My 12 year old son woke up this morning with redness in one eye, and the pupil slightly smaller than the other. The eye is also sensitive to light. He is a contact lens wearer, and did were his contacts slightly longer than normal yesterday. He also wore a latex-based face paint for Halloween yesterday, but did not have any of it in or around his eye. He had Retinopathy of Prematurity as an infant, and had surgery very early on to address abnormal blood vessel development in both his eyes. I'm wondering if we should take him to the E.R. today, or should wait to see the ophthalmologist he has seen at six month intervals tomorrow. There are no other symptoms, pain, or vision impairment being experienced.