Advertisement

Facilitating the analysis of the multifocal electroretinogram using the free software environment R

Abstract

Purpose

The large amount of data rendered by the multifocal electroretinogram (mfERG) can be analyzed and visualized in various ways. The evaluation and comparison of more than one examination is time-consuming and prone to create errors. Using the free software environment R we developed a solution to average the data of multiple examinations and to allow a comparison of different patient groups.

Methods

Data of single mfERG recordings as exported in .csv format from a RETIport 21 system (version 7/03, Roland Consult) or manually compiled .csv files are the basis for the calculations. The R software extracts response densities and implicit times of N1 and P1 for the sum response, each ring eccentricity, and each single hexagon. Averages can be calculated for as many subjects as needed. The mentioned parameters can then be compared to another group of patients or healthy subjects. Application of the software is illustrated by comparing 11 patients with chloroquine maculopathy to a control group of 7 healthy subjects.

Results

The software scripts display response density and implicit time 3D plots of each examination as well as of the group averages. Differences of the group averages are presented as 3D and grayscale 2D plots. Both groups are compared using the t-test with Bonferroni correction. The group comparison is furthermore illustrated by the average waveforms and by boxplots of each eccentricity.

Conclusions

This software solution on the basis of the programming language R facilitates the clinical and scientific use of the mfERG and aids in interpretation and analysis.

Post author correction

Article Type: ORIGINAL RESEARCH ARTICLE

Article Subject: Retina MED

DOI:10.5301/ejo.5001018

Authors

Richard Bergholz, Mirjam Rossel, Ralf M. Dutescu, Klaas P. Vöge, Daniel J. Salchow

Article History

Disclosures

Financial support: No financial support was received for this submission.
Conflict of interest: None of the authors has conflict of interest with this submission.

This article is available as full text PDF.

  • If you are a Subscriber, please log in now.

  • Article price: Eur 36,00
  • You will be granted access to the article for 72 hours and you will be able to download any format (PDF or ePUB). The article will be available in your login area under "My PayPerView". You will need to register a new account (unless you already own an account with this journal), and you will be guided through our online shop. Online purchases are paid by Credit Card through PayPal.
  • If you are not a Subscriber you may:
  • Subscribe to this journal
  • Unlimited access to all our archives, 24 hour a day, every day of the week.

Authors

Affiliations

  •  Department of Ophthalmology, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin - Germany
  •  Department of Ophthalmology, RWTH Aachen University, Aachen - Germany
  •  Department of Oral and Maxillofacial Surgery, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin - Germany

Article usage statistics

The blue line displays unique views in the time frame indicated.
The yellow line displays unique downloads.
Views and downloads are counted only once per session.

This article has supplementary materials available to download.

  • If you are a Subscriber, please log in now.

  • Article price: Eur 36,00
  • You will be granted access to the article for 72 hours and you will be able to download any format (PDF or ePUB). The article will be available in your login area under "My PayPerView". You will need to register a new account (unless you already own an account with this journal), and you will be guided through our online shop. Online purchases are paid by Credit Card through PayPal.
  • If you are not a Subscriber you may:
  • Subscribe to this journal
  • Unlimited access to all our archives, 24 hour a day, every day of the week.