Optical coherence tomography in the management of diabetic macular oedema

The diagnostic value of platelet-to-neutrophil ratio in diabetic macular edema

PURPOSE

To evaluate the diagnostic value of platelet-to-neutrophil ratio (PNR) in the occurrence of diabetic macular edema (DME) in patients with diabetic retinopathy (DR).

METHODS

This cross-sectional study included 366 participants categorized into four groups: DME group (n = 96), DR group (n = 90, DR without DME), diabetes mellitus (DM) group (n = 90, without DR), and healthy control group (n = 90). PNR was calculated by dividing the platelet count by the neutrophil count. Each subject was classified as one of three DME types according to the optical coherence tomography (OCT) features: diffuse retinal thickening (DRT), cystoid macular edema (CME), serous retinal detachment (SRD). The correlations between the PNR and the occurrence of DME, as well as the DME subtypes based on OCT were investigated. Multivariate logistic regression analysis was employed to determine the risk factors for DME. Receiver operating characteristic (ROC) curve analysis was conducted to assess the predictive value of PNR for DME.

RESULTS

DME group exhibited significantly lower PNR level compared to the other three groups [50.73 (38.92, 65.20) in DME group, 95.63 (68.83, 120.19) in DR group, 92.39 (72.38, 130.61) in DM group, and 100.66 (75.26, 152.77) in healthy control group, respectively, p < 0.001], but did not differ across the DME subtypes based on OCT (p = 0.548). The ROC curve demonstrated that the PNR could better predict DME (area under the curve = 0.832, 95% confidence interval: 0.773 - 0.891, p < 0.001). When the cut-off value of the PNR was 68.51, the sensitivity was 80.2%, and the specificity was 75.6%. Multivariate regression analysis indicated that PNR ≤ 68.51 was an independent risk factor for DME occurrence in DR patients (Odds ratio = 12.05, 95% confidence interval: 5.93 - 24.47, p < 0.001).

CONCLUSION

PNR ≤ 68.51 was strongly associated with the development of DME in DR patients, while no significant differences in PNR levels were observed across the different OCT morphological groups. Hence, PNR may serve as a valuable diagnostic biomarker for identifying DME, thereby enhancing risk stratification and management strategies for patients with DR.

Retinal Thickness Analysis Using Optical Coherence Tomography: Diagnostic and Monitoring Applications in Retinal Diseases

Retinal thickness analysis using optical coherence tomography (OCT) has become an indispensable tool in retinal disease management, providing high-resolution quantitative data for diagnosis, monitoring, and treatment planning. This analysis has been found to be particularly useful for both diagnostic and monitoring purposes across a wide range of retinal diseases, enabling precise disease characterization and treatment evaluation. This paper explores its applications across major retinal conditions, including age-related macular degeneration, diabetic retinopathy, retinal vein occlusion, and inherited retinal diseases. Emerging roles in other diseases such as neurodegenerative diseases and retinal drug toxicity are also highlighted. Despite challenges such as variability in measurements, segmentation errors, and interpretation difficulties, advancements in artificial intelligence and machine learning have significantly improved accuracy and efficiency. The integration of retinal thickness analysis with telemedicine platforms and standardized protocols further underscores its potential in delivering personalized care and enabling the early detection of ocular and systemic diseases. Retinal thickness analysis continues to play a pivotal and growing role in both clinical practice and research, bridging the gap between ophthalmology and broader medical fields.

Construction of a predictive model for the efficacy of anti-VEGF therapy in macular edema patients based on OCT imaging: a retrospective study

Background

Macular edema (ME) is an ophthalmic disease that poses a serious threat to human vision. Anti-vascular endothelial growth factor (anti-VEGF) therapy has become the first-line treatment for ME due to its safety and high efficacy. However, there are still cases of refractory macular edema and non-responding patients. Therefore, it is crucial to develop automated and efficient methods for predicting therapeutic outcomes.

Methods

We have developed a predictive model for the surgical efficacy in ME patients based on deep learning and optical coherence tomography (OCT) imaging, aimed at predicting the treatment outcomes at different time points. This model innovatively introduces group convolution and multiple convolutional kernels to handle multidimensional features based on traditional attention mechanisms for visual recognition tasks, while utilizing spatial pyramid pooling (SPP) to combine and extract the most useful features. Additionally, the model uses ResNet50 as a pre-trained model, integrating multiple knowledge through model fusion.

