A recent meta-analysis has found that a combination of orthokeratology (ortho-K) and atropine effectively slows axial elongation in myopic children. A subgroup analysis revealed that the weighted mean difference of -0.09mm was related to a follow-up period fewer than 12 months.

 The researchers evaluated five studies that involved 341 children younger than 18 (165 were prescribed atropine and ortho-K vs. 176 were using ortho-K alone). The axial elongation was lower in the combination group (0.25mm) than that of the ortho-K group (0.35mm).

Because all participants included in the studies wore ortho-K lenses, the researchers suppose that the difference between the two groups was mainly caused by the effect of atropine. As pupil dilation occurs in both high-dose and low-dose atropine, they also speculate that this effect may strengthen the effect of ortho-K in all doses of atropine with ortho-K groups.

In one study, the increase of axial length with the combination therapy was slower than that with ortho-K at the six-month mark. The researchers believe this period may be an important time point to assess the difference of axial elongation between the two types of treatments. They also believe that further studies with a follow-up period less than 12 months may provide more evidence of the effect on the axial elongation.