Myopia So Far

What we know; what we think we know and what we don’t know

Editor’s note: This is the first of several planned articles to appear in 2019 on myopia management.

Very few things in science are definitive and, therefore, not subject to continual debate and revision, as new evidence emerges. Myopia is not one of these few things.

Here, I will wade through what we know and what we do not know about the refractive disorder.


What we know about myopia that it is a refractive condition in which the eye is generally too long to provide clear optics, resulting in blurred distance vision. What we don’t know about myopia is how it really should be defined, for example what variables indicate onset and what the consequences of that definition might be.

What we know about progression is that various ocular changes, such as peripheral hyperopic defocus, increased lag of accommodation or changes in binocular vision, may be observed prior to myopia onset and progression. But they have also been reported after onset.1 What we don’t know is whether there is a difference between a pre-myope experiencing a rapid reduction of hyperopia accompanied by an accelerated axial elongation and a child experiencing exactly the same growth pattern, but who has earned the status of a true myope, having passed the barrier of -0.75 D. Depending on how the onset of myopia is defined, ocular changes, such as increased accommodative lag, experienced after the onset of myopia — and thus consequences of myopia — might more properly be considered as contributors to the onset of accelerated axial growth, which occurred during hyperopia but could be considered the beginning of the myopic process.2-6


What we think we know is that the prevalence has been increasing all around the world, particularly in urban East Asian countries, where one recent study shows a 23% increase over the last decade.7 What we don’t know is why, when that East Asian population relocates to Australia or Mongolia, they experience dramatically lower levels of myopia.7,8


What we know is that evidence from multiple studies show time spent outdoors is linked with a protective effect, in terms of delaying the onset of myopia, and is less suggestive of controlling progression once myopia has begun.9-11 What we don’t know is what it is about outdoor exposure or activities that might be responsible. Could it be light intensity, differences in light spectrum outdoors or that most time spent outdoors involves viewing distance objects? This is yet to be determined.12,13

What most practicing optometrists know through patient encounters is near work activities increase the risks for developing myopia and influence the rate of progression, as well as the duration of progression. What we don’t know is whether these anecdotal findings are well-supported in the literature, as there are many studies that find near work to be a factor,11,14-18 and many that fail to show a relationship.11,14-18 What we don’t know is how to separately assess whether there is a protective effect from being outdoors or a stimulative effect from being indoors.19


What we know is a number of studies suggest a link between myopia onset and progression and various accommodative and binocular vision measures.6,20-22 What we also know is the best control in such studies show a limited impact of optical devices on these measures.1,23-26 What we know is while esophoria has been linked to the onset and progression of myopia, and has been used as a basis for the treatment of myopia progression, the findings are quite mixed, with most revealing no effects.1,23-24,27 What we don’t know is why optometrists base their treatment decisions on the behavior of the eyes when viewing a near object while one eye is covered. What we do know is the most effective optical treatment reported to date involves the measurement of the alignment of the eyes under binocular viewing conditions, using a measurement of eso fixation disparity as the determinant of the treatment group and for prescribing the particular bifocal add power, rather than using a monocular measurement of phoria.28 What we don’t know is why no other researchers have utilized this method of assessing eye alignment and, when they do take binocular vision into account, why they still use a monocular measure of binocular vision to determine the treatment protocol.


With regard to myopia progression control, what we do know is that prescribing single vision spectacle lenses or contact lenses has been the standard of care during the time over which myopia rates have skyrocketed. What we don’t know is why optometrists and ophthalmologists continue to choose these options in treating their patients. We also think we know that undercorrection of myopia either is ineffective in slowing progression or may actually accelerate progression.29,30 A recent study, though, found that significant undercorrection of myopia from not correcting the myopia, resulted in less myopia progression than full correction.31 What we don’t know is why when doctors insist that undercorrection causes myopia and that all myopes must have full corrections, they don’t insist that those children be reappointed every month to look for progression and to keep increasing the minus power to somehow combat the increase in myopia.

