Myopia and defocus: the current understanding


  • Mhairi Day Glasgow Caledonian University
  • Lorraine A Duffy Glasgow Caledonian University



Myopia, defocus, near work, accommodation


The current theories relating to the development and progression of myopia are related to exposure of the eye to hyperopic defocus. This paper discusses these theories and the large body of recent research investigating the evidence behind them. As both human and animal studies demonstrate, when considering the potential influence of defocus on eye growth, the duration of exposure as well as the type and magnitude of the blur are important. In addition, we must understand the defocus threshold over which an eye growth signal can be made. Investigations with respect to central defocus alone have been unable to find a unified theory due to (1) insufficient evidence showing refractive group differences in the amount of central defocus actually present and (2) unsuccessful attempts to wholely reduce myopia progression using corrective lenses. Recent research measuring peripheral blur is summarised in this paper and modelled together with previous measurements of peripheral defocus thresholds, providing an up-to-date perspective on myopia.

Author Biographies

Mhairi Day, Glasgow Caledonian University


Department of Vision Sciences

Lorraine A Duffy, Glasgow Caledonian University

PhD student

Department of Vision Sciences


Abbott, M. L., Schmid, K. L. & Strang, N. C. (1998). Differences in the accommodation stimulus response curves of adult myopes and emmetropes. Ophthalmic Physiol Opt, 18(1), 13-20.

Adler, D. & Millodot, M. (2006). The possible effect of undercorrection on myopic progression in children. Clin Exp Optom, 89(5), 315-21.

Angle, J. & Wissmann, D. A. (1978). Age, reading, and myopia. Am J Optom Physiol Opt, 55(5), 302-8.

Angle, J. & Wissmann, D. A. (1980). The epidemiology of myopia. Am J Epidemiol, 111(2), 220-8.

Ashby, R. & Morgan, I. (2010). The role of light intensity in controlling ocular development in chickens. 13th International Myopia Conference, Tubingen, Germany.

Ashby, R., Ohlendorf, A. & Schaeffel, F. (2009). The effect of ambient illuminance on the development of deprivation myopia in chicks. Invest Ophthalmol Vis Sci, 50(11), 5348-54.

Atchison, D. A. (2006). Optical models for human myopic eyes. Vision Res, 46(14), 2236-50.

Atchison, D. A., Charman, W. N. & Woods, R. L. (1997). Subjective depth-of-focus of the eye. Optom Vis Sci, 74(7), 511-20.

Atchison, D. A., Jones, C. E., Schmid, K. L., Pritchard, N., Pope, J. M., Strugnell, W. E. & Riley, R. A. (2004). Eye shape in emmetropia and myopia. Invest Ophthalmol Vis Sci, 45(10), 3380-6.

Atchison, D. A., Pritchard, N. & Schmid, K. L. (2006). Peripheral refraction along the horizontal and vertical visual fields in myopia. Vision Res, 46(8-9), 1450-8.

Atchison, D. A., Pritchard, N., Schmid, K. L., Scott, D. H., Jones, C. E. & Pope, J. M. (2005). Shape of the retinal surface in emmetropia and myopia. Invest Ophthalmol Vis Sci, 46(8), 2698-707.

Atchison, D. A., Schmid, K. L. & Pritchard, N. (2006). Neural and optical limits to visual performance in myopia. Vision Res, 46(21), 3707-22.

Buehren, T., Collins, M. J. & Carney, L. G. (2005). Near work induced wavefront aberrations in myopia. Vision Res, 45(10), 1297-312.

Bullimore, M. A. & Gilmartin, B. (1987). Retinal eccentricity and the accommodative response. Am J Optom Physiol Opt, 64(8), 644-5.

Calver, R., Radhakrishnan, H., Osuobeni, E. & O'Leary, D. (2007). Peripheral refraction for distance and near vision in emmetropes and myopes. Ophthalmic Physiol Opt, 27(6), 584-93.

Campbell, F. W. (1957). The depth of field of the human eye. Optica Acta, 4, 157-64.

Campbell, F. W., Robson, J. G. & Westheimer, G. (1959). Fluctuations of accommodation under steady viewing conditions. J Physiol, 145(3), 579-94.

Carkeet, A., Luo, H. D., Tong, L., Saw, S. M. & Tan, D. T. (2002). Refractive error and monochromatic aberrations in Singaporean children. Vision Res, 42(14), 1809-24.

