Yes, fatigue does lead to blurred vision. Studies have shown that when the eyes focus for a long time, muscle tone is reduced, affecting muscle movement regulation area in the cerebral cortex, which will lead to nerve excitability decrease, disorder control of neck and shoulder muscles movement. Eyes are the most susceptible to fatigue. Suffering long-term tired eyes, one will get bad vision easily. It is very useful to let your eyes have a 10min rest every 45min.
Yes, overuse of eyes will lead to blurred vision. It is normal because your eyes are too fatigue and get not enough rest. You should usually allow your eyes to relax for a certain time. It would be quite good to do some exercises when you have worked for one or two hours. Besides, use eye drops if you feel your eyes are too dry, but be careful to choose the right type of eye drops better under the advice of a eye doctor. Pay attention to the daily cleaning work of your eyes. And if the conditions of blurred vision becomes serious, you should go to see the doctor for an optometry check of your eyes. For more information about the cause of and treatment to blurred vision as well as the right eye drops for dry eyes, please refer to the following website: https://www.allaboutvision.com/conditions/blurry-vision.htm
Blurred vision can be caused by many problems, and over tired is one of them. Have a good sleep at night, your eyes will be recover at the next morning. And if you still have blurred vision after a good rest. You'd better see an eye doctor for help because you may get some eye disease.