Eye surface inflamme. Episcleritis is an inflammation of the interspace between the conjunctiva and the underlying white of the eye. It has no known cause. The eye gets quite red usually on one side and is uncomfortable although not usually very painful. There are some other causes which might look similar so your ophthalmologist should get a look and determine treatment as it is treatable.
Many things. The disease is often from association with other diseases like wegener's granulomatosis or rheumatoid arthritis. It can also be from disorders of menstruation. For this reason, scleritis can occur in young women. It can also be the first symptom of connective tissue diseases like scleroderma. Episcleritis or inflammation of the episclera, is less serious and rarely becomes scleritis.