Amalensi ashintsha umbala, aziwa nangokuthi "ama-photosensitive lens". Ngokomgomo we-photochromatic tautometry reversible reaction, ilensi ingaba mnyama ngokushesha ngaphansi kwemisebe yokukhanya ne-ultraviolet, ivimbe ukukhanya okunamandla futhi imunce ukukhanya kwe-ultraviolet, futhi ibonise ukumuncwa okumaphakathi kokukhanya okubonakalayo. Emuva ebumnyameni, ingabuyisela ngokushesha isimo esisobala esingenambala, iqinisekise ukudluliswa kwelensi. Ngakho-ke, ama-lens ashintsha umbala afaneleka ukusetshenziswa kwangaphakathi nangaphandle ngesikhathi esifanayo ukuvimbela umonakalo wokukhanya kwelanga, ukukhanya kwe-ultraviolet nokucwebezela kwamehlo.