"Oculus" is comprised of a single movement for chamber orchestra. The title refers to the circular opening at the top of a domed structure such as the Pantheon in Rome. An oculus allows natural light to flow freely in and out of a dome. The expansion and contraction of light can dramatically alter the overall appearance and mood of a space. I attempted to create a musical atmosphere where the sound is expanding and contracting on a variety of levels. Fluctuation occurs initially through the use of orchestration. The stasis of the opening gives way to a more regular harmonic rhythm. The harmonies, rhythms, and timbres that define this work undergo constant manipulation. Expansion and contraction occur within the individual phrases as well as in the overall structure. While the materials are simple, the ever-changing texture provides definition and contrast. (Abstract shortened by UMI.)