Optical Coherence Tomography Images Research Articles

Three-dimensional optical coherence tomography for guidance of percutaneous coronary intervention for coronary bifurcation disease: a review of current clinical applications.

Percutaneous coronary intervention (PCI) for coronary bifurcation disease remains one of the most challenging situations in interventional cardiology in terms of procedural success rates and long-term cardiac events. Optical coherence tomography (OCT), with a higher signal-to-noise ratio and the ability to distinguish plaque components, can display the true condition of bifurcation lesions without overlapping or shortening and achieve detailed visualization of vascular structures, which is superior to those of other imaging modalities. Three-dimensional (3D) reconstruction of OCT images (3D-OCT) helps to gain a more informed understanding of the geometry and morphology of bifurcation lesions and provide additive information on plaque distribution. Following stent implantation, 3D-OCT can also guide the re-crossing of guide wires through stent struts jailing the side branch (SB) ostium and more clearly display the jailing strut configuration, as well as the ideal position of the guidewire recrossing point and stent struct link connection, to confirm the optimal guidewire position and understand interactions between stents and vessel walls, which may improve clinical results after PCI. The present review provides an up-to-date overview of the clinical use of 3D-OCT for accurate assessment of bifurcation anatomy, guiding the optimal guidewire rewiring into SB during bifurcation stenting, and evaluation of post-PCI results, offering novel information about atherosclerotic disease or stenting process.

MIXED PATHOPHYSIOLOGIES OF LAMELLAR MACULAR HOLES AND RELATED DISEASES: A Multimodal Optical Coherence Tomography-Based Study.

To investigate the characteristics of mixed pathophysiologies in lamellar macular holes (LMHs) and related diseases using multimodal optical coherence tomography. Overall, 126 eyes diagnosed with LMH, epiretinal membrane foveoschisis, or macular pseudohole using the horizontal B-scan image according to the definition proposed by Hubschman et al in 2020 were analyzed using multimodal optical coherence tomography imaging including horizontal and vertical 5-line B-scan, radial scan, and macular three-dimensional volume scan images. If at least two diagnostic criteria for LMH, epiretinal membrane foveoschisis, or macular pseudohole were satisfied in these scans, the patient was diagnosed as having a "mixed type." Retinal traction force was quantitatively evaluated by measuring the maximum depth of the retinal folds using en-face images. Mixed types constituted 34.1% of the cases. The LMH-related mixed group demonstrated intermediate characteristics between the epiretinal membrane foveoschisis/macular pseudohole and true LMH groups in terms of retinal traction and LMH-specific features and had a significant positive correlation between the maximum depth of the retinal folds and mean M-CHARTS scores (P = 0.034). A thorough optical coherence tomography analysis is necessary to accurately diagnose LMH and related diseases. A significant positive correlation was observed between the maximum depth of the retinal folds and the degree of metamorphopsia in the LMH-related mixed group.

The clinical features and perfusion density in paracentral acute middle maculopathy by optical coherence tomography angiography study

To observe the clinical features of the paracentral acute middle maculopathy (PAMM) and to investigate the changes in perfusion density of superficial capillary plexus (SCP) and deep capillary plexus (DCP) in PAMM by optical coherence tomography angiography (OCTA). Twelve patients (12 eyes) diagnosed with PAMM and 13 healthy participants (13 eyes) were enrolled. The clinical features of 12 PAMM patients were recorded. The perfusion density of SCP and DCP in the parafovea and perifovea (divided into Temporal, Superior, Nasal, and Inferior) was measured by OCTA in PAMM and healthy eyes. Automated macular maps, including SCP and DCP, were also performed. The mean age of patients was 48.08 (range 14-72) years. The best corrected visual acuity (BCVA) was from finger count (FC) to 1.0. Risk factors included hypertension, diabetes mellitus, COVID-19, etc. The patients had signs of retinal vascular disease except for one patient with isolated PAMM. A spectral-domain OCT image of the PAMM eye showed hyperreflectivity in the inner nuclear layer (INL). Compared with healthy eyes, SCP and DCP in PAMM eyes were significantly reduced in all sectors (all p < 0.05) in the parafovea and perifovea. The average perfusion density of SCP in parafovea and perifovea in PAMM eyes were 46.94±4.34% vs 52.21±3.98% (p=0.002), 44.01±3.95% vs 50.51±3.14 (p=0.000) in healthy eyes. The average perfusion density of DCP in parafovea and perifovea in PAMM eyes were 51.22±4.16% vs 57.15±3.87% (p=0.002), 47.375±6.23% vs 54.27±5.33% (p=0.002) in healthy eyes. PAMM often accompanies concurrent ocular and systemic diseases. OCTA results confirm that the perfusion density of SCP and DCP in the parafovea and perifovea significantly reduced in PAMM patients.

