There are a lot of things that can be done through the nose. You can breathe through your nose, sneeze through your nose, get a ring through your nose, and even pay through the nose. But did you know there’s another we can add to the list of the nose’s uses? We can also treat dry eye disease through the nose.

 

Dry Eye Disease

Dry eye disease is estimated to affect up to 50% of the world’s population. In the USA, approximately 34 million adults suffer from the condition, though a lot of them possibly don’t realize that that burning, irritation, and discomfort in their eyes actually has a name, let alone is considered a disease.

The eyecare profession is becoming increasingly aware of how complex dry eye can be – it’s more than simply not having enough moisture in the eye. We know that there are a multitude of factors involved in causing or exacerbating dry eye, and that inflammation of the eye’s surface plays a significant role. We have also realized that not everyone who has dry eye disease feels that their eyes are dry and conversely, there are a proportion of patients who feel their eyes are terribly dry and yet exhibit very few, or only mild, clinical signs of the condition. Now you’re wondering whether you’ve got dry eyes, aren’t you?

Symptoms can vary widely from person to person and sometimes only present themselves in certain environments or situations, such as every time you sit at your computer to write an article. People with dry eye can report symptoms such as:

• Dryness of the eyes
• Tired eyes
• Fluctuating vision between blinks
• The frequent need to blink, close, or rub their eyes
• Stinging, grittiness, or burning of the eyes
• A sticky, filmy sensation of the eyelids

Alternatively, you may feel none of the above, but now that we’ve got you wondering, you went for an eye exam where your eye doctor may have found:

• A thin and uneven tear film covering the surface of the eye
• Blocked sebaceous glands of the eyelids, which refused to secrete their oils even when gently squeezed, or did secrete oils that were of a poor quality
• Reduced production of the watery, aqueous layer of the tear film, measured by using small strips of paper or string hung over the eyelids to absorb the fluid
• An accumulation of dandruff-like flakes accompanied by bacteria around your eyelashes, known as anterior blepharitis
• Signs of inflammation of the eye, including redness and a tear film with excess salt content (a hyperosmolar tear film)
• A tear film that evaporates quickly into the environment between blinks
• Evidence of a desiccated ocular surface by highlighting damaged cells with various dyes

Treatment for Dry Eye Disease

Treatment for dry eye is commonly through lubricating eye drops, also known as tear supplements or artificial tears. Although the formulation of such drops has evolved over the years to provide much better relief for dry eye symptoms, they all work on the basis of supplementing and stabilizing the existing tear film. More recently, dry eye treatments have looked to how we can actually boost the eye’s tear production rather than just adding more liquid to it from a bottle. Cyclosporin is one such available treatment, a prescription eye drop shown to enhance production of natural tears.

However, there can be reasons why an individual may be deterred from using eye drops to treat their dry eye. Patients already using frequent eye drops for other conditions, such as glaucoma, those wearing contact lenses, or people who are simply not good at aiming something at their own eye, may prefer a different method of dry eye treatment – enter, your nose.

Nasal Neurostimulation for Dry Eye

Ever accidentally (or deliberately) pull out a nose hair? The tearing that ensues should be enough to tell you that the eyes and the nose are connected. That the nose runs and gets congested after a good crying session is also testament to the fact that our nasolacrimal system – the anatomical machinery responsible for tear production and drainage – intimately connects the eyes and the nose.

The benefit of stimulating the body’s natural tear production is significant. Human tears contain over a thousand different components, all supporting the health of the eye’s surface and contributing to clear vision. Although artificial tear eye drops add moisture to the eye and many newer formulations mimic some of the compounds found in a real tear film, natural tears also contain various proteins such as growth factors and antibodies that cannot be replicated in an off-the-shelf lubricant.

Neurostimulation of the nose to treat dry eye takes advantage of the fact that the same cranial nerve, known as the trigeminal nerve, has a branch that serves both the nose and the eye. This was first explored in 2015 with the use of a handheld device that delivered tiny electrical impulses using probes inserted into the nostrils. These electrical currents stimulated the nasal nerve endings to successfully activate the various tear glands of the eye to increase their secretions, boosting the production of tears onto the eye’s surface and alleviating both the signs and symptoms of dry eye. The device was FDA-approved a few years later but production has since halted due to low patient-uptake as a result of costs.

However, this isn’t the end of the nasal neurostimulation journey. Trials are currently underway for a slightly different method of treating dry eye through the nose, this time with the use of a pharmacological nasal spray. The preservative-free spray contains a compound known as a nicotinic acetylcholine receptor agonist, which works to activate that trigeminal nerve pathway, stimulating the production of the eye’s natural tears. Results so far are promising – the spray has shown significant success at improving both signs and symptoms of patients across a range of dry eye disease, from mild to severe, and demonstrates a good safety profile. The most commonly reported adverse reaction during the study was sneezing, which was – thank goodness – considered a mild event. The biopharmaceutical company behind the nasal spray is hoping FDA-approval will allow them to launch in the US at the end of 2021.

For many people, dry eye disease can be a debilitating condition with serious impacts on quality of life and finding an effective treatment can be difficult. As our understanding of the complex condition that is dry eye grows alongside our ability to treat it, perhaps this step in the direction of nasal neurostimulation will turn out to be right on the nose.