It might just be part of the movie poster art. The whole promotion so far has focused on the delta shield. I doubt that the actors actually will have little delta shields in their eyes in the film -- that's just part of the artwork. So too could be the delta pattern on the uniforms here to give them some texture. I am not convinced that's the actually fabric pattern in the film.
It was mentioned in this article
at TrekMovie that it is indeed a fabric pattern. That detail and others from the article were discussed in this thread
, which also contains links to images in which the fabric pattern can be clearly made out.
The delta shields in the eyes most likely will not be seen in the film. That's just ad stuff.