Abstract The development of optical coherence tomography (OCT) technology has helped to usher in a new era of in vivo diagnostic imaging of the eye. The utilization of OCT for imaging of the anterior ...segment and ocular surface has evolved from time-domain devices to spectral-domain devices with greater penetrance and resolution, providing novel images of anterior segment pathology to assist in diagnosis and management of disease. Ocular surface squamous neoplasia (OSSN) is one such pathology that has proven demonstrable by certain anterior segment OCT machines, specifically the newer devices capable of performing ultra high-resolution OCT (UHR-OCT). Distinctive features of OSSN on high resolution OCT allow for diagnosis and differentiation from other ocular surface pathologies. Subtle findings on these images help to characterize the OSSN lesions beyond what is apparent with the clinical examination, providing guidance for clinical management. The purpose of this review is to examine the published literature on the utilization of UHR-OCT for the diagnosis and management of OSSN, as well as to report novel uses of this technology and potential directions for its future development.
Significance: After three decades, more than 75,000 publications, tens of companies being involved in its commercialization, and a global market perspective of about USD 1.5 billion in 2023, optical ...coherence tomography (OCT) has become one of the fastest successfully translated imaging techniques with substantial clinical and economic impacts and acceptance.
Aim: Our perspective focuses on disruptive forward-looking innovations and key technologies to further boost OCT performance and therefore enable significantly enhanced medical diagnosis.
Approach: A comprehensive review of state-of-the-art accomplishments in OCT has been performed.
Results: The most disruptive future OCT innovations include imaging resolution and speed (single-beam raster scanning versus parallelization) improvement, new implementations for dual modality or even multimodality systems, and using endogenous or exogenous contrast in these hybrid OCT systems targeting molecular and metabolic imaging. Aside from OCT angiography, no other functional or contrast enhancing OCT extension has accomplished comparable clinical and commercial impacts. Some more recently developed extensions, e.g., optical coherence elastography, dynamic contrast OCT, optoretinography, and artificial intelligence enhanced OCT are also considered with high potential for the future. In addition, OCT miniaturization for portable, compact, handheld, and/or cost-effective capsule-based OCT applications, home-OCT, and self-OCT systems based on micro-optic assemblies or photonic integrated circuits will revolutionize new applications and availability in the near future. Finally, clinical translation of OCT including medical device regulatory challenges will continue to be absolutely essential.
Conclusions: With its exquisite non-invasive, micrometer resolution depth sectioning capability, OCT has especially revolutionized ophthalmic diagnosis and hence is the fastest adopted imaging technology in the history of ophthalmology. Nonetheless, OCT has not been completely exploited and has substantial growth potential—in academics as well as in industry. This applies not only to the ophthalmic application field, but also especially to the original motivation of OCT to enable optical biopsy, i.e., the in situ imaging of tissue microstructure with a resolution approaching that of histology but without the need for tissue excision.
Glaucoma is a chronic and progressive optic neuropathy characterized by the death of retinal ganglion cells and corresponding visual field loss. Despite the growing number of studies on the subject, ...the pathogenesis of the disease remains unclear. Notwithstanding, several studies have shown that the lamina cribrosa (LC) is considered an anatomic site of glaucomatous optic nerve injury, thus having a key role in the pathophysiology of glaucoma development and progression. Different morphological alterations of the LC have been described in vivo in glaucomatous eyes after the evolution of optical coherence tomography (OCT) devices. The most relevant findings were the reduction of laminar thickness, the presence of localized defects, and the posterior LC displacement. These new laminar parameters documented through OCT are not only promising as possible additional tools for glaucoma diagnosis and monitoring, but also as predictors of disease progression. In spite of the advance of technology, however, proper evaluation of the LC is not yet viable in all eyes. We describe OCT-identified LC changes related to the development and progression of glaucoma and provide future directions based on a critical data analysis, focusing on its clinical relevance and applicability.
To localize the various levels of abnormalities in multiple evanescent white dot syndrome by comparing "en face" optical coherence tomography (OCT) and OCT angiography with various conventional ...imaging modalities.
