Three-dimensional analysis of morphologic changes and visual outcomes in diabetic macular edema

Ultrastructural imaging biomarkers in diabetic macular edema: A major review

Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy and causes significant morbidity in patients. Anti-vascular endothelial growth factor (VEGF) agents are the mainstay of treatment for DME, with steroid implants being used for the treatment of anti-VEGF resistant eyes. Over the years, several classification systems have been devised to describe the patterns of DME using optical coherence tomography (OCT). With the advent of effective treatments, it has become imperative that imaging cues are not merely used for classifying the disease but also as biomarkers for prognostication of disease activity and treatment response. In this aspect, newer imaging findings such as hyperreflective dots, photoreceptor integrity, and disorganization of retinal inner layers have been characterized in detail by several authors. Macular perfusion analysis using OCT angiography is the latest in the armamentarium for imaging DME. In this narrative review, we have summarized all relevant literature related to the ultrastructural imaging-based biomarkers of DME and their correlation to treatment.

Morphological changes of foveal cysts as a predictor for visual response to anti-vascular endothelial growth factor treatments in diabetic macular edema : Degenerative cyst in DME

PURPOSE

To investigate morphological changes of intraretinal cyst in association with visual acuity following treatment for diabetic macular edema.

METHODS

This retrospective study enrolled 105 eyes from 105 treatment naïve patients with diabetic macular edema following anti-vascular endothelial growth factor injections. Best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) data were obtained at baseline, 1, 3, 6, and 12 months. The width and height of the largest intraretinal cyst (IRC) at all different visits were measured and were correlated to final visual acuity by receiver operating characteristic curve. The exudative feature was defined by the presence of hard exudates. Multivariate logistic regression was used to select the independent predictor for visual outcomes.

RESULTS

Intraretinal cyst width but not the cyst height after treatment at 1 month independently predicted final visual loss of ten letters or more (multivariate P = 0.009). The optimal cutoff value was 196 um with a sensitivity of 0.889 and a specificity of 0.656. Eyes with large IRC width using this cutoff were consistently larger than those with small IRC width through 12 months (P = 0.008, Mann-Whitney U test). Small IRC width < 196 um at 1 month was more likely to coexist with exudative feature (P = 0.011, Fisher's exact test). Among baseline factors, large IRC width predicted IRC width ≥ 196 um at 1 month (multivariate P < 0.001).

CONCLUSION

Cyst morphology following intravitreal injection predicts visual outcomes. Eyes with IRC width ≥ 196 um after treatment at 1 month tends to be more degenerative, and less likely to coexist with exudative feature.

Real-World Evidence in the Management of Diabetic Macular Edema with Intravitreal Anti-VEGFs in Asia: A Systematic Literature Review

Purpose

To evaluate the visual outcomes and safety profile of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy in the treatment of diabetic macular edema (DME) in real-world studies in Asian countries.

Methods

A systematic review of electronic literature databases (Embase, Medline, and the Cochrane Library from January 1, 2010, to March 16, 2021) was conducted to identify observational studies that reported clinical and safety outcomes of anti-VEGF treatments for DME in Asia. We analyzed baseline patient characteristics, treatment patterns, mean number of injections, best-corrected visual acuity (BCVA), retinal thickness, and safety outcomes.

Results

Seventy-one studies were included in this review. Most studies reported treatment of DME with ranibizumab (n = 33), followed by aflibercept (n = 13), bevacizumab (n = 28), and conbercept (n = 9). At 12 months, the cumulative mean number of injections for ranibizumab, aflibercept, and conbercept was 5.2, 4.6, and 6, respectively. At the 12-month follow-up, the cumulative mean BCVA gain was 6.8 letters (ranibizumab), 4.6 letters (aflibercept), 4.9 letters (bevacizumab), and 8.3 letters (conbercept). The cumulative mean reduction in retinal thickness at 12 months was 116.9 μm (ranibizumab), 105.9 μm (aflibercept), 81.7 μm (bevacizumab), and 135.2 μm (conbercept). A strong positive correlation (r = 0.78) was observed between mean number of injections and change in BCVA at 12 months. A moderate positive correlation (r = 0.54) was observed between mean number of injections and mean reduction in retinal thickness at 12 months. A weak positive correlation was observed between baseline retinal thickness and visual acuity at 12 months. Baseline BCVA and mean number of injections were predictors of BCVA at 12 months.

Conclusion

All anti-VEGFs were effective in the treatment of DME in Asia. The data suggest that a greater number of anti-VEGF injections was associated with better improvement in BCVA and moderate reduction in retinal thickness at the 1-year follow-up.

