Night vision goggles (NVGs) are designed to be used by individuals with a wide range of vision capabilities. To accommodate this, many NVGs come with diopter adjustment ranges that allow the user to adjust the focus of the goggles to their specific vision needs.
The diopter adjustment range refers to the range of diopter settings that a particular pair of NVGs can be adjusted to. The diopter setting is a measure of the focusing power of the goggles and is usually measured in diopters (dpt).
A diopter adjustment range of -6 to +2 dpt for night vision goggles means that the goggles can be adjusted to focus on objects at a distance of 6 diopters away from the eye to 2 diopters away. The negative diopter setting is used for people who have near-sighted vision, while the positive diopter setting is used for people who have far-sighted vision.
This range of diopter adjustment is not typical and it is also important to note that some goggles may have different ranges, and it also depends on the model and brand. It's important to check the diopter range of the goggles you're interested in before purchasing, to ensure that it will accommodate your vision needs.
It's important to note that diopter adjustment is a personal preference and that it's a good idea to test the goggles with different diopter settings to find the one that works best for you. It's also important to remember that diopter adjustment does not correct for color blindness or any other vision deficiencies.