Actually a tough GQ, being psychological in my opinion. I’m no expert on perception of colour, perhaps a camouflage specialist might be knowledgeable, but this thread’s been around long enough for me to chirp in with my observations. I believe a lot of our colour perceptions are subconscious, probably because they are so complex. Outdoors after sunset there is a range of light where there is almost no colour and everything is seen in grey and black, for example. Another example is, if you are painting walls with strong colours you can see funny things like (a random example vaguely from memory) a thick brushstroke of brown on a yellow wall will be perceived as purple. If you move in close and look at it, completely shielding the yellow out of your vision the brown perception will return. Anyone else notice this?
Anyway, point being that it’s all perception and mental processing. Everyone always notices eyes (“fight or flight”), consciously and subconsciously, and, when something else catches their eye, a watch or shirt, that clicks with their “catching” of your eyes, it is noticed and remarkable in a small talk kind of way, sort of “huh”. To try and sum up this blithering… people rarely notice your watch or shirt or whatever unless something about it clicks. Because they always notice your eyes they will notice a watch or shirt or tie or whatever because something about the colour clicks. That they would remark on it is just friendly small talk.