Ocular Biomarkers in Alzheimer's Disease: Insights into Early Detection Through Eye-Based Diagnostics - A Literature Review.

Abstract: Alzheimer's Disease (AD) is a significant challenge in neurodegenerative disorders, characterized by a gradual decline in cognitive functions. Diagnosis typically occurs at advanced stages when therapeutic options are less effective, underscoring the importance of early detection. Traditional diagnostic methods are often invasive and costly, spurring interest in more accessible and economical alternatives. The eye, as a direct link to the brain through the optic nerve, suggests that ocular changes could serve as early indicators of AD. This has led to the exploration of non-invasive ocular diagnostic tools. Technologies such as Optical Coherence Tomography (OCT), OCT Angiography (OCT-A), pupillometry, and eye-tracking, along with electrophysiological methods like Electroretinography (ERG) and Pattern Electroretinography (PEV), are being utilized to investigate potential ocular biomarkers. Further, tear fluid analysis has suggested that presence of amyloid-beta (Aß) protein might reflect neurogenerative processes, providing a non-invasive window into disease progression. Exploring ocular changes as potential early indicators of Alzhei-mer's Disease (AD), we aimed to provide an overview of promising biomarkers for earlier diagnosis and intervention. Our review further investigates the connections between AD and other ocular degenera-tive diseases such as age-related macular degeneration (AMD) and glaucoma, uncovering shared pathogenic pathways that could offer new therapeutic targets. To establish the sensitivity and specificity of these ocular biomarkers, comprehensive studies are required. Moreover, larger, longitudinal studies are essential to confirm the effectiveness of ocular assessments in the preemptive diagnosis of Alzheimer's Disease.

Imprint of preterm birth with very low birth weight on optic disc OCT in adulthood-A two-country birth cohort study.

PURPOSE: To determine the pattern, degree and prevalence of optic disc optical coherence tomography (OCT) alterations in adults born preterm with very low birth weight (VLBW; birth weight < 1500 g). METHODS: Optic disc OCT was assessed in 98 VLBW participants and 139 term-born controls from birth cohorts in Finland and Norway at the mean age of 36 years. The participants had not been treated for retinopathy of prematurity and had no diagnosed brain abnormality. OCT assessment included parameters for optic disc size, neural rim and peripapillary retinal nerve fibre layer thickness (pRNFLT), and for the foveal developmental stage. Background data, visual acuity, refractive error and intraocular pressure were recorded. RESULTS: In the VLBW group, optic disc neural rim and pRNFLT were significantly decreased, most frequently in the nasal and inferior sectors. In 40% (95% CI: 33-47) of the VLBW eyes, nerve fibre thickness of at least one optic disc sector was below the fifth percentile of the control group, including 9% (95% CI: 6-14) subgroup falling below the first percentile, that is, clinically below normal limits. VLBW participants with nerve fibre thickness below the fifth percentile did not differ by perinatal data or foveal developmental stage from the other VLBW participants. All participants had normal visual acuity. CONCLUSION: A moderate decrease of the optic disc neural rim and pRNFLT is frequently seen in clinically healthy adults born preterm with VLBW. Awareness of the VLBW-related optic disc nerve fibre shallowness especially in the inferior and nasal sectors is important while evaluating acquired optic disc pathology in adulthood.

Precision Segmentation of Subretinal Fluids in OCT Using Multiscale Attention-Based U-Net Architecture.

This paper presents a deep-learning architecture for segmenting retinal fluids in patients with Diabetic Macular Oedema (DME) and Age-related Macular Degeneration (AMD). Accurate segmentation of multiple fluid types is critical for diagnosis and treatment planning, but existing techniques often struggle with precision. We propose an encoder-decoder network inspired by U-Net, processing enhanced OCT images and their edge maps. The encoder incorporates Residual and Inception modules with an autoencoder-based multiscale attention mechanism to extract detailed features. Our method shows superior performance across several datasets. On the RETOUCH dataset, the network achieved F1 Scores of 0.82 for intraretinal fluid (IRF), 0.93 for subretinal fluid (SRF), and 0.94 for pigment epithelial detachment (PED). The model also performed well on the OPTIMA and DUKE datasets, demonstrating high precision, recall, and F1 Scores. This architecture significantly enhances segmentation accuracy and edge precision, offering a valuable tool for diagnosing and managing retinal diseases. Its integration of dual-input processing, multiscale attention, and advanced encoder modules highlights its potential to improve clinical outcomes and advance retinal disease treatment.

