title: [Visual acuity and full-field electroretinography in patients with Usher's syndrome].
abstract: OBJECTIVE
  Usher's syndrome (US) is a group of genetically distinct autosomal conditions, characterized by sensorineural hearing loss accompanied by a retinal dystrophy indistinguishable from retinitis pigmentosa (RP). The purpose of this study was to analyze full-field electroretinography (ERG) and visual acuity (VA) among patients with type I and II Usher's syndrome.
  
  
  METHODS
  Electroretinography responses and visual acuity were studied in 22 patients (mean age at test = 26.8+/-16.8 years). Seventeen patients had SU type I and 5 patients were diagnosed as Usher's syndrome type II.
  
  
  RESULTS
  Mean visual acuity was 0.9 logMAR (20/160, Snellen equivalent) for patients with Usher's syndrome type I and 0.4 logMAR (20/50, Snellen equivalent) for patients with Usher's syndrome type II. Scotopic rod and maximal responses were non-detectable in both groups. Mean amplitude for oscillatory potentials was 14.5 microV+/-6.1 in Usher's syndrome type I and 12.6 microV+/-5.2 in Usher's syndrome type II. Cone responses were non-detectable in 95% of the patients with Usher's syndrome I and in 100% of patients with Usher's syndrome II. Mean amplitude for 30 Hz flicker photopic cone response was 3.1 microV+/-4.1 for Usher's syndrome type I and 1.0 microV+/-0.6 for type II with mean implicit time of 34.0 ms+/-6.2 (US I) and 35.8 ms+/-3.1 (type II).
  
  
  CONCLUSIONS
  Visual acuity was relatively preserved in both groups, however Usher's syndrome II group showed better visual acuity results. Electroretinography findings were severely reduced in both groups, with most patients showing non-detectable rod and cone responses.
authors.affiliation: Departamento de Oftalmologia, Universidade Federal de São Paulo, São Paulo, SP. lmendieta@oftalmo.epm.br
authors.forename: Luana
authors.initials: L
authors.lastname: Mendieta
authors.forename: Adriana
authors.initials: A
authors.lastname: Berezovsky
authors.forename: Solange Rios
authors.initials: SR
authors.lastname: Salomão
authors.forename: Paula Yuri
authors.initials: PY
authors.lastname: Sacai
authors.forename: Josenilson Martins
authors.initials: JM
authors.lastname: Pereira
authors.forename: Sérgio Costa
authors.initials: SC
authors.lastname: Fantini
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004596:Electroretinography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020419:Photoreceptor Cells, Vertebrate / Q000502:physiology; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D052245:Usher Syndromes / Q000175:diagnosis / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*