'見えはしないか' confused


I'm sure I'm going to kick myself on this, but for some reason I just can't
get my head around it. From Harry Potter and the Philosopher's Stone:

> 二人が通りの端から端まで、車のヘッドライトが **見えはしないか** と探している間に、音は確実に大きくなってきた。

Is this the grammar construction するかしないかのうちに as in: " _no sooner had they
blah, then blah_ "?

Is 見え the noun form of the potential form of 見る or just a word that I can't
seem to find in either of my dictionaries? Does it mean a sight or a glimpse
(as per the English version)?




(From comment)

This actually is not the gramatical construction of するかしないかのうちに as in: "no
sooner had they blah, then blah"?

Here, 見えはしない, in the meaning, generally the same with 見えない (except that the
sense of は is added)

