A study published in the British Journal of Ophthalmology assessed the rate of myopia progression in children taking 7-methylxanthine (7-MX).
What is 7-MX?
7-MX is a caffeine metabolite that has been licensed in Denmark since 2009 as a treatment to reduce the rate of myopia progression in children.
Are caffeine metabolites safe for use in children?
Research has found no morphologic organ changes in rats given 1,000 mg/kg body weight/day for 6 months—a dose equivalent to around 30,000 mg per day for a 7-year-old child. Additionally, in contrast to caffeine, 7-MX has poor ability to penetrate the blood–brain barrier.
Tell me about the study.
Longitudinal cycloplegic refraction and axial length data for 711 Danish children with myopia treated with varying doses of oral 7-MX (range 0-1,200 mg per day) were analyzed using linear mixed models.
What did they find?
Children were followed for an average of 3.6 years and the average amount of myopia progression was 1.34 D. Treatment with 7-MX was associated with a reduced rate of myopia progression and axial elongation.
Modelling suggested that, on average, an 11-year-old child taking 1,000 mg 7-MX daily would develop −1.43 D of myopia over the next 6 years, compared with −2.27 D if untreated. No adverse effects of 7-MX therapy were reported.
How does 7-MX slow myopia progression?
Myopia is associated with a reduced concentration of scleral collagen; 7-MX has been reported to increase scleral collagen content, the diameter of collagen fibrils, and the thickness of the posterior sclera, potentially rendering the sclera more resistant to irreversible deformation.