In this retrospective case series, multimodal imaging was performed in 9 retinal centers on 36 patients with multiple evanescent white dot syndrome and included widefield fundus autofluorescence (FAF), fluorescein angiography (FA), and indocyanine green angiography, and B-scan and "en face" C-scan enhanced depth imaging and spectral domain OCT. Optical coherence tomography angiography was also performed at the level of the superficial and deep retinal capillary plexus and choroid.
Multiple evanescent white dot syndrome lesions were more numerous and more easily detectable with FA and FAF. Two types of lesions were identified with FAF, FA, and indocyanine green angiography: larger widely scattered "spots" (approximately 200 μ in diameter) that were hyperfluorescent with FA, hyperautofluorescent with FAF, and hyporeflective in indocyanine green angiography, representing abnormalities primarily at the retinal pigment epithelium/photoreceptor junction; and punctate "dots" (less than 100 μ in diameter) that were hyperfluorescent with FA, hyperautofluorescent, or isoautofluorescent with FAF, and hypofluorescent with indocyanine green angiography and that localized to the outer nuclear layer. These lesions colocalized with "en face" OCT. The larger confluent "spots" were hyporeflective and colocalized to the level of the ellipsoid zone, whereas smaller hyperreflective "dots" colocalized to the outer nuclear layer. The location of the "dots" in the outer nuclear layer was further confirmed by structural spectral domain optical coherence tomography which showed coalescence of the dots into hyperreflective lines extending from the external limiting membrane to the outer plexiform layer in certain cases. Optical coherence tomography angiography analysis of the retinal microvasculature and choriocapillaris and choroid were entirely unremarkable in 100% of our patients.
By combining multimodal imaging, the authors propose that multiple evanescent white dot syndrome is primarily the result of inflammation at the outer photoreceptor level leading to a "photoreceptoritis" and causing loss of the inner and outer segments. Its evanescent nature suggests that the photoreceptor cell bodies remain intact ensuring complete recovery of the photoreceptor inner and outer segments in most cases, compatible with the clinical course of spontaneous resolution of white spots and dots.
Split‐Window OCT biometry in pseudophakic eyes Sikorski, Bartosz L.; Hoffer, Kenneth J.
Acta ophthalmologica (Oxford, England),
December 2022, 2022-Dec, 2022-12-00, 20221201, Letnik:
100, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Purpose
To determine the utility of Split‐Window optical coherence tomography OCT (SW‐OCT) biometry in measuring ocular axial dimensions as well as imaging the intraocular lens (IOL) and posterior ...capsule in pseudophakic eyes.
Methods
Sixty‐nine pseudophakic eyes of 69 subjects were enrolled in the study. The results of SW‐OCT biometry implemented in the SD OCT device for posterior and anterior segment imaging (REVO NX, Optopol Technology) were compared with those obtained with the SS‐OCT‐based biometer IOLMaster 700 (Carl Zeiss Meditec). Differences in measurement values between the two biometers were determined using the paired t‐test. Agreement was assessed through intraclass correlation coefficients (ICC) and Bland–Altman plots.
Results
The correlation between measurements obtained with SW‐OCT and SS‐OCT was very high (ICC for: axial length (AL) = 1.000; anterior chamber depth (ACD) = 0.997; IOL thickness (IOL LT) = 0.997; central corneal thickness (CCT) = 0.987). The mean AL measurement difference was 0.003 ± 0.021 mm (the 95% LoA ranged from −0.04 to 0.05); the mean ACD difference was −0.009 ± 0.025 mm (95% LoA, −0.06 to 0.04); mean LT difference was 0.001 ± 0.021 mm (95% LoA, −0.04 to 0.04); and mean CCT difference was 1.4 ± 5.4 μm (95% LoA, −9 to 12).
Conclusion
The study shows small, non‐significant differences between the biometric measurements obtained with REVO NX SW‐OCT and IOLMaster 700 SS‐OCT in pseudophakic eyes. However, SW‐OCT offered significantly lower ACD and LT measurement failure rates. With high‐resolution imaging, SW‐OCT enables accurate assessment of IOL position relative to the posterior capsule and visualization of capsular fibrosis.