Sex differences in plaque characteristics of fractional flow reserve-negative non-culprit lesions after myocardial infarction.

BACKGROUND AND AIMS: Recurrent events after myocardial infarction (MI) are common and often originate from native non-culprit (NC) lesions that are non-flow limiting. These lesions consequently pose as targets to improve long-term outcome. It is, however, largely unknown whether these lesions differ between sexes. The aim of this study was to assess such potential differences. METHODS: From the PECTUS-obs study, we assessed sex-related differences in plaque characteristics of fractional flow reserve (FFR)-negative intermediate NC lesions in 420 MI-patients. RESULTS: Among the included patients, 80 (19.1 %) were female and 340 (80.9 %) male. Women were older and more frequently had hypertension and diabetes. In total, 494 NC lesions were analyzed. After adjustment for clinical characteristics and accounting for within-patients clustering, lesion length was longer in female patients (20.8 ± 10.0 vs 18.3 ± 8.5 mm, p = 0.048) and minimum lumen area (2.30 ± 1.42 vs 2.78 ± 1.54 mm2, p < 0.001) and minimum lumen diameter (1.39 ± 0.45 vs 1.54 ± 0.44 mm, p < 0.001) were smaller. The minimum fibrous cap thickness was smaller among females (96 ± 53 vs 112 ± 72 µm, p = 0.025), with more lesions harboring a thin cap fibroatheroma (39.3 % vs 24.9 %, p < 0.001). Major adverse cardiovascular events at two years occurred in 6.3 % of female patients and 11.8 % of male patients (p = 0.15). CONCLUSIONS: FFR-negative NC lesions after MI harbored more high-risk plaque features in female patients. Although this did not translate into an excess of recurrent events in female patients in this modestly sized cohort, it remains to be investigated whether this difference affects clinical outcome.

Retinal and Corneal OCT Results of Patients Hospitalized and Treated in the Acute Phase of COVID-19.

Objective: This study aimed to assess changes in the morphology of the retina and cornea in patients treated and hospitalized during the acute active phase of SARS-CoV-2 infection. Methods: A total of 24 patients with symptomatic early COVID-19 disease and 38 healthy participants from a control group were enrolled in our study. Among them, 20 received oxygen therapy at flow rates ranging from 1-10 L, while four received high-flow intranasal oxygen therapy (HFNOT). Some patients were treated with other types of therapy, such as Remdesivir, COVID-19 convalescent plasma therapy, or Tocilizumab. In the study, we focused on the analysis of optical coherence tomography (OCT) images of the cornea and retina including corneal thickness, central retinal thickness, retinal nerve fiber layer (RNFL), and optic disc parameters. The measurements were acquired using Spectral-domain OCT REVO FC 130. Results: The analysis did not show significant changes between the examined ophthalmological parameters before and after therapy. Furthermore, there were no detected significant differences between the tested parameters of the retina and cornea in COVID-19-positive patients compared to the control group. Conclusions: No ophthalmological manifestations of COVID-19 disease were observed during the study. Taking into account the results of other publications, the lack of an unambiguous position on this topic requires further research.

Comparative of OCT and OCTA parameters in patients with early chronic angle-closure glaucoma and early pituitary adenoma.

Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) have the potential application in evaluating pathological structural change of the optic nerve. We aimed to evaluate the value of the OCT and OCTA parameters of the optic disk and macular in differentiating early chronic primary angle-closure glaucoma (CPACG) and early pituitary adenoma (PA) in case of mild visual field defects (the mean defect (MD) > 6 dB). The results showed that regarding OCTA parameters, CPACG patients had lower retinal blood flow density of most layers of the optic disk and macular than PA patients. Regarding OCT parameters, CPACG patients had thinner circumpapillary retinal nerve fiber layer (CP-RNFL) in all quadrants and average CP-RNFL, ganglion cell layer (GCL) and macular ganglion cell complex (GCC) in each quadrant of macular inner and outer rings, and inner plexus layer (IPL) of macular inner ring, superior-outer ring and temporal-outer ring than PA patients. The Z test indicated that OCTA parameters and OCT parameters had similar value in the diagnosis of disease. In conclusion, in the case of similar visual field damage, early CPACG patients have smaller blood flow density and thinner optic disk and macular than early PA. OCTA has similar performance to OCT in diagnosing CPACG and PA.

