Detection of visual field progression in glaucoma

BACKGROUND: The aim of this study was to compare an event analysis and a trend analysis for the detection of progression in glaucomatous visual field loss. PATIENTS AND METHODS: Excluding initial fields (Octopus, Haag-Streit AG, Köniz, Switzerland), baseline was defined as the average result of the second and third examinations. Eyes with at least 6 additional fields entered the study. The event analysis used the method of the Collaborative Normal Tension Glaucoma Study, and the trend analysis was based on a point-wise linear regression analysis. RESULTS: Of 251 glaucoma patients, 235 left eyes and 225 right eyes qualified for the study. Using the event analysis, 44 series suggested a progressive damage, while the point-wise regression approach disclosed only 14 progressing series. In 9 eyes, the two approaches were concordant. Among the latter, 1 - 5 additional fields were necessary in 7 series to disclose progression using the trend analysis. In one series, the event analysis showed progression 7 examinations later. CONCLUSIONS: The point-wise linear regression analysis classified fewer cases as progressing than the event analysis and determined progression later.