title: Randomized crossover clinical trial of real and sham peripheral prism glasses for hemianopia.
abstract: OBJECTIVE
  There is a major lack of randomized controlled clinical trials evaluating the efficacy of prismatic treatments for hemianopia. Evidence for their effectiveness is mostly based on anecdotal case reports and open-label evaluations without a control condition.
  
  
  OBJECTIVE
  To evaluate the efficacy of real relative to sham peripheral prism glasses for patients with complete homonymous hemianopia.
  
  
  METHODS
  Double-masked, randomized crossover trial at 13 study sites, including the Peli laboratory at Schepens Eye Research Institute, 11 vision rehabilitation clinics in the United States, and 1 in the United Kingdom. Patients were 18 years or older with complete homonymous hemianopia for at least 3 months and without visual neglect or significant cognitive decline.
  
  
  METHODS
  Patients were allocated by minimization into 2 groups. One group received real (57-prism diopter) oblique and sham (<5-prism diopter) horizontal prisms; the other received real horizontal and sham oblique, in counterbalanced order. Each crossover period was 4 weeks.
  
  
  METHODS
  The primary outcome was the overall difference, across the 2 periods of the crossover, between the proportion of participants who wanted to continue with (said yes to) real prisms and the proportion who said yes to sham prisms. The secondary outcome was the difference in perceived mobility improvement between real and sham prisms.
  
  
  RESULTS
  Of 73 patients randomized, 61 completed the crossover. A significantly higher proportion said yes to real than sham prisms (64% vs 36%; odds ratio, 5.3; 95% CI, 1.8-21.0). Participants who continued wear after 6 months reported greater improvement in mobility with real than sham prisms at crossover end (P = .002); participants who discontinued wear reported no difference.
  
  
  CONCLUSIONS
  Real peripheral prism glasses were more helpful for obstacle avoidance when walking than sham glasses, with no differences between the horizontal and oblique designs. Peripheral prism glasses provide a simple and inexpensive mobility rehabilitation intervention for hemianopia.
  
  
  BACKGROUND
  clinicaltrials.gov Identifier: NCT00494676.
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Bowers
authors.affiliation: Chadwick Optical, Inc, Souderton, Philadelphia.
authors.forename: Karen
authors.initials: K
authors.lastname: Keeney
authors.affiliation: Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts.
authors.forename: Eli
authors.initials: E
authors.lastname: Peli
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005139:Eyeglasses; D005260:Female; D006423:Hemianopsia / Q000503:physiopathology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D010919:Placebos; D011474:Prosthesis Design; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D015348:Vision, Binocular / Q000502:physiology; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult
chemical_list: D010919:Placebos