Well it has been never said they dont have eyes, giger didnt include visible eyes because design wise he thought it was scarier that way, there are multiple theories (even one that they see trough the attack tongue) that they do have some sort of sight (visibile or not)
It's stated multiple times in the Dark Horse books that they do not have conventional sight, and even the AvP games indicate that the visuals of the Alien campaigns are meant to represent the aliens' mental construction of the world based on scent, pheromones, and electromagnetic sensitivity.
The most direct statement is probably from the original Aliens vs. Predator comic, in which a Predator dies because he tries to hide from the aliens using optic camo, and, as the narration observes, "Invisibility is of little use against creatures with no eyes." Considering the amount of intercompany discussions that had to occur in the planning and writing of that series (the first time the franchises crossed over), I'd say it's pretty reliable info.
Also, further evidence to back this up is the scene in A4 were Geidman threatens an alien with a red button that activates liquid nitrogen. The alien turns it's head and seems to react with fear when it sees the button. There's obviously no pheremones coming from a machine, or anywere else because there is a reinforced glass wall between them.
In the battle between 35 years of consistent creature design and one horribly thought-out sequel, I think I'm going to side with the former.
