A curved image sensor system includes (a) an image sensor substrate having a concave light-receiving surface, a pixel array located along the concave light-receiving surface, and a planar external surface facing away from the concave light-receiving surface, (b) a light-transmitting substrate bonded to the image sensor substrate by a bonding layer, and (c) a hermetically sealed cavity, bounded at least by the concave light-receiving surface, the light-transmitting substrate, and the bonding layer.