[Visual acuity and full-field electroretinography in patients with Usher's syndrome].
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.
Mendieta
Luana
L
Departamento de Oftalmologia, Universidade Federal de São Paulo, São Paulo, SP. lmendieta@oftalmo.epm.br
Berezovsky
Adriana
A
Salomão
Solange Rios
SR
Sacai
Paula Yuri
PY
Pereira
Josenilson Martins
JM
Fantini
Sérgio Costa
SC
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*