Glaucoma is a group of chronic, neurodegenerative diseases of the optic nerve, which leads to an increase in intraocular pressure, gradual changes in the visual field (VF), and progressive vision loss. Glaucomatous vision loss is preventable with proper eye care, including adherence to follow-up appointments and medications. Interventions that improve appointment adherence have the potential to prevent more severe glaucomatous disease. The primary purpose of this study is to determine the efficacy of a multifaceted intervention system, which includes a customized letter and personal telephone outreach, in improving appointment adherence in patients with glaucoma. In order to improve strategies to reduce the rate of appointment non-adherence, shared characteristics of adherent versus non-adherent patients with glaucoma will be identified and compared to patient characteristics in the previous literature. A secondary goal of this study is to analyze the cost-effectiveness of this multifaceted intervention on appointment adherence in patients with glaucoma.