Glaucoma risk factors: Fluctuations in intraocular pressure
Intraocular pressure (IOP) has been consistently demonstrated to be associated with incidence, prevalence, and progression of glaucoma. However, although there is strong evidence to support mean IOP as a risk factor for both development and progression of the disease, there is uncertainty with regard to the role of IOP fluctuations in glaucoma. One of the difficulties in investigating this relationship comes from the concept of IOP fluctuation. Some authors define fluctuation as variation in IOP during the diurnal period. Others include the nocturnal period as well and point out that one should look at 24-h fluctuation as an important parameter for glaucoma progression. Finally, others have defined IOP fluctuation as the variability in IOP measurement between visits, which is often called long-term fluctuation. The role of very short-term fluctuations in IOP is explored in Sidebar 4.1. © 2010 Springer-Verlag New York.