title: [Utilization of a new night vision enhancement device (DAVIS)].
abstract: METHODS
  Following complete ophthalmologic examination 37 patients with night blindness due to Retinitis Pigmentosa (sometimes Usher-Syndrome) and Choroideremia (n = 3) performed several tests with DAVIS during darkness. We evaluated the improvement of visual function on a special outside course in the city of Heidelberg (duration 1.5 to 4 hours).
  
  
  RESULTS
  Twenty six of the patients were able to better recognize obstacles, 28 could see objects which were not seen without DAVIS. Twenty two of the 37 patients would use the DAVIS. Patients needed a visual acuity of more than 0.1 and more than 6 degree of central visual field to experience improvement with DAVIS. However, in patients with only minimal changes of the visual field, the restriction due to the presence of the device was a drawback. Sudden occurrence of light sources leads to blinding and limits the indoor use.
  
  
  CONCLUSIONS
  DAVIS enhances contrast acuity especially during night and twilight. This leads to improvement of orientation due to better recognition of obstacles and allows rehabilitation of patients with night blindness for outdoor mobility. Individual test and adjustment of DAVIS is necessary to allow exact and adequate prescription.
authors.affiliation: Augenklinik der Ruprecht-Karls-Universität Heidelberg. Klaus_Rohrschneider@med.uni-heidelberg.de
authors.forename: K
authors.initials: K
authors.lastname: Rohrschneider
authors.forename: U
authors.initials: U
authors.lastname: Spandau
authors.forename: S
authors.initials: S
authors.lastname: Wechsler
authors.forename: A
authors.initials: A
authors.lastname: Blankenagel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D015794:Choroideremia / Q000150:complications; D015350:Contrast Sensitivity; D005139:Eyeglasses; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009755:Night Blindness / Q000209:etiology / Q000534:rehabilitation*; D017060:Patient Satisfaction; D012174:Retinitis Pigmentosa / Q000150:complications; D013577:Syndrome; D014792:Visual Acuity; D058609:Visual Field Tests; D019987:Persons with Visual Disabilities / Q000534:rehabilitation*