Comparison of choroidal thickness measurements between spectral-domain OCT and swept-source OCT in normal and diseased eyes

Purpose: Sub-foveal choroidal thickness (SFCT) is affected in many ocular diseases. The aim of this study was to compare SFCT measurements between Topcon 3D 2000 spectral-domain optical coherence tomography (SD-OCT) and Topcon swept-source OCT (SS-OCT), with different laser wavelengths, in normal and diseased populations. Materials and methods: This was a prospective, cross-sectional, noninterventional study including 27 normal volunteers and 27 participants with retinal disease. OCT scans were performed sequentially and under standardized conditions using both SD-OCT and SS-OCT. The OCT scans were evaluated by two independent graders. Paired t-tests and intraclass correlation coefficients (ICCs) were used to assess the statistically significant difference between SFCT measurements as measured by the two devices. Results: Mean SFCT measurements for all 54 participants were 264.9±103.1 µm using SD-OCT (range: 47–470 µm) and 278.5±110.5 µm using SS-OCT (range: 56–502 µm), with an inter-device ICC of 0.850. Greater variability was noted in the diseased eyes. Inter-device ICCs were 0.870 (95% CI; 0.760–0.924) and 0.840 (95% CI; 0.654–0.930) for normal and diseased eyes, respectively. However, the difference was not statistically significant (P=0.132). Conclusion: Both machines reliably measure SFCT. Larger studies are needed to confirm these findings.