Influence of Glaucomatous Damage and Optic Disc Size on Glaucoma Detection by Scanning Laser Tomography

Purpose: To investigate the impact of glaucomatous damage and optic disc size on different automated Heidelberg Retina Tomograph classifications for discriminating glaucoma and healthy controls. Patients and Methods: Two hundred seventy-three glaucoma patients and 276 healthy controls were recruited front the Erlangen Glaucoma Registry. Standard static white on white perimetry, 24-hour intraocular pressure profile, stereographic optic disc slides, and scanning laser tomography were performed in all patients and controls. The effect of glaucoma stage and disc size on the diagnostic accuracy was evaluated using receiver operating characteristic curves. Results of the Glaucoma Probability Score were compared with other recently described multivariate classifications. Results: Areas Under the receiver operating characteristic curves for discrimination between glaucoma and healthy eyes of the overall classification by Glaucoma Probability Score, Moorfields regression analysis, Bathija, Iester, Mikelberg, and Mardin increased from 0.71, 0.65, 0.70, 0.67, 0.65, and 0.63 for early glaucoma (Ionas: stage I) to 0.96 0.95, 0.94 0.94, 0.92, and 0.88 for advanced glaucomatous damage (Jonas: stage IV). Best performance of discrimination between glaucoma and healthy eyes using area under the receiver operating characteristic curve's were observed for medium-sized discs (2.1 to 2.49 mm(2)) and worst performance for large optic discs ( > 3.1 mm(2)). Glaucoma Probability Score classification was superior to other investigated classifications in most of the investigated subgroups. Conclusions: The diagnostic accuracy of all classifications depends on the optic disc size and the glaucoma stage. Glaucoma Probability Score showed a better diagnostic performance than Moorfields regression analysis and was similar to that of Bathija.