Improvement of diagnostic performance regarding retinal nerve fiber layer defect using shifting of the normative database according to vessel position

PURPOSE. To evaluate the clinical efficacy of early detection of retinal nerve fiber layer (RNFL) defect in a Korean population using shifting of the normative RNFL thickness database according to vessel position. METHODS. Retinal nerve fiber layer thickness data of 151 healthy eyes (normative group) and 120 validation subjects (validation group; additional healthy controls plus early glaucoma) were prospectively obtained using spectral-domain optical coherence tomography (SD-OCT) measurement. Clinical profiles and position of major retinal artery peaks (superotemporal, STa; inferotemporal, ITa) were investigated with position of RNFL peaks. Three different criteria for the lower 1% limit were adopted for the validation. Criterion 1 used normative data from the manufacturer. Criterion 2 used data from healthy volunteers. Criterion 3 used four combinations of two subgroups from data for volunteers, which were divided by the median value of STa in the superior region and that of ITa in the inferior region. The Κ value was used to determine the diagnostic performance of each criterion (agreement with standard answer). RESULTS. Assessment of the validation group using criterion 3 showed greater accuracy than with criterion 1 or criterion 2 (Κ = 0.571, 0.774, and 0.979). Although SD-OCT specificity for RNFL defect detection was similar among the criteria (100%, 98.8%, and 98.9%), sensitivity was highest with criterion 3 (42.4%, 72.7%, and 100%) (all values; criteria 1, 2, and 3, respectively). CONCLUSIONS. Shifting of the lower 1% reference line, according to vessel position, could remarkably improve the diagnostic performance regarding RNFL defect detection with SDOCT.