Unfortunately, computer work gets harder after 40 as our eyes become less flexible. This problem gets worse as time goes on.
Here are some tips if you have older people using computers in your shop.
I find it best not to give them a laptop screen to work on because it is too close, so use a sizeable separate monitor.
The bigger the monitor, the better. A 4K screen is best as it will offer them four times the pixels found on a traditional monitor.
You will find that factors like clarity and crispness are less important than size. People mistakenly try to increase the resolution of a screen, thinking that this will make the text look crisper and easier to read. It does make it look crisper, but it also makes the text smaller. In my experience, people with poor eyesight need bigger text. The fuzziness is less critical.
The next point is that our software can take advantage of larger screens, unlike many other point of sale software packages. Use this and set it to the largest.
Another helpful point is to cut the glare. If light from a nearby window or lamp casts a glare, try moving the monitor. Two light sources cause fatigue because of the different amounts of light hitting the eye.
I hope this helps.