Reproducibility of a confocal scanning laser ophthalmoscope that assesses optic disk topography of glaucomatous patients [Reproducibilidad de los parámetros topográficos de discos ópticos glaucomatosos, obtenidos mediante oftalmoscopia con láser de barrido confocal]

Purpose: To establish the reproducibility of a confocal scanning laser ophthalmoscope that assesses optic disk topography of glaucomatous patients. Methods: From 91 consecutive medical records that were evaluated, 26 cases met the selection criteria and were included in this study. Patients included were comprehensively examined, and underwent visual field testing (Humphrey automated perimetry, full-threshold central 24-2 test), as well as optic disk topography (using TopSS XL-2020 tomograph, Laser Diagnostic Technologies). Inter-examiner reproducibility of 12 topographic parameters was determined. Such values derived from the volumetric analysis as assessed by three different operators that determined an ellipse surrounding the optic disk edge in each case. Operators had different level of experience (inexperienced, intermediate, experienced). Analysis of variance (ANOVA) test with post hoc Bonferroni's correction were used; intra-class comparison (alpha coefficient) for assessing reproducibility was also applied. A probability less than 0.05 was considered statistically significant. Results: Nineteen female patients and 7 male ones who had mild glaucoma were studied. No statistically significant differences (P > 0.05%) were found among mean values of topographic parameters as assessed by three different operators. Agreement among the three operators for the same topographic variables was considered either good or excellent (range, alpha coefficient = 0.60 - 0.99). Conclusions: Reproducibility of TopSS XL-2020 tomograph is appropriate and non-dependent on operator level of experience to place the ellipse surrounding the optic disk edge