A new speculum electrode for electroretinography

A Storz model E4110 infant speculum was modified to record electroretinograms (ERGs) from anesthetized rabbits. The electrode combines the advantage of a corneal contact lens electrode (with blepharostat) without its major disadvantage, namely: corneal abrasion. Addition of i.v. tubings glued to both arms of the speculum allows for constant wetting of the eyeball with 0.9% NaCl. The latter not only prevents the eye (and cornea) from drying, but also favors the recording of reproducible ERGs with a noise level comparable to ERGs recorded with a corneal contact lens electrode.