Abstract: In the field of eyesight correction, there is a need for "universal" spectacles that can be tailored in situ to suit an individual's requirements. The disclosure relates to an apparatus, which may be in the form of a pair of spectacles (1) including one or more liquid lenses (11a, 11b). The apparatus also includes a sealable duct (24) and a pump (e.g., a syringe) for adjusting the pressure of liquid in the liquid lens. In use, the apparatus is adjusted to provide eyesight correction for an individual. The duct (24) is then sealed, thereby rendering the apparatus subsequently non-adjustable and therefore permanently tailored to the requirements of the individual. The disclosure also relates to an apparatus in the form of a flexible membrane mirror.