I don't find it hard and my glasses are not the right prescription at the moment. the lines are there to stop computers reading...sure some are worse than others but the main problem is when there is 0 there and you are not sure if it is o or 0.
I dont find it that hard. But some forums I joined had pics trying to work out letters upside-down with crosses through them. And yeah the 0 and o bugs me
Some registration codes are hard to stand. Some tell you to enter the exact code but some icons such as "O" could stand for 0 or O. There are also some that tells you to enter the code backwards, this tends to send back errors.