What we do know is that atropine, in various dosages, quite convincingly, controls myopia progression and axial elongation.32-39 What we also know is abrupt discontinuation of many pharmaceuticals that suppress receptors, including atropine, maximizes the rebound phenomenon, and in the case of atropine specifically, there is a greater loss of treatment effect in the higher doses, as compared to the lower doses.37,40-42 What we don’t know is why none of the existing, ongoing or planned atropine trials have sought to answer the question: “What is the most effective way to prescribe or discontinue atropine, so as to avoid or limit a rebound phenomenon, which can dramatically reverse the myopia control effect desired?”

What we do know is since the atropine studies have been interpreted to mean that the myopia-controlling effects of atropine are (unlike any drug ever studied) largely dose independent and side effects are (like virtually every drug ever studied) dose dependent, the lowest possible dose will have the best possible results.37,42 One has to wonder why atropine should behave so dramatically different than every other drug? We do know that if studies are designed to test dose-dependent treatment effects and then are designed to maximize the reversing effects of the rebound after abrupt discontinuation, dose-dependent treatment effects will be obscured.

We do know from various studies that atropine’s myopia-controlling effects are not caused by cycloplegia, as the effects persist in animals after severing ciliary nerves.43 What we have learned is atropine appears to act in the inner retina to magnify the retinal response to myopic defocus, and that it appears to inhibit choroidal thinning in response to hyperopic defocus while not suppressing the choroidal thickening found with myopic defocus.44,45

What we think we know is that orthokeratology has greater myopia control effects in children who have large pupils, and we think we know atropine added to orthokeratology may increase the myopia control effects.46-48 What we don’t know is whether this apparent additive effect is due to the larger pupils created by the atropine and/or the inherent mechanisms involved with atropine treatments.

We do know the average myopia control found in multiple orthokeratology studies is around 50%.49,50 We also know that in most of those studies, there are greater treatment effects found in either higher refractive errors or with greater corneal shape changes induced.51-53 What we don’t know is whether alternative designs intended to maximize the corneal shape changes, regardless of the initial prescription, will result in outcomes of lower levels of myopia.

What we do know is the risks of microbial keratitis with overnight orthokeratology is similar to the risks reported for overnight soft contact lenses.54 What we don’t know is whether those studies confirmed those risks or if more studies need to be done.

What we do know is the average myopia progression control found in many studies of multifocal or bifocal contact lenses is around 40%.28,49,55-58 What we don’t know about these lenses is whether they need to be distance center multifocals, as those are the only designs with published results, whether there is any effect of add power, whether there are any ways to optimize their designs to maximize treatment effects and whether there might be additive positive effects when combined with atropine.


Continuing research in the definition, prevalence, progression, prevention, signs and control is needed to fill in the gaps of what we don’t know about myopia. Additional information resources include: Essilor’s new Myopia Taskforce, Treehouse Eyes, which conducts The Myopia Meeting, Brien Holden Vision Institute, Global Specialty Lens Symposium and the Vision by Design meeting.* OM

*This list will be updated at .


1    Goss, D. A. & Jackson, T. W. Clinical findings before the onset of myopia in youth: 3. Heterophoria. Optom Vis Sci 73, 269-278 (1996).

2    Thorn, F., Gwiazda, J. & Held, R. Myopia progression is specified by a double exponential growth function. Optom Vis Sci 82, 286-297 (2005).

3    Mutti, D. O. et al. Refractive error, axial length, and relative peripheral refractive error before and after the onset of myopia. Invest Ophthalmol Vis Sci 48, 2510-2519, doi:10.1167/iovs.06-0562 (2007).

4    Xiang, F., He, M. & Morgan, I. G. Annual changes in refractive errors and ocular components before and after the onset of myopia in Chinese children. Ophthalmology 119, 1478-1484, doi:10.1016/j.ophtha.2012.01.017 (2012).

5    Berntsen, D. A., Mutti, D. O. & Zadnik, K. Study of Theories about Myopia Progression (STAMP) design and baseline data. Optom Vis Sci 87, 823-832, doi:10.1097/OPX.0b013e3181f6f776 (2010).

