Electroretinography with noncorneal and corneal electrodes.

The noncorneal ERG is essential for certain patients in which corneal recording is contraindicated. A preliminary report is presented investigating ERGs from three noncorneal montages and their correlation with the corneal ERG. Statistical analysis showed that an electrode at the medial canthus combined with medial viewing gave the closest correlation to the corneal ERG. Repeatability was good for all montages. The inner canthus electrode was considered preferable for noncorneal recording because it was less affected by other time-locked activity; it correlated well with the corneal ERG and can be used in conjunction with the electro-oculogram.