By 2050, it’s projected that nearly half of the global population will be affected by myopia, particularly in East and Southeast Asia, where 80 to 90 percent of children and young adults are already myopic. Furthermore, high myopia is expected to affect around 10 percent of the global population, or approximately 925 million people, by 2050, according to estimates by the Brien Holden Vision Institute in Sydney, Australia.
Richard L. Abbott, MD, co-chair of the Academy’s Task Force on Myopia, says that developing high myopia isn’t merely a matter of an increased need for thick glasses. “The risk of developing vision-threatening eye conditions is clearly linked to high myopia,” he says. “There’s an estimated six-times increased risk of retinal detachment for patients with high myopia, an approximately 50-percent increased risk of developing glaucoma, a 20-percent increase in need for cataract surgery and a significant risk of myopia maculopathy.”
The Academy’s task force aims to reduce the age of myopia onset and slow worldwide myopia progression by
- educating the health-care community, public policy makers and the public about the public health burden of myopia;
- promoting myopia as a global public health concern; and
- working with pediatric and family organizations to encourage outdoor time and early diagnosis of children.
The task force will collaborate with recognized experts in myopia prevention and treatment, public health experts, the American Academy of Optometry, the American Academy of Pediatrics and representatives from the American Academy of Family Physicians.
Members of the panel discussed the optical strategies currently available for myopia control: contact lenses and spectacles. “Spectacle lenses include bifocals—either progressive addition lenses or executive bifocals—and customized single-vision lenses,” says Susan Cotter, OD, MS, FAAO, a professor of optometry at Marshal B. Ketchum University in Fullerton, California, and incoming president of the American Academy of Optometry. “In the COMET and COMET 2 studies, PALs were able to slow myopia progression over three years more effectively than SVLs, but only by about a quarter-diopter (treatment differences: 0.2 D and 0.28 D, respectively). These differences were statistically, but not clinically, significant.1
“A randomized clinical trial comparing SVLs to executive bifocals +1.5 D, with and without 3∆ base-in prism, found a mean three-year progression of -2.06 D (SVL), -1.25 D (BIF) and -1.01 D (BIF/∆),” she adds.2
Customized lenses are also in development now. Dr. Cotter says that Defocus Incorporated Multiple Segments have a clear optical zone with multiple 1-mm +3.5-D segments in the periphery that create a “blurring effect.”3
“The two-year data from the clinical trial comparing DIMS lenses to SVLs found a difference of almost half a diopter of myopia (DIMS -0.41D, SVL -0.85 D; mean difference: 0.44 D),” she says. “In 21.5 percent of the DIMs group and 7.4 percent of the SVL group, there was no myopia progression.”4 She adds that there are several other lenses in the pipeline.
As for contact lenses, the current options include multifocals and keratology lenses. “A recent meta-analysis of ortho-K lenses showed a two-year slowing of axial elongation, which was clinically significant at 0.28 mm,” Dr. Cotter says.5 “Soft multifocal contact lenses, such as MiSight for daily wear, demonstrated results similar to those of the three-year randomized bifocal studies compared to SVLs.6 Soft multifocal contact lenses yielded about a two-thirds-diopter difference in myopia progression and also slowed axial elongation.
“The BLINK trial randomized children to three groups: a high add power; a medium add power; and a single-vision lens control group,” she continues. “The high add power contact lens demonstrated greater slowing of myopia progression than the medium-power contact lens and much greater slowing than the SVL.”7
Dr. Cotter says that combination strategies are currently under evaluation. One meta-analysis of four studies found that a combination of atropine 0.01% and ortho-K was more effective in slowing axial elongation than ortho-K monotherapy.8
The future of myopia prevention and intervention almost certainly points to a combination of treatments, says Michael X. Repka, the AAO’s medical director for governmental affairs. “Much of what we know about outdoor time and atropine is based on data from East Asia,” he says. “We think the mechanism is likely related to dopamine levels in the retina, which slow axial elongation. One study found a 9.1 percent reduced rate of myopia onset with an added 40-minue period outdoors,9 and a meta-analysis of outdoor activities identified a reduced myopic shift of 0.3 D compared to a control group after three years.10 This effect is small in an individual patient, but cumulatively these effects could greatly limit the public health damage caused by myopia. I must caution, however, that significant questions remain on the amount of outdoor time and the quality and intensity of light needed. We don’t know the quantitative impact in the West.
“A daily dose of one drop of atropine 0.01% to 0.05% has been shown to slow progression by 30 to 50 percent in normal, school-aged children while on treatment,” he continues. “This doesn’t seem to stop progression, so much as reduce the amount it progresses. It’s incumbent on us that both prescribing doctors and parents understand this.
“The treatment and management of myopia includes everyone,” Dr. Repka adds. “Tackling myopia will require a lot of advocacy for therapy, care and reviewing research. The Academy supports strengthening regulatory science for the evaluation of drugs and devices for myopia control. It’s also promoting patient access to safe and effective therapies, appropriate reimbursement and awareness among physicians, educators and policy makers.” REVIEW
1. Gwiazda J, Hyman L, Hussein M, 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 2003;44:1492-500.
2. Gwiazda J, Hyman L, Hussein M, et al. Correction of Myopia Evaluation Trial Study 2 Group (part of the Pediatric Eye Disease Investigator Group). 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 2011;52:5:2749-57.
3. Cheng D, Woo GC, Drobe B, et al. Effect of bifocal and prismatic bifocal spectacles on myopia progression in children: Three-year results of a randomized clinical trial. JAMA Ophthalmol 2014;132:258-64.
4. Lam C, Tang WC, Tse D, et al. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: A 2-year randomised clinical trial. Br J Ophthalmol 2019;104:363.
5. Li SM, Kang MT, Wu SS, et al. Efficacy, safety and acceptability of orthokeratology on slowing axial elongation in myopic children by meta-analysis. Curr Eye Res 2016;41:600-8.
6. Chamberlain P, Peixoto-de-Matos SC, Logan NS, et al. A 3-year randomized clinical trial of MiSight lenses for myopia control. Optom Vis Sci 2019;96:556-7.
7. Walline JJ, Walker MK, Mutti DO, et al. for the BLINK Study Group. Effect of high add power, medium add power, or single-vision contact lenses on myopia progression in children: The BLINK RCT. JAMA 2020;324:6:571-80.
8. Kinoshita N, Konno Y, Hamada 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 2018;62:5:544-553.9. He M, Xiang F, Zeng Y, et al. Effect of time spent outdoors at school on the development of myopia among children in China: A randomized clinical trial. JAMA 2015;314:11:1142-8.
10. Xiong S, Sankaridurg P, Naduvilath T, et al. Time spent in outdoor activities in relation to myopia prevention and control: A meta-analysis and systematic review. Acta Ophthalmol 2017;95:551-66.