VISUAL-FIELD PROGRESSION - COMPARISON OF HUMPHREY STATPAC2 AND POINTWISE LINEAR-REGRESSION ANALYSIS

Background: Humphrey Statpac2 'glaucoma change probability analysis' i s a widely available analysis technique to aid the clinician in the di agnosis of glaucomatous visual field deterioration. A comparison of th is technique with the more recently described pointwise linear regress ion analysis (PROGRESSOR) is given. Methods: Series of visual field da ta from a group of nine eyes of nine patients with normal-tension glau coma were selected. Each series had 16 fields with mean followup of 5. 7 years (SD 0.6 years). Statpac2 'glaucoma change probability analysis ' was used to define test locations that had unequivocally deteriorate d in the last three fields of each series, The accuracy of both Statpa c2 and PROGRESSOR in providing early detection of these deteriorated l ocations was assessed. Results: The sensitivity and specificity of the two techniques in predicting deteriorated locations were similar when a rate of luminance sensitivity loss of faster than 1 dB/year (2 dB/y ear for outer locations beyond 15 deg of eccentricity) with a slope si gnificance of P<0.10 was used as the regression definition of deterior ation. The difficulties of comparing two techniques in the early diagn osis of field progression without a true external standard for field l oss are illustrated. Conclusions: PROGRESSOR closely emulates the perf ormance of Statpac2 in detecting sensitivity deterioration at individu al test locations. This new technique, which uses all available data i n a field series and gives the rate of sensitivity loss at each locati on, may provide a clinically useful method for detecting field progres sion in glaucoma.