The 16ms X-ray pulsar PSR J0537 - 6910 in SNR N157B is the fastest known isolated ( non-recycled ) pulsar and , with a rotational energy loss \dot { E } \sim 4.8 \times 10 ^ { 38 } erg s ^ { -1 } , is the most energetic ( together with the Crab ) .
Here we report the results of optical observations of the field , recently performed with the SUSI2 camera of the NTT .
Few objects are observed inside the \simeq 3″ X-ray error circle but none of them can be convincingly associated to the pulsar , which appears undetected down to V \sim 23.4 .
With a corresponding optical luminosity L _ { opt } \leq 1.3 \times 10 ^ { 33 } erg s ^ { -1 } , PSR J0537 - 6910 is , at best , comparable to the other very young pulsars Crab and PSR B0540 - 69 .