Multi-Electrode Electroretinography: Measuring Spatial Differences in Corneal Potentials

In degenerative eye diseases like glaucoma, diabetic retinopathy and macular degeneration, it is important to detect and diagnose the disease in early stages so that treatment can be initiated to stop or slow down the progressive and irreversible vision loss. In early stages, damage to the retina due to disease or trauma is usually localized, hence assessment of local retinal function is important. In this work a novel technique was developed and its ability in detecting localized retinal damage was evaluated. A Contact Lens Electrode Array (CLEAr Lens) was employed to record 25 ERG waveforms from 25 locations on the cornea of a rat simultaneously. This technique is referred to as multi-electrode electroretinograpghy (meERG). meERG responses were recorded from healthy rat eyes (26 animals) and eyes with central (4 animals) and peripheral (9 animals) experimental lesions. Data analysis methods were developed to extract the maximum amount of information from the recorded waveforms. A cluster analysis was performed to separate healthy animals from lesioned animals. The sensitivity and specificity of meERG are compared with those of conventional ERG. The area under the receiver operative characteristic (ROC) curve for meERG was calculated to be 80%. This analysis looked only at relative spatial differences in corneal potentials, and was independent of absolute amplitude information. This represents an entirely novel approach to ERG recording and analysis.