Comparison between OCT B-scan and En Face Imaging for the Diagnosis of Early Macular Atrophy in Age-Related Macular Degeneration

The gradings of complete retinal pigment epithelium and outer retinal atrophy (cRORA) and incomplete retinal pigment epithelium and outer retinal atrophy (iRORA) on spectral domain optical coherence tomography (SD-OCT) B-scans were compared with the grading of persistent choroidal hypertransmission defects (hyperTDs) on swept-source OCT angiography (SS-OCTA) en face images. Comparative diagnostic analysis of prospective study data METHODS: Patients with late nonexudative AMD underwent same day 6 × 6 mm macular scans using both SD-OCT (Spectralis® Heidelberg, 512 × 97, ART:9) and SS-OCTA (PLEX® Elite 9000, Carl Zeiss Meditec, 500 × 500 angio pattern) instruments. SS-OCTA and SD-OCT en face images were generated from a sub-retinal pigment epithelium slab positioned 64-400 μm below Bruch's membrane. SD-OCT B-scan gradings, which included an inspection of neighboring B-scans for the diagnosis of cRORA and iRORA, were performed at the Moran Eye Center, while gradings of en face images to identify persistent choroidal hyperTDs were performed at the Bascom Palmer Eye Institute and Tel Aviv Medical Center. There was a high degree of agreement (99.6%) between the gradings of cRORA lesions and persistent hyperTDs. However, 27.4% of iRORA lesions were found to be contained within persistent hyperTDs. This discrepancy was due to the finding that 27.5% of iRORA lesions were diagnosed as having a greatest linear horizontal dimension of < 250 µm on B-scans, but on en face images, these B-scan defined iRORA lesions were found to have a greatest linear dimensions in the non-horizontal dimension that were ≥ 250 µm. This report demonstrates the benefits of using en face OCT imaging to identify cRORA lesions and highlights the need to acquire dense raster B-scans with the grading neighboring B-scans when identifying iRORA lesions to assess the full extent of the iRORA lesions in the non-horizontal dimension. Even though neighboring B-scans were inspected, 27.5% of iRORA lesions were actually part of larger cRORA lesions when graded using an en face strategy.

Non-arteritic anterior ischemic optic neuropathy in Black patients

Prior studies have shown that non-arteritic anterior ischemic optic neuropathy (NAION) is uncommon in persons of Black race compared to those of White race, but the reasons behind this discrepancy remain unknown. Our goal was to analyze the systemic and ocular features of Black NAION patients compared to White patients. Retrospective cross-sectional study METHODS: Self-reported race was collected from all NAION patients seen between 2014-2022 from a single US neuro-ophthalmology service. All Black NAION patients and a randomly selected sample of White NAION patients were included. We collected information on hypertension, hyperlipidemia, diabetes mellitus, hypothyroidism, obesity, ischemic heart disease, atrial fibrillation, pacemaker insertion, chronic kidney disease, dialysis, anemia, obstructive sleep apnea, deep vein thrombosis, stroke, use of phosphodiesterase inhibitors, and smoking status. We reviewed color fundus photographs and optic nerve OCT images to assess cup-to-disc ratio and document the presence of optic disc drusen. Counterfactual random forest was used to estimate associations for each characteristic of interest by race controlling for the other exposures. We included 32 Black NAION patients (mean age 57 ± 11 years, 38% men) and 69 of 432 White patients (mean age 57 ± 15 years, 59% men). Time between NAION onset and neuro-ophthalmic examination was significantly longer in Black patients (1.5 to <3 months: OR 4.07, P = 0.03; 6 to <12 months: OR 6.05, P = 0.007). Chronic kidney disease (OR 7.53, P = 0.003) and hemodialysis (OR 13.69, P = 0.02) were significantly more frequent in Black patients. No significant differences in cup-to-disc ratio were present (0.15 to <0.25: OR 2.83, P = 0.09; 0.25 to <0.35: OR 0.56, P = 0.46; ≥0.35: OR 0.66, P = 0.44). Referral delay occurs in Black patients with NAION, likely due to its relative rarity and concern for alternate diagnoses. Black NAION patients were substantially more likely to have chronic kidney disease and be on dialysis than White patients. Despite known racial differences in cup-to-disc ratio, we found no difference between Black and White NAION patients, suggesting that the underlying proposed compartment mechanism is the same between races.

