Multifocal correction also caused a hyperopic shift in peripheral refraction at all locations in low myopes as demonstrated in Fig. 2A. The relative peripheral refraction profile was similar between no correction and SV and MF corrections in the temporal VF (Fig. 2B). However, there was significant myopic shift in relative peripheral refraction in the nasal VF (FN10 = 9.217, p = 0.008; FN20 = 29.491, p < 0.001; FN30 = 45.328, p < 0.001; FN35 = 18.799, p = 0.001) with MF compared with SV correction (Fig. 2B). Multifocal correction also caused a hyperopic shift in peripheral refraction at all locations in moderate myopes (Fig. 3A). Moreover, overall differences in relative peripheral refraction profile between full SV and MF correction were found (F = 16.880, p < 0.001), which were confirmed by post hoc tests specifically at 35 degrees in the temporal VF (FT35 = 8.039, p = 0.012) and all locations in the nasal VF (FN10 = 0.909, p = 0.003; FN20 = 54.100, p < 0.001; FN30 = 71.018, p < 0.001; FN35 = 50.385, p < 0.001) as illustrated in Fig. 3B.
Similarly, compared with no correction, SV and MF correction caused a significant change in the J180 profile (F = 2.720, p = 0.003) in moderate myopes as shown in Fig. 4B. Single-vision SCL correction caused a positive increase in J180 at 30 degrees (p = 0.004) in the temporal VF and at 30 (p = 0.018) and 35 degrees (p = 0.003) in the nasal VF, as indicated by post hoc t tests. Furthermore, compared with no correction, MF SCLs caused a negative increase at 10 (p = 0.023) and 30 degrees (p = 0.021) in the nasal VF. In addition, compared with SV correction, MF correction caused a negative shift in J180 at 10 (p = 0.012), 20 (p = 0.014), 30 (p = 0.001), and 35 degrees (p = 0.001) in the nasal VF in moderate myopes.
Experimental animal studies investigating vision-dependent mechanisms that regulate refractive error development have demonstrated that, contrary to traditional belief, refractive error development seems to be influenced more by peripheral defocus than previously believed.27,28 Recently, Smith et al.26 imposed hyperopic peripheral defocus with unrestricted central vision in infant rhesus monkeys with intact and photoablated foveas. Imposing this hyperopic defocus in the periphery was found to promote the development of central axial myopia in the presence of both functioning and nonfunctional foveas. Liu and Wildsoet29 demonstrated in the chick eye model that a plano center and +5 D periphery concentric bifocal spectacle lens tended to produce central hyperopia coupled with apparent inhibition of axial length elongation. More recently, Ho et al.46 demonstrated differences in human retinal electrical response to defocus with the paracentral retina responding more strongly to defocus compared with the central retina, further supporting the theory that refractive error development is more influenced by peripheral visual signals. Consequently, it has been hypothesized that inducing a myopic defocus onto the peripheral retina of progressive myopes might potentially slow or stop the progression of central myopia.36 Therefore, optical means of manipulating peripheral vision have become of great interest and may provide a possible strategy for myopia control in humans.
Antimyopia MF SCLs with plus power in the periphery to induce myopic defocus onto the peripheral retina have been developed as a means of myopia control. However, there are commercially available MF SCLs, traditionally fitted for presbyopic correction, which have similar designs to these novel antimyopia SCLs. The purpose of this study was to determine the effects of Proclear Multifocals (Coopervision), a commercially available SCL that has a distance center correction and a plus add (+2.00 DS) periphery design, on peripheral refraction in young adult myopes compared with SV SCLs.
Myopic shifts in relative peripheral refraction profiles were found in both low and moderate myopes wearing MF compared with SV SCLs. Although an absolute myopic defocus was apparent at most eccentric locations in both low and moderate myopes, a full +2.00 D myopic shift in peripheral refraction was not measured. This is likely to be caused by the autorefractor averaging refraction across its 2.3-mm measurement ring rather than measuring refraction at a single defined point on the retina. The myopic shift was more apparent in the nasal compared with the temporal VF, and this is likely to be caused by temporal decentration of SCLs, an effect which has been previously noted.40,47 As animal studies have suggested that the effects of optical defocus on refractive error seem to be locally mediated,25 this asymmetric refractive shift induced by MF SCLs must be viewed with caution. Corresponding regional changes in ocular shape have been demonstrated with optical defocus induced over restricted retinal regions in primates,48,49 and thus, there is a possibility that MF SCLs may promote undesirable asymmetric ocular growth in human myopes. Future longitudinal studies on the effects of MF SCLs on ocular shape are indicated. Furthermore, eyes that demonstrate poor SCL centration may not be suitable to wear MF SCLs as a potential form of myopia control.
