Severus Snape’s line about Harry Potter having his mother’s eyes isn’t the problem it’s made out to be and shouldn’t be taken literally.
Severus Snape’s infamous line about Harry Potter’s eyes in Harry Potter and the Deathly Hallows: Part 2 isn’t actually a Harry Potter plot hole. Throughout the franchise, you never really know whose side Snape is on. For years, he seemingly tortures Harry at school, but their last moments reveal the character’s true nature.
In the Harry Potter series, Snape meets his end when Voldemort kills him, mistakenly thinking he was the master of the Elder Wand. Actually, it was Harry after he disarmed Draco at Malfoy Manor. As Snape dies, Harry comes to his side and takes his tears. After putting them in the Pensieve, he learns Snape was living a double life. He’d been helping Harry all along, and he had always loved Harry’s mom, Lily.
Before Snape dies, he tells Harry, “You have your mother’s eyes.” This is true in J.K. Rowling’s novels, where both he and his mother have green eyes. However, in the movies, that’s not the case. Actor Daniel Radcliffe was allergic to green contacts, so he kept his regular blue eye color. Obviously, that wouldn’t be a problem if the actors playing his mom had blue eyes, but it turns out Lily’s eye color changed throughout the films. While Geraldine Somerville, who played the older version of Lily Potter, has blue eyes, the younger actor playing Lily, who’s seen after Snape’s death scene, has dark eyes. Despite the color difference, the meaning behind Snape’s statement is accurate, meaning the dialogue doesn’t create a plot hole.
Snape’s line has a lot of impact in both the books and the movies. In this, his dying moment, he realizes how much Harry and Lily are alike. For the longest time, Snape seemingly thought of Harry like the boy’s father, James, a person he really hated in their younger days and who picked on him. In Order of the Phoenix, he even tells Harry that he’s “lazy” and “arrogant” like his father. But when Harry comes to Snape’s side as he dies, he sees the love and care he saw in Lily. It’s not about his eye color. It’s about the reflection of Harry’s mother, the woman he loved.
In general, the Harry Potter universe is littered with plot holes. Why didn’t Fred and George notice Peter Pettigrew hanging out with Ron on the Marauder’s Map? Why didn’t Voldemort make Death Eaters take unbreakable vows? Do wizard students ever take a math class? These are real issues that would perhaps change the story if they were addressed. How are all these wizards going about their lives without basic reading, writing, and math skills? However, Snape telling Harry he has his mother’s eyes is the least of the story’s worries. Sure, perhaps the professor should’ve told Harry with his dying breath, “You have your mother’s eyes, but I don’t mean literally.” But that would take a bit of the meaning out of the moment, wouldn’t it? To Snape, Harry does have Lily Potter’s eyes. He had them, always.