Description of Establishing Mobility Measures to Assess the Effectiveness of Night Vision Devices: Results of a Pilot Study
In addition to their restricted peripheral fields, persons with retinitis pigmentosa (RP) report significant problems seeing in low levels of illumination, which causes difficulty with night travel (Turano, Geruschat, Stahl, & Massof, 1999). Several devices have been developed to support the visual needs of persons who have night blindness. These devices include wide-angle flashlights (Morrissette, Marmor, & Goodrich, 1983), adapted military light-intensifier devices (Berson, Mehaffey, & Rabin, 1974), and systems that use high-sensitivity (or infrared-sensitive) video cameras (Friedburg, Serey, Sharpe, Trauzettel-Klosinski, & Zrenner, 1999; Hartong, Jorritsma, Neve, Melis-Dankers, & Kooijman, 2004; Spandau, Wechsler, & Blankenagel, 2002). New devices are also in development, including the Minified Augmented-View device, which incorporates expansion of the visual field, along with the enhancement of night vision, to address both the field and night vision needs of persons with RP (Bowers, Luo, Rensing, & Peli, 2004; Peli, 2001).