A recent study conducted by the Pediatric Eye Disease Investigator Group (PEDIG) and funded by the National Eye Institute (NEI) found surprising results when assessing the use of low-dose atropine eye drops for slowing myopia progression in pediatric patients.
Give me some background first.
While high doses of atropine have demonstrated efficacy for slowing myopia progression in children, the use of low-dose atropine has recently been associated with fewer side effects.
In fact, several studies—largely conducted in East Asia, in recent months—have reported findings that support its use and efficacy.
Most recently, data presented at this year’s ARVO 2023 annual meeting noted that such a dosage had a significantly meaningful effect on progression (see here for further details).
Now talk about the study.
In this randomized, multicenter, placebo-controlled, triple-masked clinical trial (NCT03334253), investigators treated 187 myopic patients (ages 5 to >13 years) with daily artificial tear drops for 2 to 4 weeks to determine their adherence to daily drops.
Patients were then randomly assigned to receive daily atropine or a placebo for 24 months, followed by a 6-month off-treatment period.
How were participants selected?
According to Clinical Trials, the patients must have low-to-moderate myopia with a refractive error that met the following criteria:
- Myopia -1.00 D to -6.00 D spherical equivalent (SE) in both eyes
- Astigmatism < 1.50 D in both eyes
- Anisometropia < 1.00 D SE
See here for the full criteria.
Demographic breakdown?
The participants included:
- 34 Black (18%)
- 20 East Asian (11%)
- 30 Hispanic or Latino (16%)
- 11 multiracial (6%)
- 6 West/South Asian (3%)
- 86 White (46%)
And the dosings?
Participants in the atropine group (n=125) received one dose of atropine, 0.01%, on a nightly basis; the placebo group (n = 62) received a placebo.
What was being measured?
Primary outcome included the comparison (from baseline to 24 months) of spherical equivalent refractive (SER) in the atropine group, as measured via cycloplegic autorefraction.
Secondary outcomes included the change in SER from baseline to 30 months (also measured via cycloplegic autorefraction) and change in axial length at both time points.
Did all patients complete the study?
Almost … 95% of atropine-treated patients and 94% of placebo-treated patients completed the study.
Gotcha. Now the findings.
Overall, investigators found that atropine on a nightly basis, when compared to the placebo, did not slow myopia progression or axial elongation.
Give me some numbers.
At 24 months, the adjusted mean (95% confidence interval [CI]) change in SER from baseline was -0.82 (-0.96 to -0.68) D and -0.80 (-0.98 to -0.62) D in the atropine and placebo groups, respectively.
And the adjusted mean (95% CI) changes in axial length from baseline to 24 months were 0.44 (0.39-0.50) mm and 0.45 (0.37-0.52) mm in the atropine and placebo groups, respectively (adjusted difference = -0.002 mm; 95% CI, -0.106 to 0.102 mm).
And at 30 months?
The adjusted difference in mean SER change from baseline was -0.04 D (95% CI, -0.25 to +0.17 D), while the adjusted difference in mean axial elongation from baseline to 30 months was +0.009 mm (95% CI, -0.115 to 0.134 mm).
Why is this data different from prior studies?
According to Michael X. Repka, MD, MBA, lead co-author of the study, this may be due to racial differences in the study’s U.S.-based patient population and, as a result, differing atropine response.
“The study enrolled fewer Asian children, whose myopia progresses more quickly, and included Black children, whose myopia progresses less quickly compared with other races,” stated Dr. Repka.
How can this be adjusted?
Katherine K. Weise, OD, the study’s other co-lead author, stated that different atropine concentrations may be needed for U.S. myopic patients in order for them to experience a reduction in myopia progression.
Other treatment forms could also be studied, Weise recommended, including “new pharmaceuticals and special “wavelengths of light in combination with optical strategies, like special glasses or contact lenses, to see what works in reducing the progression of myopia,” she stated.