A lens system comprises a first electro-active lens comprising a first focus sensor coupled to a first processor and a second electro-active lens comprising a second focus sensor coupled to a second processor. The first focus sensor periodically generates electromagnetic signals and detects electectromagnetic signals generated by the second focus sensor. The second focus sensor periodically generates electromagnetic signals and detects electectromagnetic signals generated by the second focus sensor. The first processor receives an indication of the second electromagnetic signals and, based on the received indication of the second electromagnetic signals, determines a relative convergence angle between the first and second electro-active lenses. Based on the determined relative convergence angle, the first processor determines a focal setting for the first electro-active lens and controls an electroactive element in the first electro-active lens, based on the determined focal setting.