Elkann is drawing on ancient wisdom here. In the Christian scriptures, Jesus is depicted as uttering this curious phrase: "The eye is the lamp of the body. If your eyes are healthy, your whole body will be full of light" (Matt 6:22). Furthermore, ancient scientific theories of vision believed that eyes projected rays from them to enable objects to be perceived. Eyes were seen to be openings of a certain kind, revealing things about the body--and perhaps soul-- of their bearer. Even modern science claims that certain personality traits and psychological dispositions are revealed by one's eyes.
So, perhaps, Elkann has good reason for wanting to protect these gateways.
Yet, this is also why I find it troubling to talk to someone who is wearing sunglasses, whose eyes I cannot see. I feel disconnected from them, unable to bond. I almost never wear sunglasses in part for this reason. So, while I understand Elkann's reasoning and do believe it is grounded in something very real, it's not the direction I would take.
If indeed the eyes are the window to the soul, and a source of real engagement and connection with the world, why hide them? Why shield oneself off fearfully or suspiciously from others? Why not instead seek boldly and meaningfully to connect with people and the world?
What this means to me is to endeavor to live in a way that makes clear-eyed engagement with the world and with people a joyful prospect. This means having a purposeful vision and a fearless, risk-taking attitude of relational connection. It means being open to love, and to the wounds that love might bring. It means not being afraid to be real, vulnerable, and present.
Sure, wearing sunglasses or not might be secondary to the metaphor they invoke, one of a closed posture vs. trusting openness. But they still send a signal. I won't challenge your sense of style; but, in the least, if you happen to stop to talk with me on the street someday, I would so appreciate it if you removed your sunglasses and thus expressed openness to a meaningful encounter and exchange.