On the special status of this ghazal, see {485,1}.
Here is an elegant illustration of the need to pay close attention to grammar-- not despite, but because of, the extreme shortness of the meter. When we initially encounter the first line, we can hardly help but take abr kii :tara;h as 'like a cloud', since we're so accustomed to the usage of X kii :tara;h to mean 'like X', and since 'like a cloud' is a perfectly normal and common phrase to encounter in the ghazal world. Under the mushairah performance conditions for which these verses were composed, after hearing the first line we'd be made to wait as long as possible (through an obligatory chorus of admiring exclamations from the audience and expressions of gratitude from the poet) before being allowed to hear the second line.
When we heard the second line, we'd at once realize that the grammar didn't fit-- kii sii needed something feminine to modify, and the only plausible candidate was the :tara;h in the first line. So we'd go back and reframe the grammar to turn :tara;h into a noun (see the definition above). But remember, in a mushairah setting we'd be doing this on the fly, and in our heads. The result would be an enjoyable buzz of mental activity that would soon yield a satisfying result by rewarding us with a cleverly contrived bit of what might be called not wordplay but meaning-play.
For it turns out that rather than the speaker's eyes being 'like a cloud', the exact opposite is true-- the :tara;h of the cloud is like that of his eyes, and not the other way around. His eyes are primary, and the cloud imitates or reflects them. As so often in the ghazal world, the microcosm enjoyably precedes, and sometimes even generates, the macrocosm.
In addition to this meaning-play, there's a nice bit of wordplay too. The injunction to 'look', which the first time around we hardly notice, turns out to have a wonderful kinship with the eyes-- eyes that are so full of water/tears that they might in fact be unable to see. And there are the noticeable sound effects of abr , ab , aab . Not a bad array of pleasures for Mir to offer us through thirteen small words.
Note for grammar fans: In the first line, ab ke is an adverb of time; it's invisibly followed by a colloquially-omitted vaqt . In the second line, chashm is grammatically singular but generally refers to both eyes (as with 'eyebrow(s)' in {485,5}).
