[Volumetric analysis of the optic papilla using laser scanning tomography. Parameter definition and comparison of glaucoma and control papilla].

We performed a three-dimensional structure analysis of the optic disc in 65 eyes of 65 patients (38 glaucoma patients, 27 control-group patients) using laser scanning tomography. Patients classified as glaucoma showed at least 3 points with a relative scotoma of -10 db loss or greater compared to age matched controls on static 30 degrees computerized perimetry. Control-group patients showed no relative scotoma outside the blind spot area compared to age matched controls. One way analysis of variance revealed statistically significant differences between the glaucoma (G) and the control-group (C) for excavation volume (+0.57 +/- 0.37 mm3 G/0.31 +/- 0.27 mm3 C, p less than 0.01), for the 3rd moment of the frequency distribution of excavation depths readings (-0.01 +/- -0.12 G/-0.13 +/- -0.09 C, p less than 0.001), area ratio (0.75 +/- 0.15 G/0.57 +/- 0.16 C, p less than 0.001), depth area ratio (0.35 +/- 0.24 G/0.18 +/- 0.12 C, p less than 0.001). A stepwise discriminant analysis classified 32 of 38 (84.2%) glaucoma discs and 21 of 27 (77.8%) control-group discs by a linear combination of 5 out of 15 topographic parameters. The results suggest that a combination of topographic parameters may provide an objective optic disc classification.