Validation of a new fiber electrode prototype for clinical electroretinography.

PURPOSE To validate a new fiber electrode prototype for clinical electroretinography (ERG). METHODS A recently developed prototype of a disposable reference-coupled fiber electrode (patent pending Brazilian Institute of Industrial Property # PI0602186-7), including one fiber for corneal signals and a second fiber acting as reference was tested in a group of 20 healthy volunteers (17-31 years; mean 22.7 +/- 4.5; 8 males). Standard electroretinography rod and cone responses were recorded from a fully dilated pupil simultaneously in both eyes with a reference-coupled fiber electrode prototype in one randomly assigned eye and a DTL electrode in the other eye after 30 min of dark-adaptation. After presenting dark- and light-adapted stimuli, each response was analyzed for a- and b-wave amplitude and implicit time. The VERIS 5.1.9 system was used for electroretinography data acquisition and analysis. Electroretinography outcomes were analyzed by Mann-Whitney test. Slit-lamp examination was performed in both eyes right after electroretinography session to evaluate possible adverse effects. RESULTS Responses recorded with reference-coupled fiber electrode prototypes were comparable to commercially available DTL fiber electrodes. On a qualitative analysis, reference-coupled fiber electrodes provided recordings with less amount of noise. On average, scotopic electroretinography amplitude and b-wave implicit time recorded using DTL were, respectively, 287.6 microV and 36.3 ms with similar findings for the reference-coupled fiber electrode prototype (287.9 microV and 36.3 ms). Under photopic conditions DTL mean amplitude and implicit time were, respectively 108.9 microV and 24.5 ms with similar results for the reference-coupled fiber electrodes prototypes (116.4 microV and 24.5 ms). No corneal abrasions or any other significant adverse effects were found after electroretinography recording with both electrodes. CONCLUSIONS The reference-coupled fiber electrode prototype provided stable and safe recordings of corneal electroretinograms compared to the commercially availabe DTL electrode in healthy human subjects. The prototype is a feasible alternative instrument for clinical electroretinography recording to assess retinal function, however further analysis is recommended to validate its clinical usefulness in patients with retinal disorders.