There is a kind of phenomenon called "highway hypnosis" and it's very real. It explains when you keep your eyes riveting on the road and watching where you are going, But with the long-time staring at the road and the white lines ,you may fell fatigue very much. The suggestion below may help you: Glance in your mirrors, at your gauges, at road signs, billboards, scenery, anything. Quick glances are all that's necessary. You'll still be able to focus on your driving, and will be much safer. Whatever you do, don't keep your eyes constantly fixed on the road.
And a pair of sunglasses will keep you from the intensive light when you drive, so that's better.