As previously mentioned, Proclear Multifocal SCLs used in this study are of similar design to MF SCLs that have been specifically developed for potential myopia control. The AMCL is a silicone hydrogel SCL designed to induce myopia on to the peripheral retina. The design of this contact lens is described in detail elsewhere.40 Axial length increase after 12 months of AMCL wear in 43 children of Chinese ethnicity was 0.27 mm (95% confidence interval, 0.22 to 0.32 mm) and 0.40 mm for 39 spectacle lens wearers (95% confidence interval, 0.35 to 0.45 mm), equivalent to approximately 33% less myopia progression in the AMCL group. Compared with spectacle lens wearers, myopic shift in relative peripheral refraction was found in children wearing these novel SCLs at 20, 30, and 40 degrees in the nasal VF and at 30 and 40 degrees in the temporal VF.40 A more myopic relative peripheral refractive profile was found with the AMCL compared with baseline.
The Dual-Focus lens, commercially known as the MiSight lens (Coopervision), was developed and investigated by Anstice and Phillips39 who similarly demonstrated reduced myopia progression with these MF SCLs in a group of 40 myopic children aged between 11 and 14 years. Subjects were randomized to wear the Dual-Focus lens in one eye and an SV SCL in the contralateral eye for 10 months (period 1). Lens assignment was then swapped for the second 10 months (period 2). During period 1, axial length elongation of 0.11 ± 0.09 mm compared with 0.22 ± 0.09 mm was measured in the eyes wearing the Dual-Focus lens and SV SCL, respectively. After the crossover period, the eye now wearing the Dual-Focus lens was reported to show axial elongation of 0.03 ± 0.10 mm compared with the eye now wearing SV SCLs, which had axial elongation of 0.14 ± 0.09 mm. We are unaware of any published reports on peripheral refraction changes with the Dual-Focus lens.
Although the described antimyopia MF SCLs have been developed based on the hypothesis that peripheral hyperopia, present in a typical myope, may stimulate central myopia development, there have been studies contradicting this hypothesis. Sng et al.54 found that the development of myopia was associated with a change in peripheral refraction from relative myopia to relative hyperopia, indicating that peripheral refraction may be more a reflection of ocular shape change rather than being a myopiogenic factor. Furthermore, analysis of results from the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) study found no significant association between the amount of relative peripheral hyperopia and risk of onset of central myopia.55 However, it must be noted that peripheral refraction was measured in only one position (30-degree temporal gaze) in the entire VF. Very recently, Jaeken and Artal56 measured peripheral optical quality using a Hartmann-Shack wavefront sensor. Peripheral defocus and oblique astigmatism were found to be the main contributors to degradation of the peripheral image in both emmetropic and myopic eyes. Furthermore, they found the amount of peripheral blur to be similar between the two refractive groups and therefore argued against the hypothesis of retinal defocus influencing refractive error development. They proposed that if emmetropization is driven by peripheral blur, differences in peripheral blur would be expected between emmetropic and myopic eyes. However, this was not the case.
Despite conflicting reports and new perspectives on the theory of myopia control through manipulation of peripheral defocus, studies have shown that optical methods that reduce the amount of hyperopia induced onto the peripheral retina, in particular the antimyopia MF SCLs,39,40 seem to slow down the progression of myopia. In this study, refraction measured with the Proclear MF SCLs with center distance correction and +2.00 D add periphery was myopic at most locations along the horizontal VF meridian. According to the peripheral defocus hypothesis, this peripheral myopia may be antimyopiogenic. For clinicians who do not have access to the MiSight or Dual-Focus lenses, the results from this study suggest that the Proclear MF SCL can be used as an alternative for potential myopia control in progressive myopic children, although caution must be taken as induced peripheral refraction profiles with MF SCLs were found to be asymmetric in this study. Thus, myopic children with poor lens centration may not be suitable for myopia control with MF SCLs. However, studies of the long-term efficacy of MF SCL wear for myopia control in children are lacking, and further research is indicated.
