A Fresh Look at Myopia Protocol
By Richard L. Anderson, OD, FOAA, & Edward S. Bennett, OD, MSED, FAAO
Myopia is the most common diagnosis in eyecare practices, and yet its primary treatment has essentially remained unchanged for more than 100 years. We still typically provide a spectacle correction of maximum plus for maximum acuity. Research within the last 20 years shows that it is now possible to move toward prevention and control rather than merely compensation. For that to occur, we need an updated refractive error protocol.
Various types of published refractive treatment protocols assume, whether explicitly or not, that myopia is to be compensated for when necessary, not “treated” in the classical sense of a disease process. Current guidelines typically say that myopia is treated either by minus lenses or surgery, and successive examinations are used to determine whether more minus or surgery is necessary due to increased levels of myopia. These techniques accept the inevitability of myopia progression.
An Increasing Problem
Myopia is not the eye's natural state (Morgan et al, 2010) but the result of our increasingly urbanized environment (Morgan et al, 2005). Myopia would have been highly selected against in hunter-gatherer environments of our past, so it encourages us to identify ways to compensate for something we've brought on ourselves.
Higher levels of myopia are associated with premature cataracts, glaucoma, retinal detachment, and macular degeneration. Although some presbyopes may enjoy myopia, the idea of allowing myopia to progress unimpeded to unrestricted levels should be reexamined when we have the tools to modify that progression.
Research has shown that we can manipulate myopia with lenses (Smith, 2011), drugs (Ganesan et al, 2010), and time spent outdoors (Jones et al, 2007). In fact, it may very well be that our prescribing of standard spectacle designs is actually creating more myopia (Lin et al, 2010). Nearly all children become emmetropic or slightly hyperopic at a young age, and yet myopia has increased in the United States by 66 percent over the last 30 years (Vitale et al, 2009).
A More Standard Protocol
Many methods of myopia control have been tried in the past with limited success (Walline et al, 2011), regardless of the fervor of the proponents of the different methods. Dr. Anderson and other orthokeratologists have observed how young patients' myopia did not progress nearly as quickly as spectacle patients' myopia (Walline et al, 2009). A relatively serendipitous finding that the peripheral retina has a role in myopia development becomes relevant to controlling myopia with customized lens optics. Specifically, it appears that the peripheral plus power placed on the retina by the orthokeratology optics (Queirós et al, 2010) acts as a relative stop signal for further axial growth.
The Orthokeratology Academy of America (OAA), a section of the International Academy of Orthokeratology, sees a need for a more formalized strategy for dealing with refractive errors. The OAA created a semi-independent committee composed of leading researchers and clinicians tasked to develop an updated refractive error protocol. Its first efforts are aimed at myopia. The protocol is not limited to orthokeratology but will incorporate all relevant treatment modalities. This is a rapidly expanding area of knowledge, and individual practitioners have often created their own protocols based on their perceptions or perhaps on the latest journal article. The committee will examine relevant data and make recommendations that are both scientifically valid and clinically useful. It is an exciting time to be practicing vision care! CLS
For references, please visit www.clspectrum.com/references.asp and click on document #198.
|Dr. Anderson is chairman of the Myopia Prevention Protocol Committee of the Orthokeratology Academy of America and the author of MyopiaPrevention.org. You can reach him at Dr.Anderson@orthokspecialist.com. Dr. Bennett is an associate professor of optometry at the University of Missouri-St. Louis and is executive director of the GP Lens Institute. You can reach him at email@example.com.|