Efficient semi-supervised hierarchical training for segmenting choroidal vessels and other structures on OCT images of multiple sclerosis patients

Optical coherence tomography (OCT) is a non-invasive imaging technique used to diagnose ocular and systemic diseases. Recently, several clinical studies have linked changes in different ocular layers to the development of multiple sclerosis (MS), so accurate segmentation of these structures has become an essential task. Unfortunately, segmenting the entire set of structures involved is a very difficult task, due to their large number and variability. These two factors hinder the labelling of images and therefore severely restrict the ability to achieve a large dataset with all structures manually annotated, limiting the use of a standard supervised approach. In this paper, we propose a semi-supervised learning methodology to robustly segment ocular structures in OCT images using a limited number of partially labeled images. Our methodology maximizes the information we can extract from labeled images through hierarchical learning, where multiple decoders are used to extract segmented structures progressively. We use a reconstruction loss function to provide structural coherence to the segmentation and a teacher-student strategy to effectively leverage the information present in the set of unlabeled images. In addition to the segmentation of labelled structures, this hierarchical approach allows segmenting structures that are not labelled in the dataset such as the choroidal vessels. To validate the proposed methodology, we have carried out extensive experimentation using two datasets with different characteristics. These experiments have demonstrated a great potential of this methodology to train networks efficiently with partially labeled images, which allows to accurately extract the main biomarkers linked to the development of MS.

Clinical and morphologic features of macular telangiectasia type 2: natural course of the disease

Purpose: The purpose of this study is to report the clinical characteristics of macular telangiectasia type 2 (MacTel 2) in a natural disease course. Materials and Methods: A retrospective analysis of patients diagnosed with MacTel 2 over a 4-year period. Best-corrected visual acuity (BCVA), fundus photography, and optical coherence tomography (OCT) images were reviewed. Differences in BCVA, fundoscopic findings, and OCT parameters were compared between the initial and final visits. Results: The study included 28 eyes from 14 patients (11 women, 3 males), with a mean age of 65.5 ± 9.8 years. The mean follow-up period was 55.6 ± 32.9 months. The mean BCVA at baseline and final follow-up were 0.51 ± 0.6 and 0.7 ± 0.62 logMAR, respectively. At the first and last visits, the right-angle venules were the most common fundoscopic finding (78.6% for both). Subretinal neovascularization (NV) was initially present in two eyes and developed in one eye during follow-up. The mean temporal macular thickness decreased significantly during the follow-up period, while the central and nasal thickness did not show a significant change. At the last visit, focal ellipsoid zone (EZ) loss was found in 27 eyes (96.4%), compared to 24 eyes (85.7%) at baseline. External limiting membrane (ELM) loss was found in 23 eyes (82.1%) at the first visit and in 25 eyes (89.3%) at the final visit. The increase in mean length of the EZ and ELM loss during the follow-up was not statistically significant. Conclusion: Despite the progressive effect of the disease on central visual acuity, it is very important to closely monitor these eyes for the development of secondary NV, which may develop due to degenerative and atrophic changes in the macula.

