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

PRCIS

Automated optic nerve head hemoglobin measurements through change over time 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 over time 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 through structural NR changes. Using only 2 CRs and event analysis, GIP changes over time can be a useful screening tool to evaluate structural progression.