Charman, W. N. & Heron, G. (1988). Fluctuations in accommodation: a review. Ophthalmic Physiol Opt, 8(2), 153-64.

Charman, W. N. & Whitefoot, H. (1977). Pupil diameter and the depth-of-field of the human eye as measured by the laser speckle. Optica Acta, 24, 1211-16.

Cheng, X., Bradley, A., Hong, X. & Thibos, L. N. (2003). Relationship between refractive error and monochromatic aberrations of the eye. Optom Vis Sci, 80(1), 43-9.

Chung, K., Mohidin, N. & O'Leary, D. J. (2002). Undercorrection of myopia enhances rather than inhibits myopia progression. Vision Res, 42(22), 2555-9.

Ciuffreda, K. J., Wang, B. & Wong, D. (2005). Central and near peripheral retinal contributions to the depth-of-focus using naturalistic stimulation. Vision Res, 45(20), 2650-8.

Cohen, Y., Belkin, M., Avni, I. & Polat, U. (2010). Light intensity modulates corneal power and refraction in the chick eye exposed to continuous light. 13th International Myopia Conference, Tubingen, Germany.

Collins, M. (1937). The Electronic Refractometer. Br J Physiol Opt, 1(1), 30-42.

Collins, M., Davis, B. & Wood, J. (1995). Microfluctuations of steady-state accommodation and the cardiopulmonary system. Vision Res, 35(17), 2491-502.

Collins, M. J., Buehren, T. & Iskander, D. R. (2006). Retinal image quality, reading and myopia. Vision Res, 46(1-2), 196-215.

Collins, M. J., Wildsoet, C. F. & Atchison, D. A. (1995). Monochromatic aberrations and myopia. Vision Res, 35(9), 1157-63.

Davies, L. N. & Mallen, E. A. (2009). Influence of accommodation and refractive status on the peripheral refractive profile. Br J Ophthalmol, 93(9), 1186-90.

Day, M., Gray, L. S., Seidel, D. & Strang, N. C. (2009a). The relationship between object spatial profile and accommodation microfluctuations in emmetropes and myopes. J Vis, 9(10), 5 1-13.

Day, M., Seidel, D., Gray, L. S. & Strang, N. C. (2009b). The effect of modulating ocular depth of focus upon accommodation microfluctuations in myopic and emmetropic subjects. Vision Res, 49(2), 211-8.

Day, M., Strang, N. C., Seidel, D., Gray, L. S. & Mallen, E. A. (2006). Refractive group differences in accommodation microfluctuations with changing accommodation stimulus. Ophthalmic Physiol Opt, 26(1), 88-96.

Denieul, P. (1982). Effects of stimulus vergence on mean accommodation response, microfluctuations of accommodation and optical quality of the human eye. Vision Res, 22(5), 561-9.

Dirani, M., Tong, L., Gazzard, G., Zhang, X., Chia, A., Young, T. L., Rose, K. A., Mitchell, P. & Saw, S. M. (2009). Outdoor activity and myopia in Singapore teenage children. Br J Ophthalmol, 93(8), 997-1000.

Drobe, B. (2010). Challenges in spectacle lens design for myopic children. 13th International Myopia Conference, Tubingen, Germany.

Duffy, L., Day, M., Seidel, D., Gray, L. S. & Strang, N. C. (2010). Peripheral objective blur thresholds in emmetropes and myopes. 13th International Myopia Conference, Tubingen, Germany.

Duffy, L. A., Day, M., Seidel, D., Gray, L. S. & Strang, N. C. (2009). Modulation of Static Accommodation Responses in Emmetropes and Myopes by Peripheral Stimuli. Invest. Ophthalmol. Vis. Sci., 50(5), 3921-.

Flitcroft, D. (2006). Dioptric space: extending the concepts of defocus to three dimensions. Invest Ophthalmol Vis Sci, 47, ARVO E-Abstract 4778.

Flitcroft, D. I. (1998). A model of the contribution of oculomotor and optical factors to emmetropization and myopia. Vision Res, 38(19), 2869-79.

Flitcroft, D. I. (1999). The lens paradigm in experimental myopia: oculomotor, optical and neurophysiological considerations. Ophthalmic Physiol Opt, 19(2), 103-11.

