The ciliary muscle reproduces the effect of a lens and allows the eye to focus or blur vision. The ciliary muscle became the emblem of the critical vision that Diller + Scofidio (+ Renfro) had of their heterogeneous fields of research and experimentation. Their interdisciplinary projects range from objects, installations and performances to media and architecture. In recent years they have expanded - with a third partner joining their studio - to embrace projects on an urban scale. Diller + Scofidio (+ Renfro): The Ciliary Function covers their development documenting about twenty works, from the earliest to the most recent and includes essays investigating the studio's context, influences and strategies, some interviews with the architects, and a scheme showing the evolution and growth of the studio from 1979 to today.