AXIAL SUPERRESOLUTION BY PHASE FILTER IN OPTICAL COHERENCE TOMOGRAPHY

2012 ◽  
Vol 05 (04) ◽  
pp. 1250022 ◽  
Author(s):  
ZHIHUA DING ◽  
YANG NI ◽  
JIE MENG
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Coherence ◽  
Negative Contribution ◽  
Spectral Domain Oct ◽  
Phase Filter ◽  
Depth Discrimination ◽  
Before And After ◽  
Coherence Imaging ◽  
Axial Superresolution ◽  
Depth Response

Axial superresolution in optical coherence tomography (OCT) by a three-zone annular phase filter is demonstrated. In the proposed probe of a spectral domain OCT system, the width of the central lobe of the axial intensity point spread function is apodized by the filter to be within the coherence gate determined by the light source, while its sidelobes are lying outside the coherence gate without contributing to the coherence imaging. By measurement of the depth response of the OCT system before and after inserting the filter, an improvement of about 20% in axial resolution is confirmed. OCT imaging on biological sample of orange fresh is also conducted, demonstrating increased depth discrimination without the negative contribution from sidelobes realized by the phase filter in combination with the coherence gate intrinsic to OCT. It comes to a conclusion that we can obtain axial superresolution by filter in OCT system without the degrading influence of large sidelobes.

scholarly journals Utilization potential of intraluminal optical coherence tomography for the Eustachian tube

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hayoung Byun ◽  
Yeon Hoon Kim ◽  
Jingchao Xing ◽  
Su-Jin Shin ◽  
Seung Hwan Lee ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Eustachian Tube ◽  
Balloon Dilatation ◽  
Optical Coherence ◽  
Cross Sectional ◽  
Anatomical Structures ◽  
Complex Anatomy ◽  
Before And After ◽  
Tubal Lumen ◽  
Oct Image

AbstractImaging the Eustachian tube is challenging because of its complex anatomy and limited accessibility. This study fabricated a fiber-based optical coherence tomography (OCT) catheter and investigated its potential for assessing the Eustachian tube anatomy. A customized OCT system and an imaging catheter, termed the Eustachian OCT, were developed for visualizing the Eustachian tube. Three male swine cadaver heads were used to study OCT image acquisition and for subsequent histologic correlation. The imaging catheter was introduced through the nasopharyngeal opening and reached toward the middle ear. The OCT images were acquired from the superior to the nasopharyngeal opening before and after Eustachian tube balloon dilatation. The histological anatomy of the Eustachian tube was compared with corresponding OCT images, The new, Eustachian OCT catheter was successfully inserted in the tubal lumen without damage. Cross-sectional images of the tube were successfully obtained, and the margins of the anatomical structures including cartilage, mucosa lining, and fat could be successfully delineated. After balloon dilatation, the expansion of the cross-sectional area could be identified from the OCT images. Using the OCT technique to assess the Eustachian tube anatomy was shown to be feasible, and the fabricated OCT image catheter was determined to be suitable for Eustachian tube assessment.

Quantitative evaluation of optical coherence tomography angiography images of diabetic retinopathy eyes before and after removal of projection artifacts

2018 ◽  
Vol 11 (9) ◽  
pp. e201800003 ◽  
Author(s):  
Nivedhitha Govindaswamy ◽  
Santosh G. Gadde ◽  
Lavanya Chidambara ◽  
Devanshi Bhanushali ◽  
Neha Anegondi ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Diabetic Retinopathy ◽  
Quantitative Evaluation ◽  
Optical Coherence Tomography Angiography ◽  
Optical Coherence ◽  
Before And After

Evaluation of Possible Changes in Intraocular Pressure and Optical Coherence Tomography Measurements in Severe OSAS Patients After 3 Month Positive Airway Pressure Treatment

2021 ◽  
Author(s):  
Nursel Dikmen ◽  
Ayse Idil Cakmak ◽  
Selma Urfalıoğlu
Keyword(s):  
Optical Coherence Tomography ◽  
Intraocular Pressure ◽  
Airway Pressure ◽  
Positive Airway Pressure ◽  
Corneal Thickness ◽  
Optical Coherence ◽  
Fiber Layer ◽  
Before And After ◽  
Sleep Parameters ◽  
Pre Treatment

Abstract Purpose: To identify and compare possible changes in intraocular pressure (IOP), macular and peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) before and after 3 months of positive airway pressure (PAP) in patients with severe OSAS.Materials and Methods: Twenty-five patients diagnosed with severe OSAS in the neurology sleep outpatient clinic were included in the study. Ophthalmologic examinations were performed at the time of diagnosis and after 3 months of PAP treatment. Statistical analysis of comparisons of IOP and OCT measurements taken before and after PAP treatment was performed. Before treatment, the correlations between central corneal thickness (CCT), body mass index (BMI), OCT, IOP and sleep parameters were statistically investigated.Results: When comparisons were made for both eyes, after 3 months of PAP treatment, a statistically significant decrease in IOP, thickening of the macula, and thinning of RNFL in the superior nasal sector were found when compared with the measurements previously taken at the time of diagnosis (p <0.05). There was no correlation between pre-treatment IOP, OCT, CCT, BMI and sleep parameters.Discussion: The inflammatory effects of OSAS on the IOP and macula have been shown to be reversible with a 3-month PAP treatment, but the reversibility of the neurodegenerative effects of OSAS on RNFL with this treatment seems controversial. OCT is a promising technique for monitoring disease progression in patients with severe OSAS under PAP treatment.