Fulk, G. W. & Cyert, L. A. (1996). Can bifocals slow myopia progression? J Am Optom Assoc, 67(12), 749-54.

Fulk, G. W., Cyert, L. A. & Parker, D. E. (2000). A randomized trial of the effect of single-vision vs. bifocal lenses on myopia progression in children with esophoria. Optom Vis Sci, 77(8), 395-401.

Goss, D. A., Hampton, M. J. & Wickham, M. G. (1988). Selected review on genetic factors in myopia. J Am Optom Assoc, 59(11), 875-84.

Gray, L. S., Gilmartin, B. & Winn, B. (2000). Accommodation microfluctuations and pupil size during sustained viewing of visual display terminals. Ophthalmic Physiol Opt, 20(1), 5-10.

Gray, L. S., Winn, B. & Gilmartin, B. (1993a). Accommodative microfluctuations and pupil diameter. Vision Res, 33(15), 2083-90.

Gray, L. S., Winn, B. & Gilmartin, B. (1993b). Effect of target luminance on microfluctuations of accommodation. Ophthalmic Physiol Opt, 13(3), 258-65.

Green, D. G., Powers, M. K. & Banks, M. S. (1980). Depth of focus, eye size and visual acuity. Vision Res, 20(10), 827-35.

Grosvenor, T., Perrigin, D. M., Perrigin, J. & Maslovitz, B. (1987). Houston Myopia Control Study: a randomized clinical trial. Part II. Final report by the patient care team. Am J Optom Physiol Opt, 64(7), 482-98.

Gu, Y. C. & Legge, G. E. (1987). Accommodation to stimuli in peripheral vision. J Opt Soc Am A, 4(8), 1681-7.

Gwiazda, J., Hyman, L., Hussein, M., Everett, D., Norton, T. T., Kurtz, D., Leske, M. C., Manny, R., Marsh-Tootle, W. & Scheiman, M. (2003). A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. Invest Ophthalmol Vis Sci, 44(4), 1492-500.

Gwiazda, J., Thorn, F., Bauer, J. & Held, R. (1993). Myopic children show insufficient accommodative response to blur. Invest Ophthalmol Vis Sci, 34(3), 690-4.

Hammond, C. J., Snieder, H., Gilbert, C. E. & Spector, T. D. (2001). Genes and environment in refractive error: the twin eye study. Invest Ophthalmol Vis Sci, 42(6), 1232-6.

He, J. C., Sun, P., Held, R., Thorn, F., Sun, X. & Gwiazda, J. E. (2002). Wavefront aberrations in eyes of emmetropic and moderately myopic school children and young adults. Vision Res, 42(8), 1063-70.

Hennessy, R. T. & Leibowitz, H. W. (1971). The effect of a peripheral stimulus on accommodation. Perception & Psychophysics, 10(3), 129-132.

Heron, G. & Schor, C. (1995). The fluctuations of accommodation and ageing. Ophthalmic Physiol Opt, 15(5), 445-9.

Ho, A., Lazon de la Jara, P., Martinez, A., Kwan, J., Fedtke, C., Holden, B. & Sankaridurg, P. (2010). Influence of accommodation on peripheral refraction: effect of a novel optical design contact lens for manipulating peripheral defocus. 13th International Myopia Conference, Tubingen, Germany.

Holden, B., Sankaridurg, P., Ho, A., Lazon, P., Kwan, J., Chen, X., Smith, E. L. & Ge, J. (2010). Impact of novel contact lenses on progression of myopia. 13th International Myopia Conference, Tubingen, Germany.

Hung, G. K. & Ciuffreda, K. J. (1992). Accommodative responses to eccentric and laterally-oscillating targets. Ophthalmic Physiol Opt, 12(3), 361-4.

Irving, E. L., Callender, M. G. & Sivak, J. G. (1991). Inducing myopia, hyperopia, and astigmatism in chicks. Optom Vis Sci, 68(5), 364-8.

Jensen, H. (1991). Myopia progression in young school children. A prospective study of myopia progression and the effect of a trial with bifocal lenses and beta blocker eye drops. Acta Ophthalmol Suppl(200), 1-79.

Jiang, B. C. (1997). Integration of a sensory component into the accommodation model reveals differences between emmetropia and late-onset myopia. Invest Ophthalmol Vis Sci, 38(8), 1511-6.

