 Trend analysis: Baseline
 Trend analysis: Follow-up
 Single Field Analysis | | Humphrey® Glaucoma Progression Analysis™ (GPA™) Software helps practitioners accurately identify clinically significant progression of visual field loss in glaucoma patients.
The GPA™ highlights any changes from selected baseline exams that are larger than typical clinical variability – as shown in Figure 1, and provides simple plain-language indicators whenever changes show consistent and repeatable patterns of loss. The software analyzes a series of visual field exams (white Size III stimulus) obtained using the Full Threshold, SITA™ Standard and SITA™ Fast testing strategies. The analysis corrects for ocular media effects in order to help the practitioner differentiate between localized loss typical of glaucoma, and overall depression.
Issues facing visual field progression analysis today
- Variability in patient test and re-test
- Multiple exams required to detect change
- How much change confirms change
- Estimating "rate" of progression is difficult with today's tools
Advantages of GPA-SW
- Enrolled Glaucoma Patients in 16-Center Trial to Quantify Variability
- Uses SITA and Pattern Deviation to Identify Glaucoma-Specific Progression
- Employs Strict Progression Criteria from EMGT Study ("Measuring Visual Field Progression in the Early Manifest Glaucoma Trial", Heijl, Leske,Bengtsson, Bengtsson,Hussein, et. al., Acta Opht. Scandinavica 2003)
- Mean Deviation Slope Plot Helps Identify High-Risk Patients
Criteria For Identifying Progression in Visual Fields
- Minimum of three tests required: 2 baseline and 1 follow-up exam
- Each follow-up compared to averaged thresholds of 2 baseline exams
- Additional follow-up compared both to baseline and to 2 most recent follow-ups
- Symbols:
 = Progression at 95% significance level
 = Progressing point repeated in two consecutive exams
 = Progressing point repeated in three consecutive exams
- GPA AlertTM: Three  in one exam denotes "Possible Progression" and three  indicates "Likely Progression" | |  OFS White Paper
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