Results

Our proposed model demonstrated the best performance across various experiments. In the ablation study, the model achieved an F1 score of 0.9937, an MCC of 0.7653, an AUC of 0.9928, and an ACC of 0.9877 in the test conducted on the first day after surgery. In comparison experiments, the ACC of our model was 0.9930 and 0.9915 in the first and the third months post-surgery, respectively, with AUC values of 0.9998 and 0.9996, significantly outperforming other models. In conclusion, our model consistently exhibited superior performance in predicting outcomes at various time points, validating its excellence in processing OCT images and predicting postoperative efficacy.

Conclusion

Through precise prediction of the response to anti-VEGF therapy in ME patients, deep learning technology provides a revolutionary tool for the treatment of ophthalmic diseases, significantly enhancing treatment outcomes and improving patients' quality of life.

Blueberry Anthocyanin Extracts (BAEs) Protect Retinal and Retinal Pigment Epithelium Function from High-Glucose-Induced Apoptosis by Activating GLP-1R/Akt Signaling

Diabetic retinopathy is a severe diabetes complication leading to vision impairment and blindness primarily due to the disruption of insulin signaling in the retina. This study investigated the protective effects of blueberry anthocyanin extracts (BAEs) and its main component, anthocyanin-3-glucoside (C3G), in the retinas of diabetic mice and ARPE-19 cells under high-glucose (HG) conditions. The results showed that diabetic mice suffered significant weight loss, elevated glycemic levels, and increased retinal cell apoptosis after 10 weeks. Treatment with various doses of BAEs resulted in a significant reduction in glycemic levels, weight stabilization, decreased levels of inflammatory cytokines, and inhibition of retinal cell apoptosis. These findings suggested that BAEs possess hypoglycemic properties, potentially mitigating diabetes-induced retinal damage by modulating associated signaling pathways. Immunoblotting analysis revealed that persistent hyperglycemia impaired the Akt/GSK3β signaling pathway in diabetic mice, while high doses of BAEs significantly restored the function of these pathways and promoted GLP-1 release, enhancing GLP-1R expression in the retina and potentially mitigating retinal injury. Finally, studies on the effects of C3G on ARPE-19 cell models deficient in REDD1 under HG conditions showed that C3G protected cells from HG damage through the GLP-1R/Akt signaling pathway. In conclusion, this research provides valuable insights into the therapeutic potential of BAEs and C3G for managing diabetes-related ocular complications.

Frontier applications of retinal nanomedicine: progress, challenges and perspectives

The human retina is a fragile and sophisticated light-sensitive tissue in the central nervous system. Unhealthy retinas can cause irreversible visual deterioration and permanent vision loss. Effective therapeutic strategies are restricted to the treatment or reversal of these conditions. In recent years, nanoscience and nanotechnology have revolutionized targeted management of retinal diseases. Pharmaceuticals, theranostics, regenerative medicine, gene therapy, and retinal prostheses are indispensable for retinal interventions and have been significantly advanced by nanomedical innovations. Hence, this review presents novel insights into the use of versatile nanomaterial-based nanocomposites for frontier retinal applications, including non-invasive drug delivery, theranostic contrast agents, therapeutic nanoagents, gene therapy, stem cell-based therapy, retinal optogenetics and retinal prostheses, which have mainly been reported within the last 5 years. Furthermore, recent progress, potential challenges, and future perspectives in this field are highlighted and discussed in detail, which may shed light on future clinical translations and ultimately, benefit patients with retinal disorders.

Relationship of OCT-Based Diabetic Retinal Neurodegeneration to the Development and Progression of Diabetic Retinopathy: A Cohort Study

Purpose

To evaluate the relationship between diabetic retinal neurodegeneration (DRN), as quantified by optical coherence tomography (OCT), to the development of diabetic retinopathy (DR), progression of DR, and development of proliferative DR (PDR).

Methods

This was a prospective cohort study, including 385 eyes with no DR or nonproliferative DR at baseline. The thicknesses of the macular ganglion cell-inner plexiform layer (m-GCIPL), macular retinal nerve fiber layer, and peripapillary RNFL (p-RNFL) were measured using Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA). DR outcomes were determined from macula- and optic disc-centered fundus photographs, following the modified Airlie House classification system. Cox proportional hazards models were used to estimate hazard ratio (HR) adjusting for age, mean arterial blood pressure, diabetes mellitus duration, HbA1c, diabetic kidney disease, axial length, OCT signal strength, and disc area (for p-RNFL only).

