title: Neurostimulation of the lacrimal nerve for enhanced tear production.
abstract: OBJECTIVE
  To design a proof-of-concept study to assess the effect of lacrimal nerve stimulation (LNS) with an implantable pulse generator (IPG) to increase aqueous tear production.
  
  
  METHODS
  Experimental animal study design of 6 Dutch Belted rabbits. Ultra high-resolution optical coherence tomography (UHR-OCT) quantified tear production by measuring the baseline tear volume of each rabbit's OD and OS. A neurostimulator was implanted adjacent to the right lacrimal nerve. After 2 minutes of LNS (100 μs, 1.6 mA, 20 Hz, 5-8 V), the tear volumes were measured with UHR-OCT. The change in tear volume was quantified and compared with the nonstimulated OS. Three rabbits underwent chronic LNS (100 μs, 1.6 mA, 10 Hz, 2 V) and their lacrimal glands were harvested for histopathologic analysis.
  
  
  RESULTS
  The UHR-OCT imaging of the OD tear volume showed a 441% average increase in tear production after LNS as a percent of baseline. After stimulation, OD had statistically significant greater increase in tear volumes than OS (p = 0.028, Wilcoxon test). Poststimulation OD tear volumes were significantly greater compared with baseline (p = 0.028, Wilcoxon test). Histopathologic examination of the lacrimal glands showed no discernible tissue damage from chronic neurostimulation. In addition, there were no gross adverse effects on the general well-being of the animals due to chronic stimulation.
  
  
  CONCLUSIONS
  LNS with an IPG appears to increase aqueous tear production. Chronic LNS showed no histopathologic lacrimal gland damage. This study suggests that LNS is a promising new treatment strategy to increase aqueous tear production.
authors.affiliation: *Byers Eye Institute, Stanford University School of Medicine, Palo Alto, California; and †Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, St. Miami, Florida, U.S.A.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Kossler
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: William
authors.initials: W
authors.lastname: Feuer
authors.forename: David T
authors.initials: DT
authors.lastname: Tse
mesh_terms: D000818:Animals; D004599:Electric Stimulation Therapy; D004567:Electrodes, Implanted; D007765:Lacrimal Apparatus / Q000294:innervation*; D009424:Nervous System Physiological Phenomena; D009882:Ophthalmic Nerve / Q000502:physiology*; D011817:Rabbits; D013666:Tears / Q000737:chemistry / Q000378:metabolism*; D041623:Tomography, Optical Coherence