Orally ingesting 7-methylxanthine (7-MX) tablets may slow myopia progression and axial elongation in children, according to a study published in the British Journal of Ophthalmology.
Researchers enrolled 711 children with myopia (mean age, 10.9 years; 356 girls; mean baseline refractive error, -2.43 diopters [D]) in the retrospective analysis. A total of 624 participants received 7-MX treatment, while the remaining 87 did not. Participants underwent cycloplegic refraction and axial length measurement and were followed for a mean 3.6 year duration.
Study participants received varying levels of the 7-MX treatment (0-1200 mg/day). Linear mixed models were used to predict cycloplegic refraction and axial length data. Overall, ingesting the caffeine tablets was associated with reduced myopia progression and axial elongation (P <.001 and P <.002, respectively). Linear mixed models predicted myopia progression of -1.43 D with 1000 mg per day ingestion of the 7-MX tablets in 6 years, compared with -2.27 D progression in patients left untreated. Similarly, the model predicted more axial elongation without 7-MX treatment compared with taking the caffeine metabolite (1.01 vs 0.84 mm) in 6 years.
A total of 48 participants did not exhibit any myopia progression. These individuals had an older age at baseline (median 12.4 vs 11.0 years), remained in the study for a shorter duration (median 2.5 vs 3.5 years) and received higher daily doses of 7-MX (median 670 vs 500mg/day) compared with the remaining participants (P <.001 for all).
“Our model predicts around 0.07 mm less axial elongation during the first year for children taking 1000 mg per day compared with children not taking 7-MX and an accumulated reduction of 0.18 mm over 6 years,” according to the researchers. “A treatment effect of this magnitude would be clinically meaningful as it lowers the risk of myopia related complications.”
Study limitations include a retrospective nature, single center design, the absence of a randomly selected control group, and the possibility of confounding factors.
Trier K, Cui D, Ribel-Madsen S, Guggenheim J. Oral administration of caffeine metabolite7-methylxanthine is associated with slowed myopia progression in Danish children. Br J Ophthalmol. Published online August 22, 2022. doi:10.1136/bjo-2021-320920