Aliana let Iris knew about Rora's eyes when she told her that she remembered everything about her babies.
Both of them cried for the agony of losing their babies. Even though, it had been years, since Aliana lost hers, but it didn't mean the grief would be disappeared.
Iris needed to talk about this with Aliana, because she knew she would understand her feeling better, as she had walked the same path before.
It was also Aliana, who told her that the grief would always be there, but by the time, you would be able to live with it. Iris would never be able to see her babies grew up and they would always be her babies in her memories.
Actually, Aliana didn't see Rora's eyes directly, but she heard this from Grace, because only the healer, Della and Hanna, who were there when baby Rora's golden eyes faded and the color was replaced by the bluer pair of eyes that they had ever seen.