A head-mounted device may have a housing containing displays that display images a user when the head-mounted device is worn by the user. The head-mounted device may include a light-shielding structure or light seal coupled to the housing and configured to rest on a nasal region of the user. The light-shielding structure may include flexible members and/or fabric members. For example, the flexible members may be elastomeric members having perforations that allow the light-shielding structure to conform to the facial features of the user around the nasal region, while maintaining rigidity. Additionally, the light-shielding structure may block environmental light from entering the eye boxes when the head-mounted device is worn by the user. Rigid or semi-rigid members may be added on or within the light-shielding structure to provide additional rigidity and support as the device is worn by the user.