This is a solo single by Toyoshima Machiko (豊嶋真千子) .

The tracks are as follows.

1. いつか 瞳の奥の
2. ami
3. いつか 瞳の奥の〜remix version〜
4. いつか 瞳の奥の〜off vocal version〜
5. ami〜off vocal version〜