condition is likely to have a very wide range of causes. This may allow us to identify subgroups of myopia for which specific environmental influences, genes or treatments can be found, effects that might be lost if all myopes are considered to be equivalent.
    Experimental Eye Research 02/2013; 114. DOI:10.1016/j.exer.2013.02.008 · 2.71 Impact Factor
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    • "There is evidence that different optical correction schemes influence the rate of progression of myopia. Examples are undercorrected prescriptions (Phillips, 2005; but see also Chung, Mohidin , & O'Leary, 2002; reporting the opposite effect), rigid contact lenses (Walline, Jones, Mutti, & Zadnik, 2004), bifocal spectacles (Fulk, Cyert, & Parker, 2002), bifocal soft contact lenses (Aller & Wildsoet, 2008) or progressive addition lenses (Gwiazda et al., 2003; Leung & Brown, 1999). Although there is some controversy regarding the benefit of optical intervention, given the small effects in many cases, recent analyses of subgroups of children treated with progressive addition lenses showed clinically relevant effects with about 50% of inhibition of myopia, and no rebound effect after termination of the treatment (Gwiazda, 2008). "
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    ABSTRACT: The recent observation that central refractive development might be controlled by the refractive errors in the periphery, also in primates, revived the interest in the peripheral optics of the eye. We optimized an eccentric photorefractor to measure the peripheral refractive error in the vertical pupil meridian over the horizontal visual field (from -45 degrees to 45 degrees ), with and without myopic spectacle correction. Furthermore, a newly designed radial refractive gradient lens (RRG lens) that induces increasing myopia in all radial directions from the center was tested. We found that for the geometry of our measurement setup conventional spectacles induced significant relative hyperopia in the periphery, although its magnitude varied greatly among different spectacle designs and subjects. In contrast, the newly designed RRG lens induced relative peripheral myopia. These results are of interest to analyze the effect that different optical corrections might have on the emmetropization process.
    Vision research 07/2009; 49(17):2176-86. DOI:10.1016/j.visres.2009.06.008 · 1.82 Impact Factor
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    • "Thus, a possible explanation for the cited human studies is that the level of undercorrection was insufficient to significantly reduce accommodative lags. The latter explanation is consistent with the apparent benefit, albeit small, of bifocal and progressive spectacle lenses incorporating adds in the range of + 1.50 to + 2.00 D, and the monocular slowing of myopia progression in a monovision spectacle correction trial (Phillips, 2005), in which the dominant (distance) eye was fully corrected and the fellow eye either left uncorrected or corrected to keep the refractive imbalance ≤2.00 D. The fellow eyes showed significantly slower progression in the latter study. "
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    ABSTRACT: To assess the effect of bifocal soft contact lenses on the accommodative errors (lags) of young adults. Recent studies suggest that bifocal soft contact lenses are an effective myopia control treatment although the underlying mechanism is not understood. Accommodation responses were measured for four target distances: 100, 50, 33 and 25 cm in 35 young adult subjects (10 emmetropes and 25 myopes; mean age, 22.8 +/- 2.5 years). Measurements were made under both monocular and binocular conditions with three types of lenses: single vision distance soft contact lenses (SVD), single vision near soft contact lenses (SVN; +1.50 D added to the distance prescription) and bifocal soft contact lenses (BF; +1.50 D add). For the SVD lenses, all subjects exhibited lags of accommodation, with myopes accommodating significantly less than emmetropes for the 100 and 50 cm target distances (p < 0.05). With the SVN lenses, there was no significant difference in accommodative responses between emmetropes and myopes. With the BF lenses, both emmetropic and myopic groups exhibited leads in accommodation for all target distances, with emmetropes showing significantly greater leads for all distances (p < 0.005). Overall, myopes tended to accommodate less than emmetropes, irrespective of the contact lens type, which significantly affected accommodation for both groups. The apparent over-accommodation of myopes when wearing the BF contact lenses may explain the reported efficacy as a myopia control treatment, although further studies are required to elucidate the mechanism underlying this accommodative effect.
    Ophthalmic and Physiological Optics 01/2008; 28(1):62-72. DOI:10.1111/j.1475-1313.2007.00529.x · 2.18 Impact Factor
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