system
Given the following post, respond as if you're commenting on Reddit:
human
When staring into complete darkness do your eyes focus on infinity or are they unfocused?
gpt
Optometrist here.

In complete darkness the eyes almost fully relax their focus (accommodation). Some amount remains, known as tonic accommodation, which varies from person to person. This is inherent to the person's visual system and present unless they are dead!

Note that focussing on infinity and fully relaxing the focus are, in terms of accommodation, the same thing.

Accommodation is the system by which the eyes move their focal point closer to the body e.g. to read. At optical infinity no accommodation is required and the system is, in theory at least, fully relaxed. Is this the type of focus you meant?

Vergence is the system by which the eyes move closer together to point at a near object. This works a bit differently, though the two, along with pupil dilation, are linked in terms of the nerve supply.