Enhancing the signal-to-noise ratio in ophthalmic optical coherence tomography by image registration—method and clinical examples
Optical coherence tomography (OCT) has already proven an important clinical tool for imaging and diagnosing retinal diseases. Concerning the standard commercial ophthalmic OCT systems, speckle noise i...
Corneal birefringence compensation for polarization sensitive optical coherence tomography of the human retina
In previous publications we have reported on polarization-sensitive optical coherence tomography (PS-OCT) systems that measure and image retardation and axis orientation of birefringent samples with o...
Thedevelopment of improved segmentation algorithms for more consistently accurate detectionof retinal boundaries is a potentially useful solution to thelimitations of existing optical coherence tomography (OCT) software. We modeledartifacts related to operator errors that may normally occur duringOCT imaging and evaluated their influence on segmentation results usinga novel segmentation algorithm. These artifacts included: defocusing, depolarization, decentration,and a combination of defocusing and depolarization. Mean relative reflectanceand average thickness of the automatically extracted intraretinal layers wasthen measured. Our results show that defocusing and depolarization errorstogether have the greatest altering effect on all measurements andon segmentation accuracy. A marked decrease in mean relative reflectanceand average thickness was observed due to depolarization artifact inall intraretinal layers, while defocus resulted in a less-marked decrease.Decentration resulted in a marked but not significant change inaverage thickness. Our study demonstrates that care must be takenfor good-quality imaging when measurements of intraretinal layers using thenovel algorithm are planned in future studies. An awareness ofthese pitfalls and their possible solutions is crucial for obtaininga better quantitative analysis of clinically relevant features of retinalpathology.