Visual Field Defects and Retinal Nerve Fiber Layer Thickness in Migraine Patients: A Study From a Tertiary Care Center in India.

Background This study aimed to analyze the visual field changes and retinal nerve fiber layer (RNFL) thickness during the headache phase of migraine attacks among migraine patients compared with controls. Methodology A prospective, case-control study was conducted at a tertiary care center in Palakkad, Kerala from January 2022 to August 2023. This study included 50 migraine patients and 50 age/gender-matched controls. Adults aged 20-40 years with a more than three-year history of migraine were included in this study and those who had systemic or ocular pathologies were excluded. All 100 subjects underwent complete ocular examination, including full threshold 24-2 automated perimetry for visual field analysis and optical coherence tomography for analyzing RNFL thickness. Statistical analysis was done using SPSS Statistics Version 25 (IBM Corp., Armonk, NY, USA). Results In this study, the average age for cases was 29.24 ± 5.10 years, and for controls was 30.12 ± 6.20 years. Gender distribution was identical between cases and controls with 29 (58%) females and 21 (42%) males. Among the 50 migraine patients, 22 (44%) had generalized, while 28 (56%) had localized field defects during the headache phase of migraine attacks. There was a statistically significant (p < 0.001) difference in superior quadrant RNFL thickness between cases (114.08 ± 12.25) and controls. Conclusions We found that RNFL thinning in the superior quadrant and non-specific localized visual field changes occur during migraine attacks. We conducted this study in a tertiary care center as very few studies in our country have revealed visual field changes during migraine headache attacks.

Research progress of optic nerve imaging during 1991-2023: a bibliometric analysis.

Background: Optic nerve imaging is crucial for diagnosing and understanding optic neuropathies because it provides detailed visualization of the nerve's structure and pathologies through advanced modalities. This study conducted a bibliometric analysis within the field of optic nerve imaging, aiming to pinpoint the latest research trends and focal points in optic nerve imaging. Methods: The core literature on optic nerve imaging published between January 1991 and August 2023 was retrieved from the Web of Science Core Collection. The analysis and visualization of scientific productivity and emerging trends were facilitated through the utilization of Bibliometrix software, CiteSpace, Gephi, VOSviewer, R software, and Python. Results: In total, 15,247 publications on optic nerve imaging were included in the analysis. Notably, the top 3 journals contributing to this field were Investigative Ophthalmology & Visual Science, Ophthalmology, and the British Journal of Ophthalmology. This research on optic nerve imaging extended across 97 countries, with the USA leading in research endeavors. Noteworthy burst term analysis revealed that "Segmentation" and "Machine learning" are gaining attention. Additionally, the Latent Dirichlet Allocation model indicated that image processing has been a hotspot in recent years. Conclusions: This study revealed the research trends, hotspots, and emerging topics in optic nerve imaging through bibliometric analysis and network visualization. At present, the research focus is directed towards employing artificial intelligence for image post-processing. The findings of this study offer valuable insights into future research direction and clinical applications.

Comparison of angiography-guided vs. intra-vascular imaging-guiding percutaneous coronary intervention of acute myocardial infarction: a real world clinical practice.

Background: The role of routine intravascular imaging in percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) remains unclear. This study evaluated the clinical outcomes of PCI guided by different imaging modalities in AMI patients. Materials and methods: Data from AMI patients who had undergone PCI between 2012 and 2022 were analyzed. The mean follow-up was 12.9 ± 1.73 months. The imaging modality-either intravascular ultrasound (IVUS), optical coherence tomography (OCT), or angiography alone-was selected at the operator's discretion. The primary endpoint was major adverse cardiac events (MACEs), including cardiovascular (CV) death, myocardial infarction (MI), target vessel revascularization. Results: Of the 1,304 PCIs performed, 47.5% (n = 620) were guided by angiography alone, 37.0% (n = 483) by IVUS, and 15.4% (n = 201) by OCT. PCI guided by intravascular imaging modalities was associated with lower 1-year rates of MI (1.3%, P = 0.001) and MACE (5.2%, P = 0.036). OCT-guided PCI was linked to lower rates of 1-year CV death (IVUS vs. OCT: 6.2% vs. 1.5%, P = 0.016) and MACE (IVUS vs. OCT: 6.4% vs. 2.5%, P = 0.032). Intravascular imaging modalities and diabetes were identified as predictors of better and worse 1-year MACE outcomes, respectively. Conclusion: PCI guided by intravascular imaging modalities resulted in improved 1-year clinical outcomes compared to angiography-guided PCI alone in AMI patients. OCT-guided PCI was associated with lower 1-year MACE rates compared to IVUS-guided PCI. Therefore, intravascular imaging should be recommended for PCI in AMI, with OCT being particularly considered when appropriate.

