A metabolite of caffeine may slow the progression of short-sightedness, or myopia, in children, a new study suggests. Photo courtesy of the National Eye Institute
Aug. 22 (UPI) -- If it's proven to be safe and effective in large clinical trials, a metabolite of caffeine may prove valuable in slowing the progression of short-sightedness, or myopia, in children, a new study suggests.
The caffeine metabolite, called 7-MX, short for 7-methylxanthine, been used to treat childhood myopia in Denmark since 2009, but until now it hasn't been fully evaluated in long-term studies.
The research, exploring how quickly myopia progresses in children who take 7-MX, was published Monday in the British Journal of Ophthalmology.
Myopia occurs when the eye grows too long, and preliminary research suggests that 7-MX inhibits excessive lengthening of the eye, or axial elongation, a news release said.
The condition often starts between at age 6 and 7, progressing until ages 16 to 20. It is associated with a heightened risk of conditions that affect vision and eye health, including macular degeneration, cataracts, glaucoma and retinal detachment.
The researchers said existing interventions to control nearsightedness, such as contact lens-based treatments or the use of various drugs, are not that effective at preventing the condition from worsening in children.
They reviewed the medical records of 711 children, an even split of girls and boys, treated for myopia at an eye clinic in Denmark between June 2000 and January 2021.
The children received comprehensive eye tests, including measurement of the eye's axial length. Then, 624 of them took 7-MX oral tablets of up to 1,200 milligrams daily, averaging 470 mg., while 87 children didn't take the tablets for various reasons.
They averaged 11 years old when they began treatment, and their eye length and degree of myopia were tracked for 3½ years, on average.
None reported any side effects while taking the treatment.
The researchers found that treatment with 7-MX was associated with a slower rate of worsening myopia and axial elongation, and higher doses seemed more effective, the release said.
Researchers calculated that, on average, myopia in an 11 year-old who takes 1,000 mg. of 7-MX daily would increase by -1.43 dioptres -- the units of measurement to assess eye function -- over the next six years. That compared with an increase of -2.27 dioptres without treatment over the same time period.
Moderately severe myopia is regarded as -3.00 dioptres, while -6 dioptres or more is viewed as severe myopia, the release said.
The scientists also found that the eye's axial length would increase by 0.84 millimeters when 7-MX is taken versus 1.01 ml. without treatment.
Because their study was observational, they said they could not account for "potentially influential factors, such as genetic factors, time spent outdoors, ethnicity and time spent on [close] work."
So, to establish a causal connection, the researchers urged further study via a randomized, controlled trial to see whether 7-MX may become "a valuable supplement."