What is the main cause of tunnel vision ?

Tunnel vision is often caused by a narrowing of the field of vision, resulting in the perception of only a limited area in front of the eyes. This can be caused by various factors, including stress, anxiety, fatigue, certain medical conditions such as glaucoma or retinitis pigmentosa, and the use of certain medications. In some cases, tunnel vision can also be a symptom of a more serious underlying condition such as a stroke or a brain tumor.

Restriction of blood flow to the optic nerve