I understand that Will.i.am has a bulging, clouded eye and you are rightly concerned about it.
Guinea pigs are prone to eye infections and injuries and that would explain an eye discharge and perhaps some squinting.
If the injury isn't noticed we can see a secondary infection and inflammation set in and the eye may become cloudy (that's called uveitis). The inflammatory products in the eye can block proper drainage within the eye and lead to a dangerous increase in pressure in the eye (glaucoma). I am concerned that is what is going on with your fellow. That is an emergency situation because unless addressed promptly he could lose vision in his eye permanently or if the pressure is very high his eye could rupture.
Other possible causes for what you are seeing include a penetrating eye injury that led to an infection and glaucoma, a cataract that led to uveitis and secondary glaucoma, or a tumor in the eye. Guinea pigs can get congenital cataracts (born with the tendency to form a cataract sometime in their life) and are also more prone to diabetes which can lead to cataract formation.
Whatever is going on with your fellow he needs a veterinary visit with an experienced guinea pig veterinarian, this is not something that you should attempt home treatment for for any length of time. While you are looking for some one to examine him you can use artificial tears to keep his eye hydrated, keep him in dim light as bright light may increase eye pain, and keep him quiet.
If you do not have a regular veterinarian for him here is a link to help you find one: http://www.guinealynx.info/vetlist.html
Best of luck with your fellow, please let me know if you have any further questions.