Well I know there is a stop against delaying turn to avoid the effects of save-ends or until end of your next turn effects.
End of Turn when the Creature Delays: At the moment the creature delays, any effect that it has been sustaining ends. In addition, effects that last until the end of the creature’s turn now end if they are beneficial to it and its allies—they cannot be prolonged by delaying. For instance, if the creature stunned an enemy until the end of its next turn, the stunned condition ends as soon as the creature delays.
This means pretty much all beneficial effects end on where your turn should have been
End of Turn after the Creature Acts: After the creature returns to the initiative order and takes its delayed turn, it makes the saving throws it normally makes at the end of its turn. In addition, harmful effects that last until the end of the creature’s turn now end—they cannot be avoided by delaying. For instance, if the creature is weakened until the end of its next turn, the weakened condition ends only after it acts.
And this means that you wouldn't get to save until you actually took your turn.
While these lines seem to be specifically in guard against what you mention, they are specifically for Delay Turn. If the same applied to readying an action I would imagine it would specify in a similar manner.
This means that for readied actions you would still get your save at the end of your normal turn and you could be cured of blindness between the end of your turn and your readied action.
However, looking at your example, the Readied Action isn't exactly a freebie. Readied Actions limit you to a single action for one, meaning at most a standard without blindness. On top of that your place in initiative gets moved to just before the triggering creature and they also require you to specify a trigger which you must then adhere to.
Choose Trigger: Choose the circumstance that will trigger the readied action. When that trigger occurs, the creature can use the readied action. If the trigger doesn’t occur or the creature chooses to ignore it, the creature can’t use the readied action and instead takes its next turn as normal.
If you use the trigger you specified, then fail to save on blind, your readied action wouldn't trigger. On top of that if the X doesn't happen after you're able to see, you will similarly not be able to take your action. Even if both trigger you will only have that instance to choose whether to take the trigger or not, limiting your options considerably depending on wording and what you want to do. If you choose to ignore the first opportunity to trigger you lose the readied action. Another downside most people forget is that readying an action that draws an OA draws an OA. So you could in theory get smacked for readying an action that you never get to trigger!
Overall I think a Readied Action is a great solution for those who are blind and don't have a better course of action, but it's far from foolproof or overpowered. Especially considering it risks wasting your standard action just to avoid a -5 penalty on an attack roll (considerable but not insurmountable – you still know the squares people are in unless they're actively hiding).