Multimodal optical imaging of iris flocculi in three consecutive generations: a case report.

Background: Multiple pigmented epithelial cysts at the edge of pupils, that is, iris flocculi, in both eyes, are rare ocular diseases. It has been demonstrated that this disease can be attributed to mutations in the smooth muscle α-actin 2 (ACTA2) gene, which mainly affects the function of smooth muscle cells (SMCs). SMCs are components of the iris, aorta, and several other systemic organs. In addition, iris flocculi are strongly correlated with familial thoracic aortic aneurysm and dissection (TAAD), which is caused by the mutation of amino acid 149 in the ACTA2 gene. Case description: A 6-month-old Chinese boy was found to have iris flocculi during ocular fundus screening for premature infants. His mother, a 30-year-old Chinese woman with a history of aortic dissection, underwent an ophthalmic examination and was found to have iris flocculi. Whole exome sequencing revealed a heterozygous c.445C > T (p. Arg149Cys) mutation in ACTA2 in both the boy and his mother. After his family history was traced, the boy's grandfather was diagnosed with similar iris flocculi. Due to the absence of any ocular complications caused by iris flocculi in the cases, no special treatment was given, and regular follow-up was recommended. Conclusion: We reported one case of familial iris flocculi caused by a heterozygous missense mutation in ACTA2 (p. Arg149Cys) and presented multimodal optical images of both the iris and fundus in three consecutive generations. This case report enriched the clinical features of retinal vasculature and macula associated with the mutation in the amino acid 149 of the ACTA2 gene.

A novel approach for automatic classification of macular degeneration OCT images.

Age-related macular degeneration (AMD) and diabetic macular edema (DME) are significant causes of blindness worldwide. The prevalence of these diseases is steadily increasing due to population aging. Therefore, early diagnosis and prevention are crucial for effective treatment. Classification of Macular Degeneration OCT Images is a widely used method for assessing retinal lesions. However, there are two main challenges in OCT image classification: incomplete image feature extraction and lack of prominence in important positional features. To address these challenges, we proposed a deep learning neural network model called MSA-Net, which incorporates our proposed multi-scale architecture and spatial attention mechanism. Our multi-scale architecture is based on depthwise separable convolution, which ensures comprehensive feature extraction from multiple scales while minimizing the growth of model parameters. The spatial attention mechanism is aim to highlight the important positional features in the images, which emphasizes the representation of macular region features in OCT images. We test MSA-NET on the NEH dataset and the UCSD dataset, performing three-class (CNV, DURSEN, and NORMAL) and four-class (CNV, DURSEN, DME, and NORMAL) classification tasks. On the NEH dataset, the accuracy, sensitivity, and specificity are 98.1%, 97.9%, and 98.0%, respectively. After fine-tuning on the UCSD dataset, the accuracy, sensitivity, and specificity are 96.7%, 96.7%, and 98.9%, respectively. Experimental results demonstrate the excellent classification performance and generalization ability of our model compared to previous models and recent well-known OCT classification models, establishing it as a highly competitive intelligence classification approach in the field of macular degeneration.

Dense Convolutional Neural Network-Based Deep Learning Pipeline for Pre-Identification of Circular Leaf Spot Disease of Diospyros kaki Leaves Using Optical Coherence Tomography.

