If someone's read two pages of your work and find that sufficient to call it a trope (did they mean just the part about the eyes having different colours, or did they consider your whole comic a trope because of it?), I probably wouldn't take it too seriously (though I totally understand that it's not very pleasant). You're making a long form comic from what I understand. I don't know how many pages you're planning on making, but I think it's pretty obvious the two first pages can't be seen as a fair representation of the whole comic. You haven't even had time to fully present the main character yet.
If you have a look at the list of tropes on for instance tvtropes.org, it's ENDLESS. There are so many tropes, they cover ALL sorts of storytelling tools and plot lines and character traits etc., that it's almost impossible to write a story without touching on some of these. From Wikipedia:
"The word trope has also come to be used for describing commonly recurring literary and rhetorical devices, motifs or clichés in creative works."
Example: You have for instance alliterative names; names in which the first and last names begin with the same sound, like Peter Parker and Bruce Banner. Stan Lee did this a lot, and this is a trope. But it doesn't stop people from reading comics about Spiderman or watching films about him! Alliterative names can help characters stand out and be more memorable - a good thing. But if you overuse it, it will have the opposite effect - a bad thing. So tropes aren't all bad, but you have to use them the right way. Some tropes are very popular, and people keep coming back to stories using certain tropes.
You could have a very long conversation about tropes, but to be short; they aren't all bad - it's mostly when something becomes a cliché that it might get boring. Tropes are storytelling devices and conventions, and sometimes using them makes for a good story - and breaking them in the right places might make it even better
If the person who left the comment just called it a trope and didn't give any advice or constructive criticism to help you improve, I wouldn't take them too seriously. I mean, in general I think people here know that it's better to keep even your constructive criticism to yourself unless a person has asked you to give it. But comments like that aren't constructive in any way, and even shows a lack of understanding of what tropes are really all about, so there's no help in it at all :/ What was that person hoping to achieve with a comment like that?
So I hope you won't worry too much about it. Some might think eyes with different colours are cliché, but I happen to like it nonetheless ^^