The Gavia are simple glasses without any adjustment at the sides or nose. They're designed to fit small to wide faces, though we can't see how, given the lack of adjustability.
That said, they happened to fit me well, staying put comfortably, without pinching my nose or putting pressure on my head. The wraparound gives good coverage at the sides and the lenses come down quite low onto the cheeks, but airflow is still good. We noticed a slight disruption in the view when looking out near the bottom of the lenses. It initially made things seem further away, but we quickly adapted to it without problems. They claim to transmit 36.2% of light, which worked well on bright UK days and in low light too. They are extremely light and comfortable to wear and the non-rubbery arms lie flat for little interference with helmet straps.