Carefully attentive (8)
(Other definitions for vigilant that I've seen before include "Ever watchful" , "Carefully observant or attentive" , "Watchful, on guard" , "Watchful, alert to possible danger" , "Be watchful while I gilt van" .)
(Other definitions for open-eyed that I've seen before include "Surprised - aware" , "Astonished; fully aware" , "Astonished - watchful" , "Forming an encrusted mass" .)