Testing Part 8 – Miscellaneous testing: the good, the bad and the ugly side of testing
The previous 7 parts of my testing series identifies some common testing strategies we employ – but is hardly comprehensive and really can’t be, since this field evolves almost daily.
It would be a stretch for every dry eye specialist to have every tool in the dry eye toolbox and the time to do every test, not to mention the cost, would be all-consuming. I’ll touch on some peripheral testing strategies and then speak to some of the common shortcomings we can run into. Good testing is when the tests lead us to a better understanding and then better treatment of a disease. Bad testing is when the tests can mislead us - and Ugly is what we get when we are lead down misleading, unnecessary “rabbit holes” - wasting time, resources and potentially harming our patients.
Patients who have “Pain without staining” are a special group – largely because pain is considered a subjective issue – but also because staining (with the stains mentioned in the earlier part of this series) can vary with something as simple as the weather (drier weather promoting more evaporation and dryness). But pain is a tough metric, mostly because doctors are still grasping at understanding the full gamut of pain – from the initiation of the sensation, up to the brain’s reception and interpretation of that signal. Unlocking this puzzle is getting a bit better understood and can start with a simple test - first of creating some degree of an uncomfortable event (touching the cornea with something that should register a degree of sensation – the cotton wisp, the fishing line, or some chemical such as increasingly stronger solutions of salty drops, or the common numbing drops that feel stingy before they numb).
Once we determine that there is the ability to sense some degree of “pain” at the surface, then we typically numb the eye with drops and see if the sensation of pain goes completely away. If it does, then this suggests something at the surface level and confocal microscopes are leading the way in showing swollen, inflamed nerves even when the surface “looks OK.” If the pain does not go completely away, then this implies a higher-level disorder – pointing to how certain pain centers in the brain can become amplified to where they can apparently “reverberate” or continue to signal pain (kind of like the thumb that throbs even when it appears to have recovered from a whack - you feel it, but you can’t see something wrong with it – at least unless and until it swells and turns hot and red). Sometimes all it takes to resolve this kind of pain is the therapy to make more and better tears - and to give it time to settle down – but sometimes time doesn’t heal it and it still hurts. This will be the focus of a future post as it is a complex and significant problem.
When the Schirmer’s is very low and we suspect Sjogren’s Disease (see my earlier posts on autoimmune disease, starting here: https://www.eyethera.com/blog/sjogrens-disease-autoimmune-dry-eye-part-1 ), the testing is imperfect at best. Hearing that the mouth (along with nose, throat, the GI tract and in women, the vagina) is extremely dry, along with the very low Schirmer’s, will often trigger a blood test and possibly a lip biopsy – but if everything is “negative” (and we’ve effectively ruled out other causes like certain medications and the common “anti-waters,” like too much caffeine and alcohol), then we may put a diagnosis like “clinical Sjogren’s” on it. Typically, I’ll treat it like Sjogren’s and have referred some to rheumatologists in case we missed something. Sometimes what was “negative” on lab testing may eventually turn “positive,” so this remains a bit of a “dark science.” Fortunately, there continues to be a lot of work in the medical field to help us find a better way to diagnose and treat these “autoimmune dry eye diseases.”
Because many metabolic, nutritional, and hormonal disorders can cause a constellation of health-related issues that include dry eye disease, it is often necessary to involve a larger group of specialists to sort this all out. Running wider batteries of lab testing can sometimes provide the necessary diagnostic clues to sort this out – and sometimes a good history can save a lot of lab testing – so history is key. Once we identify the prospect of associated diseases or metabolic imbalances, it is common to refer patients to the appropriate specialists in that field. Working as a team typically can afford patients the best outcome. As doctors continue to subspecialize in ever narrowing aspects of disease, we rely on them to teach less specialized doctors what they need to know to best serve their patients. These related subspecialties may include OB-GYN, Endocrine, Rheumatology, GI, ENT, Neurology, Dermatology and Allergy to name a few.
