As the prevalence of myopia is rapidly increasing throughout the world, myopia control has become a hot topic in optometry.
New Orleans-As the prevalence of myopia is rapidly increasing throughout the world, myopia control has become a hot topic in optometry. Karen Lee, OD, FAAO, FSLS; Diana Nguyen, OD, FAAO; and Harue Marsden, OD, MS, FAAO, shared some options for myopia control in children during a session at the American Academy of Optometry annual meeting in New Orleans.
“Back in the day, it was believed that undercorrecting our patients would keep them from getting worse,” says Dr. Lee.
Studies, however, have found this not to be true.
One study of 62 children ages 6-15 in Israel found that those who had been blurred by +0.50 D experienced a slight increase in myopic progression of 0.17 D compared to those who had full correction.
“It’s not preventing, it’s actually enhancing myopia,” says Dr. Lee.
Similarly, a study of 106 Malay and Chinese children ages 9-14 years found that those who were blurred by +0.75 D also experienced a slight increase in myopic progression of 0.23 D compared to full correction.
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“A method that is slightly more effective is bifocals,” says Dr. Nguyen.
The presenters highlighted an 18-month study of 14 children in which the bifocal wearers with a +1.25 D add progressed -0.39 D per year vs. -0.57 D per year in the single-vision lens group.
“It sounds like it’s a significant amount, but it’s not a clinically significant amount because if you round the numbers to the nearest 0.25 D, it’s about 0.50-very similar there,” says Dr. Nguyen.
In the COMET 2 study, 8 to 11 year-old children used progressive addition lenses (PALs) with a +2.00 D add. These children experienced -0.87 D myopic progression vs. -1.15 D in the single-vision lens group.
Dr. Lee says the difference was not very significant.
In the ATOM1 study, half of the 346 Asian children ages 6-12 who participated received 1% atropine qhs for two years in either their right eye or their left eye. These children experienced a decrease in myopic progression of 1.10 D compared to the placebo treatment.
The ATOM 2 study, which looked at varying doses of atropine-0.01%, 0.1%, and 0.5%-found that the 0.01% dose had similar efficacy to the higher concentration but with fewer side effects.
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7-methylxanthine (7-MX) is a metabolite of caffeine and theobromine that increases the thickness of posterior sclera.
“Researchers think that this helps to prevent myopia progression by preventing axial elongation,” says Dr. Lee. “7-MX causes the posterior sclera collagen fibers to increase in diameter, and thus you’re thickening that posterior sclera and preventing it from elongating.”
A Dutch study of 107 children ages 8-13 found that 400 mg tablets po qd of 7-MX decreased myopia progression by 66 percent and reduced axial length by 44 percent compared to the placebo group.
“A concern that we have with this study is there are no real studies on long-term side effects-they just said it was safe and went with it,” says Dr. Lee. “Also, it7-MX is not commercially available, so it’s not a treatment option.”
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A study examined using multifocal contact lenses for myopia control in 40 children ages 8-11. The children who were fit with CooperVision Proclear Multifocal +2.00 D add experienced a 50 percent decrease in myopic progression and a 29 percent reduction in axial elongation.
Another study featured 25 young adults ages 22-25. Those who were fit in the CooperVision Biofinity Multifocal +2.50 D add found that the lens design created a peripheral myopic defocus when looking at distance and near.
“Orthokeratology came out of a lot of the research in the '80s looking at gas permeable lenses. We knew that the gas permeable intervention was workable in terms of slowing down rates of myopia,” says Dr. Marsden. “Orthokeratology allowed us to take a new philosophy in fitting and reshape the eye.”
In a three-year retrospective study that examined ortho-k vs. atropine 0.125%, every year, ortho-k edged out atropine in both myopia progression and axial length.
“Maybe ortho-k is more effective than atropine,” says Dr. Nguyen. “It would be interesting to see how ortho-k compares to atropine 0.01% because dosage was identified as beneficial without all of the side effects.”
The study also found that ortho-k was more effective in patients with higher amounts of myopia over those with lower amounts.