1. Xie R, Zhou XT, Lu F, Chen M, Xue A, Chen S, Qu J. Correlation between myopia and major biometric parameters of the eye: a retrospective clinical study. Optom Vis Sci 2009; 86: 503–8.
2. McBrien NA, Adams DW. A longitudinal investigation of adult-onset and adult-progression of myopia in an occupational group. Refractive and biometric findings. Invest Ophthalmol Vis Sci 1997; 38: 321–33.
3. Atchison DA. Recent advances in measurement of monochromatic aberrations of human eyes. Clin Exp Optom 2005; 88: 5–27.
4. Atchison DA, Pritchard N, Schmid KL, Scott DH, Jones CE, Pope JM. Shape of the retinal surface in emmetropia and myopia. Invest Ophthalmol Vis Sci 2005; 46: 2698–707.
5. Grodum K, Heijl A, Bengtsson B. Refractive error and glaucoma. Acta Ophthalmol Scand 2001; 79: 560–6.
6. Mitchell P, Hourihan F, Sandbach J, Wang JJ. The relationship between glaucoma and myopia: the Blue Mountains Eye Study. Ophthalmology 1999; 106: 2010–5.
7. Saw SM, Gazzard G, Shih-Yen EC, Chua WH. Myopia and associated pathological complications. Ophthalmic Physiol Opt 2005; 25: 381–91.
8. Wong TY, Klein BE, Klein R, Tomany SC, Lee KE. Refractive errors and incident cataracts: the Beaver Dam Eye Study. Invest Ophthalmol Vis Sci 2001; 42: 1449–54.
9. Hsu WM, Cheng CY, Liu JH, Tsai SY, Chou P. Prevalence and causes of visual impairment in an elderly Chinese population in Taiwan: the Shihpai Eye Study. Ophthalmology 2004; 111: 62–9.
10. Xu L, Wang Y, Li Y, Cui T, Li J, Jonas JB. Causes of blindness and visual impairment in urban and rural areas in Beijing: the Beijing Eye Study. Ophthalmology 2006; 113: 1134 e1–11.
11. Grossniklaus HE, Green WR. Pathologic findings in pathologic myopia. Retina 1992; 12: 127–33.
12. Lai TY, Fan DS, Lai WW, Lam DS. Peripheral and posterior pole retinal lesions in association with high myopia: a cross-sectional community-based study in Hong Kong. Eye (Lond) 2008; 22: 209–13.
13. Lam DS, Fan DS, Chan WM, Tam BS, Kwok AK, Leung AT, Parsons H. Prevalence and characteristics of peripheral retinal degeneration in Chinese adults with high myopia: a cross-sectional prevalence survey. Optom Vis Sci 2005; 82: 235–8.
14. Edwards MH, Lam CS. The epidemiology of myopia in Hong Kong. Ann Acad Med Singapore 2004; 33: 34–8.
15. Lin LL, Shih YF, Hsiao CK, Chen CJ. Prevalence of myopia in Taiwanese schoolchildren: 1983 to 2000. Ann Acad Med Singapore 2004; 33: 27–33.
16. Rose K, Smith W, Morgan I, Mitchell P. The increasing prevalence of myopia: implications for Australia. Clin Exp Ophthalmol 2001; 29: 116–20.
17. Saw SM. A synopsis of the prevalence rates and environmental risk factors for myopia. Clin Exp Optom 2003; 86: 289–94.
18. Vitale S, Sperduto RD, Ferris FL 3rd. Increased prevalence of myopia in the United States between 1971–1972 and 1999–2004. Arch Ophthalmol 2009; 127: 1632–9.
19. Lin LL, Shih YF, Tsai CB, Chen CJ, Lee LA, Hung PT, Hou PK. Epidemiologic study of ocular refraction among schoolchildren in Taiwan in 1995. Optom Vis Sci 1999; 76: 275–81.
20. Lam CS, Goldschmidt E, Edwards MH. Prevalence of myopia in local and international schools in Hong Kong. Optom Vis Sci 2004; 81: 317–22.
21. Edwards MH. The development of myopia in Hong Kong children between the ages of 7 and 12 years: a five-year longitudinal study. Ophthalmic Physiol Opt 1999; 19: 286–94.
