Abstract
Abstract: :
Purpose: To determine the reproducibility of Optical Coherence Tomography 3 (OCT3) retinal nerve fiber layer (RNFL) measurements around the optic nerve in normal and glaucomatous patients. Methods: A total of 147 subjects were enrolled from March 2003 to May 2003. The mean age (± standard deviation, range) of normal subjects was 53 (±18, 19 – 88) and the mean age of the glaucoma group was 68 (±13, 29 – 88). One eye was chosen at random from 88 normal subjects and from 59 glaucomatous subjects—distributed among mild, moderate, and severe glaucoma by visual field. Subjects underwent 3 RNFL thickness measurements performed by a single operator over a 30–minute time period with a brief rest in between sessions. Each set of measurements included 2 nerve head scans consisting of a 3.4 mm diameter circular scan path taken in 3 separate alignments (Standard RNFL) as well as a single alignment (Fast RNFL). Results: Reliability values, as measured by intraclass correlation coefficients (ICC), were calculated for the overall mean RNFL thickness and for each quadrant. The ICC for the mean Standard RNFL thickness (and lower 95% confidence interval) in normal and glaucomatous eyes was 0.97 (0.96) and 0.98 (0.97), respectively. The ICC for the mean Fast RNFL thickness in normal and glaucomatous was 0.95 (0.93) and 0.97 (0.95), respectively. Quadrant ICCs ranged between 0.79 – 0.97, with the nasal quadrant being the least reproducible of all 4 quadrants using either the Standard or Fast RNFL program. The test–retest variability ranged from 3.5 microns for the average RNFL thickness measurements in normal eyes to 13.8 microns for the nasal quadrant measurements in glaucomatous eyes, which appeared to be the most variable. There was no difference in reproducibility of dilated as compared to undilated eyes. Conclusions: Reproducibility of RNFL measurements using OCT3 on the same day with the same operator is excellent in both normal and glaucomatous eyes. The nasal quadrant appears to be the most variable measurement. These findings may have implications for the diagnosis of glaucoma and glaucomatous progression.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • imaging/image analysis: clinical