Jiang, B. C., Bussa, S., Tea, Y. C. & Seger, K. (2008). Optimal dioptric value of near addition lenses intended to slow myopic progression. Optom Vis Sci, 85(11), 1100-5.

Jiang, B. C. & Morse, S. E. (1999). Oculomotor functions and late-onset myopia. Ophthalmic Physiol Opt, 19(2), 165-72.

Jones, L. A., Sinnott, L. T., Mutti, D. O., Mitchell, G. L., Moeschberger, M. L. & Zadnik, K. (2007). Parental history of myopia, sports and outdoor activities, and future myopia. Invest Ophthalmol Vis Sci, 48(8), 3524-32.

Kee, C. S., Hung, L. F., Qiao-Grider, Y., Ramamirtham, R., Winawer, J., Wallman, J. & Smith, E. L., 3rd (2007). Temporal constraints on experimental emmetropization in infant monkeys. Invest Ophthalmol Vis Sci, 48(3), 957-62.

Kotulak, J. C. & Schor, C. M. (1986a). The accommodative response to subthreshold blur and to perceptual fading during the Troxler phenomenon. Perception, 15(1), 7-15.

Kotulak, J. C. & Schor, C. M. (1986b). A computational model of the error detector of human visual accommodation. Biol Cybern, 54(3), 189-94.

Kotulak, J. C. & Schor, C. M. (1986c). Temporal variations in accommodation during steady-state conditions. J Opt Soc Am A, 3(2), 223-7.

Lam, C. S. Y., Tang, W. C., Tang, Y. Y., Tse, D. Y. & To, C. H. (2010). Randomized clinical trial of myopia control in myopic schoolchildren using the defocus incorporated soft contact (DISC) lens 13th International Myopia Conference, Tunbingen, Germany.

Langaas, T., Riddell, P. M., Svarverud, E., Ystenaes, A. E., Langeggen, I. & Bruenech, J. R. (2008). Variability of the accommodation response in early onset myopia. Optom Vis Sci, 85(1), 37-48.

Leung, J. T. & Brown, B. (1999). Progression of myopia in Hong Kong Chinese schoolchildren is slowed by wearing progressive lenses. Optom Vis Sci, 76(6), 346-54.

Lin, Z., Martinez, A., Chen, X., Li, L., Sankaridurg, P., Holden, B. A. & Ge, J. (2010). Peripheral defocus with single-vision spectacle lenses in myopic children. Optom Vis Sci, 87(1), 4-9.

Llorente, L., Barbero, S., Cano, D., Dorronsoro, C. & Marcos, S. (2004). Myopic versus hyperopic eyes: axial length, corneal shape and optical aberrations. J Vis, 4(4), 288-98.

Logan, N. S., Gilmartin, B., Wildsoet, C. F. & Dunne, M. C. (2004). Posterior retinal contour in adult human anisomyopia. Invest Ophthalmol Vis Sci, 45(7), 2152-62.

McBrien, N. A. & Millodot, M. (1986). The effect of refractive error on the accommodative response gradient. Ophthalmic Physiol Opt, 6(2), 145-9.

Miege, C. & Denieul, P. (1988). Mean response and oscillations of accommodation for various stimulus vergences in relation to accommodation feedback control. Ophthalmic Physiol Opt, 8(2), 165-71.

Millodot, M. (1981). Effect of ametropia on peripheral refraction. Am J Optom Physiol Opt, 58(9), 691-5.

Mutti, D. O., Hayes, J. R., Mitchell, G. L., Jones, L. A., Moeschberger, M. L., Cotter, S. A., Kleinstein, R. N., Manny, R. E., Twelker, J. D. & Zadnik, K. (2007). Refractive error, axial length, and relative peripheral refractive error before and after the onset of myopia. Invest Ophthalmol Vis Sci, 48(6), 2510-9.

Mutti, D. O., Mitchell, G. L., Moeschberger, M. L., Jones, L. A. & Zadnik, K. (2002). Parental myopia, near work, school achievement, and children's refractive error. Invest Ophthalmol Vis Sci, 43(12), 3633-40.

Mutti, D. O., Sholtz, R. I., Friedman, N. E. & Zadnik, K. (2000). Peripheral refraction and ocular shape in children. Invest Ophthalmol Vis Sci, 41(5), 1022-30.

