Comparison of Time Domain OCT and Spectrum Domain OCT for Retinal Nerve Fiber Layer Assessment

Abstract

Purpose: To compare retinal nerve fiber layer (RNFL) thickness obtained with Stratus optical coherence tomography (OCT) and Cirrus OCT. Methods: Sixty-one normal eyes were evaluated with Stratus and Cirrus OCT on the same day, and the RNFL thicknesses measured by the two OCT machines were compared. The correlation between the two data sets was obtained using Pearson's correlation coefficient. The correlation between RNFL thickness and the difference in data measured by the two OCT machines was then assessed. Results: The average RNFL thickness was significantly higher with Stratus OCT by 6.54 (p=0.0008). A strong correlation was present between the two RNFL thickness data sets (r=0.883), and the difference between Stratus and Cirrus values tended to increase as RNFL thickness increased. Conclusions: RNFL thickness measurements in normal eyes scanned with Cirrus OCT correlate well with Stratus OCT measurements. Average RNFL thickness was significantly higher with Stratus OCT, and as the RNFL thickness increased, the difference between Stratus and Cirrus values increased.