Electroretinographic (ERG) investigations are conventionally performed by using corneal or conjunctival recording electrodes. Both types have to be placed in contact with the eye, resulting invasive and providing discomfort for the patient. This paper presents a simple technique to detect ERG potentials non-invasively. It relies on the use of a conducting liquid between the eye and an external conductor, which actually derives the ocular potential without any ocular contact. These elements are the basic components of a new type of ERG electrode, referred to as Carpi-Tomei (CT) electrode. The paper describes the assembly of prototype samples of the new electrode. Preliminary testing assessed the feasibility of the proposed non-invasive technique.