Expert Evaluation of Visual Field Decay in Glaucoma Correlates With the Fast Component of Visual Field Loss

To compare the assessment of serial visual fields (VFs) based on subjective expert evaluation with the fast and slow VF component rates determined with pointwise exponential regression (PER) and pointwise linear regression (PLR).

A total of 5272 VF examinations from 376 eyes diagnosed with open-angle glaucoma were included. Three glaucoma specialists assessed each VF qualitatively to evaluate progression status and the qualitative rate of progression. The rates of VF decay were determined with PER and PLR at each VF location, which were ranked according to the regression coefficient and partitioned into 2 groups (fast and slow). A mean rate for the fast and slow partitions was obtained based on the average of the regression coefficients in each partition. κ-values were used to measure the agreement among the experts and the PER and PLR algorithms.

The average baseline VF mean deviation for the study sample was -6.6 (±5.9) dB. The agreement of the likelihood of progression among the dichotomized experts' score and PER was moderate (κ=0.41, P<0.01) and fair (κ=0.39, P<0.01) for PLR. The agreement of the likelihood of progression among the 3 dichotomized experts' scores was fair (κ=0.22, P<0.01). The agreement of the area of worsening among the dichotomized experts' score and PER and PLR were both moderate (κ=0.48, P<0.01; κ=0.46, P<0.01). The eyes flagged by experts as having "fast" progression rates had a higher average rates of decay for PER and PLR at -2.7 (±4.1) %/year and -0.8 (±1.2) dB/year; eyes flagged as "slow" had lower rates of decay at -0.3 (±1.5) %/year and -0.1 (±0.5) dB/year.

Expert qualitative evaluation of field series for change and rate of change correlate more closely with the fast component than with the slow component of VF decay.