Nicotinic acetylcholine receptor stimulation: A new approach for stimulating tear secretion in dry eye disease☆
Section snippets
Search strategy and eligibility criteria
The authors conducted a keyword search on PubMed on trigeminal nerve, dry eye, and the combination of the two. We relied heavily on the authors' previously published papers, chapters/books, and courses on anatomy as this is an anatomic review more so than a literature review. We did conduct a separate PubMed search for varenicline and dry eye (so as not to be inundated with published literature that concentrated on the drug's smoking cessation indication). That former search was conducted from
The lacrimal functional unit regulates tear secretion
The LFU consists of the ocular surface (cornea, conjunctiva, meibomian glands, and accessory lacrimal glands), the main lacrimal glands, and the neural network that monitor the ocular surface environment and regulate tear secretion [3]. Through integration of the neural and glandular components, the LFU maintains tear film stability and ocular surface homeostasis by controlling secretion, distribution, and clearance of tear components to meet the demands of the ocular surface [3,4].
A stable
Disease and dysfunction of the LFU
If the LFU is compromised, inflammation can occur at the level of the ocular surface and lacrimal glands along with a loss of homeostasis [7]. Degeneration of the epithelial nerve terminals and subbasal plexus can reduce the sensory drive of the LFU. Degeneration and reduced sensitivity of the corneal nociceptors can also occur with chronic aqueous tear deficiency (ATD) [50]. Nociceptors are sensory receptors that signal the location, size, intensity, and duration of noxious stimuli or tissue
Treatment of dry eye via trigeminal stimulation
Because parasympathetic nerves stimulate tear secretion by the LFU, this neural pathway has been suggested as a therapeutic target to re-establish tear film homeostasis [30,38,55]. The nasolacrimal neural pathway is involved in transmitting signals from mechanical and chemical stimuli to promote natural tearing [30]. The literature suggests intranasal electrical/neurostimulation of the anterior ethmoid nerve can reduce dry eye symptoms by increasing aqueous tear secretion and tear volume as
Conflicts of interest and source of funding
SCP, AG, KKN, and NC are consultants to Oyster Point Pharmaceuticals. AC and MD have no financial disclosures. Oyster Point Pharmaceuticals provided financial support for this manuscript.
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2024, Contact Lens and Anterior EyeMaximal tear secretion evoked by controlled stimulation of corneal sensory nerves in healthy individuals and dry eye subjects
2023, Ocular SurfaceCitation Excerpt :These neurons process sensory information and they regulate lacrimation through their connections in the superior salivatory nucleus [11]. In turn, they activate peripheral parasympathetic and some sympathetic ganglion neurons of the pterygopalatine and superior cervical ganglia, respectively, stimulating tear secretion by the main and accessory lacrimal glands [12,13]. Dry eye disease (DED) is a multifactorial disease of the ocular surface characterized by a loss of tear film homeostasis and other symptoms [14].
Efficacy of intense pulsed light therapy on signs and symptoms of dry eye disease: A meta.analysis and systematic review
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Portions of this manuscript were presented at the American Academy of Optometry (2021), the American Academy of Ophthalmology (2021) and EyeCon (2021) as part of continuing medical education events.