Abstract: A head-mounted device may include optical assemblies for presenting images to a user. Motors may be used to adjust the spacing between the optical assemblies to accommodate different interpupillary distances. The head-mounted device may have a housing that receives a custom-fit removable light seal with vision correction lenses. A sensor or wireless transceiver in the housing may receive interpupillary distance information from the light seal. Based on this information, the motors may adjust the optical assemblies so that the optical assemblies are spaced apart by an amount that matches the interpupillary distance associated with the user of the custom-fit removable light seal.