October 2, 2019
By Dwight Akerman, OD, MBA, FAAO
Chief Medical Editor, Review of Myopia Management
Snake oil is an expression that originally referred to fraudulent health products or unproven medicine but has come to refer to any product or treatment with a questionable or unverifiable quality or benefit. When I speak with eye care professionals regarding contact lenses, pharmaceutical products, spectacles, or treatment guidelines for progressive myopia, I am surprised by how much snake oil exists.
Several products and interventions which have been proposed for reducing the progression of myopia in the past were either found through randomized controlled clinical trials (RCTs) not to be effective at all, or the effects were so small that they are not recommended as a routine treatment for myopic children. Examples of these ineffective products are under-corrected single vision spectacle lenses, single vision gas-permeable contact lenses with alignment fit, single vision soft contact lenses, topical timolol, and acupuncture. Weak progressive myopia reduction effects were demonstrated with bifocal, PAL, and peripheral defocus spectacle lenses. Sadly, many eye care professionals still rely on these ineffective or unproven products as their primary method of myopia care.
Not all evidence is the same. Evidence-based medicine (EBM) is about finding high-quality evidence and using that evidence to make clinical decisions.1 A cornerstone of EBM is the hierarchical system of classifying proof, known as the levels of evidence. Meta-analysis is a statistical technique for combining data from multiple studies on a topic and plays a fundamental role in evidence-based healthcare. Compared to other study designs (such as randomized controlled trials or cohort studies), the meta-analysis and systematic reviews are at the top of the evidence-based medicine hierarchy. This hierarchy enables us to weigh the different levels of evidence available to make clinical decisions because as we go up the hierarchy, each level of evidence is less subject to bias than the level below it.2
When eye care practitioners read articles about products, interventions, or treatment protocols designed to reduce the progression of myopia, they should be aware of the study type, study quality, and level of clinical evidence being quoted.3
As always, I welcome your suggestions and comments.
Best professional regards,
Dwight H. Akerman, OD, MBA, FAAO, FBCLA
Chief Medical Editor
1Sackett, D. L., Rosenberg, W. M., Gray, J. M., Haynes, R. B., & Richardson, W. S. (1996). Evidence based medicine: what it is and what it isn’t.
2Rosenberg, W., & Donald, A. (1995). Evidence based medicine: an approach to clinical problem-solving. Bmj, 310(6987), 1122-1126.
3Feinstein, A. R., & Horwitz, R. I. (1997). Problems in the “evidence” of “evidence-based medicine”. The American journal of medicine, 103(6), 529-535.