6    Mutti, D. O. et al. The Response AC/A Ratio Before and After the Onset of Myopia. Invest Ophthalmol Vis Sci 58, 1594-1602, doi:10.1167/iovs.16-19093 (2017).

7    Rudnicka, A. R. et al. Global variations and time trends in the prevalence of childhood myopia, a systematic review and quantitative meta-analysis: implications for aetiology and early prevention. Br J Ophthalmol 100, 882-890, doi:10.1136/bjophthalmol-2015-307724 (2016).

8    Rose, K. A. et al. Myopia, lifestyle, and schooling in students of Chinese ethnicity in Singapore and Sydney. Archives of Ophthalmology 126, 527-530, doi:10.1001/archopht.126.4.527 (2008).

9    Ramamurthy, D., Lin Chua, S. Y. & Saw, S. M. A review of environmental risk factors for myopia during early life, childhood and adolescence. Clin Exp Optom 98, 497-506, doi:10.1111/cxo.12346 (2015).

10    Xiong, S. et al. Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. Acta Ophthalmol 95, 551-566, doi:10.1111/aos.13403 (2017).

11    Wu, P. C. et al. Myopia Prevention and Outdoor Light Intensity in a School-Based Cluster Randomized Trial. Ophthalmology 125, 1239-1250, doi:10.1016/j.ophtha.2017.12.011 (2018).

12    Flitcroft, D. I. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Progress in retinal and eye research 31, 622-660, doi:10.1016/j.preteyeres.2012.06.004 (2012).

13    Ngo, C., Saw, S. M., Dharani, R. & Flitcroft, I. Does sunlight (bright lights) explain the protective effects of outdoor activity against myopia? Ophthalmic Physiol Opt 33, 368-372, doi:10.1111/opo.12051 (2013).

14    Hsu, C. C. et al. Risk factors for myopia progression in second-grade primary school children in Taipei: a population-based cohort study. Br J Ophthalmol 101, 1611-1617, doi:10.1136/bjophthalmol-2016-309299 (2017).

15    Guo, Y. et al. Outdoor activity and myopia progression in 4-year follow-up of Chinese primary school children: The Beijing Children Eye Study. PLoS One 12, e0175921, doi:10.1371/journal.pone.0175921 (2017).

16    Lee, Y. Y., Lo, C. T., Sheu, S. J. & Yin, L. T. Risk factors for and progression of myopia in young Taiwanese men. Ophthalmic Epidemiol 22, 66-73, doi:10.3109/09286586.2014.988874 (2015).

17    Oner, V., Bulut, A., Oruc, Y. & Ozgur, G. Influence of indoor and outdoor activities on progression of myopia during puberty. Int Ophthalmol 36, 121-125, doi:10.1007/s10792-015-0091-5 (2016).

18    Saxena, R. et al. Incidence and progression of myopia and associated factors in urban school children in Delhi: The North India Myopia Study (NIM Study). PLoS One 12, e0189774, doi:10.1371/journal.pone.0189774 (2017).

19    Huang, H. M., Chang, D. S. & Wu, P. C. The Association between Near Work Activities and Myopia in Children-A Systematic Review and Meta-Analysis. PLoS One 10, e0140419, doi:10.1371/journal.pone.0140419 (2015).

20    Zadnik, K. et al. Prediction of Juvenile-Onset Myopia. JAMA Ophthalmology 133, 683-689, doi:10.1001/jamaophthalmol.2015.0471 (2015).

21    de Jong, P. Myopia: its historical contexts. Br J Ophthalmol 102, 1021-1027, doi:10.1136/bjophthalmol-2017-311625 (2018).

22    Gwiazda, J., Thorn, F. & Held, R. Accommodation, accommodative convergence, and response AC/A ratios before and at the onset of myopia in children. Optom Vis Sci 82, 273-278 (2005).

23    Goss, D. A. U., E.F. Effectiveness of bifocal control of childhood myopia progression as a function of near point phoria and binocular cross-cylinder. Journal of Optometry and Visual Development 26, 12-17 (1995).

