Progression of Glaucoma is the topic of the eighth World Glaucoma Association Consensus. There has been considerable attention to the diagnosis of glaucoma during the past twenty years. In fact, this was the topic of the inaugural WGA consensus report in 2003. During the past decade, however, numerous studies have been undertaken to also investigate the progression of glaucoma. With substantial improvement in existing diagnostic technologies and the rapid development of others, one can better determine whether there has been progressive disease. Hence, the results of this report will have broad and significant impact on clinical practice and glaucoma research. The global faculty, consisting of leading authorities on the clinical and scientific aspects of glaucoma progression, met in Paris on June 28, 2011, just prior to the World Glaucoma Congress, to discuss the reports and refine the consensus statements.As with prior meetings, it was a daunting task to seek and obtain consensus on such a complicated and nuanced subject. It is unclear how each of us decides how we practice, and evidence to guide us often is sparse. Collection of patient data to study progression often takes years. Hence, this consensus, as with the others, is based not only on the published literature, but also on expert opinion. Although consensus does not replace and is not a surrogate for scientific investigation, it does provide considerable value, especially when the desired evidence is lacking. The goal of this consensus is to provide a foundation for identifying progression of glaucoma and how it can be best done in clinical practice. Identification of those areas for which we have little evidence and, therefore, the need for additional research always is a high priority. We hope that this consensus report will serve as a benchmark of our understanding. However, this consensus report, as with each of the others, is intended to be fluid. It is expected that it will be revised and improved with the emergence of new evidence.