Board Thread:Naruto Discussions/@comment-26107879-20181004003653/@comment-32685487-20181122002452

If your synapses/nervous system are not prepared or boosted enough to help with the tech then that is why it creates tunnel vision. Raikiri/Chidori does give a great speed boost but as was pointed out it lacks the ability to boost the synapses and nervous system that help with eyesight, therfore tunnel vision occurs for those with no Dojutsu.

Edit

If Kakashi was to learn the Lightning Release Chakra Mode then he could use Chidori again, as it boosts the synapses and nervous system.

https://naruto.wikia.com/wiki/Lightning_Release_Chakra_Mode