Improvements on speed, stability and field of view in adaptive optics OCT for anterior retinal imaging using a pyramid wavefront sensor.

We present improvements on the adaptive optics (AO) correction method using a pyramid wavefront sensor (P-WFS) and introduce a novel approach for closed-loop focus shifting in retinal imaging. The method's efficacy is validated through in vivo adaptive optics optical coherence tomography (AO-OCT) imaging in both, healthy individuals and patients with diabetic retinopathy. In both study groups, a stable focusing on the anterior retinal layers is achieved. We further report on an improvement in AO loop speed that can be used to expand the imaging area of AO-OCT in the slow scanning direction, largely independent of the eye's isoplanatic patch. Our representative AO-OCT data reveal microstructural details of the neurosensory retina such as vessel walls and microglia cells that are visualized in single volume data and over an extended field of view. The excellent performance of the P-WFS based AO-OCT imaging in patients suggests good clinical applicability of this technology.

Dysfunctional lens syndrome: a literature review

Introduction. The term “Dysfunctional Lens Syndrome” (DLS) refers to age-related changes in the lens, including early cataracts and presbyopia, that do not significantly reduce visual acuity. This syndrome is characterized by a decrease in accommodative amplitude, an increase in light scattering, and a reduction in contrast sensitivity. With rising life expectancy, the prevalence of DLS is increasing, necessitating a more in-depth study of the pathogenic mechanisms underlying the syndrome and the refinement of its diagnostic criteria to establish standards for treatment correction. Aim: to summarize information on the pathogenesis of DLS, the potential for staging the syndrome using objective examination methods, and to provide treatment recommendations. Materials and methods. A bibliographic study of scientific publications was conducted using the Pubmed, ScienceDirect, and Cyberleninka databases. Literature sources were searched using the following keywords: dysfunctional lens syndrome (DLS), presbyopia correction, cataract, age-related lens changes. A total of 32 publications, primarily from the last 10 years, were included in the study from more than 100 viewed sources. Results. The DLS encompasses a wide range of conditions, from early stages characterized by a loss of accommodative amplitude and minor refractive anomalies to later stages involving a decrease in visual acuity and quality due to increased light scattering and aberrations. Currently, the evaluation of age-related lens changes involves assessing visual acuity and determining the degree of lens opacification using slit-lamp examination. Additionally, objective instrumental methods, such as optical coherence tomography and Scheimpflug imaging, can be used to assess the degree of lens opacification. Various methods are employed for the correction and treatment of DLS, ranging from glasses and contact lenses to surgical interventions, such as lens extraction and intraocular lens implantation. Research is also ongoing into drugs aimed at slowing the progression of lens changes. Conclusion. The term “Dysfunctional Lens Syndrome” is currently used to describe early cataracts and presbyopia, where the reduction in visual acuity is still minor, but patients experience visual complaints due to age-related lens changes. Further research is necessary to develop and standardize diagnostic criteria and to evaluate the effectiveness of new treatment methods and interventions in order to create the most effective and adequate approach to correcting DLS and alleviating the associated visual complaints.

Characterizing Biomechanics of Limbal Niche Using Vibrational Optical Coherence Elastography.

The limbal niche is an adult source of epithelial stem cells which regenerate the cornea epithelium. The architecture and biomechanical properties of the limbus have previously been demonstrated to change due to aging and disease. This study aims to non-destructively and simultaneously quantify these limbal niche properties, along with their age-related changes. A lab-built vibrational optical coherence elastography (OCE) device consisting of a phase-sensitive optical coherence tomography (OCT) with a vibrational stimulator has been used to collect structural images and the depth-resolved elasticity of human corneoscleral tissues (aged 4-96 years old). The limbal palisades of Vogt (POV) were delineated well in OCT images which were validated by histology. The POVs have been spatially mapped with simultaneous elasticity measurements in cross-sections, showing tissue stiffness distributions across the undulations. A significant influence of age on the dimensions of the POVs was explored. The elastic modulus within the limbal niches for the ≥65-year-old group was significantly higher than that of the <65-year-old group.

Prevalence and associations of dome-shaped maculas. The Beijing Eye Study.

