By Alan S. Crandall, MD
This very important editorial in the March issue of the Journal of Glaucoma by two of the most eminent glaucoma teachers emphasizes thinking in terms of the entire glaucomatous process, from the initial event to the end-stage loss of vision. The authors, M. Bruce Shields, MD, and George L. Spaeth, MD, discuss how this approach can help manage the entire process. They propose modifying the current definition of glaucoma to emphasize the various complex processes, including the influence of IOP, which may lead to glaucomatous optic neuropathy.
They say that the first three stages of glaucoma represent pre-glaucoma events that occur before any sign of manifest glaucoma. The final two stages of the glaucomatous process represent manifest glaucoma.
The clinical significance of being in one of the pre-glaucoma stages varies considerably depending on the likelihood of progressing toward glaucomatous optic neuropathy, but it alerts physicians and patients to the level of risk and allows for the development of a reasonable strategy for observation or possible early intervention.
The authors recommend the development of standardized definitions for the stages of the glaucomatous process. This would allow for the grouping of patients according to their disease severity, which permits more appropriate treatment. They say that staging also allows clinicians to explain to patients the relative severity of their condition.
On the research side, disease staging may help investigators who are evaluating new diagnostic techniques or treatments and need to know whether a particular method will apply equally well at all disease stages. It also helps insure that different treatment groups within a study are at a comparable stage.
The authors say that as knowledge regarding the mechanisms and management of the glaucomatous process for all forms of glaucoma continues to expand, it is likely that more patients will be diagnosed and treated at increasingly earlier stages in the process. They say that in the future, patients with a gene mutation for a form of glaucoma may be treated at the optimal time with gene therapy, despite the absence of any apparent structural or functional abnormality.
The authors hope to see the development of a comprehensive, internationally-accepted staging system for the entire glaucomatous process, including the earlier events that may lead to manifest glaucoma. They believe that emphasizing the entire glaucomatous process, including both the pre-glaucoma and manifest glaucoma stages, in the definition of glaucoma and having standardized, well-defined stages for the process will serve as a useful framework to accommodate expanding knowledge of this complex group of disorders, guide research and improve patient outcomes.