Search Results (67)

Background: Choroidal nevi are common, benign tumors. These tumors rarely cause adverse retinal sequalae, but when they do, they can lead to disruption of the outer retina and vision loss. In this paper, we used high-resolution retinal imaging modalities, optical coherence tomography (OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO), to longitudinally monitor retinal sequelae of a submacular choroidal nevus. Methods: A 31-year-old female with a high-risk choroidal nevus resulting in subretinal fluid (SRF) and a 30-year-old control subject were longitudinally imaged with AOSLO and OCT in this study over 18 and 22 months. Regions of interest (ROI) including the macular region (where SRF was present) and the site of laser photocoagulation were imaged repeatedly over time. The depth of SRF in a discrete ROI was quantified with OCT and AOSLO images were assessed for visualization of photoreceptors and retinal pigmented epithelium (RPE). Cell-like structures that infiltrated the site of laser photocoagulation were measured and their count was assessed over time. In the control subject, images were assessed for RPE visualization and the presence and stability of cell-like structures. Results: We demonstrate that AOSLO can be used to assess cellular-level changes at small ROIs in the retina over time. We show the response of the retina to SRF and laser photocoagulation. We demonstrate that the RPE can be visualized when SRF is present, which does not appear to depend on the height of retinal elevation. We also demonstrate that cell-like structures, presumably immune cells, are present within and adjacent to areas of SRF on both OCT and AOSLO, and that similar cell-like structures infiltrate areas of retinal laser photocoagulation. Conclusions: Our study demonstrates that dynamic, cellular-level retinal responses to SRF and laser photocoagulation can be monitored over time with AOSLO in living humans. Many retinal conditions exhibit similar retinal findings and laser photocoagulation is also indicated in numerous retinal conditions. AOSLO imaging may provide future opportunities to better understand the clinical implications of such responses in vivo. Full article

Background: This study aimed to evaluate retinal arteriole parameters using adaptive optics (AO) rtx1™ (Imagine Eyes, Orsay, France) and peripapillary and macular vessel densities with optical coherence tomography angiography (OCTA) in eyes with different stages of primary open-angle glaucoma (POAG) compared to healthy eyes. It also investigated the associations between vascular parameters and glaucoma severity, as defined by structural (OCT) and functional (visual field) changes. Methods: Fifty-seven eyes from 31 POAG patients and fifty from 25 healthy volunteers were examined. Retinal arteriole morphology was assessed using the AO rtx1™-fundus camera, which measured lumen diameter, wall thickness, total diameter, wall-to-lumen ratio (WLR), and wall cross-sectional area. OCTA was used to measure vessel densities in superficial (SCP) and deep (DCP) capillary plexuses of the macula and radial peripapillary capillary plexus (RPCP) and FAZ area. Structural OCT parameters (RNFL, GCC, rim area) and visual field tests (MD, PSD) were also performed. Results: Glaucoma eyes showed significantly thicker arteriole walls (12.8 ± 1.4 vs. 12.2 ± 1.3 µm; p = 0.030), narrower lumens (85.5 ± 10.4 vs. 100.6 ± 11.1 µm; p < 0.001), smaller total diameters (111.0 ± 10.4 vs. 124.1 ± 12.4 µm; p < 0.001), and higher WLRs (0.301 ± 0.04 vs. 0.238 ± 0.002; p < 0.001) than healthy eyes. In glaucoma patients, OCTA revealed significantly reduced vessel densities in SCP (36.39 ± 3.60 vs. 38.46 ± 1.41; p < 0.001), DCP (36.39 ± 3.60 vs. 38.46 ± 1.41; p < 0.001), and RPCP plexuses (35.42 ± 4.97 vs. 39.27 ± 1.48; p < 0.001). The FAZ area was enlarged in eyes with glaucoma (0.546 ± 0.299 vs. 0.295 ± 0.125 mm²); p < 0.001). Positive correlations were found between vessel densities and OCT parameters (RNFL, r = 0.621; GCC, r = 0.536; rim area, r = 0.489), while negative correlations were observed with visual field deficits (r = −0.517). Conclusions: Vascular deterioration, assessed by AO rtx1™ and OCTA, correlates closely with structural and functional damage in glaucoma. Retinal microcirculation changes may precede structural abnormalities in the optic nerve head. Both imaging methods enable the earlier detection, staging, and monitoring of glaucoma compared to conventional tests. Full article

