Reproducibility of Macular Thickness Measurement Among Five OCT Instruments: Effects of Image Resolution, Image Registration, and Eye Tracking

Department of Ophthalmology & Vision Science, University of California Davis Eye Center, Sacramento, California 95817, USA.
Ophthalmic Surgery Lasers and Imaging (Impact Factor: 1.32). 01/2012; 43(2):97-108. DOI: 10.3928/15428877-20111222-02
Source: PubMed


To study the effect of image resolution, eye tracking, and image registration on central macular thickness reproducibility (rCMT) among spectral-domain and time-domain optical coherence tomography (SD-OCT and TD-OCT) instruments.
Seventy-six eyes were imaged (44 normal, 32 maculopathy) either twice using four SD-OCT and one TD-OCT devices or three times using Spectralis SD-OCT (with and without eye tracking) (Heidelberg Engineering, Inc., Heidelberg, Germany). Cirrus images (Carl Zeiss Meditec, Dublin, CA) were further analyzed with three-point image registration.
All instruments had superior rCMT in normal versus pathologic eyes (P < .001). No difference in rCMT was noted among instruments in normal eyes (P = .92), but TD-OCT was superior to SD-OCT (P = .017) in pathologic eyes. Cirrus image registration improved rCMT for normal eyes (P = .04), with borderline improvement in pathologic eyes (P = .06). Spectralis eye tracking improved rCMT in normal (P = .01) and pathologic (P = .004) eyes.
Higher image resolution with SD-OCT may not improve rCMT, but image registration and eye tracking options may improve rCMT.

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    • "It is necessary to perform additional clinical experiments and collect more data from various volunteers to overcome the drawbacks of the conventional method and to improve the functioning status of the developed system. In the future, three issues will need to be addressed: (1) improving the image display rate by using dual GPU techniques [28]; (2) adding a fundus camera mounted on the handheld probe; and (3) improving the OCT image resolution by using eye-tracking techniques [29]. Retinal tracking techniques have specific advantages such as removing the motion error and frame averaging to enhance contrast and remove image speckle in high-resolution images. "
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