What's also interesting is that these Eyes are described as Hawk-Eyes, hence Mihawk's Epithet,
But People could have called him Red-Eyed Mihawk if They only wanted to describe his Appearance, but seeing what kind of Power They indicate, it's pretty evident now that Mihawk was indeed known for his Extraordinary Vision,
This is further proven if you go check Viola's DF, One of her Abilities allows her to send out her Sight in All Directions which enabled her to keep watch on entire Dressrosa whenever She needed to, and this Ability was designed to resemble a Bird, and guess what was it's Name? It's Clairvoyance, which Oda confirmed was gonna be Mihawk's Original Name,
One of her other Abilities is also to look into Person's Mind & Memories but what's interesting is that She can do the opposite as well, which might explain why Luffy saw his Arms Cut when He looked at Mihawk's Eyes. If that's the case, then that also means Imu can actually show her Memories to People, We might see the entire Void Century Flashback from her Perspective, just like Viola did with Sanji,
PS: This might be a stretch, but another Ability of Viola is turning her Tears into Whales, and if you go check that Ancient Mural, you will find the Whale drawn there have what it seems to be rain drops above it (Only the Whale), so those might actually be Tears, not Rain.