title: Comparison and interchangeability of macular thickness measured with Cirrus OCT and Stratus OCT in myopic eyes.
abstract: OBJECTIVE
  To investigate the difference of macular thickness measurements between stratus optical coherence tomography (OCT) and Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA) in the same myopic patient and to develop a conversion equation to interchange macular thickness obtained with these two OCT devices.
  
  
  METHODS
  Eighty-nine healthy Chinese adults with spherical equivalent (SE) ranging from -1.13 D to -9.63 D were recruited. The macular thickness was measured by Cirrus OCT and Stratus OCT. The correlation between macular thickness and axial length and the agreement between two OCT measurements were evaluated. A formula was generated to interchange macular thickness obtained with two OCT devices.
  
  
  RESULTS
  Average macular thickness measured with Stratus OCT (r=-0.280, P=0.008) and Cirrus OCT (r=-0.224, P=0.034) were found to be negatively correlated with axial length. No statistically significant correlation was found between axial length and central subfield macular thickness (CMT) measured with Stratus OCT (r=0.191, P=0.073) and Cirrus OCT (r=0.169, P=0.113). The mean CMT measured with Cirrus OCT was 53.63±7.94 µm thicker than with Stratus OCT. The formula CMTCirrus OCT=78.328+0.874×CMTStratus OCT was generated to interchange macular thickness obtained with two OCT devices.
  
  
  CONCLUSIONS
  Macular thickness measured with Cirrus OCT were thicker than with Stratus OCT in myopic eyes. A formula can be used to interchange macular thickness measured with two OCT devices in myopic eyes. Studies with different OCT devices and larger samples are warranted to enable the comparison of macular values measured with different OCT devices.
authors.affiliation: Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, Guangdong Province, China.
authors.forename: Geng
authors.initials: G
authors.lastname: Wang
authors.affiliation: Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, Guangdong Province, China.
authors.forename: Kun-Liang
authors.initials: KL
authors.lastname: Qiu
authors.affiliation: Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, Guangdong Province, China.
authors.forename: Xue-Hui
authors.initials: XH
authors.lastname: Lu
authors.affiliation: Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou 515041, Guangdong Province, China.
authors.forename: Ming-Zhi
authors.initials: MZ
authors.lastname: Zhang
keywords: interchangeability; macular thickness; myopia; spectral domain Cirrus OCT; time domain Stratus OCT