Mutti, D. O. & Zadnik, K. (1995). The utility of three predictors of childhood myopia: a Bayesian analysis. Vision Res, 35(9), 1345-52.

Nakatsuka, C., Hasebe, S., Nonaka, F. & Ohtsuki, H. (2003). Accommodative lag under habitual seeing conditions: comparison between adult myopes and emmetropes. Jpn J Ophthalmol, 47(3), 291-8.

Napper, G. A., Brennan, N. A., Barrington, M., Squires, M. A., Vessey, G. A. & Vingrys, A. J. (1997). The effect of an interrupted daily period of normal visual stimulation on form deprivation myopia in chicks. Vision Res, 37(12), 1557-64.

Norton, T. T., Siegwart, J. T., Jr. & Amedo, A. O. (2006). Effectiveness of hyperopic defocus, minimal defocus, or myopic defocus in competition with a myopiagenic stimulus in tree shrew eyes. Invest Ophthalmol Vis Sci, 47(11), 4687-99.

Ogle, K. N. & Schwartz, J. T. (1959). Depth of focus of the human eye. J Opt Soc Am, 49(3), 273-80.

Onal, S., Toker, E., Akingol, Z., Arslan, G., Ertan, S., Turan, C. & Kaplan, O. (2007). Refractive errors of medical students in Turkey: one year follow-up of refraction and biometry. Optom Vis Sci, 84(3), 175-80.

Ong, E., Grice, K., Held, R., Thorn, F. & Gwiazda, J. (1999). Effects of spectacle intervention on the progression of myopia in children. Optom Vis Sci, 76(6), 363-9.

Pacella, R., McLellan, J., Grice, K., Del Bono, E. A., Wiggs, J. L. & Gwiazda, J. E. (1999). Role of genetic factors in the etiology of juvenile-onset myopia based on a longitudinal study of refractive error. Optom Vis Sci, 76(6), 381-6.

Paritsis, N., Sarafidou, E., Koliopoulos, J. & Trichopoulos, D. (1983). Epidemiologic research on the role of studying and urban environment in the development of myopia during school-age years. Ann Ophthalmol, 15(11), 1061-5.

Quek, T. P., Chua, C. G., Chong, C. S., Chong, J. H., Hey, H. W., Lee, J., Lim, Y. F. & Saw, S. M. (2004). Prevalence of refractive errors in teenage high school students in Singapore. Ophthalmic Physiol Opt, 24(1), 47-55.

Radhakrishnan, H., Pardhan, S., Calver, R. I. & O'Leary, D. J. (2004). Effect of positive and negative defocus on contrast sensitivity in myopes and non-myopes. Vision Res, 44(16), 1869-78.

Ramsdale, C. (1985). The effect of ametropia on the accommodative response. Acta Ophthalmol (Copenh), 63(2), 167-74.

Read, S. A., Collins, M. J. & Sander, B. (2010). Defocus and short term axial length changes in humans. 13th International Myopia Conference, Tubingen, Germany.

Richler, A. & Bear, J. C. (1980). Refraction, nearwork and education. A population study in Newfoundland. Acta Ophthalmol (Copenh), 58(3), 468-78.

Ronchi, L. & Molesini, G. (1975). Depth of focus in peripheral vision. Ophthalmic Research, 7, 152-157.

Rose, K. A., Morgan, I. G., Ip, J., Kifley, A., Huynh, S., Smith, W. & Mitchell, P. (2008a). Outdoor activity reduces the prevalence of myopia in children. Ophthalmology, 115(8), 1279-85.

Rose, K. A., Morgan, I. G., Smith, W., Burlutsky, G., Mitchell, P. & Saw, S. M. (2008b). Myopia, lifestyle, and schooling in students of Chinese ethnicity in Singapore and Sydney. Arch Ophthalmol, 126(4), 527-30.

Rosenfield, M. & Abraham-Cohen, J. A. (1999). Blur sensitivity in myopes. Optom Vis Sci, 76(5), 303-7.

Rosenfield, M. & Carrel, M. F. (2001). Effect of near-vision addition lenses on the accuracy of the accommodative response. Optometry, 72(1), 19-24.

Rosner, M. & Belkin, M. (1987). Intelligence, education, and myopia in males. Arch Ophthalmol, 105(11), 1508-11.

