The first thing that you need to do in this regard is to improve the posture that you are using while you are sitting on a chair in front of a screen and working for long hours. The best way to relax the posture of your neck and head would be to get the screen position of your computer correct. It is always better in these cases to tilt the screen a bit backward so that your head is a bit lowered and your neck muscles are relaxed. You have to make sure that the height of the screen is at a level where its top line is a bit lower than the horizontal axis of your vision.
When you are working before a computer screen you have to deal with risks such as reflection and glare. This is where blue cut lenses can help you to such an extent. If you want to avoid that particular possibility you should position the screen at 90 degrees to a window. This way, the sunlight would not be cast straight away over the screen. You should never place your monitor straight in front of a window as well. This is because the difference between the brightness within the office and the one outside would cause eyestrain.
Reducing the strain on your eyes
If you wish to make sure that the chances of eyestrain, headaches, and fatigue are reduced it is better that you set the display at a proper character size. The resolution should be appropriate as well. You can always go for the likes of blue light filter glasses. Apart from that, it would also be great if you invested in equipment such as 4K monitors as they show images and texts in a highly optimized and sharp format. Even then the character size needs to be at an optimum level.
You can always wear eyeglasses every day to work. That way, you would be in a good position to deal with these issues as well. However, that may not always be sufficient in these cases as well since our vision gets worse even as we get older. This is why you need specialized products for working on the computer from the top brands such as Essilor India. You can get a prescription in this regard from your optician or occupational health physician. However, you need to make sure that you keep your work-related requirements in mind in these cases too.