In this paper we describe the electro-optical characterization of three types of CCDs manufactured by the English Electric Valve (EEV). The sensitive area of these CCDs is treated in order to enhance the UV response; in particular one is 'coronene'-coated, thinned, back-illuminated, one is 'lumigen'-coated, front-illuminated, and one is 'ion-implanted' thinned, back-illuminated. A technical description of the CCDs and the adopted coating process is given. The CCD characteristics such as the read-out noise, the pixel non- uniformity, the dark current and the quantum efficiency in the 2000 - 10500 angstroms range, are compared. A cosmic-rays analysis for these CCDs is also given.