Optical coherence tomography (OCT) employs light to acquire high-resolution 3D images and is widely applied in fields such as ophthalmology and forensic science. A popular technique for visualizing the top view (en face) is to slice it with flat horizontal plane or apply statistical functions along the depth axis. However, when the target appears as a thin layer, strong reflections from other layers can interfere with the target, rendering the flat-plane approach ineffective. We apply Otsu-based thresholding to extract the object’s foreground, then use least squares (with Tikhonov regularization) to fit a polynomial curve that describes the sample’s structural morphology. The surface is then used to obtain the latent fingerprint image and its residues at different depths from a translucent tape, which cannot be analyzed using conventional en face OCT due to strong reflection from the diffusive surface, achieving FSIM of 0.7020 compared to traditional en face of 0.6445. The method is also compatible with other signal processing techniques, as demonstrated by a thermal-printed label ink thickness measurement confirmed by a microscopic image. Our approach empowers OCT to observe targets embedded in samples with arbitrary postures and morphology, and can be easily adapted to various optical imaging technologies. Full article

Background/Objectives: To investigate the role of multimodal imaging, specifically optical coherence tomography angiography (OCTA) and adaptive optics (AO), in the diagnosis and monitoring of diabetic retinopathy. Methods: Our study represents an observational, cross-sectional analysis including sixty-nine patients from four distinct groups: a control group (17 patients), diabetic patients without diabetic retinopathy (no DR) (14 patients), diabetic patients with non-proliferative diabetic retinopathy (NPDR) (18 patients), and diabetic patients with proliferative diabetic retinopathy (PDR patients). A comprehensive ophthalmological evaluation, along with high-resolution imaging using OCTA and AO, was performed. OCTA images of the superficial capillary plexus, acquired with the OCT Angio Topcon, were analyzed using a custom-developed MATLAB algorithm, while AO retinal vascular images were evaluated with the manufacturer’s software of the Adaptive Optics Retinal Camera rtx1™. Results: Our findings demonstrated statistically significant reductions in foveal avascular zone circularity, superficial capillary plexus density, vessel length density, and fractal dimension, correlating with the severity of diabetic retinopathy, particularly in the PDR. Additionally, mean wall thickness and wall-to-lumen ratio were significantly increased in patients with diabetic retinopathy, notably in PDR. Conclusions: In conclusion, our findings demonstrate that the combined use of OCTA and AO imaging offers complementary insights into the microvascular alterations associated with diabetic retinopathy progression and severity. These high-resolution modalities together reveal both perfusion deficits and structural vascular changes, underscoring their utility as essential tools for early detection, staging, monitoring, and informed management of DR. Full article

Adaptive optics scanning laser ophthalmoscopy optoretinography quantifies cellular function in the living retina by measuring the en face intensity change in cone photoreceptors due to visual stimulation. To fulfill the potential of optoretinography as a biomarker for assessing function in disease, we require normative optoretinographic measurements across the retina. Here we provide such measurements. We use a custom adaptive optics scanning laser ophthalmoscope to investigate cone optoretinogram (ORG) amplitudes across retinal eccentricity in five normal-sighted participants. For this purpose, we aggregated signals across cones in each measurement (~1° by 1° patch) to provide a measurement we call the population ORG. Average population ORG amplitudes decreased with increasing eccentricity for all participants, although there were individual differences in the detailed pattern of the decrease. ORG amplitudes were correlated with the thickness of the outer retina as measured using clinical OCT, which also decreases with eccentricity. Characterizing the population cone ORG as a function of eccentricity in normal-sighted participants is an important step towards establishing norms that will allow it to be used as a biomarker for assessing photoreceptor function in retinal disease. Full article

