En face image-based classification of diabetic macular edema using swept source optical coherence tomography

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

PURPOSE

To investigate the characteristics of mixed pathophysiologies in lamellar macular holes (LMHs) and related diseases using multimodal optical coherence tomography.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Investigating the impact of empagliflozin on the retina of diabetic mice

BACKGROUND

Diabetic retinopathy (DR) frequently results in compromised visual function, with hyperglycemia-induced disruption of the blood-retinal barrier (BRB) through various pathways as a critical mechanism. Existing DR treatments fail to address early and potentially reversible microvascular alterations. This study examined the effects of empagliflozin (EMPA), a selective Sodium-glucose transporter 2 (SGLT2) inhibitor, on the retina of db/db mice. The objective of this study is to investigate the potential role of EMPA in the prevention and delay of DR.

METHODS

db/db mice were randomly assigned to either the EMPA treatment group (db/db + Emp) or the model group (db/db), while C57 mice served as the normal control group (C57). Mice in the db/db + Emp group received EMPA for eight weeks. Body weight, fasting blood glucose (FBG), and blood VEGF were subsequently measured in all mice, along with the detection of specific inflammatory factors and BRB proteins in the retina. Retinal SGLT2 protein expression was compared using immunohistochemical analysis, and BRB structural changes were observed via electron microscopy.

RESULTS

EMPA reduced FBG, blood VEGF, and retinal inflammatory factors TNF-α, IL-6, and VEGF levels in the eye tissues of db/db mice. EMPA also increased Claudin-1, Occludin-1, and ZO-1 levels while decreasing ICAM-1 and Fibronectin, thereby preserving BRB function in db/db mice. Immunohistochemistry revealed that EMPA reduced SGLT2 expression in the retina of diabetic mice, and electron microscopy demonstrated that EMPA diminished tight junction damage between retinal vascular endothelial cells and prevented retinal vascular basement membrane thickening in diabetic mice.

CONCLUSION

EMPA mitigates inflammation and preserves BRB structure and function, suggesting that it may prevent DR or serve as an effective early treatment for DR.

Japan-epiretinal membrane (J-ERM) registry: A prospective cohort study protocol investigating the surgical outcome of epiretinal membrane

BACKGROUND

Epiretinal membrane (ERM) causes visual impairment such as reduction in visual acuity and metamorphopsia due to retinal traction. With the improvement of optical coherence tomography (OCT) and microincision vitrectomy surgery (MIVS), the surgery of ERM has significantly advanced. However, there have been no large-scale studies on the following: (1) how to evaluate visual impairment in ERM, (2) the relationship between OCT findings and visual function, (3) when is the optimal timing of surgery, and (4) the relationship between the surgical instruments as well as techniques and prognosis. The purpose of this study was to obtain evidence regarding these ERM surgeries.

METHODS AND DESIGN

This is a prospective, multicenter cohort study of ERM surgery in Japan from March 1, 2023, to March 31, 2027 (UMIN000048472, R-3468-2). Patients who underwent ERM surgery during the study period and agreed to participate in this study will be included. The goal is to have a total of 5,000 eyes surgically treated for ERM. The following data will be collected: age, gender, medical history, subjective symptoms, visual function before and 6 and 12 months after surgery, clinical findings, OCT data, surgical technique, instruments used in surgery, and complications.

DISCUSSION

The results of this study will support the surgical decisions and procedures in ERM practices.

Evaluation of epiretinal membrane formation after scleral buckling for treating rhegmatogenous retinal detachment: En face optical coherence tomography image-based study

PURPOSE

To assess epiretinal membrane (ERM) formation, severity, and the associated risk factors after scleral buckling using en face optical coherence tomography (OCT) images.

METHODS

Medical records of 61 consecutive patients (66 eyes) with rhegmatogenous retinal detachment who underwent scleral buckling were retrospectively reviewed. Posterior vitreous detachment (PVD) was determined based on B-scan OCT images. En face OCT images were used to visualize the ERM and retinal folds. ERM formation was identified by comparing en face images pre- and post-surgery. The maximum depth of the retinal folds (MDRF) was measured using en face imaging to objectively assess traction strength.