I can briefly touch on a couple of other common problems with testing and how I currently approach them:
- First, is the issue with Meibomography – covered in the first segment of this series on testing. It appears the InfraRed (IR) cameras commonly used to image Meibomian Glands are best able to show the “active” portions of the glands. This can make it hard to see portions of the glands that may still be present and otherwise healthy enough to “recover” their function. Patients and doctors can get overly nervous when presented with the pictures that show nearly (or wholly) absent gland tissue – yet on so-called “transillumination” the doctor may uncover substantial evidence of residual, less apparent gland presence. At least one Meibomography unit utilizes the combination of both direct-IR and transillumination technologies (Lipiview). Fortunately, a dark room, a slit-lamp (an eye doctor’s typical microscope) and a small flashlight can do a similar exam when paired with the IR photography – so a better idea of the likely level of recovery is available to most dry eye centers. Another issue with meibography is the inability to sort out the source of obstructions. Many times it is the common “waxy plugging” that may be visible at the level of the doctor’s microscope. Other times it may be from scaring or keratin plugs. (check out my earlier post on this here: https://www.eyethera.com/blog/why-do-expensive-dry-eye-treatments-fail-and-what-is-maskin-probing ) These are critical pieces of information, and technology-driven companies continue to innovate in this field – so more and better devices are continually coming into the dry eye specialist’s equipment marketplace.
- Second is the issue with drug interactions, medicamentosa and tachyphylaxis (a lot of confusing words!). Drug interactions seem self-explanatory, suggesting when two or more drugs react together, the sum of their effects (good or bad) can be amplified – or negated. The nature of their effects can turn in a fully new direction from the expected effect of either alone. As the field of medicine expands and the number of drugs continue to grow, this issue can (and does) quickly get out of hand. Computers and databases can (and do) help, and most pharmacies offer advice when their computers pick up the possibility of such interactions – but not all interactions can be known as some are uniquely dependent on a patient’s genetics and other disease states. Lastly, a drug interaction does not have to require another drug to “interact with” – as they can simply interact with the patient’s underlying genetic makeup or allergies to cause their unwanted effects. Using the history of which medications a patient is currently on as well as past history (especially anti-oil-gland medications like Accutane or some intentionally toxic medications like anti-cancer drugs), is necessary, since even relatively short courses of some medications can leave a long-term, dry eye imprint in their wake.
Medicamentosa is basically an unwanted reaction to a product, or the vehicle used to apply or carry the product. This product can be a single drug, cosmetic, preservative or even an “artificial tear,” where it causes an ill effect. It can also be an ill effect caused by a combination of drugs, cosmetics, preservatives or the oxidation caused by the interaction of air with the product (in or out of a bottle). This problem appears to be more common that I think most of us realize. One such example can be seen in glaucoma medications, where a single, or in some cases, multitude of drops - applied to reduce eye pressure, can “gang up” on the surface of the eye, causing redness and irritation. These drops can be necessary to prolong the quantity of vision but can reduce the quality of vision and therefore of life. Sometimes the problem is with the preservatives and sometimes it is the drug itself - or a combination, that causes this grief. It is up to the prescribing doctor to help sort this out and to hopefully find alternative ways that can be less toxic to the eye.
Tachyphylaxis is when the eye becomes “used to” a medication so that it requires more and more of that medicine to achieve a similar effect. Drops that cause blood vessels to squeeze (to reduce redness) are an example of this problem. As the drops wear off, the “rebound” of redness requires more frequent applications to get a similar effect (until even continuous applications may not be enough to reduce redness). See my earlier posting on this problem here: https://www.eyethera.com/blog/can-i-use-eye-whiteners-like-visine-or-lumify-when-my-eyes-get-red
The best way to resolve medicamentosa or tachyphylaxis issues varies, but we often have to require our patients to stop all medications, drops and products (never do this without the blessing of the prescribing doctors involved in your care) and then take a fresh inventory of the patient’s problems before adding them back. This is usually done by adding them back one at a time, to discover which are the more offending. Sometimes there are well known issues with medications and/or patterns of reactions that are immediately obvious to the dry eye specialist who can then more easily identify the likely culprit – so best to seek out a good one who can help in this regard.
To schedule an appointment with Dr. Jaccoma, call Excellent Vision at either of these two dry eye offices:
(1) 155 Griffin Rd, Portsmouth, NH 03801 (603) 574-2020
(2) 3 Woodland Rd, STE 112 Stoneham, MA 02180 (near Boston) (781) 321-6463