Purpose: To estimate the conversion factors to transpose macular thickness measurements on time-domain (TD) to various spectral-domain (SD) optical coherence tomography (OCT) machines in patients with macular telangiectasia type 2a (MacTel). Procedures: Macular scans on TD- and SD-OCT were performed on patients at the same visit. The retinal thickness values in various ETDRS subfields and macular volume were compared between different OCT machines. Results: The macular thickness and volume were significantly greater (p < 0.0001, r = 0.678-0.822) on SD-OCT. The mean differences in macular thickness between TD Stratus and SD-OCT by Spectralis, Cirrus and Topcon were 62, 41 and 20 μm, respectively. The conversion factor of macular thickness from TD-OCT to Spectralis, Cirrus and Topcon were +65, +39 and +25 μm, respectively. Conclusion and Message: The estimates of conversion of macular thickness from TD- to SD-OCT using simple mean differences between machines and those by linear regression were similar suggesting that the former may be used for the longitudinal follow-up of MacTel patients.

Keywords:
Macular telangiectasia type 2a, Spectral-domain optical coherence tomography, Time-domain optical coherence tomography, Macular thickness
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© 2013 S. Karger AG, Basel
2013
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