It may sound self-pitying, but one of the most disturbing features of my life –  disturbing in every sense of the word – is being woken up multiple times almost every night, unable to open my eyes. This is caused by my condition, known technically as lacrimal keratoconjunctivitis, or more commonly, “dry eyes.” 

It’s extremely uncomfortable because the insides of my eyelids, deprived of the natural tear film that lubricates the eyes when we blink, are scraping against the corneas. The cornea is by far the most sensitive surface in the human body, sensitive enough to feel just a puff of air or brush of a feather. When I’m awake and in pain, it’s also highly frustrating because I know that there is a small tube of lubricating eye solution that I carefully place next to my bed in anticipation of this happening, but to open my eyes is excruciating, so I am left having to grope for it with my eyes tightly closed hoping to lay my hand on it without knocking over my drink or the bedlight.

Having lived with this for over a decade and with it growing increasingly frequent, I’m keen to try anything new that at least promises me some relief, even if it’s not a cure. In fact, I have learned from hard experience and many hours of searching on the internet and questioning professionals that there is no absolute cure for my form of dry eyes. There are, however, a few products that provide substantial relief in reducing both the frequency and the intensity of the bouts. One such brand-new one is called Miebo (also known in some countries as Evo Tears). It comes with some special features, but before I go into them, I want to take a step back to briefly outline some of the details of the causes and effects of dry eyes before I explain how I’m expecting Miebo can help me.

Lacrimal keratoconjunctivitis is also called aqueous tear deficiency or sometimes evaporative tear deficiency. It can cause discomfort both at night, as in my case, and during the day, when a shortage of lubricating tears can turn each blink into a scrape against the cornea, giving rise to a cycle of increasing irritation. People have an instinct to blink more frequently or rub their eyes when there is a sense of discomfort, and this reinforces the irritation.

The multi-functions of tears

The primary function of tears is to keep the eyes’ surface moist and lubricated, allowing each blink to wash away dust, dirt, and other tiny particles that could cause damage. In a healthy eye, dryness or irritation should provoke the production of more tears. Some medical conditions can interfere with this and result in dry eyes. 

Tears are also essential in protecting the eye against infections. Dissolved in the water of each teardrop are special proteins called lysozymes, which have anti-bacterial properties that combat invading microbes. 

Tears also provide the oxygen and nutrients that the cornea needs to stay transparent and flexible. The cornea is unique in the body because it has no access to oxygenated blood (for the obvious reason that veins would reduce the cornea’s transparency and affect vision). The cornea’s outer layer is lubricated by tears, which spread over its surface with each blink.

Where do tears come from?

Tears are produced by the lacrimal glands located near the temples. When working correctly, the glands secrete small volumes of tears continuously. When the eyes are irritated by smoke, dust, or even simple irritants like chopped onions, tear production increases to respond to the irritation. With each blink, tears spread across the eye, covering the surface and ensuring that it remains moist.

Tear deficiencies – causes and effects of dry eyes

Dry eyes can be caused by either an insufficiency of tear production or an increase in evaporation rate from the open eye’s surface. I am the victim of the first group. My tear deficiency is simply a result of growing older. It was clear that as I aged into my 50s, my body’s ability to produce tears began to decrease. The quality of the tears also changed, becoming more watery, making it look like I was crying, especially in bright lights. My doctor told me that it was just an age-related decline that is a natural part of the process and, in my case, was made worse by hormonal changes. He suggested at least trying to reduce the degree of the symptoms that were coming from a testosterone deficiency. Initially, I was prescribed the AndroForte cream, which he told me had good extra features because it’s not an oral medication, and so it was less likely to interfere with the other drugs I was taking for non-related conditions. He also suggested that there were some simple dietary changes that I could make.  

As I have also learned, menopausal women also tend to experience the onset of dry eyes when their hormones start to go out of balance, and I’m sure that they would get the same sort of advice that I did and use something like AndroFeme. 

