My cousin reads book for half an hour his eyes turns to reddish color and sleeps. What is his problem? why he is straining like that?

Question

He should undergo refraction if there is some refractive error,even if you have minimal refractive error kindly use spectacles.
A common problem when working on a screen for long or near work periods is 'dry eye'. This is because concentrated work tends to reduce the blink reflex that replenishes the tears, and the dry atmosphere and lack of fresh air adds to the problem of insufficent tears. Allowing the cornea to become dry can cause irritation and blurred and variable vision.  Use some lubricating eye drops like refresh tears ,use them at least 4 times a day at least.
You do need to look at every aspect of your work environment also.
Use proper lighting , dont work in dim conditions
Should use table and chair  for studying
Your table should be of proper height so that you dont have to bend too much.
Take rest after 30 mins for few mins ,put the tear drops and work again.
Do blink intermittently.

Shah Nawaz · Accepted Answer

He should undergo refraction if there is some refractive error,even if you have minimal refractive error kindly use spectacles.
A common problem when working on a screen for long or near work periods is 'dry eye'. This is because concentrated work tends to reduce the blink reflex that replenishes the tears, and the dry atmosphere and lack of fresh air adds to the problem of insufficent tears. Allowing the cornea to become dry can cause irritation and blurred and variable vision.  Use some lubricating eye drops like refresh tears ,use them at least 4 times a day at least.
You do need to look at every aspect of your work environment also.
Use proper lighting , dont work in dim conditions
Should use table and chair  for studying
Your table should be of proper height so that you dont have to bend too much.
Take rest after 30 mins for few mins ,put the tear drops and work again.
Do blink intermittently.