Stimulating Tear Production: Spotlight on Neurostimulation

Michael D Yu,1 Ji Kwan Park,2 Andrea L Kossler1 1Oculoplastic Surgery and Orbital Oncology Service, Byers Eye Institute, Stanford University, Palo Alto, CA, USA; 2Oculofacial Plastic and Orbital Surgery, Indianapolis, IN, USACorrespondence: Andrea L KosslerOculoplastic Surgery and Orbital Oncology Service, Byers Eye Institute, Stanford University, 2452 Watson Ct, Palo Alto, CA 94303, USATel +1 650-724-0105Email akossler@stanford.eduAbstract: Dry eye disease (DED) affects up to one-third of the global population. Traditional therapies, including topical lubricants, have been employed with variable success in the treatment of DED. Recently, neurostimulation of the lacrimal functional unit (LFU) has emerged as a promising alternative therapy for DED. In this review, we describe the neuroanatomical and pathophysiological considerations of DED and the LFU that make neurostimulation a viable therapeutic alternative. We further detail the various neurostimulatory approaches taken thus far—from implanted stimulators to external devices to chemical neurostimulation. Existing studies reveal the strengths of the neurostimulatory approach in increasing tear volume and improving dry eye symptoms, but further studies are needed to elucidate its true potential in treatment of DED.Keywords: oculoplastics, ocular surface, cornea, lacrimal gland, dry eye disease, tears, neurostimulation