Circular leaf spot (CLS) disease poses a significant threat to persimmon cultivation, leading to substantial harvest reductions. Existing visual and destructive inspection methods suffer from subjectivity, limited accuracy, and considerable time consumption. This study presents an automated pre-identification method of the disease through a deep learning (DL) based pipeline integrated with optical coherence tomography (OCT), thereby addressing the highlighted issues with the existing methods. The investigation yielded promising outcomes by employing transfer learning with pre-trained DL models, specifically DenseNet-121 and VGG-16. The DenseNet-121 model excels in differentiating among three stages of CLS disease (healthy (H), apparently healthy (or healthy-infected (HI)), and infected (I)). The model achieved precision values of 0.7823 for class-H, 0.9005 for class-HI, and 0.7027 for class-I, supported by recall values of 0.8953 for class-HI and 0.8387 for class-I. Moreover, the performance of CLS detection was enhanced by a supplemental quality inspection model utilizing VGG-16, which attained an accuracy of 98.99% in discriminating between low-detail and high-detail images. Moreover, this study employed a combination of LAMP and A-scan for the dataset labeling process, significantly enhancing the accuracy of the models. Overall, this study underscores the potential of DL techniques integrated with OCT to enhance disease identification processes in agricultural settings, particularly in persimmon cultivation, by offering efficient and objective pre-identification of CLS and enabling early intervention and management strategies.

Pattern Visually Evoked Potentials (pVEPs) and Retinal Nerve Fiber Thickness in a Japanese Girl With Anti-myelin Oligodendrocyte Glycoprotein Antibody Seropositive Optic Neuritis.

We report our findings in a 5-year-old Japanese girl with unilateral optic neuritis who was seropositive for anti-myelin-oligodendrocyte glycoprotein (MOG) antibody. Functional and microstructural changes were assessed longitudinally for 3.5 years by serial recordings of the pattern visual evoked potentials (pVEPs) and optical coherence tomography (OCT) during the acute and chronic phases. On the initial visit, the best-corrected visual acuity (BCVA) in the right eye was light perception. She was treated with 450 mg of intravenous methylprednisolone pulses followed by a gradual tapering of the oral prednisolone. The visual acuity decreased to no light perception, and plasmapheresis combined with high-dose intravenous immunoglobulin therapy was performed. The BCVA quickly improved to 1.0, and no recurrence was detected for approximately four years. The implicit times of N75, P100, and N145 of the pVEPs and peripapillary retinal nerve fiber (pRNFL) thickness in the OCT images were measured during the course of the disease process. The pRNFL thickness of the right eye decreased and was less than one-half of the baseline value at one year and then stabilized. In contrast, the optic pathway function assessed by pVEPs improved. The implicit times of the N75 and P100 components of the right eye were shortened and stabilized at approximately one year. However, the implicit times in the right eye were still longer than that of the left eye. Our findings documented the course of the function and structures of an eye with anti-MOG antibody-positive optic neuritis. This information should be helpful for the understanding of the pathology and prognosis of this disease entity. Further analysis of the pVEPs and structural changes in more cases is needed.

Investigation of the Effect of Compression Pressure in Contact OCT Imaging on the Measurement of Epidermis Thickness.

Optical coherence tomography (OCT) is a noninvasive 3D imaging technique that offers significant advantages over traditional microscopy and biopsy in measuring epidermal thickness (ET) when assessing skin conditions. However, OCT imagining is often required to be in a contact mode for mitigating the issues of subject movement and uneven skin topology. It is not known whether the contact would affect the ability of ET measurements. In this study, we investigate the relationship between the contact pressure applied and the ET measurements. We observed progressive deformation in the epidermis with the increase of compression forces, where a notable decrease of up to 13% in ET measurement and 70% decrease in capillary vessels was noted when imaging was in contact mode. We also observed 8.1% less deformation properties in scar tissue than in nearby healthy tissue. Our study underscored the importance of controlled pressure in contact imaging mode, which is often neglected.

Unveiling the Potential: A Comprehensive Review of Artificial Intelligence Applications in Ophthalmology and Future Prospects.

Artificial intelligence (AI) has emerged as a transformative force in healthcare, particularly in the field of ophthalmology. This comprehensive review examines the current applications of AI in ophthalmology, highlighting its significant contributions to diagnostic accuracy, treatment efficacy, and patient care. AI technologies, such as deep learning algorithms, have demonstrated exceptional performance in the early detection and diagnosis of various eye conditions, including diabetic retinopathy (DR), age-related macular degeneration (AMD), and glaucoma. Additionally, AI has enhanced the analysis of ophthalmic imaging techniques like optical coherence tomography (OCT) and fundus photography, facilitating more precise disease monitoring and management. The review also explores AI's role in surgical assistance, predictive analytics, and personalized treatment plans, showcasing its potential to revolutionize clinical practice and improve patient outcomes. Despite these advancements, challenges such as data privacy, regulatory hurdles, and ethical considerations remain. The review underscores the need for continued research and collaboration among clinicians, researchers, technology developers, and policymakers to address these challenges and fully harness the potential of AI in improving eye health worldwide. By integrating AI with teleophthalmology and developing AI-driven wearable devices, the future of ophthalmic care promises enhanced accessibility, efficiency, and efficacy, ultimately reducing the global burden of visual impairment and blindness.

