There’s been a lot of news about myopia (nearsightedness) recently, much of which I thought might be of interest to some of you.
In December, the results of a large survey were released in the Archives of Ophthalmology. The findings were that the number of nearsighted people in the United States (age 12 – 52) has risen by 66% in the last 30 years (abstract here).
The reason for this increase is the subject of quite a lot of discussion and debate. Just last week, NPR (National Public Radio) ran a story on one of the investigations into the cause. While genetics certainly play a role, it appears that time spent outside is another big factor. One study found that children who spend 14 hours per week outside see a dramatic reduction in the risk of becoming nearsighted. And the outdoors part seems to be the key – children who get plenty of exercise indoors don’t see the same benefit. And perhaps even more surprising, the amount of time reading or doing other close-up activities doesn’t seem to make a difference in how likely a child is to develop myopia. You can read or listen to the full NPR story here.
One final recent report, this one on the topic of the progression of nearsightedness in children – the tendency for some children’s nearsightedness to get worse over time: Archives of Ophthalmology just published the results of a 2 year study of nearsighted children age 8-13 years old who had seen significant worsening of their myopia in the previous year – their prescription changed by at least 0.5. The study looked at whether prescribing bifocals instead of single focus glasses made any difference in how much their prescription changed over 2 years. In all of the cases, the prescriptions worsened over the 2 years, but for children who wore bifocals or prismatic bifocals, their nearsightedness increased less (the progression was reduced). The children with prismatic bifocals saw the least amount of worsening. The authors of the study caution that prismatic bifocals should not be prescribed to all nearsighted children, and it remains to be seen if the bifocals continue to control the progression of nearsightedness past the 2 year window. Nonetheless, the research is promising. You can read the full study here.