Exegesis:

autōn de diēnoichthēsan hoi opthalmoi lit. ‘of them the eyes were opened.’ autōn is emphatic by position. The opening of the eyes is to be understood in a metaphorical way. Its result is expressed non-metaphorically in the following clause. As in v. 16 the agent is God.

dianoigō ‘to open,’ in a figurative sense of the opening of the eyes, i.e. of making people recognize (here), of the opening of the scriptures, i.e. of making people understand them (v. 31), of the opening of the mind, i.e. of making people understand (v. 45, also with reference to the scriptures).

epegnōsan auton ‘they recognized him,’ ingressive aorist.

kai autos aphantos egeneto ap’ autōn ‘and he became invisible from them,’ i.e. ‘he disappeared from their sight.’

aphantos ‘invisible.’

Translation:

The sentence their eyes were opened and they recognized him is in meaning the opposite of v. 16 (which see), and closely corresponds to it in form. This formal similarity can quite often, it seems, be preserved in translation without discarding the requirements of idiom and clarity, e.g. ‘the spell was taken from their eyes,’ ‘their eyes/sight became clear,’ etc. The preservation of another stylistic feature, however, i.e. the repetition of ‘opened’ in vv. 32 and 45, appears often to be incompatible with such requirements.

And he vanished out of their sight, or, ‘then (or, at that very moment) he became invisible to them’ (cf. Ramabai’s Marathi version: ‘he became he could not be seen by them’). In Kele the idiom is, ‘he no longer appeared before their eyes,’ and in Tzeltal, ‘he was lost to their eyes.’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.