Macular Thickness Measurements in Healthy Eyes Using Six Different Optical Coherence Tomography Instruments
Ute EK Wolf-Schnurrbusch 1,
Lala Ceklic 2,
Christian Karl Brinkmann 1,
Milko Iliev 3,
Manuel Frey 1,
Simon Paul Rothenbuehler 1,
Volker Enzmann 3,
and
Sebastian Wolf 1*
1 Universitatsklinik fur Augenheilkunde, University Bern, Bern, Switzerland; Bern Photographic Reading Center, University Bern, Bern, Switzerland
2 Klinicki centar Isotocno Sarajevo, Dobrosava Jevdjevica, Bosnia and Herzegovina; Universitatsklinik fur Augenheilkunde, University Bern, Bern, Switzerland
3 Universitatsklinik fur Augenheilkunde, University Bern, Bern, Switzerland
* To whom correspondence should be addressed. E-mail: sebastian.wolf{at}insel.ch.
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Abstract |
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Purpose To compare central retinal thickness (CRT) measurements in healthy eyes by different commercially available OCT instruments and to compare the intersession reproducibility of such measurements.
Methods: Six different OCT instruments (StratusTMOCT, SOCTCopernicus, SpectralOCT/SLO, RTVue-100, SpectralisTMHRA+OCT,and CirrusTMHD-OCT) were used to assess the central retinal thickness in both eyes of healthy subjects. Measurements were performed in two different sessions on the same day with each of the systems. From these measurements mean values for CRT were calculated. For the assessment of the intersession reproducibility of the instruments we calculated the coefficient of the variation of test-re-test variation.
Results: Twenty healthy subjects were included in the study. Compared to the StratusTMOCT all spectral OCT instruments showed significantly higher CRT values. The SpectralisTMHRA+OCT and CirrusTMHD-OCT showed similar CRT values but significantly higher values than all other instruments.
The coefficients of variation for repeated measurements was 3.33% for the Stratus OCT, 0.46% for the SpectralisTMHRA+OCT, 3.09% for the CirrusTMHD-OCT, 2.23% for the OCT/SLO, 2.77% for the RTVue-100, and for the SOCT 3.5% respectively.
Discussion: The six OCT systems provided different values for central retinal thickness. CRT measurements with the StratusTMOCT showed the lowest values, whereas measurements with the CirrusTMHD-OCT and SpectralisTMHRA+OCT yielded the highest values. These differences can be explained by differences in retinal segmentation algorithms used by the various OCT systems. Whereas, the SpectralisTMHRA+OCT, and CirrusTMHD-OCT include the RPE layer in the retinal segmentation the other instruments do not include this layer. The data implicate that the different OCT systems cannot be used interchangeably for the measurement of macular thickness.
Key Words:
optical coherence tomography, image analysis, retinal thickness