Optical Coherence Tomography and Glaucoma

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Alexi Geevarghese ◽  
Gadi Wollstein ◽  
Hiroshi Ishikawa ◽  
Joel S. Schuman
Keyword(s):  
Optical Coherence Tomography ◽  
Adaptive Optics ◽  
Imaging Modality ◽  
Annual Review ◽  
Publication Date ◽  
Optical Coherence ◽  
Swept Source ◽  
Diagnosis And Management ◽  
Spectral Domain Oct ◽  
Glaucoma Diagnosis

Early detection and monitoring are critical to the diagnosis and management of glaucoma, a progressive optic neuropathy that causes irreversible blindness. Optical coherence tomography (OCT) has become a commonly utilized imaging modality that aids in the detection and monitoring of structural glaucomatous damage. Since its inception in 1991, OCT has progressed through multiple iterations, from time-domain OCT, to spectral-domain OCT, to swept-source OCT, all of which have progressively improved the resolution and speed of scans. Even newer technological advancements and OCT applications, such as adaptive optics, visible-light OCT, and OCT-angiography, have enriched the use of OCT in the evaluation of glaucoma. This article reviews current commercial and state-of-the-art OCT technologies and analytic techniques in the context of their utility for glaucoma diagnosis and management, as well as promising future directions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

scholarly journals Corrigendum to “Enamel Thickness before and after Orthodontic Treatment Analysed in Optical Coherence Tomography”

2020 ◽  
Vol 2020 ◽  
pp. 1-1
Author(s):  
Monika Machoy ◽  
Julia Seeliger ◽  
Robert Koprowski ◽  
Krzysztof Safranow ◽  
Tomasz Gedrange ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Orthodontic Treatment ◽  
Optical Coherence ◽  
Enamel Thickness ◽  
Before And After

Effects of Retinal Angiography on Optical Coherence Tomography Measurements

2015 ◽  
Vol 234 (3) ◽  
pp. 160-166 ◽  
Author(s):  
Young-Joon Jo ◽  
Hyung-Bin Lim ◽  
Soo-Hyun Lee ◽  
Jung-Yeul Kim
Keyword(s):  
Optical Coherence Tomography ◽  
Indocyanine Green ◽  
Retinal Thickness ◽  
Optical Coherence ◽  
Fiber Layer ◽  
Nerve Fiber Layer Thickness ◽  
Interclass Correlation ◽  
Significant Difference ◽  
Before And After ◽  
Sd Oct

Purpose: To evaluate the effects of retinal angiography, using fluorescein and indocyanine green dyes, on optical coherence tomography (OCT) measurements. Methods: In total, 76 eyes from 76 consecutive patients were included. Macular cube 512 × 128 combination scanning and optic disc 200 × 200 scanning using spectral-domain (SD)-OCT were performed twice, before and after retinal angiography, with fluorescein or indocyanine green. Signal strength, regional retinal thickness of the 9 Early Treatment Diabetic Retinopathy Study subfields, total macular volume, and retinal nerve fiber layer thickness obtained before and after angiography were compared. Repeatability was also investigated. Results: Comparing the results of OCT measured before and after retinal angiography, there was no statistically significant difference in any parameter assessed. The interclass correlation values for each measurement were all >0.808 (range 0.808-0.999). Conclusion: Retinal angiography using fluorescein and indocyanine green dyes has no significant effect on OCT measurements.

Macular capillary plexuses after macular hole surgery: an optical coherence tomography angiography study

2017 ◽  
Vol 102 (7) ◽  
pp. 966-970 ◽  
Author(s):  
Yoon Jeon Kim ◽  
Jaehyuck Jo ◽  
Joo Yong Lee ◽  
Young Hee Yoon ◽  
June-Gone Kim
Keyword(s):  
Optical Coherence Tomography ◽  
Macular Hole ◽  
Structural Changes ◽  
Foveal Avascular Zone ◽  
Vascular Density ◽  
Optical Coherence ◽  
Foveal Thickness ◽  
Functional Changes ◽  
Spectral Domain Oct ◽  
En Face

AimsTo investigate the structural changes of the superficial capillary plexuses (SCP) and deep capillary plexuses (DCP) using optical coherence tomography (OCT) angiography (OCTA) in patients with idiopathic macular hole (MH) after surgery, determine the factors related to changes of macular capillary plexuses and evaluate its association with postoperative visual outcomes.MethodsThirty-three patients with unilateral MH who were followed for ≥6 months after surgery were included. Ophthalmologic evaluations included best corrected visual acuity (BCVA) and spectral-domain OCT before surgery and 6 months postsurgery. En face OCTA images were obtained for both eyes at 6 months postsurgery, and the postoperative foveal avascular zone (FAZ) area and parafoveal vascular density were identified.ResultsCompared with fellow eyes, eyes after MH surgery had a smaller FAZ area in both SCP and DCP (p<0.05 for all). The FAZ area was positively correlated with postoperative foveal thickness of the whole, inner and outer layers (p<0.05 for all). In the parafoveal region, eyes after MH surgery had a tendency to have lower parafoveal vascular density, particularly in DCP (p=0.019). The parafoveal vascular density in DCP was positively correlated with retinal thickness of the whole, inner and outer layers (p<0.05 for all). Correlations between BCVA and FAZ area in both SCP and DCP were significant 6 months after MH surgery (p<0.05 for all).ConclusionAssessment of macular capillary plexuses using OCTA may be useful for monitoring retinal structural and functional changes in MH.

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