Robust Ultrafast Projection Pipeline for Structural and Angiography Imaging of Fourier-Domain Optical Coherence Tomography.

The current methods to generate projections for structural and angiography imaging of Fourier-Domain optical coherence tomography (FD-OCT) are significantly slow for prediagnosis improvement, prognosis, real-time surgery guidance, treatments, and lesion boundary definition. This study introduced a robust ultrafast projection pipeline (RUPP) and aimed to develop and evaluate the efficacy of RUPP. RUPP processes raw interference signals to generate structural projections without the need for Fourier Transform. Various angiography reconstruction algorithms were utilized for efficient projections. Traditional methods were compared to RUPP using PSNR, SSIM, and processing time as evaluation metrics. The study used 22 datasets (hand skin: 9; labial mucosa: 13) from 8 volunteers, acquired with a swept-source optical coherence tomography system. RUPP significantly outperformed traditional methods in processing time, requiring only 0.040 s for structural projections, which is 27 times faster than traditional summation projections. For angiography projections, the best RUPP variation took 0.15 s, making it 7518 times faster than the windowed eigen decomposition method. However, PSNR decreased by 41-45% and SSIM saw reductions of 25-74%. RUPP demonstrated remarkable speed improvements over traditional methods, indicating its potential for real-time structural and angiography projections in FD-OCT, thereby enhancing clinical prediagnosis, prognosis, surgery guidance, and treatment efficacy.

Volumetric Biomarkers of Visual Outcome after Surgical Repair in Lamellar Macular Holes.

BACKGROUND: We investigate novel OCT parameters, based on the volumetric analysis of lamellar macular holes (LMHs), as prognostic indicators for visual outcomes after surgery. METHODS: LMHs were divided into degenerative LMHs (D-LMHs) and ERM-foveoschisis (ERM-FS). Pre-operative clinical, OCT linear and volumetric parameters were collected. Volumes were obtained using the OCT automatic segmentation, such as central retinal volume (CRV) and outer nuclear layer (ONL) volume, or using a novel method to calculate volumes of specific LMH entities like epiretinal proliferation (ERP), foveal cavity (FC) in D-LMH and schitic volume (SV) in ERM-FS. Univariate and multivariate linear regression analysis evaluated the factors predictive for post-operative best-corrected visual acuity (BCVA). RESULTS: We included 31 eyes of 31 patients (14 D-LMH,17 ERM-FS). A pre-operative BCVA ≤ 0.48 logMAR was a predictor for achieving ≤0.30 logMAR at final follow-up. A lower pre-operative BCVA (p = 0.008) and the presence of ERP (p = 0.002) were associated with worse visual outcomes post-surgery. Moreover, novel pre-operative OCT parameters significantly associated with worse post-operative BCVA, such as increased FC volume (p = 0.032) and lower CRV (p = 0.034) in the D-LMH subtype and lower CRV (p < 0.001) and ERP volume (p < 0.001), higher SV (p < 0.001) and foveal ONL volume (p < 0.001) in the ERM-FS subtype. CONCLUSIONS: Novel volumetric OCT parameters can be prognostic indicators of visual outcome following surgery in LMHs.

Reproducibility of Portable OCT and Comparison with Conventional OCT.

Optical coherence tomography (OCT) is an indispensable instrument in ophthalmology; however, some facilities lack permanent OCT devices. ACT100, a portable SD-OCT system, allows for medical examinations at hospitals that do not have OCT and house calls. We investigated the usefulness of ACT100 by examining the reproducibility of retinal thickness measurements in 35 healthy participants with normal eyes using ACT100 and Cirrus. Using two OCTs, the OCT imaging of both eyes of each subject was performed. Macular retinal thickness was evaluated using the average value in nine lesions of the Early Treatment Diabetic Retinopathy Study (ETDRS) circle. Both models captured images in all cases. In the right eye, mean retinal thickness was significantly lower than in the ACT100 group in all regions; however, the measured values correlated well. The intraclass correlation coefficients showed the same high reliability as the Cirrus. The coefficients of variation (CVs) of both models showed little variation and high stability; however, the CV of ACT100 was significantly higher. The left eye was almost identical. Macular retinal thickness measured using ACT100 showed slightly greater variability than that by Cirrus; the reproducibility was good and correlated well with that of Cirrus. This technique is a suitable alternative to conventional OCT.

