I don’t know if the Frame is exactly the same, but the lens in previous headsets made it so that the screens are in focus at a perceived distance of about 6 feet or 2 meters. I think the only time you might notice that distance is when the screens are purely black.

Most of the time, you’ll be looking at a virtual environment where your brain is predisposed to determine depth by the parallax effect, both the offset from each eye and how things visually move when you move (faster = closer).

You should never actually feel like the screens are very close outside your brain conceptually knowing that they are. At most, the actual feeling should be closest to looking through goggles, so if you can handle that, you should be fine.

Also, in case it’s related to your fear, the widespread idea of screens permanently damaging your vision is a myth. It came about, because children who needed vision correction would naturally sit closer to televisions to be able to see them. The televisions got blamed for poor vision when the actual cause and effect were swapped. At most, screens can cause some eye strain, but it’s the same idea as holding a muscle in one position too long, uncomfortable but not actually debilitating.