April 2019

CORNEA

Research Highlight
Use of intranasal tear stimulation


by Maxine Lipner EyeWorld Senior Contributing Writer


Proper use of the TrueTear neurostimulator
Source: John Sheppard, MD

 

For those with dry eye disease, an intranasal tear stimulation device can help to produce a significant amount of tears, according to the results of a study1 published in The Ocular Surface, reported John Sheppard, MD. A second study also indicated that with continued usage, the result did not wear off, he said.
The TrueTear neurostimulator (Allergan) is the brain child of Michael Ackerman, PhD, who initially developed a tear stimulating device that was placed directly into the lacrimal gland area. Many ophthalmologists were averse to this earlier prototype. Dr. Ackerman later hit upon the idea of placing an external neurostimulation device inside the nose. “The nerves in the superior nasal mucosa are the same ones that innervate the tear production apparatus,” Dr. Sheppard said.
The two-pronged device is placed into both nares simultaneously, thereby accessing the anterior ethmoidal nerve. This nerve triggers natural tear stimulation during normal respiration. “This emulates the normal physiological neurological control mechanisms for producing the tri-partite tear film,” Dr. Sheppard said, adding that it stimulates a tear containing water, lipid, and mucin in normal ratios but in higher volumes. “The eye and trigeminal nerve can be trained to do just that better and better with repeated neurostimulation,” he said.

Investigating TrueTear

In one of the studies described in the paper, investigators wanted to make sure that the combination of the micro-voltages and the location in the nasal mucosa upon the ethmoidal nerve in a patient with dry eye was the optimal admixture of conditions needed to create a useful clinical response, Dr. Sheppard noted.
Three different applications of the TrueTear device were tried, each in the same patient. This was done in random sequence for 48 subjects. “One format was the real one approved by the FDA, and it involved putting the prongs all the way up to the anterior ethmoidal nerve at the anterior nasal mucosa and actuating the custom programmed randomized current,” he said. “In another variation, we put the normal current onto the lip.” In the third go-round, the researchers took a nonactivated electrically charged sham prong and put it in the nose but gave it no current. “I think this clinical study comparator in three different scenarios in the same patient proved that it was the combination of the location and the current that produced the desired physiologic response,” Dr. Sheppard said.
Investigators determined that while the mean Schirmer’s test for those in the two control groups only measured 9 mm, for those treated with the device in the right location and triggered with the current, tear production with the test measured 25+ mm.
The second study was a 6-month trial that examined neurostimulation users chronically to look for tachyphylaxis. The effect did not wear off. Although after an intense start tear production leveled out somewhat early on, with up to 6 months of consistent use, patients maintained the same positive effect. “They developed no tachyphylaxis, and they showed continuous maintenance of the improved tear film,” Dr. Sheppard said.

Clinical applications

Dr. Sheppard views the device as one that could be applicable to all dry eye patients because they all have different components in varying proportions triggering their tear insufficiency. “I think all patients have at least some part of each of the components, but in different ratios,” he said, adding that TrueTear addresses compromised neurophysiological control of potentially normal tear production for the first time. In particular, this may be an option for those who have not responded well to other treatments or who want to minimize or do away with drops. “You can use it when other treatments have either failed or are not acceptable for the patient,” Dr. Sheppard said. “Major exceptions to recommendation include patients with severe tremors, cardiac pacemakers, nasal septum deviation, nasal polyps, or a history of recurrent epistaxis.”
The TrueTear treatment is likely to be synergistic with all of the currently available modes of therapy, Dr. Sheppard pointed out, adding that it has a unique mode of action, “ providing a drop-free, surgery-free intervention that is completely directed and regulated by the patients themselves,” he said. “This creates a new niche for the treatment of moderate to severe dry eye.”

About the doctor
John Sheppard, MD

President
Virginia Eye Consultants
Norfolk, Virginia

Reference

1. Sheppard JD, et al. Characterization of tear production in subjects with dry eye disease during intranasal tear neurostimulation: Results from two pivotal clinical trials. Ocul Surf. 2019;17:142–150.

Financial interests
Sheppard
: Allergan

Contact information
Sheppard
: jsheppard@vec2020.com

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