title: Longterm visual prognosis in Usher syndrome types 1 and 2.
abstract: OBJECTIVE
  To estimate the age at diagnosis of retinitis pigmentosa and to determine visual acuity deterioration, visual field impairment and the frequency of cataracts in Usher syndrome types 1 and 2.
  
  
  METHODS
  We carried out a retrospective study of 328 affected subjects with Usher syndrome types 1 and 2. Study subjects were divided into seven different age groups by decade. Data were analysed using descriptive statistics, general linear model anova and survival analysis.
  
  
  RESULTS
  Retinitis pigmentosa was diagnosed significantly earlier in subjects with Usher syndrome type 1 than in those with type 2. Visual acuity was significantly more impaired in affected subjects with Usher syndrome type 1 than in those with type 2 from 50 years of age onwards. Survival analysis revealed a significant difference in visual field loss (<or= 10 degrees) between the two groups, with type 2 subjects tending to be more impaired, while comparison indicated no significant differences between the groups in any of the other visual field categories. Cataract was found to be generally more common in Usher syndrome type 1 than type 2.
  
  
  CONCLUSIONS
  Progressive loss of visual acuity and visual field begins to be substantial between the second and third decades of life in both Usher types. The rate of degeneration varies between individuals in both groups. The data are useful for the counselling of affected subjects with Usher syndrome types 1 and 2.
authors.affiliation: Sahlgrenska Academy, Institute of Neurology and Physiology, Department of Audiology, Gothenburg, Sweden. am.sadeghi@audiology.gu.se
authors.forename: André M
authors.initials: AM
authors.lastname: Sadeghi
authors.forename: Kristina
authors.initials: K
authors.lastname: Eriksson
authors.forename: William J
authors.initials: WJ
authors.lastname: Kimberling
authors.forename: Anders
authors.initials: A
authors.lastname: Sjöström
authors.forename: Claes
authors.initials: C
authors.lastname: Möller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002386:Cataract / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012174:Retinitis Pigmentosa / Q000175:diagnosis* / Q000503:physiopathology; D012189:Retrospective Studies; D052245:Usher Syndromes / Q000175:diagnosis* / Q000503:physiopathology; D014786:Vision Disorders / Q000175:diagnosis* / Q000503:physiopathology; D014792:Visual Acuity; D014794:Visual Fields