The Second Department concluded the trial court should have allowed the cross-examination of a witness about a physical characteristic of the defendant the witness had not mentioned to the police:

“[A] witness may not be impeached simply by showing that he [or she] omitted to state a fact, or to state it more fully at a prior time” … . However, impeachment by omission is permissible when the witness omits a critical fact … . “An omission of fact at a prior time is insufficient for impeachment purposes unless it is shown that at th[at] prior time the witness’ attention was called to the matter and that he [or she] was specifically asked about the facts embraced in the question propounded at trial'” … . ” [C]urtailment [of cross-examination] will be judged improper when it keeps from the jury relevant and important facts bearing on the trustworthiness of crucial testimony'” … . Here, given the eyewitness’s testimony which demonstrated that the defendant’s “squinting,” “partly closed” left eye was a significant factor in his identifying the defendant as the assailant, the trial court erred in precluding the defendant from cross-examining the eyewitness about his omission of this observation of the assailant’s appearance when he described the assailant to the police… . People v Greene, 2013 NY Slip Op 06589, 2nd Dept 10-9-13