RESULTS

ERM formation occurred in 15 (22.7%) eyes at the final visit; the foveal pit was preserved in all cases. Parafoveal retinal folds were present in 5 (7.6%) eyes, with a mean MDRF of 21.8 ± 12.6 µm. No significant difference was observed in best-corrected visual acuity (logarithm of the minimal angle of resolution) between the ERM formation (-0.019 ± 0.128) and non-ERM formation (-0.001 ± 0.213) groups at the final visit (P = 0.593; Mann-Whitney U test). Multivariate logistic regression analysis revealed that older age and the presence of PVD were significant risk factors for ERM formation (odds ratio 1.07, 95% confidence interval 1.01-1.14, P = 0.032; odds ratio 5.26, 95% confidence interval 1.06-26.10, P = 0.042; respectively).

CONCLUSION

ERM occurred in 22.7% of cases but was mild and did not affect visual acuity. Older age and the presence of PVD are risk factors for ERM formation.

Early effects of intravitreal anti-VEGF agents on cornea and visual acuity in patients with diabetic retinopathy

PURPOSE

This study aimed to investigate the early effects of intravitreal anti-vascular endothelial growth factor (anti-VEGF) agents on the cornea and visual acuity in patients with diabetic retinopathy (DR).

METHODS

This retrospective study enrolled patients who were administered conbercept or ranibizumab to treat DR. Fundus photograph, fluorescein angiograph, and optical coherence tomography were preoperatively performed. The patients were classified into two groups: nonproliferative DR (NPDR) and PDR. Best-corrected visual acuity (BCVA), specular microscopy, central corneal thickness (CCT), and intraocular pressure were obtained before injection and at 1 day and 7 days after injection. The effects of anti-VEGF agents on BCVA and CCT were compared between the groups receiving conbercept and ranibizumab and between NPDR and PDR eyes.

RESULTS

A total 38 eyes (30 patients) were enrolled in this study. Twenty-one eyes received conbercept, and 17 eyes received ranibizumab. Twenty eyes were classified as NPDR and 18 eyes as PDR. No significant differences were found between the groups receiving conbercept and ranibizumab in the increase in BCVA nor in the increase of CCT at 1 day and 7 days after injection. As compared with NPDR eyes, PDR eyes demonstrated a significantly greater increase in CCT (-5.3 ± 3.7 vs. 6.5 ± 2.9 μm, P = 0.02 < 0.05) but not in BCVA (P = 0.33) at 1 day after injection. At 7 days after injection, no significant differences were found in the increase in BCVA nor in the increase of CCT between NPDR eyes and PDR eyes.

CONCLUSION

Intravitreal administration of anti-VEGF agents could cause a small but significant greater increase in CCT in PDR than in NPDR eyes in the early period. In patients with DR, no significant difference was found between conbercept and ranibizumab in the early effects on the visual acuity nor in the cornea.

Endpoints for clinical trials in ophthalmology

With the identification of novel targets, the number of interventional clinical trials in ophthalmology has increased. Visual acuity has for a long time been considered the gold standard endpoint for clinical trials, but in the recent years it became evident that other endpoints are required for many indications including geographic atrophy and inherited retinal disease. In glaucoma the currently available drugs were approved based on their IOP lowering capacity. Some recent findings do, however, indicate that at the same level of IOP reduction, not all drugs have the same effect on visual field progression. For neuroprotection trials in glaucoma, novel surrogate endpoints are required, which may either include functional or structural parameters or a combination of both. A number of potential surrogate endpoints for ophthalmology clinical trials have been identified, but their validation is complicated and requires solid scientific evidence. In this article we summarize candidates for clinical endpoints in ophthalmology with a focus on retinal disease and glaucoma. Functional and structural biomarkers, as well as quality of life measures are discussed, and their potential to serve as endpoints in pivotal trials is critically evaluated.

Quantitative Analyses of Retinal Traction Force and Metamorphopsia in Lamellar Macular Hole and Related Diseases

Purpose

To investigate the involvement of retinal traction in the pathogenesis of lamellar macular hole (LMH) and related diseases based on OCT-based consensus definition.

Design

Retrospective, observational study.

Participants

Seventy-two eyes with LMH, epiretinal membrane foveoschisis (ERM-FS), or macular pseudohole (MPH).

Methods

To quantitatively evaluate the involvement and strength of retinal traction in their pathogenesis, retinal folds were visualized with en face OCT imaging, and the maximum depth of the parafoveal retinal folds (MDRF) was measured. Metamorphopsia was quantified by measuring the minimum visual angle of dotted lines needed to cause it to disappear using M-CHARTS (Inami).

Main Outcome Measures

Maximum depth of retinal folds and M-CHARTS scores.

