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A.C. Kara–Jose, M. Endo, L.A. S. Melo, Jr., J.A. Prata, Jr.; Reproducibility and Evaluation of Progression Analysis Program of Confocal Scanning Laser Ophthalmoscopy and Scanning Laser Polarimetry in Glaucomatous Patients . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3645.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the progression analysis program and reproducibility of optic nerve head and retinal nerve fiber layer thickness measurements using Confocal Scanning Laser Ophthalmoscopy (HRT–II) and Scanning Laser Polarimetry with variable corneal compensation (GDx–VCC).
Twenty–three open–angle glaucoma patients were included. Each patient underwent three HRT–II and GDx–VCC exams with an interval of 30 minutes between exams. Optimal quality images were taken by the same examiner. The within–subject standard deviation (SD) and repeatability coefficient of the measurements provided by both devices were calculated. Based on the HRT progression analysis map, the optic disc sectors showing significant (P<0.05) topographic alterations were recorded. Based on the GDx–VCC Serial Analysis, the three exams were analyzed to identify the altered pixels. The identified retinal nerve fiber layer thickness alterations were classified by the number of altered pixels in each probability interval provided by the GDx–VCC. The intraclass correlation coefficient (ICC) was determined for each probability interval.
Except for disc area, which does not vary between exams, the HRT parameters demonstrating the lowest within–subject SD/repeatability coefficient were mean cup depth (0.0167 mm/0.0463 mm) and cup shape measure (0.0255/0.0706), whereas the highest ones were rim area (0.0784 mm2/0.2172 mm2) and cup area (0.1578 mm2/0.4371 mm2). Optic disc regions that demonstrated more significant topographic alterations were inferotemporal and temporal (related to depression) and nasal (related to elevation). The GDx–VCC parameters demonstrating the lowest within–subject SD/repeatability coefficient were TSNIT standard deviation (1.235 µm/ 3.421 µm) and TSNIT average (1.797 µm/4.978 µm); and the highest ones were inferior average (2.118 µm/ 5.867 µm) and superior average (2.526 µm/ 6.997 µm). The probability interval with the lowest ICC was 2%≤ P <5% (ICC = 0.87), whereas the probability interval with the highest ICC was 1%≤ P <2% (ICC = 0.95).
HRT–II and GDx–VCC demonstrated reasonable reproducibility of optic disk head and retinal nerve fiber layer thickness measurements, respectively, in glaucomatous patients. HRT–II progression analysis map demonstrates a high false–positive rate (pseudo–progression). Repeatability coefficients calculated for each parameter may be useful to identify significant alterations, contributing to the identification of true glaucomatous progression.
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