Why after we turn off the light we can’t see anything but after a few minutes we can see almost everything?
Your eyes’ iris opens thus letting more light enter your eye. It just takes your body a short time to adjust.
I see some other answers in here about pupil dilation but that’s actually incorrect. Your pupils react to changes in light almost instantly. The real reason is because of a chemical called rhodopsin. Rhodopsin is a light sensitive pigment in the rods of the retina (the rods are the cells that detect light and dark). Rhodopsin is part of chemical reaction that converts light to electrical signals to send to your brain. When exposed to bright light, the rhodopsin molecules change configuration, which makes them less sensitive to light. Once you turn off the lights, it takes about 30 minutes for the rhodopsin to regenerate again so you can see in low light levels.
The size of your pupils adjusts depending on the amount of light being received. When there is good lighting, the pupils are smaller, allowing less light. If that light source is suddenly removed, your eyes are not receiving enough light to form an image. In response, your pupils dialate and get larger, allowing in more light and allowing you to see better in the dark.