2. Discharge
If the eye emits discharge, it may be a sign of conjunctivitis. The kind of discharge that is present indicates the type of infection.
If the infection is viral, the discharge is likely to be thin and watery and be accompanied by reddish eyes. With bacterial infections, the discharge may be greenish or yellow and thicker.
It can be quite sticky and be concentrated on the corner of the eye. When this discharge dries, it is likely to be crusty and cause the eye to become stuck in a closed position when waking.