One of the side effects of the agent used to make chimps smart was turning their eyes green. Is there any explanation for how that may have happened?
Changes in eye color depend on the production of melanin and has been known to take place as a result of hormonal changes (adulthood, puberty, pregnancy). In the case of this movie, it could even be a result of genetic mutation. The agent's effects are passed down vertically so it must alter the host's DNA. In addition to the genes the corporation targeted, the agent may be inadvertently mutating ajacent genes responsible for eye pigmentation, such as OCA2.