Is there a period of adaption when moving between regular vision and darkvision?

Question

A torch gives 20' radius plus another 20' dim light. The enemy is 55' away in the dark. Character #1 cannot see the enemy as it is not illuminated by the torch. Character #2 though has darkvision so can see the enemy as if in dim light.

What about if the enemy is 110' away. Character #2 double moves 60' so is now 20' outside of the light source. Still can see the enemy as if in dim light.

My question is based around adaption - the ability of the eye to adjust to various levels of darkness and light. Does darkvision require any time to adapt to sudden change in illumination?

Answer 1

No.

Darkvision works as it says it does -- you can see in the dark as if in dim light for 60', and only in black and white. This means that you would have trouble if your goal involves grabbing the red gem, but not if your goal is to kill the skeletons. Otherwise, there are no rules in D&D 5e regarding adaption to different light levels.