Minimal effective dose: Just what you need and nothing more
OK, I know what you are thinking. Am I not the same guy who has been spouting off about our new dry eye world of “and,” not “either/or?” It is only a little more than a year in this new treatment paradigm, and I am already changing my tune?
Fear not, me droogies! The minimal effective dose (MED) is as fundamental a concept in medicine as can be. It is as efficient as a haiku, containing the poet’s art in the tiniest of packages, and as elegant as a Picasso drawing in pencil, the art shining through the simple black and white.
The MED is the medical equivalent of a three-ingredient recipe at a Michelin-starred restaurant: everything you need, and not one ingredient more.
Given the veritable cornucopia of options we now have to treat dry eye disease (DED), it is tempting to simply layer one upon another, building an ever more complex and burdensome concoction of treatments. This “kitchen sink” strategy is particularly prevalent in more severe cases of dry eye, but we are starting to see evidence of “complex plumbing” in mixed mechanism DED — aqueous deficient and evaporative DED both present — that is moderate or even mild in severity.
Outside influences are sometimes to blame for this. One must acknowledge that doctors of all sorts work in an environment that is not as free from inescapable or even avoidable barriers that the poet or the painter would be entirely unaware of. Armed with pencil, pen or palette, the artist is free to choose how elaborate or how spare their work will be. Not us, though. We live and work in a world where forces wholly out of our control intrude on the work that we do with and on behalf of our patients, in DED care and otherwise. A single ingredient option may be unavailable to your patient due to the byzantine process of health insurance coverage, for example.
How should we define the MED when we are discussing DED? Let me use an example from the fitness community, one that I offered as a framework for success to my CrossFit friends years ago. In fitness as well as health care, it is important to establish what it is that we will call success. Generally speaking, this will comprise something that includes both maximizing a positive outcome (eg, increased fitness or decreased DED symptoms) while minimizing adverse events or side effects (eg, exercise-related injury or site instillation pain).
Outcomes typically fall within broader categories. For example, in CrossFit, an athlete might wish to qualify for the CrossFit Games, perform well in the international CrossFit Open, create a certain physique or, in my case, maintain the ability to levitate one’s hindquarters off the loo after age 80 without assistance. Each of these outcomes will require a certain minimum when it comes to the number of sessions in the gym, the duration of those sessions, the weight lifted and the intensity level reached, all while simultaneously minimizing injuries that would keep an athlete out of the gym and reduce the effectiveness of this “dose.”
In short, what is the smallest number of the shortest visits to the gym that utilize the lowest weights and the least amount of intensity that will allow the CrossFitter to meet their goal? This is the fitness MED.
Any eye doctor who has treated glaucoma can relate to this concept. Our evaluations allow us to assign a severity to the diagnosis and determine a risk level associated with the untreated IOP. Initial therapeutic efforts aim to reduce the IOP to a target range at which we are hopeful additional damage to the optic nerve will not occur. Our goal is to hit this target range with a single intervention. Once we demonstrate that our goal has been achieved and has robust staying power, we progressively reduce the frequency of visits and the intensity of diagnostic testing to reduce the burdens of both time and expense borne by our patient.
How about a few examples of what the MED might look like in DED? One of our most common interventions is to use an immunomodulator in cases with obvious inflammatory-driven DED, especially if we see a decrease in tear volume. Most of us would include a short burst of topical steroid to reduce side effects and enhance adherence. Consistent with our commitment to MED principles, we always stop the steroid before the next follow-up visit; we want to see how they are doing on one single medication. Alternatively, you could use Lacrifill (Nordic Pharma) in the lower punctum of both eyes as a single treatment, again returning in 6 weeks to evaluate their progress.
But not both! We want to see if the patient will be comfortable using Lacrifill only. Leave the “belt and suspenders” philosophy to the directors of bad country music videos.
Everything about your intervention comprises a part of the “D,” the dose. Things like heating and cleaning the eyelids take time; they are also a part of the “D.” Same thing goes with the time-cost of follow-up visits.
Let me finish with a few thoughts on the virtues of considering cost when we are designing our MED plan. It is my deeply held opinion that patient cost must be considered when we are choosing interventions for DED treatment. Co-pays and co-insurance for clinic visits and testing. Medication costs and in-office treatments that are not covered by insurance. Minimizing these is an ineluctable part of the MED.
You may sincerely feel that a particular drug or version of a drug is so much more effective that you are duty bound to prescribe it regardless of the eventual cost to the patient. One of my DED colleagues has written just this, here and elsewhere, that you should “stick to your guns.” Still, others might find the work necessary to obtain prior authorization or prescribe through a specialty pharmacy to be inherently unreasonable, so they decline to prescribe medicines that require either (or both). DED doctors share these sentiments on social media forums all the time.
Neither of these positions is consistent with the MED philosophy. How can one call a proposed therapy “minimal” if no effort is made to spare a patient from exorbitant costs by examining alternatives? If they never actually obtain treatment, with or without your knowledge, how could it ever be effective? I do not wish to sound like a scold (I hate that) or a grumpy old man (hmmm, I did just have a birthday), but I just cannot see how one can be an effective DED doctor without helping your patient afford their treatments.
There you have it. A 30,000-foot look at the philosophy we use at SkyVision regarding the minimal effective dose. We seek the smallest possible intervention, one posing the fewest obstacles (including time burden and cost) while still providing optimal effectiveness. MED strategy allows for individualized treatment and leaves room for the eye doctor’s preferences and practice style. MED may not be quite as catchy a name as DEWMD or MADE, but we can add it to the list of DED terms you heard here first.
And when is the last time you saw CrossFit mentioned in an article about eye care?!
- For more information:
- Darrell E. White, MD, of SkyVision Centers in Westlake, Ohio, can be reached at dwhite@healio.com.
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