There is a large scope of vision outside the central vision, which is called peripheral vision. Put it in this way, perippheral vision means you could see out of the corner of your eyes. Peripheral vision loss creat a sensation that you are looking at everything through a narrow tunnel, which explained exactly why it is called tunnel vision in medical term. Basic causes of peripheral vision loss include retina detachment, glaucoma, eye stroke or occlusion, optic neuritis, papilliedema and concussions. Normally speaking, it won't be triggered by your exercises, unless you did some fierce or contact sports. Eyes are delicate and easy to get hurt. If you got any collision or got any trauma on head, it might cause retina detachment or concussion, which might finally lead to peripheral vision loss. You don't have to be panic about it, because some cases are just temporary, while some are permanent. You just need to visit your ophthalmologist once you found this symptom. With proper and timely treatment, it is possible to prevent it developing to permanent cases. Tunnel vision gives bad direct and guide when you are walking or driving. Be careful. Good luck!
