Now, if you ever look much into dry eyes, you will no doubt have stumbled upon the condition known as Sjogren’s syndrome. In this blog post, I’ll have a look at the causes of dry eyes and also the significance of Sjogren’s syndrome as concluded by the leading research study on dry eye disease, and finally, why this is important for treating dry eyes successfully.
Dry eye research, such as the work by Schiffman et al. 2003, suggests that the long term impact of even moderate dry eyes can result in worse quality of life for individuals than someone suffering from a condition such as angina and with that in mind, let’s discuss the causes by dissecting the key summary of the leading study on dry eyes, which is the Dry Eye Workshop Study II or the DEWS II study as is also known.
Below are links to the DEWS organization website if you want to check that out and if you’re interested in finding out more about the report, I think is useful and valuable information for people who have dry eyes;
The DEWS II dry eye study report http://www.tfosdewsreport.org/report-…
Tear Film & Ocular Surface Society website http://www.tfosdewsreport.org/)
Also, do check out my first video Part 1 – What is dry eye? https://youtu.be/o4oZIGSYz50) in this three-part series, for more information on what dry eyes is, and if you haven’t yet watched that, then go watch that first and then come back to this one.
Now, let’s begin with the latest definition by the DEWS study, so dry eye is a multifactorial disease of the tears and surface of the eye that results in symptoms of discomfort, visual disturbance, and tear instability. It is accompanied by increased osmolarity of the tear film and inflammation of the eye surface, so there are some big words in there. I know, but the key ones to how we go about soothing our eyes and making them more comfortable are tear instability osmolarity, and inflammation of the eye surface. Also, as the definition suggests, dry eye is caused by a multitude of factors, but they all produce well-documented symptoms that include burning, itching of the eyes, redness, pain, tired eyes, and, strangely enough, even watery eyes.
Now, the following image is a quick overview of the classes of dry eye and the basic causes as outlined by the DEWS to study. Now, as we have a look at the flow chart here, there are two main types of dry eyes. One where your eye does not produce enough tears, and this is called Aqueous Deficiency Dry Eyes, and then the other where your tears evaporate away too quickly and we call this Evaporative Dry Eyes. The vast majority of dry eyes are due to evaporative type with the aqueous deficiency type leading to more serious symptoms and often a more challenging discomfort to treat and manage.
The causes of the evaporative type fall into two classes.
First of all, we have external factors which are things in your environment, environmental factors that reduce or impact the quality of your tears, and include things like contact lens wear and also Lasik. Then you have eye-related problems and these are factors which are caused by abnormal functioning of your eyes, which then affect the quality of your tears, of which Meibomian Gland Dysfunction is one of the most common causes.
The causes of the Aqueous Deficiency type are classified in two ways also.
First of all, it is due to Sjogren’s Syndrome and then secondly is everything else that is Non-Sjogrens Syndrome related but causes a lack of tear production and the same serious long-term dry eyes. I think this is a good time to briefly talk about Sjogren’s Syndrome because it’s clearly important enough and common enough to have a category all of its own in the DEWS II research. So Sjogren’s Syndrome is caused by the immune system, which is the body’s defense against infection, damaging healthy parts of the body through incorrectly activating an ongoing inflammatory response in the area where no infection exists. So this is known as an autoimmune condition, and many autoimmune conditions ranging from rheumatoid arthritis to a psoriasis and Crohn’s disease.
However, Sjogren’s Syndrome usually affects areas of the body that produce fluids such as your tears and your salivary glands, but other parts of the body, such as the nerves and the joints, can be affected by Sjogren’s Syndrome as well.
Coming back to those big words from earlier on, tear instability, osmolarity, and inflammation of the eye surface, here’s how they all fit in. Firstly, with tear instability, it’s worth knowing that your tears are made up of three distinct fluid layers that are released by different glands and pores to form the mixture that is our tears. First of all, we have an oil layer at the front that stops the watery layer from evaporating too quickly, and then secondly, in the middle, we have the watery middle lamb, which provides moisture to the eye that is needed, and then thirdly, we have the mucus layer at the bottom, which holds all the layers together and evenly spread over the eye.
So starting with inflammation of the eyes surface, inflammation is a process by which the body’s white blood cells and substances that they release protect us from infection by foreign organisms such as bacteria and viruses. The inflammation is great for very short term protection, but if it continues for some time, it can cause serious issues and damage to otherwise healthy tissue on the eye, it’s a key problem that can either cause dry eyes or it can also be the result of ongoing dry eye, depending on the path in the above classification and flow chart that is taken as part of an inflammatory process, we get heat produced as well as other signs like redness and dilated blood vessels and swelling.
Tear instability comes about when the tear film doesn’t stay evenly spread over the surface of the eye and this can happen because the mucus production from the mucous glands is low or the surface of the eye is slightly damaged and the mucus can’t evenly spread or anchor onto the surface of the earth. The result is soreness and the triggering of inflammation and the symptoms of dry eye.
Osmolarity; This is basically how concentrated your tear is for example, the more evaporation of the watery layer that occurs, then the greater the osmolarity and the dry eyes as well. The result is soreness and the triggering of information and symptoms of dry eyes.
So why is this all-important?
Well, all of the ways that we go about treating dry eyes and managing dry eyes should involve addressing one or all of the problems are related to tear instability, tear osmolarity, and also inflammation of the eye’s surface.
Now, having said that, one last point that I think is helpful to touch on is the severity of dry eye symptoms and there is an official grading scale of your symptoms, which can be useful as a point to the kind of solution that might best suit your dry eyes. Here’s a simple example, there are many cases where the symptoms or the visible signs of a condition are not a good indication of the severity of the condition, however, in the case of dry eyes, the DEWS study has concluded that dry eye symptoms are a very good indicator of how severe your condition is and this is important for several reasons. For one, it means that we can get a very good indication of how well your dry eye is being managed by how severe the symptoms are. The reason that symptoms are such a good indicator is that inflammation is the biggest cause of dry eye discomfort and the problems associated with dry eyes, so by dealing with the inflammation, we can manage and even cure dry eye symptoms. In the next blog post in this three-part series, I’ll be talking about dry eye treatments, so don’t miss that.
Let me know in the comments section as well, what’s been your experience with dry eyes? Have you found it manageable? Have you had a cure for your dry eyes? Is it something that you’ve been struggling with for a long time without a solution? Let me know, I’d love to get your feedback on that as well.
Until the next time, I look forward to catching you in the next one.
Take care.
