The Department has not made any assessment of the affect of prolonged exposure to television and computer schemes. However the Health and Safety Executive (HSE) do offer advice on the impact of computer screens or monitors (Visual Display Units) on eye health on their website:
Extensive research has found no evidence that VDUs can cause disease or permanent damage to eyes. But long spells of VDU work can lead to tired eyes and discomfort. Also, by giving your eyes more demanding tasks, it might make you aware of an eyesight problem you had not noticed before. You and your employer can help your eyes by ensuring your VDU is well positioned and properly adjusted, and that the workplace lighting is suitable. Ask for an eye test if you still think there is a problem.