Results

Of the 72 eyes, 26 were classified as having LMH, 25 as having ERM-FS, and 21 as having MPH. Parafoveal retinal folds were observed in 7 (26.9%) eyes with LMH, 25 (100%) with ERM-FS, and 21 (100%) with MPH. The MDRF (7.5 ± 17.6 μm) was significantly smaller in LMH than in ERM-FS (86.3 ± 31.4 μm) and MPH (74.5 ± 24.6 μm) (both P < 0.001), whereas no significant difference in MDRF between MPH and ERM-FS was observed (P = 0.43). A significant positive correlation between MDRF and M-CHARTS scores was observed in ERM-FS and MPH (P = 0.008 and 0.040, respectively) but not in LMH (P = 0.073).

Conclusions

Retinal traction was significantly weaker in the LMH group than in the ERM-FS and MPH groups. The MDRF was significantly associated with the degree of metamorphopsia in the ERM-FS and MPH groups. These results provide insights into the diseases' pathophysiology and treatment strategy.

Epiretinal Membrane Impairs the Inner Retinal Layer in a Traction Force-Dependent Manner

Purpose

To investigate the relationship between retinal traction force and impairment of the inner retinal layer in patients with epiretinal membrane (ERM).

Design

Nonrandomized, retrospective consecutive case series.

Participants

Two hundred nine eyes of 201 patients with idiopathic ERM who underwent vitrectomy for idiopathic ERM were enrolled.

Methods

Retinal folds caused by ERM were visualized using en face OCT, and the maximum depth of retinal folds within the parafovea (MDRF) was measured. Focal macular electroretinogram (ERG) was used to measure the amplitude and implicit time of each component for the ERM eyes and the normal fellow eyes. B-scan OCT images were used to measure the thicknesses of the inner nuclear layer (INL) and outer nuclear layer (ONL) + outer plexiform layer (OPL). Expression of α-smooth muscle actin (α-SMA) in surgically removed ERM specimens was quantified by reverse-transcription polymerase chain reaction.

Main Outcome Measures

We analyzed the relationship between MDRF and the relative amplitudes of focal macular ERG (affected eye/fellow eye), the relationships between MDRF and the mean INL thickness and ONL+OPL thickness, comparison of INL thickness and ONL+OPL thickness for each area when cases were classified according to MDRF localization in the ETDRS chart, and the relationship between MDRF and the relative expression of α-SMA in the ERM specimens.

Results

The MDRF significantly correlated with the relative amplitudes (affected eye/fellow eye) of b-waves and oscillatory potentials (r = -0.657, P = 0.015; r = -0.569, P = 0.042, respectively) and the mean INL thickness and ONL+OPL thickness (r = 0.604, P < 0.001; r = 0.210, P = 0.007, respectively). However, only the INL thickness progression rate was significantly correlated with the MDRF progression rate (r = 0.770, P < 0.001). On case stratification by localization of MDRF based on the ETDRS chart, in regions other than temporal regions, the INL thickness was significantly greater in regions with MDRF than in other regions. The MDRF significantly correlated with α-SMA expression in the ERM specimens (r = 0.555, P = 0.009).

Conclusions

The findings suggest that ERM impairs the inner retinal layer in a traction force-dependent manner.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Mid-term safety and effectiveness of macular peeling one month after intravitreal dexamethasone implant for tractional diabetic macular edema

Macular peeling combined or followed by intravitreal dexamethasone implant (DEX-i) was recommended as an efficacy approach for tractional diabetic macular edema (tDME). Knowing the synergistic effect of cataract surgery and DEX-i one month earlier in eyes with DME, we compared Epiretinal Membrane/Inner Limiting Membrane (ERM/ILM) peeling preceded by DEX-i one month before versus ERM/ILM peeling alone for the treatment of tDME. A retrospective study on patients affected by tDME who underwent ERM/ILM peeling one month after DEX-i (n = 11; Group A) or ERM/ILM peeling alone (n = 10; Group B) was performed. Longitudinal comparison of best-correct visual acuity (BCVA), central retinal thickness (CRT), and intraocular pressure (IOP) between the time of surgery (T₀) and each time point (months 1,3,5,6) within and among the groups were assessed. To evaluate the repeated measurements of BCVA, CRT, and IOP, a linear mixed-effects model was used. In Group A, DEX-i significantly improved mean BCVA and CRT (P < 0.001) just after 1 month (T₀). After ERM/ILM peeling, mean BCVA and CRT significantly improved from month 1 in Group A and month 3 in Group B. Mixed model revealed a significant difference in BCVA (P ≤ 0.0001) and CRT (P ≤ 0.02) at different time-points among the groups with better results in Group A. Neither complications nor uncontrolled IOP increase was detected. ERM/ILM peeling confirmed its effectiveness in treating tDME. DEX-i performed one month before surgery seemed to be a safe approach and ensured a greater and faster recovery considering functional and tomographic parameters.

