IOP Fluctuation and Glaucoma Progression: What Do We Know?
IOP Fluctuation and Glaucoma Progression: What Do We Know?
In light of these differing conclusions regarding IOP fluctuation, a reliable method to measure the 24 h IOP curve is paramount. Fogagnolo et al have used regression analysis to predict diurnal IOP based on seated and supine measurements every 3 h in three populations (healthy, young and healthy, elderly patients, and patients with POAG). Based on mathematical analysis, they determined that even by their best estimate of a 24 h IOP curve, values were incorrect in 40% of healthy, young patients, 5% of healthy, elderly patients, and 20% of those with POAG. They concluded that seated IOP alone is inadequate for providing information about peak and mean IOP, and IOP fluctuation.
Bagga et al assert that a telemetric device must be created to measure IOP throughout the night if we are to truly understand IOP variation. There have been several animal studies on the use of surface and implantable IOP monitors, suggesting they may be safe and accurate. Authors have also begun reporting promising results in human studies of contact lens-based IOP sensors.
Potential limitations of this technology that must be addressed include: user discomfort; effects on visual acuity; power supply to allow for IOP monitoring over several days or months; and a continued reliance on measurements inferred in reference to corneal properties as opposed to a true measure of ocular tension.
Future of IOP Analysis
In light of these differing conclusions regarding IOP fluctuation, a reliable method to measure the 24 h IOP curve is paramount. Fogagnolo et al have used regression analysis to predict diurnal IOP based on seated and supine measurements every 3 h in three populations (healthy, young and healthy, elderly patients, and patients with POAG). Based on mathematical analysis, they determined that even by their best estimate of a 24 h IOP curve, values were incorrect in 40% of healthy, young patients, 5% of healthy, elderly patients, and 20% of those with POAG. They concluded that seated IOP alone is inadequate for providing information about peak and mean IOP, and IOP fluctuation.
Bagga et al assert that a telemetric device must be created to measure IOP throughout the night if we are to truly understand IOP variation. There have been several animal studies on the use of surface and implantable IOP monitors, suggesting they may be safe and accurate. Authors have also begun reporting promising results in human studies of contact lens-based IOP sensors.
Potential limitations of this technology that must be addressed include: user discomfort; effects on visual acuity; power supply to allow for IOP monitoring over several days or months; and a continued reliance on measurements inferred in reference to corneal properties as opposed to a true measure of ocular tension.