To explore the prevalence and associated factors of a dome-shaped macula (DSM) in a general population. Out of the population-based Beijing Eye Study cohort (n = 3468 participants), the investigation included all eyes with an axial length of ≥25 mm, and a randomized sample of eyes with an axial length of <25 mm. Using optical coherence tomographic (OCT) images, we examined presence and height of DSMs, defined as an inward convexity of the foveal retinal pigment epithelium (RPE)/Bruch's membrane (BM) line, detectable in at least two OCT scans perpendicularly orientated to each other. The study cohort consisted of 366 eyes (314 individuals) with a mean age of 63.7 ± 9.7 years and a mean axial length of 24.8 ± 2.1 mm (median: 25.1 mm; range: 18.96-30.88 mm). Prevalence of DSMs (found in 6/366 eyes; 1.9%; 95%CI: 1.0, 3.0) increased from 0/125 (0%) in non-myopic eyes to 1/152 (0.7%; 95%CI: 0.0, 2.0) in moderately myopic eyes, and to 6/83 (7.2%; 95%CI: 1.7, 12.7) in the highly myopic group. In multivariable analysis, higher DSM prevalence corelated with longer axial length (OR: 2.05; 95%CI: 1.36, 3.08; p < 0.001) and higher stage of myopic macular degeneration (OR: 1.08; 95%CI: 1.01, 1.16; p = 0.03). The mean maximal DSM height was 139 ± 107 μm (median: 100 μm; range: 25-350 μm). It was associated with higher stage of myopic macular degeneration (beta: 0.24; p < 0.001) and higher prevalence of macular BM defects (beta: 0.17; p < 0.001). None of the DSMs showed a serous retinal detachment or relative choroidal thickening. Higher DSM prevalence correlated non-linearly with longer axial length, with DSM height increasing with the presence of a BM defect. DSMs may be associated with an axial elongation-related BM overproduction in the fundus midperiphery in all meridians.

The Microphthalmia-Associated Transcription Factor (MITF) and Its Role in the Structure and Function of the Eye.

The microphthalmia-associated transcription factor (Mitf) has been found to play an important role in eye development, structure, and function. The Mitf gene is responsible for controlling cellular processes in a range of cell types, contributing to multiple eye development processes. In this review, we survey what is now known about the impact of Mitf on eye structure and function in retinal disorders. Several mutations in the human and mouse Mitf gene are now known, and the effects of these on eye phenotype are addressed. We discuss the importance of Mitf in regulating ion transport across the retinal pigment epithelium (RPE) and the vasculature of the eye. The literature was searched using the PubMed, Scopus, and Google Scholar databases. Fundus and Optical Coherence Tomography (OCT) images from mice were obtained with a Micron IV rodent imaging system. Defects in neural-crest-derived melanocytes resulting from any Mitf mutations lead to hypopigmentation in the eye, coat, and inner functioning of the animals. While many Mitf mutations target RPE cells in the eye, fewer impact osteoclasts at the same time. Some of the mutations in mice lead to microphthalmia, and ultimately vision loss, while other mice show a normal eye size; however, the latter, in some cases, show hypopigmentation in the fundus and the choroid is depigmented and thickened, and in rare cases Mitf mutations lead to progressive retinal degeneration. The Mitf gene has an impact on the structure and function of the retina and its vasculature, the RPE, and the choroid in the adult eye.

Prevalence and associations of parapapillary scleral ridges: the Beijing Eye Study

PurposeTo explore the prevalence and associated factors of parapapillary scleral ridges (PSRs).MethodsOut of the cohort of the population-based Beijing Eye Study (n=3468 participants), the study included all eyes with an...