22. Fan DS, Lam DS, Lam RF, Lau JT, Chong KS, Cheung EY, Lai RY, Chew SJ. Prevalence, incidence, and progression of myopia of school children in Hong Kong. Invest Ophthalmol Vis Sci 2004; 45: 1071–5.
23. He M, Zeng J, Liu Y, Xu J, Pokharel GP, Ellwein LB. Refractive error and visual impairment in urban children in southern China. Invest Ophthalmol Vis Sci 2004; 45: 793–9.
24. Saw SM, Tong L, Chua WH, Chia KS, Koh D, Tan DT, Katz J. Incidence and progression of myopia in Singaporean school children. Invest Ophthalmol Vis Sci 2005; 46: 51–7.
25. Wallman J, Winawer J. Homeostasis of eye growth and the question of myopia. Neuron 2004; 43: 447–68.
26. Smith EL 3rd, Hung LF, Huang J. Relative peripheral hyperopic defocus alters central refractive development in infant monkeys. Vision Res 2009; 49: 2386–92.
27. Smith EL 3rd, Kee CS, Ramamirtham R, Qiao-Grider Y, Hung LF. Peripheral vision can influence eye growth and refractive development in infant monkeys. Invest Ophthalmol Vis Sci 2005; 46: 3965–72.
28. Smith EL 3rd, Ramamirtham R, Qiao-Grider Y, Hung LF, Huang J, Kee CS, Coats D, Paysse E. Effects of foveal ablation on emmetropization and form-deprivation myopia. Invest Ophthalmol Vis Sci 2007; 48: 3914–22.
29. Liu Y, Wildsoet C. The effect of two-zone concentric bifocal spectacle lenses on refractive error development and eye growth in young chicks. Invest Ophthalmol Vis Sci 2011; 52: 1078–86.
30. Mutti DO, Hayes JR, Mitchell GL, Jones LA, Moeschberger ML, Cotter SA, Kleinstein RN, Manny RE, Twelker JD, Zadnik K. Refractive error, axial length, and relative peripheral refractive error before and after the onset of myopia. Invest Ophthalmol Vis Sci 2007; 48: 2510–9.
31. Hoogerheide J, Rempt F, Hoogenboom WP. Acquired myopia in young pilots. Ophthalmologica 1971; 163: 209–15.
32. Lin Z, Martinez A, Chen X, Li L, Sankaridurg P, Holden BA, Ge J. Peripheral defocus with single-vision spectacle lenses in myopic children. Optom Vis Sci 2010; 87: 4–9.
33. Tabernero J, Vazquez D, Seidemann A, Uttenweiler D, Schaeffel F. Effects of myopic spectacle correction and radial refractive gradient spectacles on peripheral refraction. Vision Res 2009; 49: 2176–86.
34. Backhouse S, Fox S, Ibrahim B, Phillips JR. Peripheral refraction in myopia corrected with spectacles versus contact lenses. Ophthalmic Physiol Opt 2012; 32: 294–303.
35. Charman WN, Radhakrishnan H. Peripheral refraction and the development of refractive error: a review. Ophthalmic Physiol Opt 2010; 30: 321–38.
36. Smith EL 3rd. Prentice Award Lecture 2010: a case for peripheral optical treatment strategies for myopia. Optom Vis Sci 2011; 88: 1029–44.
37. Shen J, Clark CA, Soni PS, Thibos LN. Peripheral refraction with and without contact lens correction. Optom Vis Sci 2010; 87: 642–55.
38. Kang P, Fan Y, Oh K, Trac K, Zhang F, Swarbrick H. Effect of single vision soft contact lenses on peripheral refraction. Optom Vis Sci 2012; 89: 1014–21.
39. Anstice NS, Phillips JR. Effect of dual-focus soft contact lens wear on axial myopia progression in children. Ophthalmology 2011; 118: 1152–61.
40. Sankaridurg P, Holden B, Smith E 3rd, Naduvilath T, Chen X, de la Jara PL, Martinez A, Kwan J, Ho A, Frick K, Ge J. Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results. Invest Ophthalmol Vis Sci 2011; 52: 9362–7.
41. Grosvenor T. Primary Care Optometry, 5th ed. St Louis, MO: Butterworth-Heinemann/Elsevier; 2007.
42. Rosenfield M. Subjective refraction. In: Rosenfield M, Logan N, eds. Optometry: Science, Techniques and Clinical Management, 2nd ed. Edinburgh, UK: Butterworth-Heinemann/Elsevier; 2009: 209–28.