24    Berntsen, D. A., Sinnott, L. T., Mutti, D. O. & Zadnik, K. A randomized trial using progressive addition lenses to evaluate theories of myopia progression in children with a high lag of accommodation. Invest Ophthalmol Vis Sci 53, 640-649, doi:10.1167/iovs.11-7769 (2012).

25    Gwiazda, J., Chandler, DL, Cotter SA, Everett DF, Hyman L, Kaminski BM, et al. Progressive-Addition Lenses versus Single-Vision Lenses for Slowing Progression of Myopia in Children with High Accommodative Lag and Near Esophoria. Invest Ophthalmol Vis Sci 52, 2749-2757, doi:10.1167/iovs.10-6631 (2011).

26    Gwiazda, J. et al. A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. Invest Ophthalmol Vis Sci 44, 1492-1500 (2003).

27    Goss, D. A. & Grosvenor, T. Rates of childhood myopia progression with bifocals as a function of nearpoint phoria: consistency of three studies. Optom Vis Sci 67, 637-640 (1990).

28    Aller, T. A., Liu, M. & Wildsoet, C. F. Myopia Control with Bifocal Contact Lenses: A Randomized Clinical Trial. Optom Vis Sci 93, 344-352, doi:10.1097/OPX.0000000000000808 (2016).

29    Chung, K., Mohidin, N. & O’Leary, D. J. Undercorrection of myopia enhances rather than inhibits myopia progression. Vision Res 42, 2555-2559 (2002).

30    Adler, D. & Millodot, M. The possible effect of undercorrection on myopic progression in children. Clin Exp Optom 89, 315-321, doi:10.1111/j.1444-0938.2006.00055.x (2006).

31    Sun, Y. Y. et al. Effect of uncorrection versus full correction on myopia progression in 12-year-old children. Graefes Arch Clin Exp Ophthalmol 255, 189-195, doi:10.1007/s00417-016-3529-1 (2017).

32    Chua, W. H. et al. Atropine for the treatment of childhood myopia. Ophthalmology 113, 2285-2291, doi:10.1016/j.ophtha.2006.05.062 (2006).

33    Galvis, V. et al. Topical Atropine in the Control of Myopia. Med Hypothesis Discov Innov Ophthalmol 5, 78-88 (2016).

34    Galvis, V., Tello, A., Parra, M. M., Rodriguez, C. J. & Blanco, O. Re: Chia et al.: Five-year clinical trial on atropine for the treatment of myopia 2: myopia control with atropine 0.01% eyedrops (Ophthalmology 2016;123:391-9). Ophthalmology 123, e40-41, doi:10.1016/j.ophtha.2015.12.037 (2016).

35    Gimbel, H. V. The control of myopia with atropine. Can J Ophthalmol 8, 527-532 (1973).

36    Gong, Q. et al. Efficacy and Adverse Effects of Atropine in Childhood Myopia: A Meta-analysis. JAMA Ophthalmology 135, 624-630, doi:10.1001/jamaophthalmol.2017.1091 (2017).

37    Pineles, S. L. et al. Atropine for the Prevention of Myopia Progression in Children: A Report by the American Academy of Ophthalmology. Ophthalmology, doi:10.1016/j.ophtha.2017.05.032 (2017).

38    Tran, H. D. M. et al. A Review of Myopia Control with Atropine. J Ocul Pharmacol Ther 34, 374-379, doi:10.1089/jop.2017.0144 (2018).

39    Yam, J. C. et al. Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Ophthalmology 126, 113-124, doi:10.1016/j.ophtha.2018.05.029 (2019).

40    Miller, R. R., Olson, H. G., Amsterdam, E. A. & Mason, D. T. Propranolol-withdrawal rebound phenomenon. Exacerbation of coronary events after abrupt cessation of antianginal therapy. N Engl J Med 293, 416-418, doi:10.1056/NEJM197508282930902 (1975).

41    Karachalios, G. N. et al. Withdrawal syndrome following cessation of antihypertensive drug therapy. Int J Clin Pract 59, 562-570, doi:10.1111/j.1368-5031.2005.00520.x (2005).