OCTNet: A Modified Multi-Scale Attention Feature Fusion Network with InceptionV3 for Retinal OCT Image Classification

OCTNet: A Modified Multi-Scale Attention Feature Fusion Network with InceptionV3 for Retinal OCT Image Classification

Corneal densitometry measurements comparison between anterior segment OCT and scheimpflug imaging

PurposeTo evaluate and compare the repeatability of corneal densitometry (CD) measurements obtained using both an anterior-segment optical coherence tomography (AS-OCT) device and a Scheimpflug camera system, while also assessing the level of agreement. The study also sought to investigate the correlation of CD with age, gender, and central corneal thickness (CCT) in normal eyes.MethodsCD measurements were obtained using the Casia 2 and the Pentacam AXL Wave. Data were collected on Total Corneal Densitometry and 4 concentric corneal annular areas, these are referred to as zone 1, denoting the central area, through to zone 4, designating the outermost peripheral region. Repeatability was assessed using intra-session test–retest variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC). The agreement was evaluated using Bland–Altman plots. Correlation analysis was performed between CD, age, gender, and CCT.ResultsThe study included 96 healthy volunteers. The Casia 2 demonstrated high repeatability with ICC values exceeding 0.9 in all the corneal zones and lower CoV values compared to the Pentacam AXL Wave (ranging from 1.07% to 2.25% for Casia 2 and from 1.91% to 6.89% for Pentacam).95% LoA were within ± 2 standard deviation from the average mean except from zone 1 (± 2.42).However, the measurements showed a consistent bias among all the corneal zones. CD values were positively correlated with age, except for zone 1 with the Pentacam (p = 0.083).ConclusionsThe findings suggest that the Casia 2 can be a reliable tool for assessing corneal transparency in healthy individuals, however its measurements are not interchangeable with those provided by the Pentacam. The AS-OCT device may be more sensitive in detecting subtle age-related changes in CD within the central zone.

Quantitative Characterization of Zebrafish Caudal Fin Regeneration Based on Mueller Matrix OCT In Vivo.

Zebrafish serves as a valuable model for studying tissue regeneration due to their comprehensive regenerative abilities, particularly in bone tissue. In this study, a Mueller matrix optical coherence tomography (OCT) system was applied to monitor the regenerative processes of zebrafish caudal fins in vivo. The analysis focused on evaluating the thickness of the caudal fin tip and the distribution of internal bone tissue during the regenerative process. Subsequently, the effect of ectoine solution on the regeneration process was observed and discussed. Our findings revealed that the caudal fin blastema did not exhibit phase-induced polarization characteristics in the Mueller matrix OCT images. Statistical analyses indicated that the caudal fins did not fully regenerate to their original state within 21 days. Furthermore, the results suggested that ectoine solution could enhance tissue regeneration. This approach provides a method for quantifying zebrafish caudal fin regeneration and advances observation techniques for biomedical and clinical applications.

Macular, Choroidal, and Peripapillary Perfusion Changes in Mild and Moderate Traumatic Brain Injury Using Optical Coherence Tomography and Angiography.

Introduction: To compare the retinal and choroidal architecture and microvasculature between patients with mild or moderate traumatic brain injury (TBI) and controls with normal cognition using optical coherence tomography (OCT) and OCT angiography (OCTA). Methods: Patients with a documented history of TBI, and age-matched and sex-matched controls were recruited. The primary outcome measures were differences between OCT parameters, including the choroidal vascularity index, and between OCTA superficial capillary plexus metrics, including foveal avascular zone (FAZ) circularity, 3.0 mm × 3.0 mm and 6.0 mm × 6.0 mm macular vessel density and perfusion density, and 4.5 mm × 4.5 mm peripapillary capillary perfusion density and capillary flux index. Results: Sixty-seven eyes of 36 patients with TBI and 72 eyes of 36 control patients met the inclusion criteria. Twelve patients (33.3%) had a diagnosis of mild TBI without loss of consciousness (LOC), 21 (58.3%) had mild TBI with LOC, and 3 (8.3%) had moderate TBI. There was a significant reduction in FAZ circularity and in 3.0 mm × 3.0 mm macular OCTA vessel density and perfusion density in patients with TBI. In cases with TBI associated with posttraumatic stress disorder, all macular OCTA parameters were significantly reduced. There was an increase in the choroidal vascularity index across the severity of TBI; however, it was reduced in those with more than 1 TBI (P = .03). Conclusions: There was a reduction in macular perfusion in eyes of patients with mild or moderate TBI. The choroidal vascularity index helps differentiate subtle effects of more severe or mild repeated TBI. Further prospective investigation will evaluate OCT imaging and OCTA imaging as a noninvasive screening modalities to assess changes in retinal and choroidal microvasculature.