•Three-dimensional Optical Coherence Tomography Angiography (OCTA) imaging of human eye anterior segment reported.•The system utilizes a 100 KHz A-scan rate with 1060 nm swept source OCT system.•In ...vivo depth-resolved volumetric imaging for microstructure & microvasculature visualization was performed.•Joint Spectral and Time domain OCT (STdOCT) method was employed to calculate direction of blood flow.•The vascular systems at limbus were imaged and is presented.
The study demonstrates in-vivo three-dimensional depth-resolved Optical Coherence Tomography Angiography (OCTA) and Doppler OCT imaging performed on the anterior segment of the human eye. A high-speed swept-source OCT system was developed utilizing a swept-source laser having a 100 kHz A-scan sweep rate and centre wavelength at 1060 nm. The proposed system has an axial resolution of 4.5 µm and a transverse imaging resolution of 14 µm. The Doppler OCT provides information regarding the direction of blood flow in corneoscleral junction vessels, which employs the Joint Spectral and Time domain OCT (STdOCT) method. Parameters influencing the imaging of various vessels, like scanning density, A-scan rate, B-scan averaging, and number of BM scanning repeats, were also studied. Slit lamp images and OCT angiography en-face projections produced from PVOCTA (Phase-variance OCTA) and STdOCTA from the same regular patients were compared in order to demonstrate the additional potential of the system. The vascular systems at the Limbus consisting of circulatory, lymphatic, and aqueous outflow systems were imaged and presented. The output clinical parameters of the system will contribute to understanding the blood circulation with directionality at the limbus location, which can be further utilized to identify glaucoma. In the author's opinion, this article represents the first attempt to provide Doppler OCTA data for the anterior chamber of the human eye.
This study was aimed to evaluate the agreement between the swept-source optical coherence tomography (SS-OCT)-based biometry, fundus photographs, and their combination, in comparison to the gold ...standard spectral-domain optical coherence tomography (SD-OCT) for the detection of center-involving diabetic macular edema (CI-DME).
We conducted a retrospective cross-sectional study involving 55 subjects (78 eyes) diagnosed with diabetic macular edema (DME) detected clinically and on SD-OCT (Carl Zeiss Meditec AG). Post-mydriatic 45-degree color fundus photograph (Crystal-Vue NFC-700), 1 mm macular scan obtained from SS-OCT-based biometry (IOL-Master 700), and macula cube scan obtained from SD-OCT was used to detect and grade DME into CI-DME and NCI-DME.
Our findings revealed that SS-OCT-based biometry was noted to have a high sensitivity of 1 (0.94-1.00) and a specificity of 0.63 (0.31-0.89) in detecting CI-DME compared to the gold standard (SD-OCT). When combined with data from fundus photographs, specificity decreased to 0.32 (0.15-0.53). Fundus photographs alone exhibited a low sensitivity of 0.52 (0.38-0.64) and a specificity of 0.45 (0.16-0.76) in CI-DME detection.
In conclusion, SS-OCT-based biometry can be used as an effective tool for the detection of CI-DME in diabetic patients undergoing cataract surgery and can serve as a screening tool in centers without SD-OCT facilities.
Andrea Valerio Marino, Marco Gioia, Ludovica Reda, Aniello La Marca Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, Baronissi, Salerno, Italy ...Correspondence: Ludovica Reda, Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana” University of Salerno, via S. Allende, Baronissi, Salerno, 84081, Italy, Tel +39 089672407, Email email protected View the original paper by Dr Moleiro and colleagues A Response to Letter has been published for this article.
Purpose
The aim of this study was to measure and compare the retinal vascular parameters and foveal avascular zone (FAZ) in Chinese and Caucasian populations by using optical coherence tomography ...angiography (OCT‐A).
Methods
Fifty‐one eyes of Han Chinese and 43 eyes of Caucasians were retrospectively included in our study. The measurements were acquired using Zeiss Cirrus 5000, with the same software version 10 in Poland and China.