Sankaridurg, P., Donovan, L., Varnas, S., Ho, A., Chen, X., Martinez, A., Fisher, S., Lin, Z., Smith, E. L., 3rd, Ge, J. & Holden, B. (2010a). Spectacle lenses designed to reduce progression of myopia: 12-month results. Optom Vis Sci, 87(9), 631-41.

Sankaridurg, P., Donovan, L., Varnas, S., Ho, A., Kwan, J., Fedtke, C., Chen, X., Ge, J., Smith, E. L. & Holden, B. (2010b). Impact of spectacle lens on peripheral refractive errors. 13th International Myopia Conference, Tubingn, Germany.

Saw, S. M., Chua, W. H., Hong, C. Y., Wu, H. M., Chan, W. Y., Chia, K. S., Stone, R. A. & Tan, D. (2002a). Nearwork in early-onset myopia. Invest Ophthalmol Vis Sci, 43(2), 332-9.

Saw, S. M., Shih-Yen, E. C., Koh, A. & Tan, D. (2002b). Interventions to retard myopia progression in children: an evidence-based update. Ophthalmology, 109(3), 415-21; discussion 422-4; quiz 425-6, 443.

Saw, S. M., Wu, H. M., Seet, B., Wong, T. Y., Yap, E., Chia, K. S., Stone, R. A. & Lee, L. (2001). Academic achievement, close up work parameters, and myopia in Singapore military conscripts. Br J Ophthalmol, 85(7), 855-60.

Saw, S. M., Zhang, M. Z., Hong, R. Z., Fu, Z. F., Pang, M. H. & Tan, D. T. (2002c). Near-work activity, night-lights, and myopia in the Singapore-China study. Arch Ophthalmol, 120(5), 620-7.

Schaeffel, F., Glasser, A. & Howland, H. C. (1988). Accommodation, refractive error and eye growth in chickens. Vision Res, 28(5), 639-57.

Schmid, K. L. & Wildsoet, C. F. (1997). The sensitivity of the chick eye to refractive defocus. Ophthalmic Physiol Opt, 17(1), 61-7.

Seidel, D., Gray, L. S. & Heron, G. (2003). Retinotopic accommodation responses in myopia. Invest Ophthalmol Vis Sci, 44(3), 1035-41.

Seidemann, A., Schaeffel, F., Guirao, A., Lopez-Gil, N. & Artal, P. (2002). Peripheral refractive errors in myopic, emmetropic, and hyperopic young subjects. J Opt Soc Am A Opt Image Sci Vis, 19(12), 2363-73.

Shapiro, J. A., Kelly, J. E. & Howland, H. C. (2005). Accommodative state of young adults using reading spectacles. Vision Res, 45(2), 233-45.

Shih, Y. F., Hsiao, C. K. & Lin, L. K. (2000). Effects of atropine and multi-focal glasses in controlling myopic progression. VIII International Conference of Myopia, Boston.

Singh, K. D., Logan, N. S. & Gilmartin, B. (2006). Three-dimensional modeling of the human eye based on magnetic resonance imaging. Invest Ophthalmol Vis Sci, 47(6), 2272-9.

Smith, E. L., 3rd & Hung, L. F. (1999). The role of optical defocus in regulating refractive development in infant monkeys. Vision Res, 39(8), 1415-35.

Smith, E. L., 3rd, Hung, L. F. & Huang, J. (2009). Relative peripheral hyperopic defocus alters central refractive development in infant monkeys. Vision Res, 49(19), 2386-92.

Smith, E. L., 3rd, Hung, L. F., Huang, J., Blasdel, T. L., Humbird, T. L. & Bockhorst, K. H. (2010). Effects of optical defocus on refractive development in monkeys: evidence for local, regionally selective mechanisms. Invest Ophthalmol Vis Sci, 51(8), 3864-73.

Smith, E. L., 3rd, Kee, C. S., Ramamirtham, R., Qiao-Grider, Y. & Hung, L. F. (2005). Peripheral vision can influence eye growth and refractive development in infant monkeys. Invest Ophthalmol Vis Sci, 46(11), 3965-72.

Smith, E. L., 3rd, Ramamirtham, R., Qiao-Grider, Y., Hung, L. F., Huang, J., Kee, C. S., Coats, D. & Paysse, E. (2007). Effects of foveal ablation on emmetropization and form-deprivation myopia. Invest Ophthalmol Vis Sci, 48(9), 3914-22.

