Caffeine Metabolite May Slow Progression of Nearsightedness in Children

If proven effective in clinical trials, 7-MX could be a valuable future treatment.

A metabolite of caffeine, known as 7-MX, might slow the progression of myopia, also known as myopia, in children. This is according to observational research published on August 22, 2022 British Journal of Ophthalmology.

According to the researchers, 7-MX could become a valuable treatment for a condition for which current options are somewhat limited if it proves safe and effective in large clinical trials.

Myopia occurs when the eye becomes too long, stretching and thinning it. It often begins at the age of 6-7 years, progressing until the age of 16-20 years.

In addition to causing myopia, myopia is associated with an increased risk of various conditions that affect vision and eye health, including macular degeneration, glaucoma, cataracts and retinal detachment.

Early research indicates that the caffeine metabolite 7-methylxanthines, or 7-MX for short, prevents excessive eye length (axial elongation).

7-MX has been used to treat childhood myopia in Denmark since 2009. But this has not been fully evaluated in long-term studies so far, and the investigators wanted to find out how quickly myopia progresses in children taking 7-MX.

Scientists reviewed the medical records of 711 children (356 girls and 355 boys) treated for myopia between June 2000 and January 2021 at an eye clinic in Denmark.

Extensive eye examinations including measurement of axial length were performed on the children. 624 (88%) children took 7-MX tablets up to 1,200 mg (average 470 mg) for various reasons, while 87 did not.

When they started treatment, their mean age was 11 (range 7–15), and their eye length and degree of myopia were tracked for an average of 3½ years (range 11 months–9 years).

Diopters (d) are the units of measurement used to assess the extent of eye function: the mean degree of refractive error (near-sightedness) to start was −2.43 d, which averaged 1.34 d during the monitoring period. D increased. -3.00 d is considered moderately severe myopia; -6 d or more is considered severe myopia.

Initially the mean axial length was 24.4 mm, increasing by an average of 0.21 mm/year.

Treatment with 7-MX was associated with a slower rate of worsening of myopia and axonal elongation, with higher doses appearing to be more effective.

Based on these data, the scientists estimated that for a normal 7-year-old man with a refractive error of -2.53 D, that child’s myopia would increase to -3.49 D without treatment over the next 6 years.

But with a daily dose of 1000 mg of 7-MX, the same child’s myopia will increase to -2.65D over the next 6 years.

Similarly, without treatment, axillary length would increase by 1.80 mm over the next 6 years, whereas at a daily dose of 1000 mg it would only increase by 1.63 mm.

According to the researchers’ calculations, on average, an 11-year-old child taking 1000 mg 7-MX daily would increase the child’s myopia by −1.43 d over the next 6 years, compared to −2.27 d without treatment., And the axial length will increase by 0.84mm compared to 1.01mm without treatment.

None of the children taking 7-MX reported any side effects during the monitoring period.

According to the scientists, the findings are similar to experimental studies. However, they acknowledge that their study is observational, and they were not able to account for potentially influencing factors, such as genetic factors, ethnicity, time spent outside, and time spent on close work. Therefore, their findings cannot establish causality.

“The question of causality and potential treatment effect size can only be determined through a randomized trial,” they write.

But they conclude: “Current myopia control intervention methods are not fully effective in preventing children from progressing to high myopia, and if causality and efficacy can be confirmed in future randomized controlled trials, So 7-MX could become a valuable supplement.”

Reference: “Oral administration of the caffeine metabolite 7-methylxanthines is associated with slower myopia progression in Danish children” by Klaus Trier, Dongmei Cui, Soren Riebel-Madsen and Jeremy Guggenheim, 22 August 2022. British Journal of Ophthalmology,
DOI: 10.1136/bjo-2021-320920