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SUMMARY:Ophthalmic electro-neural Iinterfaces: from photovoltaic restorati
 on of sight to dry eye therapy
DTSTART:20170630T133000
DTEND:20170630T150000
DTSTAMP:20260920T164840Z
UID:9d0dcb290442e54e881cb00d8b9c3fc57a195171d9d060bde18b4fdd
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Daniel Palanker Stanford University Department of Ophtha
 lmology and Hansen Experimental Physics Laboratory\nNeurons mediate majori
 ty of the body functions\, from sensory input\, to secretion\, cognition\,
  and muscle control. Electrical control of neural signaling can help resto
 re damaged organs and body functions. I will review two examples of electr
 o-neural interfaces in applications to treatment of ocular diseases: retin
 al degeneration and dry eye syndrome.\n\nRetinal degenerative diseases lea
 d to blindness due to loss of the “image capturing” photoreceptors\, w
 hile neurons in the “image-processing” inner retinal layers are relati
 vely well preserved. Information can be reintroduced into the visual syste
 m using electrical stimulation of the surviving inner retinal neurons. Som
 e electronic retinal prosthetic systems have been already approved for cli
 nical use\, but they provide low resolution and involve very difficult imp
 lantation procedures. \n\nWe developed a photovoltaic subretinal prosthes
 is which converts light into pulsed electric current\, stimulating the nea
 rby inner retinal neurons. Visual information is projected onto the retina
  by video goggles using pulsed near-infrared (~880nm) light. This design a
 voids the use of bulky electronics and wiring\, thereby greatly reducing t
 he surgical complexity. Optical activation of the photovoltaic pixels allo
 ws scaling the implants to thousands of electrodes\, and multiple modules 
 can be tiled under the retina to expand the visual field.\n\nWe found that
  similarly to normal vision\, retinal response to prosthetic stimulation e
 xhibits flicker fusion at high frequencies (>20 Hz)\, adaptation to static
  images\, antagonistic center-surround organization and non-linear summati
 on of subunits in the receptive fields\, providing high spatial resolution
 . Photovoltaic arrays with 70?m pixels restored visual acuity up to a sing
 le pixel pitch\, which is only two times lower than natural acuity in rats
 . If these results translate to human retina\, such implants could restore
  visual acuity up to 20/250. Higher resolution arrays (40?m pixels)\, whic
 h are currently being tested\, may provide acuity up to 20/140. Ease of im
 plantation and tiling of these wireless modules to cover a large visual fi
 eld\, combined with high resolution opens the door to highly functional re
 storation of sight.\n\nTear film maintains a clear optical path and smooth
  refractive surface\, protects the eye against environmental conditions\, 
 infections\, facilitates nutrient transport\, and carries away cellular de
 bris. Decreased aqueous or lipid secretion lead to dry eye and ocular surf
 ace disease\, which may result in a significant loss of vision.\n\nElectri
 cal stimulation of the efferent fibers controlling the lacrimal gland can 
 enhance aqueous secretion by about 50%. Stimulation of the afferent nerves
  (anterior ethmoid nerve) activates all components of the lacrimal system\
 , which increased tear volume by as much as 130%\, resulting in reduced te
 ar osmolarity. It also added lipid\, increased the concentration of normal
  lacrimal gland proteins\, and induced release of mucin\, which is respons
 ible for stabilization of the tear film on corneal surface. Clinical trial
 s with intranasal neurostimulator demonstrated significant improvements in
  subjective symptoms and objective measures of the corneal health in patie
 nts with dry eye disease. Recent approval of this system (TrueTearTM\, All
 ergan) for clinical use will allow exploring its efficacy in patients with
  various forms of dry eye disease. \n \nBio: Daniel Palanker is a Profes
 sor in the Department of Ophthalmology and Director of the Hansen Experime
 ntal Physics Laboratory at Stanford University. He received MSc in Physics
  in 1984 from the Yerevan State University in Armenia\, and PhD in Applied
  Physics in 1994 from the Hebrew University of Jerusalem\, Israel. \n\nDr
 . Palanker studies interactions of electric field with biological cells an
 d tissues\, and develops optical and electronic technologies for diagnosti
 c\, therapeutic\, surgical and prosthetic applications\, primarily in opht
 halmology. These studies include laser-tissue interactions with applicatio
 ns to ocular therapy and surgery\, and interferometric detection of neural
  signals. In the field of electro-neural interfaces\, Dr. Palanker is deve
 loping retinal prosthesis for restoration of sight to the blind and implan
 ts for electronic control of secretory glands and blood vessels.\n\nSevera
 l of his developments are in clinical practice world-wide: Pulsed Electron
  Avalanche Knife (PEAK PlasmaBlade\, Medtronic)\, Patterned Scanning Laser
  Photocoagulator (PASCAL\, Topcon)\, and OCT-guided Laser System for Catar
 act Surgery (Catalys\, AMO). Several others are in clinical trials: Gene t
 herapy of the retinal pigment epithelium (Ocular BioFactory\, Adverum Biot
 echnologies Inc)\; Neural stimulation for enhanced tear secretion (TrueTea
 r\, Allergan Inc.)\; Smartphone-based ophthalmic diagnostics and monitorin
 g (Paxos\, DigiSight Inc.).\n 
LOCATION:SV 1717 https://plan.epfl.ch/?room==SV%201717
STATUS:CONFIRMED
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