Sperduto, R. D., Seigel, D., Roberts, J. & Rowland, M. (1983). Prevalence of myopia in the United States. Arch Ophthalmol, 101(3), 405-7.

Stark, L. R. & Atchison, D. A. (1997). Pupil size, mean accommodation response and the fluctuations of accommodation. Ophthalmic Physiol Opt, 17(4), 316-23.

Strang, N. C., Schmid, K. L. & Carney, L. G. (1998). Hyperopia is predominantly axial in nature. Curr Eye Res, 17(4), 380-3.

Tabernero, J. & Schaeffel, F. (2009). Low myopes have more irregular eye shapes than emmetropes. Invest Ophthalmol Vis Sci.

Tabernero, J., Vazquez, D., Seidemann, A., Uttenweiler, D. & Schaeffel, F. (2009). Effects of myopic spectacle correction and radial refractive gradient spectacles on peripheral refraction. Vision Res, 49(17), 2176-86.

Tan, N. W., Saw, S. M., Lam, D. S., Cheng, H. M., Rajan, U. & Chew, S. J. (2000). Temporal variations in myopia progression in Singaporean children within an academic year. Optom Vis Sci, 77(9), 465-72.

Teikari, J. M., Kaprio, J., Koskenvuo, M. & O'Donnell, J. (1992). Heritability of defects of far vision in young adults--a twin study. Scand J Soc Med, 20(2), 73-8.

Teikari, J. M., Kaprio, J., Koskenvuo, M. K. & Vannas, A. (1988). Heritability estimate for refractive errors--a population-based sample of adult twins. Genet Epidemiol, 5(3), 171-81.

Teikari, J. M., O'Donnell, J., Kaprio, J. & Koskenvuo, M. (1991). Impact of heredity in myopia. Hum Hered, 41(3), 151-6.

van der Heijde, G. L., Beers, A. P. & Dubbelman, M. (1996). Microfluctuations of steady-state accommodation measured with ultrasonography. Ophthalmic Physiol Opt, 16(3), 216-21.

Vasudevan, B., Ciuffreda, K. J. & Wang, B. (2006a). Objective blur thresholds in free space for different refractive groups. Curr Eye Res, 31(2), 111-8.

Vasudevan, B., Ciuffreda, K. J. & Wang, B. (2006b). An objective technique to measure the depth-of-focus in free space. Graefes Arch Clin Exp Ophthalmol, 244(8), 930-7.

Wang, B. & Ciuffreda, K. J. (2004). Depth-of-focus of the human eye in the near retinal periphery. Vision Res, 44(11), 1115-25.

Wildsoet, C. F. (1997). Active emmetropization--evidence for its existence and ramifications for clinical practice. Ophthalmic Physiol Opt, 17(4), 279-90.

Winawer, J. & Wallman, J. (2002). Temporal constraints on lens compensation in chicks. Vision Res, 42(24), 2651-68.

Winawer, J., Zhu, X., Choi, J. & Wallman, J. (2005). Ocular compensation for alternating myopic and hyperopic defocus. Vision Res, 45(13), 1667-77.

Winn, B., Pugh, J. R., Gilmartin, B. & Owens, H. (1990a). Arterial pulse modulates steady-state ocular accommodation. Curr Eye Res, 9(10), 971-5.

Winn, B., Pugh, J. R., Gilmartin, B. & Owens, H. (1990b). The frequency characteristics of accommodative microfluctuations for central and peripheral zones of the human crystalline lens. Vision Res, 30(7), 1093-9.

Zhong, X., Ge, J., Nie, H. & Smith, E. L., 3rd (2004). Compensation for experimentally induced hyperopic anisometropia in adolescent monkeys. Invest Ophthalmol Vis Sci, 45(10), 3373-9.

Zhu, X., Park, T. W., Winawer, J. & Wallman, J. (2005). In a matter of minutes, the eye can know which way to grow. Invest Ophthalmol Vis Sci, 46(7), 2238-41.

Zhu, X. & Wallman, J. (2009). Temporal properties of compensation for positive and negative spectacle lenses in chicks. Invest Ophthalmol Vis Sci, 50(1), 37-46.




How to Cite

Day, M., & Duffy, L. A. (2011). Myopia and defocus: the current understanding. Scandinavian Journal of Optometry and Visual Science, 4(1), 1–14.



Review Article