Some medical conditions produce tear deficiency as an offshoot of some other process. One of these is Sjögren’s syndrome, which is an autoimmune disease in which the immune system mistakenly attacks its own moisture-producing glands, including those in the eyes. This autoimmune response leads to inflammation and damage to the lacrimal glands, reducing their ability to produce tears. As a result, people with Sjögren’s syndrome often experience severe dryness in the eyes, leading to discomfort, irritation, and potential long-term damage to the eye’s surface.

Some other causes of tear deficiencies are blepharitis, contact lens use, and a reaction to some medications. Blepharitis is an inflammation of the eyelids, often involving the meibomian glands, which are located in the eyelids and secrete some oils that also help to keep the eyes lubricated. When the glands become blocked or inflamed, it can lead to a condition known as meibomian gland dysfunction (MGD). MGD is one of the most common causes of dry eyes, as it impairs the ability of the tear film to retain moisture, leading to increased evaporation of tears and dryness. Symptoms include redness, irritation, a feeling of grittiness, and crusting on the eyelashes.

Long-term use of contact lenses, especially soft lenses, can cause dry eyes. This is because contact lenses can disrupt the natural tear film that covers the eye and lead to increased evaporation. People may develop contact lens-induced dry eye, where the lens causes mechanical irritation, reducing the quality and quantity of tears.

Some widely used medications can create dry eyes as a side effect. These include antihistamines, decongestants, diuretics, antidepressants (SSRIs and SNRIs), and hormone replacement therapy.

My expectations of Miebo / EVO Tears

I have great faith in what Miebo can do for me, although it’s too early to say with certainty that everything I am hoping for will be justified. My hopes are based on how the compound inside Meibo, with the generic name perfluorohexyloctane, can prevent excessive evaporation of tears. Instead of the eye drops I am using now, which are just lubricants to replenish the layers of tear film quickly and enable me to open my dry eyes, I am hoping that Miebo will slow down the whole process of tear depletion so that I don’t experience the symptoms as frequently and intensely as I do now. As I said before, there is generally no cure for aqueous tear deficiency, but it looks like Miebo can come closer to addressing at least some of the causes of my discomfort. I will report back in due course.

FAQ

What is aqueous tear deficiency, and what causes it?

Aqueous tear deficiency is a condition in which the eyes do not produce enough of the watery component of tears, leading to dry, irritated eyes. Common causes include age-related changes, autoimmune diseases like Sjögren’s syndrome, certain medications (e.g., antihistamines, antidepressants), and damage to the lacrimal glands. Aqueous tear deficiency can also be linked to certain environmental factors, such as dry air or prolonged screen use.

How does evaporative tear deficiency differ from aqueous tear deficiency?

Evaporative tear deficiency occurs when the quality of the outer lipid layer of the tear film is compromised. The outer lipid layer slows evaporation, which can otherwise cause dryness, irritation, and discomfort. Common causes include Blepharisis (meibomian gland dysfunction—MGD), which impairs the secretion of lipids from the lids, and environmental factors like wind or air conditioning. Unlike aqueous deficiency, in evaporative deficiency, the volume of the watery tear component is typically normal, but the tears dry out too quickly.

What is lacrimal keratoconjunctivitis, and how is it related to dry eyes?

Lacrimal keratoconjunctivitis, often referred to as dry eye disease (DED), is a condition that involves inflammation of the cornea and conjunctiva (the thin membrane covering the eye) due to insufficient or poor-quality tear production. It is commonly caused by either aqueous or evaporative tear deficiency or can be a combination of both. The result is chronic irritation, discomfort, redness, and potential damage to the eye’s surface. The inflammation associated with lacrimal keratoconjunctivitis can further worsen tear production and exacerbate symptoms.

What are the common symptoms of aqueous or evaporative tear deficiency?

Both conditions can cause symptoms like dry, itchy, or gritty eyes, excessive tearing (as the body compensates for dryness), blurry vision, and sensitivity to light. People may also experience a feeling of a foreign body in the eye or pain when blinking. The symptoms of evaporative tear deficiency may also include increased discomfort in wind or dry environments, while aqueous deficiency can lead to more severe dryness and irritation.