Spectral domain optical coherence tomography: a better OCT imaging strategy

We report the virtual instrumentation of both time-domain (TD) and spectral-domain (SD) optical coherence tomography (OCT) systems. With a virtual partial coherence source from either a simulated or measured spectrum, the OCT signals of both A-scan and B-scan were demonstrated. The spectrometric detector's pixel number, dynamic range, noise, as well as spectral resolution can be simulated in the virtual spectral domain (SD-OCT). The virtual-OCT system provides an environment for parameter evaluation and algorithm optimization for experimental OCT instrumentation, and promotes the understanding of OCT imaging and signal post-processing processes.

Download Full-text

Spectral Domain Optical Coherence Tomography Imaging Performance Improvement Based on Field Curvature Aberration-Corrected Spectrometer

Applied Sciences ◽

10.3390/app10103657 ◽

2020 ◽

Vol 10 (10) ◽

pp. 3657

Author(s):

Seung Seok Lee ◽

Woosub Song ◽

Eun Seo Choi

Keyword(s):

Optical Coherence Tomography ◽

Spectral Domain ◽

Optical Coherence ◽

Modulation Transfer ◽

Field Curvature ◽

Spatial Frequencies ◽

Oct Imaging ◽

Imaging Depth ◽

Imaging Performance ◽

Sd Oct

We designed and fabricated a telecentric f-theta imaging lens (TFL) to improve the imaging performance of spectral domain optical coherence tomography (SD-OCT). By tailoring the field curvature aberration of the TFL, the flattened focal surface was well matched to the detector plane. Simulation results showed that the spot in the focal plane fitted well within a single pixel and the modulation transfer function at high spatial frequencies showed higher values compared with those of an achromatic doublet imaging lens, which are commonly used in SD-OCT spectrometers. The spectrometer using the TFL had an axial resolution of 7.8 μm, which was similar to the theoretical value of 6.2 μm. The spectrometer was constructed so that the achromatic doublet lens was replaced by the TFL. As a result, the SD-OCT imaging depth was improved by 13% (1.85 mm) on a 10 dB basis in the roll-off curve and showed better sensitivity at the same depth. The SD-OCT images of a multi-layered tape and a human palm proved that the TFL was able to achieve deeper imaging depth and better contrast. This feature was seen very clearly in the depth profile of the image. SD-OCT imaging performance can be improved simply by changing the spectrometer’s imaging lens. By optimizing the imaging lens, deeper SD-OCT imaging can be achieved with improved sensitivity.

Download Full-text

Spectral domain optical coherence tomography (SD-OCT) Imaging of the Vascular-Avascular junction in the nursery in infants with retinopathy of prematurity

Journal of American Association for Pediatric Ophthalmology and Strabismus ◽

10.1016/j.jaapos.2016.07.057 ◽

2016 ◽

Vol 20 (4) ◽

pp. e15

Author(s):

Sharon Freedman ◽

Cynthia A. Toth ◽

Xi Chen ◽

Christian Viehland ◽

Shwetha Mangalesh ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Retinopathy Of Prematurity ◽

Spectral Domain ◽

Optical Coherence ◽

Oct Imaging ◽

Sd Oct

Download Full-text

Comparison of Physiologic versus Pharmacologic Mydriasis on Anterior Chamber Angle Measurements Using Spectral Domain Optical Coherence Tomography

Journal of Ophthalmology ◽

10.1155/2015/845643 ◽

2015 ◽

Vol 2015 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

Anna I. Dastiridou ◽

Xiaojing Pan ◽

ZhouYuan Zhang ◽

Kenneth M. Marion ◽

Brian A. Francis ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Spectral Domain ◽

Optical Coherence ◽

Anterior Chamber Angle ◽

Lighting Condition ◽

Inferior Angle ◽

Oct Imaging ◽

Chamber Angle ◽

Sd Oct

Purpose. To compare the effects of physiologic versus pharmacologic pupil dilation on anterior chamber angle (ACA) measurements obtained with spectral domain optical coherence tomography (SD-OCT).Methods. Forty eyes from 20 healthy, phakic individuals with open angles underwent anterior segment OCT imaging under 3 pupillary states: (1) pupil constricted under standard room lighting, (2) physiologic mydriasis in a darkened room, and (3) postpharmacologic mydriasis. Inferior angle Schwalbe’s line-angle opening distance (SL-AOD) and SL-trabecular-iris-space area (SL-TISA) were computed for each eye and pupillary condition by masked, certified Reading Center graders using customized grading software.Results. SL-AOD and SL-TISA under pupillary constriction to room light were0.87±0.31 mm and0.33±0.14 mm2, respectively; decreased to0.75±0.29 mmP<0.01and0.29±0.13 mm2 P<0.01, respectively, under physiologic mydriasis; and increased to0.90±0.38 mmP<0.01and0.34±0.17 mm2 P=0.06under pharmacologic mydriasis compared to baseline.Conclusions. Using SD-OCT imaging, pharmacologic mydriasis yielded the widest angle opening, whereas physiologic mydriasis yielded the most angle narrowing in normal individuals with open iridocorneal angles. Accounting for the state of the pupil and standardizing the lighting condition would appear to be of importance for future studies of the angle.

Download Full-text