Waking up to find that your eyes are red and bloodshot is never fun. If your eyes are also exuding yellow or green discharge, then you need to make a doctor's appointment as you likely have pinkeye. However, if your eyes are just red and slightly irritated with no discharge -- and the redness disappears throughout the day before reappearing the next morning -- one of these other causes is probably to blame.
Allergies to Materials and Detergents
When you sleep at night, the tissues around your eyes spend a lot of time in close proximity to your pillow and bedding. If you're sensitive to your laundry detergent and the residue it leaves on these items, this could easily cause eye redness. Try switching to a hypoallergenic laundry detergent. Using castile soap, rather than laundry detergent, is another good option as this soap is made with simple, natural ingredients and no added scent. Also, make sure your pillows and bedding are made from natural, hypoallergenic materials.
Especially if you have a forced air heating system, environmental allergens could be blowing through your air all night, irritating your eyes as they land on the mucous membranes around them. Since you're not blinking while you're sleeping, they are not rinsed away as easily as they are in the daytime. For some people, mold spores are to blame. Others are irritated by pet dander. Try vacuuming your home, changing your HVAC filter, and having your ducts cleaned. If environmental allergens are to blame, this should clear up the problem.
Think about what you put on your skin before you head to bed. Do you use a night cream or an undereye cream? Perhaps you wipe down your skin with an anti-acne toner. It's possible that, as you sleep and rub your face on your pillow, these products are getting transferred to the skin near your eyes, and even into the corners of your eyes. This could cause the redness and irritation. Try switching to more natural versions of the cosmetics you use -- or even going without them for a few nights.
If you play around with the possible causes above and still don't get any relief from eye redness in the morning, contact your eye doctor. They can help diagnose your problem and may prescribe you some eye drops to use before bed or in the morning to lubricate and soothe your red eyes.