The coating agent on the corneal contact lens in electroretinography

Two animal groups were subjected to electroretinographic studies under identical circumstances with the exception of the coating agent on the surface of the corneal electrode, which consisted in one group of an ophthalmic artificial tear solution containing 1.6% hydroxyethylcellulose, and in the other group, an ophthalmic artificial tear solution containing 0.2% hydroxyethylcellose. A similar comparative recording was performed on five human subjects. Electrophysiological responses recorded with 0.2% ophthalmic artificial tear solution increased up to 81%, as compared to the values obtained with the 1.6% solution. The difference in electrical conductivity of these two solutions, which is also time dependent, correlated with differences in electroretinographic amplitudes. I cannot explain these observations at the present time.