The most common cause for eye strain is wearing the wrong optical correction.This may be due to a refractive change in your eyes and your spectacle lenses need to be updated. On average, one should have a check up every two years.
Are your specs properly made?
If your spectacles are poorly made, it could cause eye strain. The optical centres of the lenses have to be set up very accurately to coincide with your visual axis and one’s work station and visual needs have to be considered.
Do your glasses fit properly?
Many things can be wrong with the way your glasses sit on your face. Should your specs not be straight, one lens closer to your eye, the angles wrong, sliding down your nose, it can definately cause visual strain and discomfort.