A novel validation trial suggests that an intranasal neurostimulation device (TrueTear Intranasal Tear Stimulator, Allergan), approved by the FDA earlier this year, could be a useful treatment for dry eye disease. The device stimulates the production of tears that can return the ocular surface to a more normal condition.
“[The product] demonstrated increased endogenous tear production upon stimulation of the nasal cavity,” said John Sheppard, MD, MMSc.
“It looks like [the treatment]is appropriate for any patient with dry eye who has a normal external nasal passageway,” said Dr. Sheppard, professor of ophthalmology, Eastern Virginia Medical School and president, Virginia Eye Consultants in Norfolk, VA. “It provides rapid amelioration of the symptoms of dry eye and a return to a more normal physiologic state.”
How it works
As the first portable, external neurostimulator to be approved in eye care, the handheld device features a reusable base with a dual-pronged replaceable tip that is inserted into the nose to contact the anterior nasal mucosa. The tip transmits a precisely timed series of low-voltage electrical pulses to the trigeminal nerve, triggering the nasolacrimal reflex to emulate the neural signals that stimulate natural tear production.
“If you eat something like jalapeno peppers, you get a brisk stimulation to the ophthalmic branch of the trigeminal nerve within the nasal cavity and produce tears,” Dr. Sheppard said.
“Normal respiratory activity stimulates this same pathway, constitutively producing normal tears,” he said. “Sensory signals are carried via afferent neurons to the brain; then efferent neurons in the parasympathetic and sympathetic nervous system carry signals back to the lacrimal functional unit (LFU).”
The treatment activates those same pathways that carry signals to the brainstem and back to the ocular surface, lacrimal glands, goblet cells, and meibomian glands to create tears.
Slicing onions and eating spicy foods can create unpleasant burning sensations as tears are produced, he added, but the intranasal device stimulates endogenous tear production without the physical irritation by emulating the afferent loop of the natural pathway. The patient can control intensity and duration of stimulation using buttons on the base of the device.