Human beings are technology too, albeit very complicated technology. Another quote from Douglas Adams[1] sums up humans as machines quite well: "Any sufficiently advanced technology is indistinguishable from magic"

Altering and improving human beings is not undoable, it's simply a hard engineering problem. The technological improvement of human eyes started out with glasses, then contact lenses, then laser operations and eye surgery. There's no reason to believe we won't eventually overcome the problems stated in the article by clever engineering of the eyes and brain.

[1]As Bellaire pointed out below, the quote is from Arthur C. Clarke and not Douglas Adams.