Results

After a median follow-up of 6.2 years (range 5.0-7.7 years), 79 eyes developed DR, 99 eyes developed DR progression, and 38 eyes developed PDR. Thinner mean and sectorial m-GCIPL thicknesses were significantly associated with higher risk of DR development, with HRs ≥ 1.373 (1.023-1.843), except for the superonasal and superotemporal sectors. Similar to DR development, thinner m-GCIPL thicknesses were significantly associated with DR progression and PDR development, with HRs ranging from 1.306 (1.094-1.559) to 2.331 (1.524-3.566). Additionally, the inclusion of inferior m-GCIPL thickness significantly improved the predictive discrimination for DR development (C statistics: 0.661 vs. 0.705, P < 0.001), and DR progression (C statistics: 0.704 vs. 0.729, P < 0.001), as well as inferotemporal m-GCIPL for PDR development (C statistic: 0.917 vs. 0.930, P < 0.001) beyond established risk factors.

Conclusions

OCT measurements that elucidate DRN may enhance prognostic identification and predictive discrimination of DR development, DR progression, and PDR development beyond established risk factors.

Characterization of the Disorganization of the Inner Retinal Layers in Diabetics Using Increased Axial Resolution Optical Coherence Tomography

Purpose

To compare a novel high-resolution optical coherence tomography (OCT) with improved axial resolution (High-Res OCT) with conventional spectral-domain OCT (SD-OCT) with regard to their capacity to characterize the disorganization of the retinal inner layers (DRIL) in diabetic maculopathy.

Methods

Diabetic patients underwent multimodal retinal imaging (SD-OCT, High-Res OCT, and color fundus photography). Best-corrected visual acuity and diabetes characteristics were recorded. DR was graded using the international clinical diabetic retinopathy severity scale (DRSS). In each OCT B-scan, retinal layers were segmented and the loss of discernibility was annotated. DRIL areas were analyzed in en face projection using FIJI plugins. The Wilcoxon test and regression models were used for statistical analysis.

Results

In 93 eyes of 93 patients (mean age, 61.8 ± 12.9 years) DRIL was identified in 48 eyes. DRIL was most frequent in the central subfield (27%). In DRIL eyes, DRSS was significantly higher (4.43 ± 1.01 vs. 2.12 ± 1.66; P < 0.001), BCVA was significantly worse (0.34 ± 0.38 vs. 0.13 ± 0.22; P < 0.001), and the loss of discernibility of the individual inner retinal layers was significantly smaller in High-Res OCT compared with SD-OCT (0.21 ± 0.29 vs. 1.21 ± 1.21 mm2; P < 0.001). The discernibility loss was greatest in the retinal nerve fiber layer and ganglion cell layer.

Conclusions

DRIL occurs in eyes with advanced diabetic retinopathy, with a characteristic spread: from the inner toward the outer retina. High-Res OCT shows significantly smaller DRIL areas compared with SD-OCT, because of a more precise delineation of the inner retinal layers.

Translational Relevance

Using OCT with increased axial resolution could enhance our understanding of DRIL development and progression, providing deeper insights into pathophysiological aspects, including malperfusion in the inner capillary plexus.

Role of inflammation in diabetic macular edema and neovascular age-related macular degeneration

Diabetic macular edema (DME) and neovascular age-related macular degeneration (nAMD) are multifactorial disorders that affect the macula and cause significant vision loss. Although inflammation and neoangiogenesis are hallmarks of DME and nAMD, respectively, they share some biochemical mediators. While inflammation is a trigger for the processes that lead to the development of DME, in nAMD inflammation seems to be the consequence of retinal pigment epithelium and Bruch membrane alterations. These pathophysiologic differences may be the key issue that justifies the difference in treatment strategies. Vascular endothelial growth factor inhibitors have changed the treatment of both diseases, however, many patients with DME fail to achieve the established therapeutic goals. From a clinical perspective, targeting inflammatory pathways with intravitreal corticosteroids has been proven to be effective in patients with DME. On the contrary, the clinical relevance of addressing inflammation in patients with nAMD has not been proven yet. We explore the role and implication of inflammation in the development of nAMD and DME and its therapeutical relevance.

