Eye Screening and Intractable Pain Management
by Forest Tennant, MD, DrPH
 A daily challenge to the pain physician who treats intractable pain
is the proper regulation of serum medication levels. A key routine clinical assessment
must be to document whether over-medication is present in order to prevent mental and
physical impairments which may interfere with proper driving, climbing stairs, or
performing work activities. Does the patient require a higher dose for good pain control?
Or is the current dosage adequate? The patient is now on anti-inflammatory agents and
states she/he needs something “stronger.” Could this be true? These are routine,
common questions that constantly confront the physician who treats pain. A knowledge of
how uncontrolled pain and medication levels affect the eye may be extremely helpful in
answering the above questions. For example, a patient who has good opioid pain
control—and who isn’t overmedicated with sedatives or muscle relaxants—will
be able to converge their eyes and not demonstrate nystagmus, conjunctival reddening, or
droopy eyelid.1
While the focus of this article will be regulating opioid dosage for intractable pain,
it is critical to first assess medications in these patients. Pain patients usually take
multiple drugs that may include antidepressants, sedatives, and muscle relaxants. A most
unappreciated, pharmacologic fact is the great synergistic and potentiative capacity of
benzodiazepines, muscle relaxants, some antidepressants, and some sedatives to interact
with opioids and produce neurologic suppression. Although eye signs may not correlate to a
specific drug, over-medication can usually be detected by screening for specific ocular
signs. In particular, excess sedatives and muscle relaxants may cause these common eye
signs:2,3
1. Non-reactive pupil to light and accommodation
2. Nystagmus
2. Non-convergence
4. Droopy upper eyelid
5. Conjunctival reddening
6. Watering
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— June 2008
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