Application of novel non-invasive ophthalmic imaging to visualize peripapillary wrinkles, retinal folds and peripapillary hyperreflective ovoid mass-like structures associated with elevated intracranial pressure.

Background: Elevated intracranial pressure (ICP) is a serious and potentially life-threatening condition, for which clinically useful non-invasive measures have been elusive, in some cases due to their inadequate sensitivity and specificity. Our aim was to evaluate novel non-invasive ophthalmic imaging of selected pathological features seen in elevated ICP, namely peripapillary hyperreflective ovoid mass-like structures (PHOMS), peripapillary wrinkles (PPW) and retinal folds (RF) as potential biomarkers of elevated ICP. Methods: This single-center pilot study included subjects with untreated or incompletely treated high ICP. The retinas of these subjects were evaluated with averaged en-face optical coherence tomography (OCT), OCT retinal cross-sections (OCT B-scans), adaptive optics scanning light ophthalmoscopy (AOSLO), and fundus photos. Results: Seven subjects were included in the study. 6 subjects with high ICP (5 idiopathic intracranial hypertension, 1 medication induced, 30.8 ± 8.6 years, 75% female, 5 with papilledema) and 1 control (20-25 years) were included. PHOMS, PPW and RF were present in all subjects with papilledema, but neither in the high ICP subject without papilledema nor in the control subject. Averaged en-face OCT scans and AOSLO were more sensitive for PPW and RF than OCT B-scans and commercial fundus photos. Conclusion: PPW, RF and PHOMS volume have potential as non-invasive biomarkers of ICP. Novel imaging modalities may improve sensitivity. However, lack of automated image acquisition and processing limits current widespread adoption in clinical settings. Further research is needed to validate these structures as biomarkers for elevated ICP and improve clinical utility.

Quantitative optical coherence tomography angiography assessments in the fellow eyes of those with central serous chorioretinopathy.

BACKGROUND: To analyze the vessel density (VD) of the retina and choriocapillaris (CC) layer and the structure of the foveal avascular zone (FAZ) in the fellow eyes of central serous chorioretinopathy (CSC) patients by using optical coherence tomography angiography (OCTA). METHODS: This was a case-control study. Unilateral CSC patients and age-matched healthy subjects were recruited from the Affiliated Eye Hospital of Wenzhou Medical University between July 2016 and July 2021. All eyes were divided into three groups: acute CSC (aCSC), chronic CSC (cCSC), and healthy controls. Both aCSC and cCSC were again divided into two subgroups: the affected eyes and the fellow eyes. In this study, all parameters of VD and FAZ were measured by self-software of OCTA. RESULTS: A total of 231 eyes of 137 subjects were included, with 47 aCSC patients, 47 cCSC patients, and 43 healthy controls. In the fellow eyes of CSC, the retinal VD was significantly lower (all P < 0.05), and the FAZ was significantly larger (all P < 0.05) in the cCSC group than in healthy controls, while no difference was detected in the CC layer. There was no significant difference between the aCSC group and healthy controls in all OCTA parameters. In the affected eyes of CSC, the superficial retinal vessel density (SRVD) was significantly higher (all P < 0.05) in healthy controls than in the aCSC and cCSC groups, while the deep retinal vessel density (DRVD) was significantly lower (all P < 0.05) and the FAZ was larger (all P < 0.05) in the cCSC group than in the aCSC group and healthy controls. A liner regression equation was established: Y (BCVA, best corrected visual acuity) = 3.692-0.036✱X1 (DRVD-Fovea)-0.031✱X2 (FD-300, vessel density around the 300 µm width of the FAZ), R2 = 0.427. CONCLUSION: Based on OCTA measurements, this study revealed that the retinal microvascular network was impaired even in the fellow eyes of those with cCSC, which should arouse attention to the observation of unilateral CSC.