Assessment of Structural Progression in Glaucoma Through Automated Optic Nerve Head Hemoglobin Measurements.

Abstract

Prcis: Automated optic nerve head hemoglobin measurements through change overtime in the Globin Individual Pointer (GIP) index, provided by the Laguna ONhE software, can be useful to evaluate structural progression in glaucoma.

Purpose: To assess the performance of automated optic nerve head hemoglobin measurements (ONH Hb) for detection of structural progression in glaucoma patients using event analysis.

Patients and methods: Treated glaucoma patients were included in this cross-sectional study. Two experienced examiners classified patients into progressors and non-progressors (controls) based on serial color retinographies (CR). Progressors were then subdivided in structural changes of the neuroretinal rim (NR) or retinal nerve fiber layer (RNFL). Globin individual pointer (GIP) index, derived from ONH Hb measurements, was calculated for each CR using the Laguna ONhE software. Differences in GIP values, ​​between baseline and last visit CRs, were used to assess structural progression. Sensitivity at a fixed specificity (50%; median GIP difference in controls) and areas under receiver operating characteristic curves (AUROC) were calculated.

Results: Eight-seven eyes (35 progressors and 52 controls) from 64 patients were enrolled. Mean GIP reduction overtime was greater in progressors (-13.0±18.6) than controls (-2.9±10.4; P=0.001). In progressors, mean GIP reduction was greater in patients with NR changes (-19.6±19.5) than RNFL changes (-3.1±12.1; P=0.008). GIP difference correctly identified 69% of the progressors (AUROC: 0.66), being 76% of these progressions related to NR changes (AUROC: 0.76) and 57% to RNFL changes (AUROC: 0.52).

Conclusions: The GIP index, based on automated ONH Hb measurements demonstrated good sensitivity to differentiate progressors from controls, especially in cases in which progression was documented trough structural NR changes. Using only two CRs and event analysis, GIP changes overtime can be a useful screening tool to evaluate structural progression.