Fundus vasospasm is usually caused by elevated blood pressure, emotional excitement, vasoconstrictor drugs and other reasons. 1. High blood pressure: High blood pressure stimulation can easily lead to spasm of blood vessels in many parts of the body, and vasospasm of the fundus, which is a more common situation, will cause patients to experience a transient loss of vision. 2. Emotional excitement: Emotional excitement may also trigger transient fluctuations in blood pressure, and it is possible that the blood vessels are provoked to spasm. 3. Vasoconstrictor drugs: If patients use or mistakenly take vasoconstrictor drugs such as epinephrine for the treatment of other diseases, it is possible that the blood vessels in the fundus contract and then spasm occurs. It is recommended that patients with vision loss should consult the hospital in time to assess their condition and have a reasonable treatment plan formulated by the doctor.