What’s up when the “sprinkler system” dries up?
While I’ve posted about Autoimmune Dry Eye Diseases (an extensive series starts here: https://www.eyethera.com/blog/sjogrens-disease-autoimmune-dry-eye-part-1) and on degrees of Aqueous Tear Deficiency (ATD, starting with a post on inflammation here: https://www.eyethera.com/blog/segment-10-aampb-what-we-know-about-inflammation ) separately before, I’ve been asked recently about determining causes for severely poor tear volume (common to ATD) when the autoimmune tests are not revealing. Knowing that the worst ATD is often associated with Autoimmune Diseases, it is usual to suspect autoimmunity at work, but sometimes all the testing related to autoimmunity comes back “negative” or “borderline” and we are left wondering what else is going on.
I posted on my favorite test for ATD (as part of a series on dry eye testing) here: https://www.eyethera.com/blog/what-do-dry-eye-tests-mean-part-7-tear-volume-and-how-we-measure-it and I’ve included some of my thoughts on causation in all of these prior posts. This week, I’ll attempt to summarize some of this information and offer some renewed insights.
I often use artistic license in my analogies and apologize in advance to those who can appreciate my oversimplification of complex topics. Having said that, I proceed to do the same here. Recalling that the surface of our eyes are covered in living cells that need support to survive, I point out that tears are the “lifeblood” of that surface. Job number one for their survival is that they must be kept moist and we have two means for that. One is what I like to refer to as the “emergency backup system” or “firehose” - the large tear glands that can pour salty water over our eyes (and often down our cheeks). Being salty water, this tear is not much more than moist support - so we have what I call the “sprinkler system” - the number Two means for support - but this group of cells and glands provide the 24/7 “clear blood” defined by a lot of water, with some salts, proteins and oils added in (a kind of clear-blood-like “salad dressing” - where the watery stuff is covered by a layer of oils that doesn’t “mix” with the water - so can act as an evaporative shield).
The emergency backup “firehose” will draw water from our bodies to the last drop, to make that salty solution, but the sprinklers are very sensitive to our overall level of hydration. If we get a little dry, they get dry and the drier we get, the drier they can get. This was first brought home to me when conducting an early study on clogged oil gland (MGD) treatment, where we had to exclude patients with severe ATD. The cutoff was 6mm on the Schirmer’s test strips and a young nurse who was both a friend and known MGD patient came rushing in from dropping off her kids at school to get screened for a treatment under this protocol. Sadly, her Schirmer’s numbers were around 3 and 4mm - well below the 6 we needed to see. On further discussion, she admitted to having had only a cup (or two) of coffee since rising and was obviously “under hydrated.” I advised she return after consuming a couple of quarts of water and we’d try again. Fortunately, re-testing came in around 8 and 9mm and we were able to proceed with the study treatment.
When I find numbers less than 10mm, I dig deeply into water consumption habits - including the “anti-waters” (things that encourage peeing and dehydration) like caffeine, alcohol and the host of medications that can dry us out. When less than 6mm, it is time to also look harder for sources of inflammation. Autoimmunity is the king (or queen) of inflammation, as it can single out water-producing cells and effectively kill them off - resulting in body-wide damages to tissues and organs dependent on their water production (commonly leading to eye, brain, gut, reproductive and joint issues, among others). Dry mouth, with severe, related dental issues, is common to Sjogren’s (perhaps the leading cause of autoimmune dry eye), so asking about a dry mouth can frequently lead to identifying this cause. Since autoimmunity is still relatively poorly understood, it is hard to know the exact portions of populations affected and likely varies widely through the many nature and nurture variables. Ocular Cicatricial Pemphigoid (OCP) appears to be a relatively uncommon cause of autoimmune dry eye, but since it can only be diagnosed through a biopsy of affected conjunctiva (the membrane on the surface of the white part of the eye), it is probably significantly under-diagnosed. Similarly, Sjogren’s is perhaps best identified by a biopsy (of salivary glands inside the lip area), so since most are not subjected to this level of testing, it is hard to know how many patients might be revealed as “positive” this way. Other autoimmune diseases can affect these water glands. Reactions to some medications can trigger an autoimmune dry eye (as well as affecting the moist membranes throughout the GI tract), called Stevens Johnson Syndrome - but since this can occur at different levels of severity, it can also likely be under-diagnosed (the full blown illness is extraordinary in its ability to inflict damages and usually requires hospitalization - but at that level of presentation it is hard to miss). Graft versus host reactions in those who receive tissue transplants fall into a similar spectrum. In the end, the key is what we can do for these autoimmune-diseased patients and while we are coming up with better protocols all the time, we are still sadly lacking in a definitive treatment plan for many.
Dr. Elizabeth James, a PhD in Medicine and Healthcare, gives a good rundown of causes of dry eyes and dry mouth without having an autoimmune disorder or thyroid problems, here: https://qr.ae/pKzfYt I began an answer to treating dry eye-related inflammation here: https://www.eyethera.com/blog/segment-10-b-when-we-are-at-war-with-ourselves but it is clear that we need to determine “root causes” of inflammation in order to best treat it and I advise working with a good dry eye specialist to help (often in concert with a team that should include your Primary Care Provider and may include Rheumatology, Endocrinology, Gastroenterology - among others as the findings require).
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