That is NOT a retained eye cap in my opinion.
If you try and remove it you will, in all likelyhood, blind your snake.
A fringe of skin from a retained eyecap is torn at the edges as the rest of the skin is pulled away. That picture shows smooth, attatched, skin that has been pulled out and displaced when the old eyecap came off during the shed. If you look at the eye itself it is clear and shows no sign of dimpling or creasing.
dr del