Abstract
Purpose: :
To evaluate the effect of 24-hour peak intraocular pressure (IOP) on the progression of primary open-angle glaucoma (POAG).
Methods: :
A retrospective analysis of clinical data evaluating long-term glaucomatous progression in patients who: were previously in a 24-hour study (IOP readings at 2/6/10 AM and 2/6/10 PM) of the authors (AGPK/LQ/WCS); had ≥3 treated 10 AM (± 1 hour) IOP measurements over 5-years following an untreated 24-hour baseline; and had a treated 24-hour curve with a 10 AM IOP ± 2 mm Hg within the 10 AM mean IOP over 5-years.
Results: :
We included 98 non-progressed and 53 progressed POAG patients (n=151). The mean 24-hour peakIOP was 19.9 ± 2.7 for progressed and 18.3 ± 2.0 mm Hg for non-progressed patients (P<0.001). Progressed patients also showed a higher mean 24-hour IOP than non-progressed patients. Peak 24-hour IOP occurred most frequently at 10 AM. However, 31 (20%) of all patients and 9 (17%) of progressed patients had their peak IOP at a time point(s) only outside normal office hours (10 PM, 2/6 AM). Generally, patients with a mean or peak daytime (readings at 10 AM, 2/6 PM), or 24-hour peak IOP, of ≤18 mm Hg remained non-progressed in 75-78% of cases. Further, measuring IOP at night found a higher peak in only 20% of cases which was ≤2 mm Hg of the daytime peak in 98% of cases. In addition, using the daytime peak IOP, together with the daytime mean IOP, to better identify progressed patients added little (78% non-progression rate at ≤18 mm Hg) beyond those found by the daytime mean IOP alone (75% non-progression rate). A multivariate regression analysis showed only the 24-hour peak IOP as an independent risk factor for progression (P=0.002).
Conclusions: :
This study suggests that daytime peak IOP may be clinically important in predicting long-term glaucomatous progression. Further, daytime peak IOP may assist, as much as daytime mean IOP and, in most cases, 24-hour peak IOP, in helping to guide long-term treatment in POAG.
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials • clinical (human) or epidemiologic studies: risk factor assessment