title: Comparison of choroidal thickness measurements between spectral-domain OCT and swept-source OCT in normal and diseased eyes.
abstract: OBJECTIVE
  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.
  
  
  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. Pairedt-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).
  
  
  CONCLUSIONS
  Both machines reliably measure SFCT. Larger studies are needed to confirm these findings.
authors.affiliation: Medical College, Aga Khan University Hospital.
authors.forename: Sidra
authors.initials: S
authors.lastname: Zafar
authors.affiliation: Department of Ophthalmology, Shahzad Eye Hospital; South City Hospital, Karachi, Pakistan.
authors.forename: Ma Rehman
authors.initials: MR
authors.lastname: Siddiqui
authors.affiliation: Medical College, Aga Khan University Hospital.
authors.forename: Rida
authors.initials: R
authors.lastname: Shahzad
keywords: SD-OCT; SS-OCT; choroidal imaging; diseased; normal