Abstract
Purpose: :
To estimate global and pointwise rates of progression in glaucoma eyes progressing according to event analysis (Guided Progression Analysis or GPA).
Methods: :
274 eyes (207 patients) with suspected or definite glaucoma and 5 or more years of follow-up and 7 or more reliable visual fields were selected from UCLA’s clinical database. Eyes detected as progressing according to GPA criteria were identified. Global regression analyses using mean deviation (MD) and visual field index (VFI) and pointwise linear regression analyses (PLR) were performed including only exams up to the time of first progression according to GPA for progressors or including all exams for nonprogressors. Rates of progression were compared in progressing and nonprogressing eyes with various criteria.
Results: :
The average (± SD) baseline MD, number of VFs, and follow-up time was -4.3 (± 4.5) dB, 10.8 (± 2.8) and 8.5 (± 2.4) years, respectively. Seventy-one eyes (26%) of 62 patients progressed based on GPA with a median (range) of 3 (3-8) worsening test locations per eye. The median (interquartile range) absolute change in MD and VFI in progressing eyes was -3.1 (-1.6 to -4.8) dB and -8% (-4% to -15%), compared to -0.9 (0.6 to -2.6) dB and -1% (0 to -5%) in nonprogressing eyes (p <0.001). A statistically significant global slope (p<0.05) was observed in 54% and 62% of the progressing eyes according to MD and VFI compared to 22% and 22% in nonprogressing eyes (kappa=0.34 ± 0.06 vs. 0.46 ± 0.06, respectively, for agreement with GPA). The median pointwise rate of progression was -2.1 dB/year (interquartile range: -3.6 to -1.0 dB/year) and decreased with increasing time to event (Spearman’s r =0.57; p<0.001). Worsening according to established PLR criteria (slope <-1.0 dB/year and p<0.01) was observed in 84 out of 270 test locations (31%) demonstrating progression on GPA compared to 64% and 81% of test locations when less stringent p cutoff values of <0.05 and <0.1 were used without cutoff points for the rate of change.
Conclusions: :
There was only fair agreement between trend analyses of global indices and event analysis (GPA) for detection of glaucoma progression. VFI trend analysis demonstrated a stronger agreement with event analysis as compared to MD. Less stringent criteria for PLR improved its agreement with pointwise event analysis (GPA).
Keywords: visual fields • perimetry