97th DOG Annual Meeting 1999
REPRODUCIBILITY MEASUREMENTS OF THE RETINAL NERVE FIBER LAYER BY SCANNING LASER POLARIMETRY (NFA) AND OPTICAL COHERENCE TOMOGRAPHY (OCT)
M. Klemm, R. Schwartz, A. Walter
NFA and OCT represent diagnostic imaging technologies to measure the thickness of the retinal nerve fiber layer (RNFL). The purpose of this prospective study was to analyze and compare the reproducibility of data obtained by the two different techniques.
Subjects: Reproducibility was analyzed in 20 eyes of 20 patients with a mean age of 44 years (range: 18 - 56 years). In each eye 6 measurements were made by the same operator with one of the instruments. The quantitative thickness of the RNFL was examined on a circular scan of 3.37 mm around the optic nerve head. Mean RNFL thickness was determined both as averages for the superior, inferior, nasal and temporal regions and as averages over the total scan circumference. As a measure for agreement between the measurements the intraclass correlation coefficient (ICC) and the coefficient of variation (CV%) were calculated.
Results: The ICCs obtained by NFA were about 0.9, those obtained by OCT about 0.5. The coefficient of variation data (about 6.0) of NFA measurments was only half of CV% (about 12.0) of OCT measurements.
Conclusion: The higher agreement between the measurements (ICC) showed the NFA. Data obtained by NFA seem to be more reliable.
University Eyehospital, Martinistr. 52, D-20246 Hamburg