Abstract
Purpose: :
To compare the reproducibility of various spectral-domain optical coherence tomography (SD-OCT) instruments with time-domain OCT instrument in measuring central macular thickness (CMT) in normal and pathologic maculas.
Methods: :
Prospective observational study of forty eyes with macular pathologies (i.e. disciform scar, cystoid macular edema, geographic atrophy) and forty eyes with normal maculas scanned twice in one session by same operator on one time-domain OCT instrument (Stratus) and three SD-OCT instruments (Cirrus, Topcon 3D, and Optovue). CMT referred to the central 1mm zone of the ETDRS macular thickness map.
Results: :
The mean paired difference in CMT with Stratus OCT in eyes with pathologic and normal maculas was 6.6±7.1 and 3.4±2.7µm. The mean paired difference in CMT in eyes with pathologic and normal maculas with SD-OCT was as follows: Cirrus (14.9±19.5 and 3.5±3.1µm), Optovue (16.6±20.8 and 3.6±2.0µm) and Topcon (15.5±18.1 and 2.9±2.4µm). There was no statistically significant difference in mean paired difference in CMT among the four OCT instruments in eyes with normal maculas. However, among eyes with pathologic maculas, there was a significantly lower paired difference in CMT with time-domain when compared to various SD-OCT instruments: Stratus vs. Cirus (p=0.05); Stratus vs. Optovue (p=0.02); and Stratus vs. Topcon (p=0.03).
Conclusions: :
Although there was no statisically significant difference in reproducibility of CMT between spectral-domain and time-domain OCT instruments among eyes with normal maculas. A surprisingly higher reproducibility in CMT was noted with time-domain OCT when compared to SD-OCT in eyes with pathologic maculas.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • clinical (human) or epidemiologic studies: systems/equipment/techniques