Introduction: Recent technological progress in optical imaging—such as adaptive optics, interferometry and tomography—has greatly improved the resolution of retinal imaging. The ability to capture sequential images over time is particularly valuable for continuous monitoring and assessment of retinal diseases. Methods: This cross-sectional study involved patients with type 2 diabetes mellitus and age-matched controls from the Diabetes and Ophthalmology Department of the Emergency Military Clinical Hospital “Dr. Constantin Papilian” Cluj-Napoca between October 2023 and October 2024. These patients were assessed for inclusion and exclusion criteria and then categorized into two groups: the diabetes group and control group. Each participant underwent a comprehensive ophthalmological examination and retinal evaluation using SS-OCT (Spectralis Heidelberg Engineering, Heidelberg, Germany). The parameters measured included the superficial and deep foveal avascular zones (FAZ) in only one eye for each patient, selected based on image quality. Additionally, each patient underwent quantitative analysis of serum C-reactive protein (CRP) levels. Results: A total of 33 patients (33 eyes) featured, 13 men and 20 women. The DM group showed statistically significant higher results for CRP value compared to healthy subjects (p < 0.001). Also, both superficial and deep FAZ areas were statistically significantly higher for diabetes patients compared to the healthy controls (p < 0.05). The correlation analysis revealed that there was no significant correlation between CRP and either superficial FAZ (p = 0.809) or deep FAZ (p = 0.659). However, a significant positive moderate correlation was found between superficial FAZ and deep FAZ (r = 0.577, p = 0.015). Conclusions: Our findings showed a significantly enlarged FAZ in diabetic patients compared to healthy individuals, highlighting its potential as an early indicator of microvascular alterations in diabetes. While CRP levels were notably elevated in the diabetic group, no significant association was found between CRP and FAZ measurements, suggesting that FAZ changes may occur independently of systemic inflammatory status. Full article

Background: Adaptive optics transscleral flood illumination (AO-TFI) enables in vivo, non-invasive, high-resolution imaging of retinal pigment epithelium (RPE) and photoreceptor (PR) cells, paving the way for a new potential characterization of retinal diseases. This study aimed to analyze RPE and PR cells in a case of acute zonal occult outer retinopathy (AZOOR) using AO-TFI. Methods: A patient affected by AZOOR underwent a comprehensive eye examination, perimetry, electroretinography (ERG), autofluorescence, and optical coherence tomography (OCT) during the acute phase (T0). After three years (T1), OCT angiography (OCTA) and AO-TFI were also performed. Voronoi analysis was utilized to quantify RPE and PR cells. Results: At T0, OCT revealed interruptions in the ellipsoid zone (EZ) of the right eye, while the structure of the left eye appeared normal. Perimetry and ERG were abnormal in both eyes. At T1, OCT indicated recovery of the EZ in the right eye, while thinning of the ONL persisted. Perimetry and mfERG values remained below normative limits. OCTA exhibited globally reduced vessel density in the inner retina of the right eye. AO-TFI demonstrated reduced PR density in affected areas despite preserved EZ, while RPE cell density appeared unaffected. Conclusion: AO-TFI enabled a detailed visualization and quantification of macular RPE and PR cells, providing valuable insights into the pathophysiology of AZOOR. Full article

Adaptive optics-transscleral flood illumination (AO-TFI) is a novel imaging technique with potential for detecting retinal pigment epithelium (RPE) changes in dry age-related macular degeneration (AMD). This single-center prospective study evaluated its ability to visualize pathological features in AMD. AO-TFI images were acquired using the prototype Cellularis^® camera over six 5 × 5° macular zones in patients with good fixation and no exudative changes. Conventional imaging modalities, including spectral-domain optical coherence tomography (OCT), color fundus photography and fundus autofluorescence, were used for comparison. AO-TFI images were correlated with OCT using a custom method (Fiji software, v. 2.9). Eleven eyes of nine patients (70 ± 8.3 years) with early (n = 5), intermediate (n = 1) and atrophic (n = 5) AMD were analyzed. AO-TFI identified relevant patterns in dry AMD. RPE cell visibility was impaired in affected eyes, but AO-TFI distinguished cuticular drusen with hyporeflective centers and bright edges, large ill-defined drusen and stage 3 subretinal drusenoid deposits as prominent hyperreflective spots. It provided superior resolution for small drusen compared to OCT and revealed crystalline structures and hyporeflective dots in atrophic regions. Atrophic borders remained isoreflective unless RPE displacement was absent, allowing precise delineation. These findings highlight AO-TFI’s potential as a sensitive imaging tool for characterizing early AMD and clinical research. Full article