42    Chia, A., Lu, Q. S. & Tan, D. Five-Year Clinical Trial on Atropine for the Treatment of Myopia 2: Myopia Control with Atropine 0.01% Eyedrops. Ophthalmology 123, 391-399, doi:10.1016/j.ophtha.2015.07.004 (2016).

43    Wildsoet, C. Neural pathways subserving negative lens-induced emmetropization in chicks--insights from selective lesions of the optic nerve and ciliary nerve. Current Eye Research 27, 371-385 (2003).

44    Chiang, S. T., Chen, T. L. & Phillips, J. R. Effect of Optical Defocus on Choroidal Thickness in Healthy Adults With Presbyopia. Invest Ophthalmol Vis Sci 59, 5188-5193, doi:10.1167/iovs.18-24815 (2018).

45    Khanal, S., Turnbull, P. R. K., Lee, N. & Phillips, J. R. The Effect of Atropine on Human Global Flash mfERG Responses to Retinal Defocus.  Invest Ophthalmol Vis Sci  60, 218-225, doi:10.1167/iovs.18-24600 (2019).

46    Chen, Z. et al. Adjunctive effect of orthokeratology and low dose atropine on axial elongation in fast-progressing myopic children-A preliminary retrospective study. Cont Lens Anterior Eye, doi:10.1016/j.clae.2018.10.026 (2018).

47    Kinoshita, N., Konno, Y., Hamada, N. & Kakehashi, A. Suppressive effect of combined treatment of orthokeratology and 0.01% atropine instillation on axial length elongation in childhood myopia. Invest Ophthalmol Vis Sci  58, 2386-2386 (2017).

48    Kinoshita, N. et al. Additive effects of orthokeratology and atropine 0.01% ophthalmic solution in slowing axial elongation in children with myopia: first year results. Jpn J Ophthalmol 62, 544-553, doi:10.1007/s10384-018-0608-3 (2018).

49    Huang, J. et al. Efficacy Comparison of 16 Interventions for Myopia Control in Children: A Network Meta-analysis. Ophthalmology 123, 697-708, doi:10.1016/j.ophtha.2015.11.010 (2016).

50    Si, J. K. et al. Orthokeratology for Myopia Control: A Meta-analysis. Optom Vis Sci 92, 252-257, doi:10.1097/OPX.0000000000000505 (2015).

51    Charm, J. & Cho, P. High myopia-partial reduction orthokeratology (HM-PRO): study design. Cont Lens Anterior Eye 36, 164-170, doi:10.1016/j.clae.2013.02.012 (2013).

52    Cho, P., Cheung, S. W. & Edwards, M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Current Eye Research 30, 71-80 (2005).

53    Fu, A. C. et al. Higher spherical equivalent refractive errors is associated with slower axial elongation wearing orthokeratology. Cont Lens Anterior Eye 39, 62-66, doi:10.1016/j.clae.2015.07.006 (2016).

54    Bullimore, M. A., Sinnott, L. T. & Jones-Jordan, L. A. The risk of microbial keratitis with overnight corneal reshaping lenses. Optom Vis Sci 90, 937-944, doi:10.1097/OPX.0b013e31829cac92 (2013).

55    Anstice, N. S. & Phillips, J. R. Effect of dual-focus soft contact lens wear on axial myopia progression in children. Ophthalmology 118, 1152-1161, doi:10.1016/j.ophtha.2010.10.035 (2011).

56    Lam, C. S., Tang, W. C., Tse, D. Y., Tang, Y. Y. & To, C. H. Defocus Incorporated Soft Contact (DISC) lens slows myopia progression in Hong Kong Chinese schoolchildren: a 2-year randomised clinical trial. Br J Ophthalmol 98, 40-45, doi:10.1136/bjophthalmol-2013-303914 (2014).

57    Sankaridurg, P. et al. Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results. Invest Ophthalmol Vis Sci 52, 9362-9367, doi:10.1167/iovs.11-7260 (2011).

58    Cooper, J. et al. Case Series Analysis of Myopic Progression Control With a Unique Extended Depth of Focus Multifocal Contact Lens. Eye Contact Lens 44, e16-e24, doi:10.1097/ICL.0000000000000440 (2018).