Diabetic Macular Edema: Current Understanding, Molecular Mechanisms and Therapeutic Implications

Diabetic retinopathy (DR), with increasing incidence, is the major cause of vision loss and blindness worldwide in working-age adults. Diabetic macular edema (DME) remains the main cause of vision impairment in diabetic patients, with its pathogenesis still not completely elucidated. Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of DR and DME. Currently, intravitreal injection of anti-VEGF agents remains as the first-line therapy in DME treatment due to the superior anatomic and functional outcomes. However, some patients do not respond satisfactorily to anti-VEGF injections. More than 30% patients still exist with persistent DME even after regular intravitreal injection for at least 4 injections within 24 weeks, suggesting other pathogenic factors, beyond VEGF, might contribute to the pathogenesis of DME. Recent advances showed nearly all the retinal cells are involved in DR and DME, including breakdown of blood-retinal barrier (BRB), drainage dysfunction of Müller glia and retinal pigment epithelium (RPE), involvement of inflammation, oxidative stress, and neurodegeneration, all complicating the pathogenesis of DME. The profound understanding of the changes in proteomics and metabolomics helps improve the elucidation of the pathogenesis of DR and DME and leads to the identification of novel targets, biomarkers and potential therapeutic strategies for DME treatment. The present review aimed to summarize the current understanding of DME, the involved molecular mechanisms, and the changes in proteomics and metabolomics, thus to propose the potential therapeutic recommendations for personalized treatment of DME.

Optical Coherence Tomography Classification Systems for Diabetic Macular Edema and Their Associations With Visual Outcome and Treatment Responses - An Updated Review

ABSTRACT

Optical coherence tomography (OCT) is an invaluable imaging tool in detecting and assessing diabetic macular edema (DME). Over the past decade, there have been different proposed OCT-based classification systems for DME. In this review, we present an update of spectral-domain OCT (SDOCT)-based DME classifications over the past 5 years. In addition, we attempt to summarize the proposed OCT qualitative and quantitative parameters from different classification systems in relation to disease severity, risk of progression, and treatment outcome. Although some OCT-based measurements were found to have prognostic value on visual outcome, there has been a lack of consensus or guidelines on which parameters can be reliably used to predict treatment outcomes. We also summarize recent literatures on the prognostic value of these parameters including quantitative measures such as macular thickness or volume, central subfield thickness or foveal thickness, and qualitative features such as the morphology of the vitreoretinal interface, disorganization of retinal inner layers, ellipsoid zone disruption integrity, and hyperreflec-tive foci. In addition, we discuss that a framework to assess the validity of biomarkers for treatment outcome is essentially important in assessing the prognosis before deciding on treatment in DME. Finally, we echo with other experts on the demand for updating the current diabetic retinal disease classification.

Performance of a Machine-Learning Computational Image Analysis Algorithm in Retinal Fluid Quantification for Patients With Diabetic Macular Edema and Retinal Vein Occlusions

BACKGROUND AND OBJECTIVE

The objective is to validate an automated artificial intelligence model in detecting and quantifying fluid in diabetic macular edema (DME) and retinal vein occlusion (RVO) optical coherence tomography images.

PATIENTS AND METHODS

DME (n = 100) and RVO (n = 100) images of adult patients were reviewed. The performance of machine-learning (ML) computational image analysis algorithm was evaluated against consensus manual grading. Main outcomes were accuracy and sensitivity for detection and Pearson's correlation coefficients for quantification.

RESULTS

The ML algorithm had a high accuracy and sensitivity in both DME (intraretinal fluid [IRF]: 0.92, 0.97; subretinal fluid [SRF]: 0.93, 1.00) and RVO (IRF: 0.94, 0.99; SRF: 0.93, 1.00). It had moderate-high correlation in quantifying fluid in DME (total retinal fluid: 0.88; IRF: 0.88; SRF: 0.97) and RVO (total retinal fluid: 0.83; IRF: 0.76; SRF: 0.64).

CONCLUSION

The ML algorithm is highly accurate and sensitive in detecting fluid in DME and RVO optical coherence tomography images and effectively quantifies IRF and SRF in both disease states, particularly in images with low to moderate fluid burden. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:123-131.].