Dry eye is a growing problem in industrialized countries and the leading cause of visual impairment. What if you could increase the production of your OWN natural tears at home with an easy to use device?
Well, what I just described is possible through something called NEUROSTIMULATION. In today’s video we’ll discuss neurostimulation for dry eye past, present and future and I’ll try to convince you why it's something you should consider if you suffer from aqueous deficient dry eye syndrome.
The theme of eye school is lifelong *eye-ducation so I always invite you to let me know what you’re learning and request videos about new topics!
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A big thanks today to Dr. Paul Karpecki. A great deal of the pathophysiology information in today's video comes from an exceptional article he wrote for Review of Optometry in 2015, and I’ll make sure to link that article in the description below.
Alright eye school pupils, let’s take a look at today’s topic: Neurostimulation, an At-home dry eye treatment you may not have heard of!
How Does Neurostimulation for Dry Eyes Work?
Neurostimulation is an activation of the nervous system for therapeutic means. You may have heard of its usage in pain management specifically related to implantable devices. Recently, neuroscience technology has emerged in the Dry Eye space that is extremely effective at helping patients produce more tears.
Scientists have discovered that the trigeminal nerve plays a critical role in ocular surface health and symptomatology.
Research shows the parasympathetic nervous system (PNS), via the trigeminal parasympathetic pathway, controls tear film homeostasis through innervation of the lacrimal functional unit (LFU), which includes the cornea, conjunctiva and the structures that secrete tear film components, such as the lacrimal glands, meibomian glands and goblet cells.1-3 The PNS can most easily be accessed through the nose (Figure 1). In fact, 34% of basal tear production is due to sensory stimulation from inhaled air through the nasal passage.4
When nasal neurostimulation hit the research scene, investigators weren’t sure if the tears generated would be quality tears. Many assumed neurostimulation would generate reflex tears, which do not have the same composition as basal tears. Others wondered if the technique would only stimulate the lacrimal glands or increase tear volume by producing aqueous without the other components needed for a healthy tear film.
Increasingly, however, the evidence suggests that nasal neurostimulation affects all parts of the LFU and increases natural, basal tearing.
By applying energy to peripheral nerves on the sides of the nose, you’re able to send a signal back to the brain and tell the lacrimal gland to produce tears, the meibomian glands to secrete meibum, and the goblet cells to produce mucin.
More About Neurostimulation Devices for Dry Eyes
TrueTear: The first prototype
The first device on the market was TrueTear (Allergan), an intranasal tear stimulator. It activates the nasolacrimal reflex by delivering small electrical currents to sensory neurons of the nasal cavity, temporarily increasing tear production. The device is designed for home use for at least two minutes and up to 30 minutes per day. Studies show that regular use for six months results in a statistically significant increase in tear production and reduction in dry eye symptoms, as well as an increase in tear meniscus height.9,10
iTear100: Current model
The noninvasive device is applied to the outside of the nose to activate the trigeminal parasympathetic pathway using a sonic frequency. Studies show a decrease in symptom scores, an increase in the baseline Schirmer score and a persistent acute tear response at 180 days. Safety and subject comfort scores to date suggest a favorable risk-benefit ratio.
Recent studies were performed using the device twice per day, 30 seconds each side, and these studies have shown an increase in tear production immediately after stimulation. An increase was also seen in Schirmer scores at each visit, measured at day 14 and day 30. As with anything, there were adverse events, but they were minimal and included a 1-2% rate of lightheadedness and/or dizziness.
Who can use it?
THe actual studies during Phase 3 of FDA looked at severe dry eye patients, but it can be used much earlier and in just about any patients with dry eye. Long term CL wearers, those with autoimmune disease and anyone who has had refractive surgery.
Contraindications: Nasal polyps, significant nose bleed history, pacemakers, metal in nasal area. Migraines
To use the device, you’ll need to look for the spot in the nose where the hard and soft parts meet. The device will buzz a bit, that’s normal. When you hit the right spot, you may feel like it is tickling your nose. I personally tend to sneeze! The goal is to use for 30 s each side but you will likely need to work up to that length of time.=
The device does require a prescription. There is no insurance coverage at this time, but you should be able to use your HSA dollars toward the device. At this time in early 2021, the cost of the initial device for 30 days is around $150 and refills each month are $50.
The Future?: Nasal spray
A nasal spray from Oyster Point Pharma is the first to tackle this pathway using a pharmacological approach. This preservative-free spray contains a nicotinic acetylcholine receptor (nAChR) agonist to stimulate the trigeminal parasympathetic pathway. nAChR receptors are found throughout the peripheral and central nervous system.
Nasal neurostimulation is an entirely different mechanism than topical medications that target inflammation, so it has the potential to be an alternative first-line therapy in eyes before significant inflammation occurs and a complementary treatment to topical drops.
There is no substitute for natural tears and a healthy, natural tear film, both of which protect and lubricate the eye, improving ocular comfort and helping to maintain consistently clear vision.
Used consistently, our current option for Neurostimulation, the “Itear 100” has been proven to reduce signs and symptoms of Dry Eye syndrome while increasing your production of basal tears. (Basal vs. Reflex vs. Emotional)
That’s it for today’s lesson! I hope you enjoyed it and learned something. Remember, learning is lifelong so make sure to stay tuned in the future by subscribing. I continually update my videos as my understanding evolves and I wouldn’t want you to miss a thing! I’ll see you next time!