title: Comparison between fullfield electroretinography obtained from handheld and tabletop devices in normal subjects.
abstract: OBJECTIVE
  To compare full-field electroretinography (ERG) parameters obtained from Ephios handheld and VERIS tabletop ERG devices in normal subjects for interchangeable usability and reliability.
  
  
  METHODS
  Comparison study.
  
  
  METHODS
  Comparison of full-field ERG between two devices for 57 normal subjects.
  
  
  METHODS
  ERG was recorded for 57 normal subjects using tabletop device (VERIS 5.2.2X; Electro-Diagnostic Imaging Inc, San Mateo, Calif.) and handheld ERG device (Ephios handheld portable ERG system; ephios ab; Teknikringen, Linkoping, Sweden). Bland-Altman plot was done to measure the agreement between the 2 devices. Intraclass correlation coefficient (ICC) was calculated for amplitudes, implicit times, and b/a ratio to assess the reliability. Coefficient of variation (CV = 100 × [standard deviation/mean]) with 95% CI was calculated to measure the variability between the devices. Wilcoxon sign rank test was used to assess the repeatability of the Ephios handheld device.
  
  
  RESULTS
  The mean a-wave and b-wave amplitudes of dark-adapted 3.0 ERG for the tabletop were 220.3 ± 52.6 and 471.5 ± 84.3 μV, respectively, whereas the mean a-wave and b-wave amplitudes in the same scotopic setting for the handheld device were 152.6 ± 34.2 and 379.7 ± 75.9 μV, respectively. The values represent mean ± standard deviation. The ICC of b/a ratio was 0.660 between the devices. The amplitudes CV of tabletop and handheld ERG devices ranged from 17.9% to 29.1% and from 22.4% to 30.1%, respectively.
  
  
  CONCLUSIONS
  The pattern of waveform of the Ephios handheld device is similar to the VERIS tabletop device. The ERG parameters showed variability between the 2 devices. Hence Ephios handheld ERG device can be used along with its normative data for measuring ERG. Because of variability, the devices cannot be used interchangeably.
authors: Optometrist, Department of Optometry.
authors: Ramya
authors: R
authors: Sachidanandam
authors: Departments of †?>Ocular Oncology.
authors: Vikas
authors: V
authors: Khetan
authors: Vitreoretina Medical Research Foundation, Nungambakkam, Chennai, Tamil Nadu, India. Electronic address: parveensen@gmail.com.
authors: Parveen
authors: P
authors: Sen
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003623:Dark Adaptation; D004596:Electroretinography / Q000295:instrumentation* / Q000379:methods; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012160:Retina / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult