Perimetric progression in open angle glaucoma and the Visual Field Index (VFI).

Area of Science:

• Ophthalmology
• Glaucoma Research
• Visual Field Analysis

Background:

• Glaucoma is a progressive optic neuropathy leading to irreversible vision loss.
• Accurate detection of perimetric glaucomatous progression is crucial for timely intervention.
• The Visual Field Index (VFI) is a summary metric derived from standard automated perimetry (SAP).

Purpose of the Study:

• To evaluate changes in the Visual Field Index (VFI) in eyes with perimetric glaucomatous progression.
• To compare VFI progression against stable glaucoma patients.
• To assess the diagnostic performance of VFI and Glaucoma Progression Analysis II (GPA II) against expert consensus.

Main Methods:

• Retrospective analysis of open-angle glaucoma patients with at least 6 reliable visual fields and 2 years of follow-up.
• Perimetric progression assessed by 4 masked glaucoma experts, categorized as definite, suspected, or no progression.
• Comparison of expert assessment with VFI linear regression slope and GPA II, defining progression as a significant negative slope (<5%).

Main Results:

• 397 visual fields from 51 eyes of 39 patients were analyzed.
• Mean VFI linear regression slope showed statistically significant differences across progression categories (P<0.001).
• VFI analysis and GPA II demonstrated high specificity (0.93 and 0.90) but low sensitivity (0.45 and 0.41) compared to expert consensus.

Conclusions:

• The mean VFI regression slope significantly differed between eyes with no progression versus those with suspected or definite progression.
• Both VFI analysis and GPA II offer high specificity but limited sensitivity for detecting glaucoma progression when compared to expert opinion.