Do you by any chance have migraines ? Might be migraine aura . But , as a guy who has eye issues , I recommend going to the ophtalmologist and checking your retina with dilated pupils . Also ask them to check your eye pressure . They will put drops that dilate your pupil and look directly at the retina , that is the part that senses light and color . They will also check your eye pressure by puffing some air into it . Both things are not painful and need no physucal contact between your eyes and any instruments . Also this linkhealth 83 d k x s e e n p u rplespotvisionnightturned . html says it might be the vitreous clear gel that fills your eye slowly detaching from your retina . It is harmless by itself , but might be dangerous . Go see an ophtalmologist and as to see your retina with a dilated pupil .