Okay but...symbolism of what exactly? You can't just have something off the cuff and highlighted like that and handwave it away with "it's symbolic". Symbols have meaning, what is the meaning of the starburst pupils? Why do Ruby and Aqua have them as children if it's meant to be symbolic of something relating to acting/talent/whatever. Ruby and Aqua have no talent as children, the only reason Aqua was cast in TV/Movies was because he behaved like an adult in a child's body which was really off putting and uncanny. If it's related to Ai and Hikaru in some way then why did the starlet Hikaru murdered also have the starburst in her eyes? Why can Akane get the same starburst when she mimics Ai?
There has to be a reason for its existence other than "it looks cool and makes key characters stand out". We can pretty much figure out at this point that the color of the starburst reflects the emotions of the person who has them, with Hikaru and Aqua having black starbursts when they are being all menacing and revenge-y. Ruby gets black starbursts too when she overhears Aqua talking about who murdered their mom and his plans and she gets all aboard the revenge train as well. Still doesn't explain why they have a starburst to begin with and why that random starlet also had it (and yet no one else in the entertainment industry seems to have it).
It really might just be a visual..... maybe you are just over thinking unique designs.....
But it might also represent how they all have one star they look up to..... while Kana, having an entire Galaxy might be free.....
Like, it's probably more for just viewers to enjoy, but also maybe symbolize the characters and their thoughts or something....
People have various theories with the ones I mentioned being one of them.....
But it's probably mostly just artistic and not something that needs to really be explained or over thought of or something....
It's a character design choice for viewers. And even if it has symbolism, it's probably meant for viewers to figure out rather than for characters to tell us, because, for these characters, those things don't exist, they are just regular eyes...
That is what art is about. We as viewers have to figure these things out.
Try to actually find the meaning of why the author used those eyes....
It's not like they are magic eyes or anything like that, it's symbolism for viewers to figure out.