Disembodied spirits phasing into this reality do receive photon light emissions from our environment as they themselves emit electromagnetic radiation. Their consciousness interacts with incoming electromagnetic waves of light and translates them into equivalent objects they were familiar with in their life. Basically, ghosts take the middle man, aka the human eye, out of the equation. Their metaphysical mind does all the work. Naturally, the biological brain that ultimately interfaces with the human soul is removed from the sight formula as well. However, the bombardment of so many electromagnetic waves can be disorienting and takes some time to decipher for a new ghost. This contributes to the confusion they experience upon birth in their new metaphysical form. In addition, our world will never look the same as it did through biological human eyes.
A Ghosts sight can accurately be called surround sight since the photon emissions are coming at them from every angle. They view the physical world in a 360-degree holographic manner rather than from one narrow 3-D two eye perspective. In other words, if a ghost appears you have no hope of sneaking up behind them. It saw you the minute you entered the room. As four-dimensional beings, they also have 4-D vision which means they can see through your body, walls, or any other physical obstruction. If they are strong-willed they will soon realize they can see through time as well straight into the past and future. When appearing as a human-like specter the eyes are merely window dressing and serve no real purpose.