By the way, “again” in that context doesn’t necessarily imply his eyes deteriorated before. It references the previous change, but that includes the improvement, not just some hypothetical previous instance of deterioration.
It’s like saying “he went in the door, then he went back out again,” which doesn’t imply he had previously exited.
He mentions that his eyes will deteriorate again once he leaves Ba’ku
From https://memory-alpha.fandom.com/wiki/Geordi_La_Forge#Early_life :
By the way, “again” in that context doesn’t necessarily imply his eyes deteriorated before. It references the previous change, but that includes the improvement, not just some hypothetical previous instance of deterioration.
It’s like saying “he went in the door, then he went back out again,” which doesn’t imply he had previously exited.