If they do, the VDU may need servicing or adjustment. The key issue. Don't sit in the same position for long periods. Make sure you change your posture as often as practicable. The Regulations require breaks or changes of activity but do not specify their timing or length because the need for breaks depends on the nature and intensity of the work.
Most jobs provide opportunities to take a break from the screen, eg to do filing or photocopying.
Make use of them. If there are no such natural breaks in your job, MAKE THEM . Frequent short breaks are better than fewer long ones. Some work e.g. checking for spelling errors are better done with a printed off draft rather than on screen. If you work on a computer at home, remember to fit in breaks there.