“Avoid the seven deadly sins that doom one to Hell..." “…Associating others with Allah (Shirk), magic, killing a soul whom Allah has forbidden killing, consuming Interest (Riba), consuming the property of orphans, fleeing on the day of the march (to the battlefield), and slandering chaste women… ” (An-Nisai)
If ones eyes are constantly watching sexual movies, magazines, etc. it would be considered zina of the eyes. If one goes to the place to commit zina or to the place of sexual movies, magazines, etc., it would be considered zina of the feet. Similarly, the act of masturbation, could be considered a zina of the eyes, or hands, etc.
The Prophet (blessings and peace of Allah be upon him) explained the seven sins that doom a person to Hell in a saheeh hadeeth that was narrated by the two Shaykhs, al-Bukhaari and Muslim, in as-Saheehayn, in which it was narrated that the Prophet (blessings and peace of Allah be upon him) said: “Avoid the seven sins that doom a person to Hell.” We said: What are they, O Messenger of Allah?