Additional Contributions: Hans Von Gizycki, PhD, provided statistical consultation. Zoya Belakovskaya, BS, and Mr. Alexander Belakovski provided technical support. Nancy Blace, MD, PhD, performed preliminary data collection. Muhammad Javaid, MD, assisted with graph preparations. Manuela E. Minko, MD, assisted in scheduling patients. Patricia Kavanagh, MD, referred and recruited patients. Hossam Attia, MD, performed a preliminary study comparing GDx Nerve Fiber Analyzer measures in patients with glaucoma and PD; he and Preeti Poley, MD, performed preliminary Glaucoma Diagnosis data collection.