Eye drops for myopia control in kids disappoint in US study

Nightly administration of atropine 0.01% eye drops does little to slow myopia progression or axial elongation in a cohort of school-aged children in the US who have low-to-moderate myopia, as shown in a study.

Following 24 months of treatment, the primary outcome of change in spherical equivalent refractive error (SER) did not significantly differ between the children who received atropine and those who received placebo (−0.82 vs −0.80 dioptres [D], respectively; adjusted difference, −0.02 D, 95 percent confidence interval [CI], −0.19 to 0.15; p=0.83). [JAMA Ophthalmol 2023;doi:10.1001/jamaophthalmol.2023.2855]

There was still no significant between-group difference observed at 30 months, after 6 months of not receiving treatment (−0.04 D, 95 percent CI, −0.25 to 0.17).

Likewise, changes in axial length from baseline were similar in the atropine and placebo groups at both 24 months (adjusted difference, −0.002 mm, 95 percent CI, −0.106 to 0.102) and 30 months (adjusted difference, 0.009 mm, 95 percent CI, −0.115 to 0.134).

The analysis included 187 children (mean age 10.1 years, 54 percent women, 46 percent White). Of these, 125 (67 percent) received one drop of atropine 0.01% nightly and 62 (33 percent) received one drop of placebo. A total of 119 and 118 children completed follow-up at 24 and 30 months, respectively.

Contradictory to East Asian studies

“We found, interestingly, and honestly shockingly, that there was no difference in the use of 0.01% atropine and placebo in treating these children who ranged in age from 5 to 12,” said principal study investigator for the Vanderbilt site Prof Lori Ann Kehler of Vanderbilt University Medical Center in Nashville, Tennessee, US.

Kehler alluded to the earlier studies from Asia, wherein the low dose of atropine was shown to be effective at slowing the progression of myopia. The findings from these studies were endorsed by the Academy of Ophthalmology in 2017, with the association saying that there was sufficient evidence for prescribing low-dose atropine for myopia, although the FDA had not approved the drug for such indication. [Asia Pac J Ophthalmol 2019;8:360-365; Ophthalmology 2012;119:347-354; Ophthalmology 2016;123:391-399; Ophthalmology 2019;126:113-124]

“That was a really exciting finding at the time because we had had no treatment options for many years,” Kehler said.

Racial differences

“The absence of a treatment benefit in our US-based study, compared to East Asian studies, may reflect racial differences in atropine response,” said lead co-author Dr Michael Repka from the Wilmer Eye Institute in Baltimore, Maryland, US.

“The study enrolled fewer Asian children, whose myopia progresses more quickly, and included Black children, whose myopia progresses less quickly compared with other races,” Repka pointed out.

Nevertheless, continuing to prescribe the 0.01% dose should not put children at risk, given that all the studies have shown the eye drops to be safe, according to Kehler. “But we are telling them there is a difference in these studies and it might have to do with your genetics; it might be that [the drug is] more effective in children from Asia than in the US population.”

The next step in the study, Kehler said, is to examine a higher dose of atropine to see if children in the US experience a benefit. For example, the LAMP study from Hong Kong showed that atropine 0.05% might be more effective. [Ophthalmology 2019;126:113-124]

Aside from eye drops, red-light therapy is being evaluated, with new eyeglass lenses having been developed to slow the progression of myopia, but these lenses are not yet available in the US.

“It’s much harder to get drops in very young children,” Kehler said. “But if we had a spectacle option, that would open the door to treating our younger patients.”

Increasing incidence

The findings have important implications, given the continuous spike in the incidence of myopia worldwide. Kehler noted that 39 million people in the US are predicted to have myopia by 2030, with the number expected to increase to more than 44 million or 50 percent of the global population by 2050. Why this is so may be explained by several theories.

“Some believe it's the increase in the use of screens and screen time, but myopia was increasing even before screens were part of children’s lives. Others think it has to do with industrialization. We were an agricultural society. We were outside more. We weren't reading. We weren't looking up close all day,” said Kehler.

“Really, the prevailing thought is whether we’re at a screen or looking at a math book or reading most of the day, we think the lack of sunlight and sustained near effort is what’s causing the increase of myopia,” she added.