adverb/a vy d‿œj/
right before one's eyes, visibly, noticeably, before one's very eyes, by the minute
“Il fait tellement chaud et humide que les plantes poussent à vue d'œil.” — It is so hot and humid that plants are growing before your eyes.
Antonyms: imperceptiblement, insensiblement
Compare Italian a vista d'occhio.