Purple under the eyes may be related to trauma, periorbital hyperpigmentation, heart disease and other causes. 1. Trauma: If the eye or its surrounding area suffers an impact injury, it can cause bruising in the eye, resulting in purple under the eye. 2. Periorbital hyperpigmentation: This is commonly known as “dark circles”. Lack of sleep and other conditions can cause poor local blood flow, resulting in purple under the eyes. 3. Heart disease: cyanotic congenital heart disease, such as tetralogy of Fallot, may cause purple under the eyes. It is recommended that people with purple eyes go to the hospital in a timely manner to clarify the cause of the disease and under the guidance of the doctor to carry out standardized treatment to avoid delaying the condition.