Evaluation of the Brusini Glaucoma Staging System for Typing and Staging of Perimetric Results

Abstract

Background: Brusini’s recently introduced glaucoma staging system (GSS) categorizes visual-field damages into different types (i.e. generalized, mixed and localized) and classifies them into stages similar to those of Aulhorn-Karmeyer. Basically, the Brusini GSS is a scatterplot of mean defect (x-axis) and corrected loss variance (CLV; y-axis). The Brusini GSS charts are claimed to be simple to understand due to their 2-dimensional spatial representation and there is no subjective interpretation necessary, since their numerical presentation provides an objective evaluation. Inter- and intraindividual comparisons are, thus, provided ‘at a glance’. Methods: Retrospectively, 610 visual fields (Octopus 201, Program G1) for each eye of 32 glaucoma patients were inspected on screen with PeriData 7.0. The performance of the Brusini GSS was evaluated in terms of typing of visual-field defect and staging as defined by the Aulhorn-Karmeyer classification. Results: Typing of defects into ‘normal’ and various degrees of generalized and localized damage agreed with PeriData in 89% of fields; 5% were wrongly classified as normal by the Brusini GSS. The type of visual defect showed in 1.3% fields as marked and in 5% a minor discrepancy. Most of the 11% of nonagreement was due to high short-term fluctuation. Agreement could potentially be enhanced by using loss variance instead of CLV. Staging of visual-field defects with Brusini GSS charts was in agreement with the Aulhorn-Karmeyer classification in 73% of fields. Conclusion: The authors recommend the Brusini GSS because of its simplicity to concisely describe visual-field damage for clinical use as well as research work and because of the remarkably good agreement with the well-known Aulhorn-Karmeyer classification.