If the vision or combat penalty for poor lighting is between -1 and -4 for most people, your penalty is the worse of double the usual penalty or -3. If the usual penalty is -5 or worse, you function as though you were completely blind. If you have Acute Vision, it only applies in situations with no darkness penalty.
If the vision or combat penalty for poor lighting is between -1 and -4 for most people, your penalty is the worse of double the usual penalty or -3. If the usual penalty is -5 or worse, you function as though you were completely blind. If you have Acute Vision, it only applies in situations with no darkness penalty.