A recent study published in the Archives of Opthalmology compare patching of one eye vs acupuncture in the treatment of amblyopia in older children, and finds positive results from acupuncture. The study, and its press, are a good example of the hazards of studying highly implausible modalities.
First let’s dissect the study itself – from the abstract:
In a single-center randomized controlled trial, 88 eligible children with an amblyopic eye who had a best spectacle-corrected visual acuity (BSCVA) of 0.3 to 0.8 logMAR at baseline were randomly assigned to receive 2 hours of patching of the sound eye daily or 5 sessions of acupuncture weekly. All participants in our study received constant optical correction, plus 1 hour of near-vision activities daily, and were followed up at weeks 5, 10, 15, and 25. The main outcome measure was BSCVA in the amblyopic eye at 15 weeks.
For background, amblyopia occurs when the brain tends to ignore visual information from one eye. This results from a variety of causes, but commonly from the two eyes having different refractive errors (anisometropic) – one eye may be more near-sighted or far-sighted than the other. The brain cannot combine information from both eyes, so it ignores one. This can be corrected in younger children, up to age 7, by correcting the vision for the refractive problems. If visual correction alone is not enough, then patching one eye (the strong eye) to force the brain to use the weak eye can be effective. This is usually done for only 2 hours a day, otherwise amblyopia of the patched eye can occur.
In children over 7 years old amblyopia is harder to treat. As the brain matures it becomes less plastic and less responsive to interventions used to treat amblyopia. In this study the researchers investigated standard treatment – constant optical correction plus near-vision activities – plus either patching or acupuncture. Not surprisingly, both groups improved:
The mean BSCVA of the amblyopic eye at 15 weeks improved from baseline by 1.83 and 2.27 lines in the patching and acupuncture groups, respectively. After baseline adjustment, the mean difference of BSCVA between the 2 groups was 0.049 logMAR (95% confidence interval, 0.005-0.092; P = .03), meeting the definition of equivalence (difference within 1 line). The BSCVA had improved by 2 lines or more in 28 (66.7%) and 31 (75.6%) eyes in the patching and acupuncture groups, respectively. Amblyopia was resolved in 7 (16.7%) and 17 (41.5%) eyes in the patching and acupuncture groups, respectively.
The weaknesses of this study make interpretation of the results difficult. It is a small, single-center study. Follow up was relatively short for this outcome. But most importantly – both groups received some standard therapy, and the variables of interest were not blinded at all. Further, there were no acupuncture controls – no sham or placebo acupuncture.
At best this is a pilot study. In the abstract the authors conclude: “Further studies are warranted to investigate its value in the treatment of amblyopia.” That is the only conclusion warranted by pilot studies. However, in the discussion the authors go further:
“Because of the good results obtained in our study, the acupoints that we used could be considered for use in clinical practice.”
Changes to clinical practice are not warranted based upon an unblinded pilot study such as this. The history of acupuncture specifically is one in which unblinded pilot studies tend to be positive, but then follow up well-controlled blinded acupuncture studies have tended to be negative. If history is any judge, these results will not hold up under further study, and therefore changes to clinical practice are premature.
This episode is just one example of the hazard of studying was is essentially a nonsensical system – the notion that acupuncture needles placed in specific (and non-existent) acupoints can cause specific physiological effects. The authors write:
“Although the treatment effect of acupuncture appears promising, the mechanism underlying its success as a treatment for amblyopia remains unclear,” the authors write. Targeting vision-related acupoints may change the activity of the visual cortex, the part of the brain that receives data from the eyes. It may also increase blood flow to the eye and surrounding structures as well as stimulate the generation of compounds that support the growth of retinal nerves, they note.
There is no evidence for such wild speculation about possible mechanisms of acupuncture, and speculating about mechanisms is premature when the best acupuncture studies all find no effect.
This is the merry-go-round of such highly implausible but culturally supported therapies. Studies that carefully control for the specific elements of acupuncture (sticking needles through the skin at specific points) show no effect from those specific elements. As I have written many times before – it doesn’t matter where you stick the needles or even if you stick the needles. What we get from acupuncture, at best, are very non-specific effects from the therapeutic ritual that surrounds acupuncture. There also appears to be non-specific effects from the local trauma of piercing the skin with needles, essentially mechanisms that dampen down pain and inflammation following local trauma.
Proponents of acupuncture typically will justify the claim that “acupuncture works” with these non-specific effects, missing the point (either naively or disingenuously) that non-specific effects do not justify specific claims or mechanisms. Often the claim is made that it does not matter how acupuncture works (again, missing the point) if it shows some clinical utility – non-specific effects (the argument goes) are worthwhile.
But such arguments are ultimately a bait-and-switch, a desperate attempt at misinterpreting the literature to justify the specific interventions of acupuncture. And then – with the next acupuncture study that does not control for needle location or insertion (those elements that define acupuncture) the authors happily credit a positive result to the specific elements of acupuncture and start speculating wildly about possible specific physiological mechanisms.
And around we go again on the merry-go-round of acupuncture – a poorly-controlled and unblinded study with (not surprisingly) positive results. The authors are superficially circumspect, but ultimately promote the findings as sufficient to justify clinical practice and continued speculation about the magical mechanisms of acupuncture. Follow up studies (when they occur) tend to be negative, meaning that any positive effects have nothing to do with the acupuncture itself, in which case proponents trumpet the non-specific and placebo effects as also supporting acupuncture (head I win, tails I win).
The ultimate problem is that the underlying notions of acupuncture itself – that there are specific acupuncture points on the body, and that there are mysterious energies that can be manipulated by sticking needles in these points that then have specific physiological effects – are highly implausible. They are, in fact, nothing but pre-scientific superstition. The energy and acupuncture points of acupuncture, according to decades of research and multiple independent lines of evidence, simply do not exist. Acupuncture is ultimately a shell game of preliminary unreliable results and misinterpreted non-specific/placebo effects.