Purpose:
To compare electroretinogram (ERG) responses to full-field stimuli recorded with microfiber electrode prototype, DTL® and contact lens electrodes (Burian-Allen) in patients with retinal dystrophy.
Methods:
Right eye of 50 patients with previously diagnosed retinal dystrophy had full-field ERG recorded (ISCEV standard full-field protocol) using three distinct types of electrodes in three consecutive visits in the same week. Subjects were aged 10-76 years (36.0±16.9 years, 26 females). VERIS 5.1.9 system was used for data acquisition and analysis. ERG outcomes were analyzed by Kruskal-Wallis test and multiple comparison procedures by Dunnett’s method. Retinal dystrophy type was classified on the basis of standard clinical criteria as: retinitis pigmentosa, cone dystrophy, Stargardt’s disease and others. ERG responses were compared with normative data from our own lab.
Results:
The specific type of ERG abnormality was consistent with clinical findings in all tested patients. Median values amplitudes and b-wave implicit time for both scotoptic and photopic responses using the three types of electrodes are shown in the following table. Waveform morphology of rod and cone electrodes responses were similar to those obtained with the three types of electrodes. There was a trend for larger amplitudes using Burian-Allen when compared to either the microfiber electrode prototype or DTL® for rod, maximal, cone and 30Hz flicker responses. No statistical differences were found for amplitude and implicit time among microfiber electrode prototype, DTL® and Burian-Allen for all ISCEV responses.
Conclusions:
ERGs were successfully recorded using these three types of electrodes in patients with retinal dystrophies. microfiber electrode prototype electrodes were validated as a diagnostic tool since its results were comparable to the other two types of electrodes. Therefore, this new instrument is an alternative method to assess retinal function and might be a feasible choice for ERG recordings especially in patients with abnormalities in the ocular surface and uncooperative/sensitive patients.
Keywords: electroretinography: clinical • electrophysiology: clinical • retina