The color of Harry's eyes in the movie is different from the one described in the books. While the books clearly state that Harry has bright green eyes, the movies show his eyes as a deep shade of blue. Many fans have speculated that the reason for this change is that the green color of Harry's eyes would interfere with the green screen technology used in the movie.
However, there is no evidence to support this theory. In fact, the filmmakers have given a different reason for the change in Harry's eye color. In an interview, director David Yates explained that they chose to give Harry blue eyes because they felt it would better match the eyes of actress Emma Watson, who played Hermione. Yates said that they wanted to make sure that the actors had some physical resemblance to each other, and that changing Harry's eye color was a way to achieve this.
It's also worth noting that the color of an actor's eyes is not a significant factor in green screen technology. The purpose of a green screen is to allow filmmakers to replace the green background with a different image in post-production. The color of the actor's eyes would not interfere with this process, as long as the actor is properly lit and positioned on set.
In conclusion, the reason for the change in Harry's eye color in the movies was not due to the green screen technology. Instead, it was a creative decision made by the filmmakers to better match the appearance of the actors. While some fans may have preferred to see Harry's eyes portrayed as green, the change in eye color does not significantly affect the story or the themes of the Harry Potter series.