Replicant eyes glow
|Rachael during her Voight-Kampff test|
This notion that Replicants are "more alive" than humans is developed throughout the film, as Roy determinedly seeks out Tyrell and a way to extend his own life. During the climactic chase, Roy gives Deckard a head start and repeatedly lets pass opportunities to kill the Blade Runner. He is less toying with Deckard, however, than teaching him — teaching him to recognize the value of life and to fight for his own. After Deckard hits Roy in the head with a pipe, the Replicant exclaims "That's the spirit!" perhaps seeing in Deckard for the first time some of the spark that shines in his own eyes.
|Tyrell's large eyeglasses|
Tyrell's glasses make him look like his pet, the owl, a symbol of Tyrell's wisdom. It is telling, however, that Tyrell's owl is artificial, for despite all Tyrell's technical knowledge, he is unable to extend Roy's life or to offer any comforting or "real" wisdom to the murderous creation that has escaped his control.
|Rachael's eye on the VK screen|
Despite this visual assistance, humans are slow to comprehend. During Leon's examination, Holden is tipped off by Leon's reaction to the question about a tortoise, though does not act quickly enough to avoid being shot. He may see Leon as a Replicant, but he does not perceive the immediate danger. Similarly, it is not until the end of the movie that, after being saved by Roy and then watching him die, Deckard is able to glimpse the Replicant's motives, his "point of view."
The eye shop
|"If only you could see what I've seen with your eyes."|
Nowhere are eyes more emphasized than in the eye shop, where Roy and Leon confront Chew, a genetic engineer specializing in eyes. Chew recognizes Roy as a Nexus 6, the most advanced Replicant model, and explains that he designed Roy's eyes. "If only you could see what I've seen with your eyes," Roy says in response.
Not only has Roy seen different, presumably spectacular off-world things that Chew could not have seen, being stranded on Earth, but Roy may also be referring to an ability to see — Roy has "seen" the value of life, and his drive to preserve his own demonstrates a passion not apparent in the humans. Chew, not being a Replicant with such a limited life span, could not have "seen" the same things because his perspective on life is so different — his mortality does not hang over his head as ominously as Roy's hangs over his.
|Roy plays with artificial eyes at JF's place. While comical,|
the large eyes suggest Roy's great capacity for "seeing."
|"I've seen things you people wouldn't believe."|
The difference between what Replicants and humans "see" and value is emphasized in Roy's dying speech, when he tells Deckard, "I've seen things you people wouldn't believe." On the surface it seems that Roy is referring to amazing visions — "attack ships on fire off the shoulder of Orion," "C-beams glitter[ing] in the dark near the Tannhäuser Gate," things that Deckard and other Earth-bound humans could not see from Earth, yet which they would nonetheless find too spectacular to comprehend. Or perhaps the attack ships and C-beams wouldn't be such spectacle to humans after all, but to Roy and other Replicants with a looming death sentence, these visions — any visions — would be worth treasuring, as Leon treasures his photos, as Roy treasures the memories that he fears will be lost like "tears in rain." Seeing is reassurance to Replicants that their experiences are real, not artificial like the memories implanted by Tyrell, but things they have "lived." Seeing validates their existence and makes them feel alive.
(Of course, it is not certain that Roy has seen any of these things. Like Rachael's childhood, Roy's recollections may be implanted memories of things he has never experienced. If Roy has considered this, it is likely that what he has "seen" is instead metaphysical, something he has realized and which he knows has not been understood by the humans of his time, by Tyrell and the society of Frankensteins that have created artificial life without fully considering the consequences. Or perhaps Roy is unaware of the use of implants and accepts his memories as experience, or perhaps more interestingly accepts them as experience while knowing they are false, as Deckard chooses to accept Rachael as human...)
Loss of sight equals death
|The end of Tyrell|
If seeing is necessary for a Replicant to feel truly alive, then loss of sight is equivalent to death. It is fitting, then, that when Roy kills Tyrell he does so by pushing in Tyrell's eyes, inflicting on him the highest penalty, the loss of sight/life. This punishment makes certain what Tyrell's large eyeglasses have suggested all along — that despite his scientific ability, he lacks vision. He, like all the visually impaired genetic engineers, is unable to see what consequences his work has on the work itself, on the Replicants.
|The half-blind bartender|
Pris' eyes (de)emphasized