43. Thibos LN, Wheeler W, Horner D. Power vectors: an application of Fourier analysis to the description and statistical analysis of refractive error. Optom Vis Sci 1997; 74: 367–75.
44. Smith G, Millodot M, McBrien NA. The effect of accommodation on oblique astigmatism and field curvature of the human eye. Clin Exp Optom 1988; 71: 119–25.
45. Mathur A, Atchison DA, Kasthurirangan S, Dietz NA, Luong S, Chin SP, Lin WL, Hoo SW. The influence of oblique viewing on axial and peripheral refraction for emmetropes and myopes. Ophthalmic Physiol Opt 2009; 29: 155–61.
46. Ho WC, Wong OY, Chan YC, Wong SW, Kee CS, Chan HH. Sign-dependent changes in retinal electrical activity with positive and negative defocus in the human eye. Vision Res 2012; 52: 47–53.
47. Lopes-Ferreira D, Ribeiro D, Maia R, Garcia-Porta N, Quéiros A, Villa-Collar C, Gonzalez-Meijome J. Peripheral myopization using a dominant design multifocal contact lens. J Optom 2011; 4: 14–32.
48. Smith EL 3rd, Hung LF, Huang J, Blasdel TL, Humbird TL, Bockhorst KH. Effects of optical defocus on refractive development in monkeys: evidence for local, regionally selective mechanisms. Invest Ophthalmol Vis Sci 2010; 51: 3864–73.
49. Smith EL 3rd, Huang J, Hung LF, Blasdel TL, Humbird TL, Bockhorst KH. Hemiretinal form deprivation: evidence for local control of eye growth and refractive development in infant monkeys. Invest Ophthalmol Vis Sci 2009; 50: 5057–69.
50. Ticak A, Walline JJ. Peripheral optics with bifocal soft and corneal reshaping contact lenses. Optom Vis Sci 2013; 90: 3–8.
51. Rosen R, Jaeken B, Lindskoog Petterson A, Artal P, Unsbo P, Lundstrom L. Evaluating the peripheral optical effect of multifocal contact lenses. Ophthalmic Physiol Opt 2012; 32: 527–34.
52. Howland HC. A possible role for peripheral astigmatism in the emmetropization of the eye: Symposium 17, Paper 3. In: Tarutta E, Chua WH, Young T, Goldschmidt E, Saw S-M, Rose KA, Smith EL, 3rd, Mutti DO, Ashby R, Stone RA, Wildsoet C, Howland HC, Fischer AJ, Stell WK, Reichenbach A, Frost M, Gentle A, Zhu X, Summers-Rada J, Barathi V, Jiang L, McFadden S, Guggenheim JA, Hammond C, Schippert R, To CH, Gwiazda J, Marcos S, Collins M, Charman WN, Artal P, Tabernero J, Atchison DA, Seidemann A, Uttenweiler D, Troilo D, Norton TT, Wallman J, eds. Myopia: Why Study the Mechanisms of Myopia? Novel Approaches to Risk Factors Signaling Eye Growth—How Could Basic Biology Be Translated into Clinical Insights? Where Are Genetic and Proteomic Approaches Leading? How Does Visual Function Contribute to and Interact with Ametropia? Does Eye Shape Matter? Why Ametropia at All? Optom Vis Sci 2011; 88: 447.
53. Charman WN. Keeping the world in focus: how might this be achieved? Optom Vis Sci 2011; 88: 373–6.
54. Sng CC, Lin XY, Gazzard G, Chang B, Dirani M, Lim L, Selvaraj P, Ian K, Drobe B, Wong TY, Saw SM. Change in peripheral refraction over time in Singapore Chinese children. Invest Ophthalmol Vis Sci 2011; 52: 7880–7.
55. Mutti DO, Sinnott LT, Mitchell GL, Jones-Jordan LA, Moeschberger ML, Cotter SA, Kleinstein RN, Manny RE, Twelker JD, Zadnik K. Relative peripheral refractive error and the risk of onset and progression of myopia in children. Invest Ophthalmol Vis Sci 2011; 52: 199–205.
56. Jaeken B, Artal P. Optical quality of emmetropic and myopic eyes in the periphery measured with high-angular resolution. Invest Ophthalmol Vis Sci 2012; 53: 3405–13.