A chamber includes a sealed connection assembly sliding inside a translation plane, having two rigid parts, one of which comprises a groove. A planar seal and at least one O-ring seal are positioned in the groove, with the O-ring seal under the planar seal. An active surface of the planar seal, which projects above the groove, is compressed against a planar bearing surface of the other rigid part. The chamber can be used in a device for applying a plastic film onto a spectacle lens, in order to move the lens inside a variable-pressure space.