Multimodal imaging in diabetic retinopathy and macular edema: An update about biomarkers

Diabetic macular edema (DME), defined as retinal thickening near, or involving the fovea caused by fluid accumulation in the retina, can lead to vision impairment and blindness in patients with diabetes. Current knowledge of retina anatomy and function and DME pathophysiology has taken great advantage of the availability of several techniques for visualizing the retina. Combining these techniques in a multimodal imaging approach to DME is recommended to improve diagnosis and to guide treatment decisions. We review the recent literature about the following retinal imaging technologies: optical coherence tomography (OCT), OCT angiography (OCTA), wide-field and ultrawide-field techniques applied to fundus photography, fluorescein angiography, and OCTA. The emphasis will be on characteristic DME features identified by these imaging technologies and their potential or established role as diagnostic, prognostic, or predictive biomarkers. The role of artificial intelligence in the assessment and interpretation of retina images is also discussed.

Hyperreflective choroidal foci in diabetic eyes with and without macular edema: Novel insights on diabetic choroidopathy

Histopathologic studies of diabetic choroid suggest that diabetic choroidopathy is a key aspect secondary to diabetes. Recently, hyperreflective choroidal foci (HCF) have been introduced as novel optical coherence tomography (OCT) parameter. The aim of this study was to identify and quantify HCF in diabetic subjects with retinopathy, with or without diabetic macular edema (DME). Eighty-five diabetic subjects with different degrees of DR were enrolled: 37 without DME and 48 with DME. All subjects underwent full ophthalmologic examination including spectral domain optical coherence tomography (OCT). OCT images were analyzed to quantify and localize HCF. Each image was analyzed by two independent, masked examiners. OCT images showed that all subjects (100%) had HCF in the different layers of the choroid. The number of HCF was significantly higher in diabetics with DME versus those without DME (p < 0.0001). HCF showed variable size, shape and location inside the choroid. They were mainly located in choriocapillaris and Sattler's layer, on the edges of blood vessels. The intraobserver and interobserver agreement was almost perfect (ICC >0.9). This study suggests that hyperreflective foci in the choroid of subjects with DR may be accurately identified with structural OCT. Their number significantly increases with the progression of DME. These HCF may represent, as in the retina, a sign of infiltration of inflammatory cells (mainly migrating microglia) into the choroid, according to the hypothesis raised by Jerry Lutty. HCF may confirm in vivo the histopathologic findings suggesting that diabetic choroidopathy may be primarily a neuroinflammatory disorder.

Switching to an Intravitreal Dexamethasone Implant after Intravitreal Anti-VEGF Therapy for Diabetic Macular Edema: A Review

Among working-age people, diabetic retinopathy and diabetic macular edema are currently considered the main causes of blindness. Nowadays, intravitreal injections are widely acknowledged as a significant milestone in ophthalmology, especially for the treatment of several retinal diseases, including diabetic macular edema. In particular, anti-vascular endothelial growth factor (VEGF) agents are typically the first line of treatment; however, monthly injections are required, at least, during the loading dosage. Notably, an intravitreal 0.7 mg dexamethasone (DEX) implant (Ozurdex®, AbbVie Inc., North Chicago, IL, USA) is considered a legitimate substitute treatment for diabetic eyes that have not responded to anti-VEGF treatment. In fact, clinical trials and real-life studies have demonstrated the effectiveness and safety of an intravitreal DEX implant in treating such conditions over a period of three to six months. For this reason, wisely selecting diabetic patients might be crucial to decreasing the load of injections in clinics and hospitals. The purpose of this review is to analyze the available scientific literature to highlight the benefits, efficacy, and clinical criteria for choosing whether to switch from intravitreal anti-VEGF therapy to an intravitreal DEX implant in diabetic macular edema.

Analysis of OCT Scanning Parameters in AMD and RVO

Optical coherence tomography (OCT) is an extensively used imaging tool for disease monitoring in both age-related macular degeneration (AMD) and retinal vein occlusion (RVO). However, there is limited literature on minimum requirements of OCT settings for reliable biomarker detection. This study systematically investigates both the influence of scan size and interscan distance (ISD) on disease activity detection. We analyzed 80 OCT volumes of AMD patients and 12 OCT volumes of RVO patients for the presence of subretinal fluid (SRF), intraretinal fluid (IRF), and pigment epithelium detachment (PED). All volume scans had a scan size of 6 × 6 mm and an ISD of 125 µm. We analyzed both general fluid distribution and how biomarker detection sensitivity decreases when reducing scan size or density. We found that in AMD patients, all fluids were nearly normally distributed, with most occurrences in the foveal center and concentric decrease towards the periphery. When reducing the scan size to 3 × 3 and 2 × 2 mm, disease activity detection was still high (0.98 and 0.96). Increasing ISD only slightly can already compromise biomarker detection sensitivity (0.9 for 250 µm ISD against 125 µm ISD).