Peripapillary choroidal vascularity of paediatric myopic eyes with peripapillary hyperreflective ovoid mass-like structures.

To assess the peripapillary choroidal vasculature in paediatric myopic patients with and without peripapillary hyperreflective ovoid mass-like structures (PHOMS). This prospective study includes 60 eyes of 60 myopic (spherical equivalent [SE] <-1.00 dioptre [D]) patients with (n = 30) and without (n = 30) PHOMS (PHOMS [+] and PHOMS [-] groups, respectively), and 30 eyes of 30 age- and sex-matched emmetropic children (control group). Peripapillary choroidal parameters, including total choroidal (TCA), luminal (LA), and stromal areas (SA) and choroidal vascularity index (CVI) calculated from vertical and horizontal single-line enhanced depth imaging-optical coherence tomography scans centred on optic nerve head. Peripapillary retinal nerve fibre layer thicknesses were not different between the groups (p > 0.05). In the PHOMS (+) group, TCA, LA and SA were lower, and CVI was higher in all quadrants compared to the control (p < 0.05). However, only the mean TCA and LA in the inferior and nasal quadrants and the mean SA in the nasal quadrant were lower in PHOMS (+) than in PHOMS (-) (p < 0.05). In the PHOMS (-) group, higher CVI was observed in all quadrants except temporal compared to the control group. Although the mean CVI of the PHOMS (+) group was also higher than in the PHOMS (-) group, this difference was not statistically significant. This study indicates that choroidal parameters differ in paediatric myopic patients with PHOMS. Further studies with larger sample sizes are needed to understand the details of choroidal parameters in eyes with PHOMS.

Revolutionizing diabetic eye disease detection: retinal image analysis with cutting-edge deep learning techniques

Globally, glaucoma is a leading cause of visual impairment and vision loss, emphasizing the critical need for early diagnosis and intervention. This research explores the application of deep learning for automated glaucoma diagnosis using retinal fundus photographs. We introduce a novel cross-sectional optic nerve head (ONH) feature derived from optical coherence tomography (OCT) images to enhance existing diagnostic procedures. Our approach leverages deep learning to automatically detect key optic disc characteristics, eliminating the need for manual feature engineering. The deep learning classifier then categorizes images as normal or abnormal, streamlining the diagnostic process. Deep learning techniques have proven effective in classifying and segmenting retinal fundus images, enabling the analysis of a growing number of images. This study introduces a novel mixed loss function that combines the strengths of focal loss and correntropy loss to handle complex biomedical data with class imbalance and outliers, particularly in OCT images. We further refine a multi-task deep learning model that capitalizes on similarities across major eye-fundus activities and metrics for glaucoma detection. The model is rigorously evaluated on a real-world ophthalmic dataset, achieving impressive accuracy, specificity, and sensitivity of 100%, 99.8%, and 99.2%, respectively, surpassing state-of-the-art methods. These promising results underscore the potential of our deep learning algorithm for automated glaucoma diagnosis, with significant implications for clinical applications. By simultaneously addressing segmentation and classification challenges, our approach demonstrates its effectiveness in accurately identifying ocular diseases, paving the way for improved glaucoma diagnosis and early intervention.

Microscope integrated MHz optical coherence tomography system for neurosurgery: development and clinical in-vivo imaging.

Neurosurgical interventions on the brain are impeded by the requirement to keep damages to healthy tissue at a minimum. A new contrast channel enhancing the visual separation of malign tissue should be created. A commercially available surgical microscope was modified with adaptation optics adapting the MHz speed optical coherence tomography (OCT) imaging system developed in our group. This required the design of a scanner optics and beam delivery system overcoming constraints posed by the mechanical and optical parameters of the microscope. High quality volumetric OCT C-scans with dense sample spacing can be acquired in-vivo as part of surgical procedures within seconds and are immediately available for post-processing.