Here's how the physicist David Deutsch (2011) describes qualia:
Consider the following thought experiment. You are a biochemist with the misfortune to have been born with a genetic defect that disables the blue receptors in your retinas. Consequently you have a form of colour blindness in which you are able to see only red and green, and mixtures of the two such as yellow, but anything purely blue also looks to you like one of those mixtures. Then you discover a cure that will cause your blue receptors to start working. Before administering the cure to yourself, you can confidently make certain predictions about what will happen if it works. One of them is that, when you hold up a blue card as a test, you will see a colour that you have never seen before. You can predict that you will call it 'blue', because you already know what the colour of the card is called (and can already check which colour it is with a spectrophotometer). You can also predict that when you first see a clear daytime sky after being cured you will experience a similar quale to that of seeing the blue card. But there is one thing that neither you nor anyone else could predict about the outcome of this experiment, and that is: what blue will look like. Qualia are currently neither describable nor predictable — a unique property that should make them deeply problematic to anyone with a scientific world view (though, in the event, it seems to be mainly philosophers who worry about it).
It is now sometimes possible for those born deaf (or blind) to hear (or see) for the first time in adulthood.
Have philosophers studied these experiences? How have these experiences changed (or not changed) philosophers' understanding of qualia?
Is it for example true that those who were born deaf/blind but then were able to hear/see for the first time were completely unable to describe or predict before the fact what hearing or seeing is like?