Evolutionary Medicine and Behavioral Optometry

Applied Concepts Cover

In the chapter on myopia in my textbook I referenced Randolph Nesse, one of the pioneers in what he called Darwinian Medicine in the early 1990s.  Over time, the term has evolved into evolutionary medicine.  The construct that originally attracted me to the work by Nesse & Williams was the premise that certain biological states were indicative of a mismatch between the individual and the environment.  While

Evolutionary medicine hasn’t gotten very far since Ness & Williams pushed their agenda in the early 1990s, but there are signs afoot that this may be changing.  As recently reviewed, evolutionary medicine is not a field, like genetics or biochemistry. It is a set of concepts and approaches with which to analyse many different parts of medical science.  My premise is that much of what behavioral optometry has been trying to advance has roots in evolutionary biology, and myopia – even juvenile myopia, is simply one framework.  This relates to theories about hunter/gather societies, the drive toward sustained near work, visual stress, and scleral distensibility.  Some consider this to be in the realm of paleoneurology.

I raise this issue because  just finished reading a delightful book on evolutionary medicine by Jeremy Taylor (sorry, Katie – another one you’ll have to add to your list).

Evolutionary Medicine

In a chapter entitled “The Downside of Upright”, Taylor cites the research of Dominque Rousie and Alain Berthoz on head-to-toe asymmetries in children with scoliosis.  Consider this fascinating paragraph:

“Rousie and Berthoz used MRI scanners to measure cranial and facial asymmetry in the location of left and right eye orbits, the development of the nasal septum, and the jaw and cheekbone.  In turn the jaw and cheekbone are linked to the basicranium, the underside of the brain case, which houses the cerebellum (which has also been found to be asymmetric in scoliosis) and the bony labyrinths of the inner ear.  When the latter are distorted, they explain, this could result in asymmetry in the way that the otoliths (the tiny particles in the flied-filled inner ear that trigger the sensory cells that register gravity and acceleration) pass information to the postural system – again causing imbalance.  Specifically, they propose that these semi-circular canal abnormalities send abnormal outputs to the vestiubulopsinal tract a part of the motor nervous  system that coordinates movement.”

A few bells went off in my head as I read this.  Putting scoliosis per se aside, how often do we see patients that have craniofacial asymmetries who have binocular imbalances with postural implications that extend from head to toe?  I blogged about this previously in the context of this asymmetry experienced by one of the giants in optics of the 20th century, Adelbert Ames, Jr.  This is one reason why I have grown much more receptive through the years in collaborating with craniosacral therapists and others who understand how asymmetries between the two orbits can result in extrocular muscle asymmetries and adaptive postural problems.  It’s not that we’re going to have these patients undergo oculoplastic surgery, or that therapeutic interventions have to necessary feed back into a change in orbital symmetry, but anything that we can do to work toward lessening asymmetry typically has a salient effect.  That encompass primitive reflexes, bilateral integration, and a host of other head-to-toe concepts.

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