Abstract
Purpose:
The earlier studies showed that the retinal thickness measured by various makes of optical coherence tomography (OCT) machines differed significantly due to the segmentation algorism equipped with each machine. Although manual correction of outer retinal boundary allowed the average retinal thickness to be equal level between machines (Heussein et al. Br J Ophthalmol 2012), foveal centeral point thickness (CPT) evaluated by manual measurement has not been evaluated in detail. Considering the diagnostic value of CPT rather than that of average retinal thickness in pathologic eyes, the reproducibility and the repeatability of CPT in different machines needs to be clarified. The purpose of this study is to compare CPT of the healthy eyes by two commonly used SD-OCT machines with manual measurements.
Methods:
Forty-five Japanese subjects with no history of retinal disease and with normal vision were enrolled in the study. Both Zeiss Cirrus-HD OCT (Zeiss) and Heidelberg Spectralis OCT (Heidelberg) scanning were performed by the same operator on all subjects in right eye within five minutes. CPT was measured by a single grader. Spherical equivalent of the subjects were also obtained.
Results:
The mean age of participants was 30.8 ± 8.8 years, with 20 (44.4 %) men. The average of SE was -3.97 ± 2.76 diopter. The average CPT was 226.5 ±17.4 μm (Zeiss) and 228.1 ± 15.8 μm (Heidelberg), there was no significant difference between the two group (p=0.119, paired t test), and there was very strong positive relationshop (r=0.917, p<0.01, Pearson's correlation coefficient). Male gender was associated with a slight thicker CPT, but there was no significant difference between males and females (p=0.344-0.579, independent samples t-test). There was negative relationship between spherical equivalent and CPT without reaching statistical significance (r=-0.162~-0.125, p>0.05, Pearson's correlation coefficient). There would be no relationship between age and CPT (r=0.124~0.166, p>0.05, Pearson's correlation coefficient).
Conclusions:
There was no significant difference in CPT manually between by Zeiss machine or Heidelberg machine, indicating that these two machines are interchangeable. In normal subjects, SD-OCT showed that CPT was not related to age or spherical equivalent.
Keywords: 550 imaging/image analysis: clinical •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)