Retinal detachment (RD) is a vision-threatening ocular emergency that necessitates rapid diagnosis and intervention. This review examines the evolving role of optical coherence tomography (OCT) in RD by synthesizing the literature on preoperative biomarkers and advanced image modalities that inform diagnosis, prognosis, and surgical planning. We evaluated studies employing spectral-domain OCT, swept-source OCT, OCT angiography, adaptive optics OCT, and en face OCT to assess photoreceptor integrity, retinal detachment height, intraretinal cystic cavities, outer retinal corrugations and undulation, and macular involvement. The incorporation of OCT assessment into clinical practice may facilitate more precise surgical timing, technique selection, and postoperative monitoring. Further research is needed to standardize imaging protocols and validate specific prognostic biomarkers for optimal surgical outcomes. Key aspects include uniform imaging protocols, validating OCT-derived biomarkers such as ellipsoid zone integrity, and correlating OCT metrics with functional outcomes. Full article

Optical coherence tomography (OCT) has been extensively utilized in cardiovascular diagnostics due to its high resolution, rapid imaging capabilities; however, its adaptation for cerebrovascular applications remains constrained by the narrow, tortuous anatomical structure of cerebral vessels. To address these limitations, this study introduces a cerebrovascular-specific OCT (bOCT) catheter, an advanced adaptation of the cardiovascular OCT (cOCT) catheter, with significant structural modifications for improved access to brain blood vessels. The bOCT catheter incorporates a braided wire within a braided tube, strategically reinforcing axial strength. The distal shaft was reconfigured as a single-lumen structure, facilitating unified movement of the rotating fiber optic core and guidewire, thereby reducing guidewire bending and augmenting force transmission stability. Additionally, the anterior protrusion was removed and replaced with a dual-lumen configuration, significantly enhancing lesion accessibility. The bOCT catheter’s performance was validated in a 3D physical model and an animal model, demonstrating pronounced enhancements in flexibility, pushability, and navigability. Notably, the pushability through curved flow paths significantly improved, enhancing access to cerebral blood vessels. Therefore, this innovation promises to revolutionize cerebrovascular diagnostics with high-resolution imaging suited to the complex brain vasculature, setting a new standard in intravascular imaging technology. Full article

Background/Objectives: An assessment of the retinal image quality in adaptive optics optical coherence tomography (AO-OCT) is challenging. Many factors influence AO-OCT imaging performance, leading to greatly varying imaging results, even in the same subject. The aim of this study is to introduce quantitative means for an assessment of AO-OCT image quality and to compare these with parameters retrieved from the pyramid wavefront sensor of the system. Methods: We used a spectral domain AO-OCT instrument to repetitively image six patients suffering from diabetic retinopathy over a time span of one year. The data evaluation consists of two volume acquisitions with a focus on the photoreceptor layer, each at five different retinal locations per visit; 7–8 visits per patient are included in this data analysis, resulting in a total of ~420 volumes. Results: A large variability in AO-OCT image quality is observed between subjects and between visits of the same subject. On average, the image quality does not depend on the measurement location. The data show a moderate correlation between the axial position of the volume recording and image quality. The correlation between pupil size and AO-OCT image quality is not linear. A weak correlation is found between the signal-to-noise ratio of the wavefront sensor image and the image quality. Conclusions: The introduced AO-OCT image quality metric gives useful insights into the performance of such a system. A longitudinal assessment of this metric, together with wavefront sensor data, is essential to identify factors influencing image quality and, in the next step, to optimize the performance of AO-OCT systems. Full article

