Electroretinography using a fiber electrode prototype in patients with retinal dystrophy

Abstract

Purpose: To compare full-field electroretinogram (ERG) responses recorded in patients with retinal dystrophy with monopolar DTL® electrode to those obtained with a microfiber electrode prototype, using the ERG standards of the International Society for the Clinical Electrophysiology of Vision (ISCEV).

Methods: This study was approved by the Ethics Committee of the Federal University of São Paulo (1087/08). Fifty six patients (mean age 36.8±16.9 years, 29 females) with previously diagnosed retinal dystrophy had full-field ERG recorded (ISCEV standard full-field protocol) using two distinct electrodes randomly selected in two consecutive visits in the same week. VERIS 5.1.9 system by EDI was used for data acquisition and analysis. ERG outcomes were analyzed by independent linear regression method by StataSE 11 statistical software. Retinal dystrophy type was classified on the basis of standard clinical criteria as: retinitis pigmentosa, cone dystrophy, Stargardt’s disease, Cone-rod dystrophy and others. ERG responses were compared with normative data from our own lab.

Results: The magnitude and waveform quality obtained with the two electrodes were similar for all ERG responses. No statistical differences were found for amplitude and implicit time between microfiber electrode prototype and DTL® responses. Linear regression showed a trend line equation for rod amplitude response (DTL=6.01+1.070 *prototype) and for cone amplitude (DTL=-0.90+1.100*prototype).

Conclusions: The results showed that the ERG waveforms obtained with the two electrode types were remarkably similar for all ERG responses. The microfiber electrode prototype might be a choice for low-cost alternative instrument for clinical ERG recording for retinal function assessment.

Keywords: 509 electroretinography: clinical • 702 retinitis