We know that for any object to be seen by a human eye, the light from any source must be reflected from that object so that it reaches our eye and we can detect it.....but how do we see light itself? Bcoz obviously light can't bounce off light itself, it just pass right through each other, do our eyes absorb the light for it to be detected??
The retina in your eye contains light sensitive structures called rods and cones. The light sensitive agent within these is a class of molecules called opsins, and the bit that actually absorbs the light is a chemical called retinaldehyde that is a derivative of vitamin A.
When light is absorbed by retinaldehyde it causes the molecule to change its shape, which in turn causes the opsin to change its shape and this triggers a process called phototransduction that eventually ends up with an electrical signal being sent into the optic nerve. Your brain does the rest.
You do see the light itself. That is what your eyes do - send electrical signals to your brain based on the energy from light hitting cells in your retina. Without getting into wave/particle duality, there are cells which respond to photons at different wavelengths and the signal sent to the brain is proportional to the energy of these photons. Our brains then translate these signals into colours, shapes and so on.
That light all comes from sources - so you are effectively seeing light either directly from a source, or after reflection/refraction etc from other objects. When light bounces off another object (or is absorbed etc) it passes on some of it's energy. When it hits your retina it passes on energy - and this is what you "see"
We can't actually see light. The reason we can only detect light that strikes our retina and not light that passes us is because we feel light. We have specialized light detectors which react only to specific wavelengths and when they are triggered they send electrochemical impluses to our brains optic center. The brain converts these impulses into a 3 dimensional visual representation of our surroundings. This is what we see. We also see things in our dreams without the involvement of light. Detecting light is part of the visual process but it's not the entire process. Light is what causes our brain to create images. There is no objective brightness caused by light but merely a subjective experience. This might seem counterintuitive after centuries of hearing terms like visible light spectrum, red light, blue light, etc and it's unlikely everyone can grasp this concept, but feeling light makes more sense than seeing light.