For a literal translation:
* À tes yeux seulement: This is the most direct translation, but it can sound a bit formal.
* Dans tes yeux seulement: This is another literal translation that is slightly more poetic.
For a more nuanced expression:
* Pour tes yeux uniquement: This emphasizes the exclusivity of the information.
* Tu es le seul à pouvoir le savoir: This means "You are the only one who can know it."
* C'est un secret entre nous: This means "It's a secret between us."
For a more romantic expression:
* Dans tes yeux, je vois tout: This means "In your eyes, I see everything."
* Tu es le seul à voir mon âme: This means "You are the only one who sees my soul."
The best choice will depend on the specific situation.