title: Agreement between time-domain and spectral-domain optical coherence tomography in the assessment of macular thickness in patients with idiopathic macular telangiectasia type 2.
abstract: OBJECTIVE
  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).
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.
authors.forename: Raeba
authors.initials: R
authors.lastname: Mathew
authors.forename: Sobha
authors.initials: S
authors.lastname: Sivaprasad
authors.forename: Daniela
authors.initials: D
authors.lastname: Florea
authors.forename: Irene
authors.initials: I
authors.lastname: Leung
authors.forename: Ferenc
authors.initials: F
authors.lastname: Sallo
authors.forename: Traci
authors.initials: T
authors.lastname: Clemons
authors.forename: Alan C
authors.initials: AC
authors.lastname: Bird
authors.forename: Tunde
authors.initials: T
authors.lastname: Peto
mesh_terms: D006801:Humans; D011446:Prospective Studies; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D058456:Retinal Telangiectasis / Q000175:diagnosis*; D013997:Time Factors; D041623:Tomography, Optical Coherence / Q000295:instrumentation* / Q000379:methods