Results
The size of the FAZ was 0.33 ± 0.012 and 0.28 ± 0.014 mm2 (p = 0.0289) and the diameter was 2.43 ± 0.06 and 2.18 ± 0.07 mm (p = 0.0057) for Chinese and Caucasian populations, respectively. However, no differences were observed in circularities between the populations. The full Early Treatment of Diabetic Retinopathy Study (ETDRS) vessel length density was significantly different for Chinese (17.05 ± 0.24 mm/mm2) and Caucasian (16.08 ± 0.43 mm/mm2) populations. In addition, the outer ETDRS vessel length density was significantly different for Chinese (16.43 ± 0.42 mm/mm2) and Caucasian (17.47 ± 0.24 mm/mm2) populations, but the central 7.33 ± 1.68 versus 9.32 ± 1.54 mm/mm2 for the Caucasian and Chinese and inner 16.14 ± 0.52 for Caucasian and 16.93 ± 0.27 mm/mm2 for Chinese subjects density was not. A significant yet weak positive correlation between FAZ and vessel density was observed (r = 0.216). Furthermore, no significant intersexual differences were observed in study parameters.
Conclusion
The Chinese population had larger FAZ with higher vessel length density in the superficial layers of the retina than the Caucasian population.
Background/Objectives
Optical coherence tomography (OCT) uses low coherence interferometry to obtain depth‐resolved tissue reflectivity profiles (M‐mode) and transverse beam scanning to create images ...of two‐dimensional tissue morphology (B‐mode). Endoscopic OCT imaging probes typically employ proximal or distal mechanical beam scanning mechanisms that increase cost, complexity, and size. Here, we demonstrate in the gastrointestinal (GI) tracts of unsedated human patients, that a passive, single‐fiber probe can be used to guide device placement, conduct device−tissue physical contact sensing, and obtain two‐dimensional OCT images via M‐to‐B‐mode conversion.
Materials and Methods
We designed and developed ultrasmall, manually scannable, side‐ and forward‐viewing single fiber‐optic probes that can capture M‐mode OCT data. Side‐viewing M‐mode OCT probes were incorporated into brush biopsy devices designed to harvest the microbiome and forward‐viewing M‐mode OCT probes were integrated into devices that measure intestinal potential difference (IPD). The M‐mode OCT probe‐coupled devices were utilized in the GI tract in six unsedated patients in vivo. M‐mode data were converted into B‐mode images using an M‐to‐B‐mode conversion algorithm. The effectiveness of physical contact sensing by the M‐mode OCT probes was assessed by comparing the variances of the IPD values when the probe was in physical contact with the tissue versus when it was not. The capacity of forward‐ and side‐viewing M‐mode OCT probes to produce high‐quality B‐mode images was compared by computing the percentages of the M‐to‐B‐mode images that showed close contact between the probe and the luminal surface. Passively scanned M‐to‐B‐mode images were qualitatively compared to B‐mode images obtained by mechanical scanning OCT tethered capsule endomicroscopy (TCE) imaging devices.
Results
The incorporation of M‐mode OCT probes in these nonendoscopic GI devices safely and effectively enabled M‐mode OCT imaging, facilitating real‐time device placement guidance and contact sensing in vivo. Results showed that M‐mode OCT contact sensing improved the variance of IPD measurements threefold and side‐viewing probes increased M‐to‐B‐mode image visibility by 10%. Images of the esophagus, stomach, and duodenum generated by the passively scanned probes and M‐to‐B‐mode conversion were qualitatively superior to B‐mode images obtained by mechanically scanning OCT TCE devices.
Conclusion
These results show that passive, single optical fiber OCT probes can be effectively utilized for nonendoscopic device placement guidance, device contact sensing, and two‐dimensional morphologic imaging in the human GI tract in vivo. Due to their small size, lower cost, and reduced complexity, these M‐mode OCT probes may provide an easier avenue for the incorporation of OCT functionality into endoscopic/nonendoscopic devices.
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