Refining Visual Field Trend Progression Criteria in Glaucoma

Abstract

Purpose

To assess the stability of visual field (VF) progression events and to evaluate strategies to reduce false-positive (FP) progression.

Design

Retrospective study.

Subjects

Two thousand one hundred thirty-three eyes of 2133 patients with 12 consecutive VF tests from five National Health Service glaucoma clinics.

Methods

A progression event was defined as a negative slope and P value < 0.05. False-positive progression events (“reversions”) were defined as events where the P value fell below 0.05 at ≥ 1 visit and subsequently rose above 0.05 at a later time point. The impact of stricter probability thresholds (P < 0.02, 0.01 and 0.005) and event assessment at later visits on FP progression was evaluated.

Main Outcome Measures

Frequency of FP progression events.

Results

Four hundred fifty-seven (21.4%) eyes had at least one reversion at the P < 0.05 threshold, for a median interval of 2 visits. The mean rate of change at the time of apparent progression was –1.05 dB/year (95% confidence interval –1.19 to –0.92 dB/year). The proportions of eyes with FP progression events were significantly lower at stricter probability thresholds (13.7%, 9.9%, and 7.7% at P < 0.02, < 0.01, and < 0.005, respectively; P < 0.001). Using stricter thresholds conferred significantly lower hazards of FP progression (hazard ratio 0.60 for P < 0.02, 0.42 for P < 0.01, and 0.38 for P < 0.005; all P < 0.001).

Conclusions

A substantial proportion of apparent progression at the established P < 0.05 threshold may be falsely positive. Using stricter probability thresholds and initiating event detection at later visits may improve progression specificity in clinical practice.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.