Optical coherence tomography (OCT) imaging plays a major role in the field of diagnosing, monitoring, and treating ophthalmological diseases. Since its introduction in the early 1990s, OCT technology has continued to advance both in the direction of acquisition quality and technique. In this manuscript, we concentrate on actual and future applications of OCT in the ophthalmology field, reviewing multiple types of OCT techniques and systems, such as visible-light OCT, adaptative optics OCT, intraoperative OCT, wide-field OCT, and more. All of them allow better monitoring of ocular diseases, earlier and broader diagnosis, and a more suitable treatment. Furthermore, overviewing all these technologies could play a pivotal role in research, leading to an advance in understanding the pathophysiology of targeted diseases. Finally, the aim of the present review was to evaluate the technical advances in OCT and their actual and potential clinical applications. Full article

The precision of imaging and the number of other risk-assessing and diagnostic methods are constantly growing, allowing for the uptake of additional strategies for individualized therapies. Personalized medicine has the potential to deliver more adequate treatment, resulting in better clinical outcomes, based on each patient’s vulnerability or genetic makeup. In addition to increased efficiency, costs related to this type of procedure can be significantly lower. Useful assistance in designing individual therapies may be assured by the adoption of artificial intelligence (AI). Recent years have brought essential developments in deep and machine learning techniques. Advances in technologies such as convolutional neural networks (CNNs) have enabled automatic analyses of images, numerical data, and video data, providing high efficiency in the creation of prediction models. The number of AI applications in medicine is constantly growing, and the effectiveness of these techniques has been demonstrated in coronary computed tomography angiography (CCTA), optical coherence tomography (OCT), and many others. Moreover, AI models may be useful in direct therapy optimization for patients with coronary artery disease (CAD), who are burdened with high risk. The combination of well-trained AI with the design of individual treatment pathways can lead to improvements in health care. However, existing limitations, such as non-adapted guidelines or the lack of randomized clinical trials to evaluate AI’s true accuracy, may contribute to delays in introducing automatic methods into practical use. This review critically appraises the developed tools that are potentially useful for clinicians in guiding personalized patient management, as well as current trials in this field. Full article

Background: Inherited retinal diseases (IRDs) are a genetically complex group of disorders, usually resulting in progressive vision loss due to retinal degeneration. Traditional imaging methods help in structural assessments, but limitations exist in early functional cellular-level detection that are crucial for guiding new therapies. Methods: This review includes a systematic search of PubMed and Google Scholar for studies on advanced imaging techniques for IRDs. Results: Key modalities covered are adaptive optics, fluorescence lifetime imaging ophthalmoscopy, polarization-sensitive optical coherence tomography, optoretinography, mitochondrial imaging, flavoprotein fluorescence imaging, and retinal oximetry. Each imaging method covers its principles, acquisition techniques, data from healthy eyes, applications in IRDs with specific examples, and current challenges and future directions. Conclusions: Emerging technologies, including adaptive optics and metabolic imaging, offer promising potential for cellular-level imaging and functional correlation in IRDs, allowing for earlier intervention and improved therapeutic targeting. Their integration into clinical practice may significantly improve IRD management and patient outcomes. Full article

Deep learning solutions can be used to classify pathological changes of the human retina visualized in OCT images. Available datasets that can be used to train neural network models include OCT images (B-scans) of classes with selected pathological changes and images of the healthy retina. These images often require correction due to improper acquisition or intensity variations related to the type of OCT device. This article provides a detailed assessment of the impact of preprocessing on classification efficiency. The histograms of OCT images were examined and, depending on the histogram distribution, incorrect image fragments were removed. At the same time, the impact of histogram equalization using the standard method and the Contrast-Limited Adaptive Histogram Equalization (CLAHE) method was analyzed. The most extensive dataset of Labeled Optical Coherence Tomography (LOCT) images was used for the experimental studies. The impact of changes was assessed for different neural network architectures and various learning parameters, assuming classes of equal size. Comprehensive studies have shown that removing unnecessary white parts from the input image combined with CLAHE improves classification accuracy up to as much as 4.75% depending on the used network architecture and optimizer type. Full article