If you're having eye pain/redness, I strongly discourage going to the ER or your primary care doctor. Let me tell you a little story. When I first started practicing, I saw a patient with severe pain in one eye. She had gone to the ER one week prior to seeing me. The ER doctor gave her a bottle of Atropine dilating drops. By the time she came in to see me, she had a corneal ulcer so large that she could barely see. Luckily, with a heavy course of antibiotics, I was able to restore most of the vision she had lost. Had she been given antibiotic eye drops to begin with, she likely would have not lost any vision in that eye. Is this a one-time case? Unfortunately, no. I see this type of thing several times a year. It makes sense, though! If I didn't have a slit lamp microscope in my office, I wouldn't be able diagnose a corneal ulcer either! Case in point: If your EYES hurt, see an EYE doctor!
