Board Thread:Questions and Answers/@comment-24510507-20160918144826/@comment-5398287-20160919053552

I'm not quite certain that it was a retcon so much as it was a simple color change to fit the palette of the spread - after all, the anime showed Gin with red eyes for ages, but once Kubo drew him with blue eyes it corrected that right away, so I don't see why they wouldn't have done the same for Ukitake if his eyes were really changed to green.

But regardless of that, I've checked the color pages and all the spreads featuring him are too zoomed out to detail his eye color, so I suppose we'll have to stick with green.