Comparison Between Dawson, Trick, and Litzkow Electrode and Contact Lens Electrodes Used in Clinical Electroretinography

Abstract

Purpose: To determine the reliability of the Dawson, Trick, and Litzkow (DTL) electrode in electroretinographic recordings (ERG) in subjects of all ages, we evaluated ERG responses obtained with the contact lens (CL) and DTL electrodes and estimated a DTL/CL ratio for each sample. Methods: Seventy-nine volunteers aged 2–84 years (79 normal eyes) were recruited for the study. Electroretinographic recordings elicited by monocular single-flash stimuli delivered by an automatic ERG recording system were recorded using both CL and the DTL electrodes (CL-ERG and DTL-ERG, respectively). Results: The relative amplitude of the DTL-ERG to the CL-ERG was 79.6–99.8% (mean = 93.4%) for the a-wave and 84.4–106.3% (mean = 92.3%) for the b-wave. The relative latency of the DTL-ERG to the CL-ERG was 86.0–107.6% (mean = 98.2%) for the a-wave and 96.1–113.0% (mean = 97.9%) for the b-wave. The a- and b-wave amplitudes differed significantly between DTL and CL electrodes only in the 40- to 49-year-old age groups ( P < .05). Regression analysis indicated moderate to strong relationships between the electrodes for amplitude (a-wave, r = 0.690; b-wave, r = 0.824) and latency (a-wave, r = 0.667; b-wave, r = 0.725). Conclusion: The DTL electrode has as high stability as the conventional CL electrodes for ERG recordings in most age groups.