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M.-D.-R. Garcia-Catalan, J. Reche-Frutos, C. Calvo-Gozalez, A.-M. Muñoz-Hernández, F. Saenz-Frances; Comparison of Retinal Thickness Measurements and Choroidal Neovascularization Activity Between Spectral-Domain and Time-Domain Optical Coherence Tomography in Age-Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4941.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the ability to detect choroidal neovascularization (CNV) activity on Spectralis compared with Stratus and agreement in retinal thickness between the two retinal measurement techniques.
90 eyes of 83 age-related macular degeneration patients treated with intravitreal injections of ranibizumab were included. Non contact OCT imaging, Spectralis-OCT and Stratus-OCT were performed in all patients. We used the Fast Macular Thickness protocol for Stratus OCT (Software version 4.0) and Volume Scan for Spectralis HRA+OCT (Software version 4.0.2) to measure the central retinal thickness (CRT). To assess CNV activity, six radial scans protocol was used in Spectralis and macular protocol in Stratus. All OCT examination were performed by one operator within one session. Patients had time to rest between the procedures. Statistical analysis was performed using SPSS 12.0 software.
Mean central retinal thickness (CRT) measurement obtained by Spectralis and Stratus were 358,89 µm (SD ± 88,22 µm) and 263,43 µm (SD ± 68,1 µm) respectively. Compared with Stratus OCT, Spectralis OCT showed significantly higher CRT using t-test (p<0,005).Significant correlation was found between Spectralis and Stratus CRT (r=0,728; p<0,001). Agreement between the two OCT systems was assessed with intraclass correlation coefficient (ICC) and Bland Altman plot. The two instruments produced measurements that agreed poorly with each other. ICC was 0,41 and the 95% limits of agreement was -1 to 0,72. Mean CRT difference (Stratus minus Spectralis) was -95,45 µm (IC95%: -214,22 to 23,31). Passing-Bablok regression line obtained from the Bland-Altmann plots showed a significant proportional bias, with differences increasing with increasing CRT. B = 0,7 (95%CI: 0,6 to 0,84). We did not detect a significant systematic bias. A= 33,74 (95%CI -10,82 to 65,57).We also compared the difference between proportions detected with Spectralis and Stratus with regard to subretinal fluid. 100% of subretinal fluid was detected with Spectralis (95% IC: 93-100%) in contrast to the 82% detected by Stratus (IC95%: 65,6% to 93,6%). Difference between proportions was 18% (IC95% 4,6% to 35,4), statistically significant (p<0,005).
We found that Stratus and Spectralis OCT systems provided different values for CRT. Measurements with Stratus showed lower values. Spectralis OCT had a better ability to detect CNV activity compared with Stratus.
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