Agreement to Detect Glaucomatous Visual Field Progression by Using Statistical Analysis and Clinical Judgment

Abstract

Purpose: : To examine the level of agreement between statistical analysis and clinical judgment by using standard Humphrey printout (SHP), glaucoma progression analysis 1 (GPA) and 2 (GPA2).

Methods: : This is a multicenter, retrospective and longitudinal study. Forty glaucomatous eyes were recruited in the study. Each visual field (VF) was assessed by Humphrey Field Analyzer (HFA), program SITA standard 30-2 or 24-2 (Carl Zeiss Meditec, Inc., Dublin, CA). Progression was analyzed by using statistical analysis and clinician judgment. For the statistical analysis, linear regression (r²) was calculated for MD, PSD and VFI and when it was significant, each series of VF was considered progressive. Then 9 expert clinicians assessed the progression status of each series by using SHP, GPA and GPA2. The progression criteria adopted by the clinicians were similar to the GPA algorithm comparing single field printout with the baseline exams. The agreement was evaluated using a weighted kappa statistic.

Results: : Forty visual field series were analyzed by the 9 physicians. The mean follow-up time was 6.2 ± 1.53 years (mean ± standard deviation). At baseline the mean MD was -7.34 ± 7.18 dB and at the end of the follow-up the mean MD was -9.25 ± 8.65 dB, this difference was statistically significant (p<0.001). The agreement to detect progression was 0.28 ± 0.17 between MD r² and PSD r², 0.67 ± 0.13 between MD r² and VFI r² and 0.28 ± 0.19 between PSD r² and VFI r². When we compared statistical analysis to clinical judgment, the mean agreement was 0.58 ± 0.14 between MD r² and VFI judgment, 0.75 ± 0.11 between VFI judgment and VFI r², 0.43 ± 0.15 between overview judgment and MD r², 0.12 ± 0.15 between overview judgment and PSD r² and 0.53 ± 0.15 between GPA judgment and MD r².

Conclusions: : A substantial agreement was found between MD r² and VFI r² and between VFI judgment and VFI r². GPA2 can help ophthalmologists to detect glaucoma progression.

Keywords: perimetry • visual fields