title: A fast automated method for calculating the EOG Arden ratio.
abstract: BACKGROUND
  Recording of the dark trough/light peak of the electrooculogram (EOG) remains a useful electrodiagnostic tool. Manual analysis of the recording is tedious and lengthy, and automated analysis needs to deal with artefacts due to suboptimal patient cooperation.
  
  
  METHODS
  We present a novel method of automating the processing and analysis of raw EOG data using the open-source statistical software R. Rather than attempting saccade detection, we utilize the fact that basic properties of the response (rough waveform timing) are known and simply fit a square wave to each response run-free parameters are amplitude and phase. To assess this analysis method, responses from 54 eyes of 27 patients with a variety of ophthalmic diagnoses were analysed with manual calculation and with a number of automated methods of fitting the response curve. The Arden ratio was the main outcome measure.
  
  
  RESULTS
  Robust regression of a fundamental with a three-harmonic approximation of a square wave was found to be the best method. Classification accuracy with this method compared with the manual calculations as gold standard; using a lower normal threshold of 200%, Arden ratio was found to achieve a sensitivity of 96% and specificity of 81%. Time taken to process and analyse the data for a subject was reduced from 20 min for the manual method to 2 min for the automated method.
  
  
  CONCLUSIONS
  The simple approach yielded a surprisingly effective automatic estimation of the Arden ratio. In one author's laboratory (MB), this procedure has proved to be useful over 5 years for routine analysis.
authors.affiliation: Centre for Eye Research Australia, Melbourne, Australia, marc.sarossy@eyeandear.org.au.
authors.forename: Marc G
authors.initials: MG
authors.lastname: Sarossy
authors.forename: Matthew H A
authors.initials: MH
authors.lastname: Lee
authors.forename: Michael
authors.initials: M
authors.lastname: Bach
mesh_terms: D004585:Electrooculography / Q000379:methods*; D006801:Humans; D008027:Light; D015233:Models, Statistical; D055213:Retinal Pigment Epithelium / Q000502:physiology*; D012189:Retrospective Studies