Optical Coherence Tomography Reflectivity in Foveal Cysts: A Novel Biomarker for Early-Response Prediction of Diabetic Macular Edema Treated with Dexamethasone

This study investigated spectral-domain optical coherence tomography (OCT) biomarkers to predict short-term anatomical improvement for diabetic macular edema (DME) after dexamethasone (DEX) injection in intravitreal anti-vascular endothelial growth factor (anti-VEGF) non-responders. This retrospective comparative study included 31 eyes of 31 patients with DME unresponsive to anti-VEGF, divided into better and lesser responder groups. OCT prior to DEX injection was used to evaluate the morphological features including optical density (ODN) and optical density ratio (ODR) of the outer nuclear layer (ONL) cysts. Correlations between baseline OCT parameters and mean central macular thickness (CMT) changes at 1 month were analyzed. There were no between-group differences in age, sex, number of previous anti-VEGF injections, duration of diabetes, or HbA1c level. However, ODN and ODR values in ONL cysts were lower in the better responder group (p = 0.020 and p < 0.001, respectively). ODN and ODR showed negative correlations with CMT changes (R = −0.546, p = 0.002 and R = −0.436, p = 0.014, respectively). Higher OCT reflectivity in the foveal cystoid space was associated with a lesser decrease in CMT after DEX injection in anti-VEGF non-responders, suggesting the usefulness of this parameter in predicting short-term CMT responses after DEX injection.

Macular Edema and Visual Acuity Observation after Cataract Surgery in Patients with Diabetic Retinopathy

Objective. The purpose was to explore the effect of cataract surgery on postoperative macular edema and visual acuity in patients with diabetic retinopathy. Methods. 88 patients with diabetic retinopathy treated in our hospital (December 2019–December 2020) were chosen as research subjects and divided into experimental group of 44 patients (52 eyes) and control group of 44 patients (54 eyes) according to the odd and even admission numbers. The control group received laser photocoagulation treatment, while the experimental group underwent cataract surgery. The central macular thickness (CMT) and visual acuity of the two groups after treatment were detected to evaluate the therapeutic effect of different treatment methods on diabetic retinopathy. Results. No obvious differences in sex ratio, average age, average course of disease, average weight, average BMI, average glycosylated hemoglobin, and residence were found between the two groups $\left(P>0.05\right)$ . The total clinical effective rate in the experimental group was obviously higher compared with the control group $\left(P<0.05\right)$ . The CMT at T1, T2, and T3 in the experimental group was obviously lower compared with the control group $\left(P<0.05\right)$ . The BCVA in the experimental group at 1 month and 3 months after treatment was obviously higher compared with the control group $\left(P<0.05\right)$ . The VEGF levels of both groups after treatment were obviously lower $\left(P<0.001\right)$ , and the VEGF level in the experimental group after treatment was obviously lower compared with the control group $\left(P<0.001\right)$ . The total incidence of complications in the experimental group was obviously lower compared with the control group $\left(P<0.05\right)$ . Conclusion. Cataract surgery is a reliable method to improve visual acuity and reduce serum inflammatory indicators in patients with diabetic retinopathy, with better clinical effect than laser photocoagulation, which is recommended for the treatment of diabetic retinopathy.

Challenges in Diabetic Macular Edema Management: An Expert Consensus Report

Purpose

This paper aimed to present daily-practice recommendations for the management of diabetic macular edema (DME) patients based on available scientific evidence and the clinical experience of the consensus panel.

Methods

A group of Spanish retina experts agreed to discuss different aspects related with the clinical management of DME patients.

Results

Panel was mainly focused on therapeutic objectives in DME management; definition terms; and role of biomarkers as prognostic and predictive factors to intravitreal treatment response. The panel recommends to start DME treatment as soon as possible in those eyes with a visual acuity less than 20/25 (always according to the retina unit capacity). Naïve patient was defined, in a strict manner, as a patient who, up to that moment, had never received any treatment. A refractory DME patient may be defined as the one who did not achieve a complete resolution of the disease, regardless of the treatment administered. Different optical coherence tomography biomarkers, such as disorganization of the retinal inner layers, hyperreflective dots, and cysts, have been identified as prognostic factors.

Conclusion

This document has sought to lay down a set of recommendations and to identify key issues that may be useful for the daily management of DME patients.

AI-based monitoring of retinal fluid in disease activity and under therapy

Retinal fluid as the major biomarker in exudative macular disease is accurately visualized by high-resolution three-dimensional optical coherence tomography (OCT), which is used world-wide as a diagnostic gold standard largely replacing clinical examination. Artificial intelligence (AI) with its capability to objectively identify, localize and quantify fluid introduces fully automated tools into OCT imaging for personalized disease management. Deep learning performance has already proven superior to human experts, including physicians and certified readers, in terms of accuracy and speed. Reproducible measurement of retinal fluid relies on precise AI-based segmentation methods that assign a label to each OCT voxel denoting its fluid type such as intraretinal fluid (IRF) and subretinal fluid (SRF) or pigment epithelial detachment (PED) and its location within the central 1-, 3- and 6-mm macular area. Such reliable analysis is most relevant to reflect differences in pathophysiological mechanisms and impacts on retinal function, and the dynamics of fluid resolution during therapy with different regimens and substances. Yet, an in-depth understanding of the mode of action of supervised and unsupervised learning, the functionality of a convolutional neural net (CNN) and various network architectures is needed. Greater insight regarding adequate methods for performance, validation assessment, and device- and scanning-pattern-dependent variations is necessary to empower ophthalmologists to become qualified AI users. Fluid/function correlation can lead to a better definition of valid fluid variables relevant for optimal outcomes on an individual and a population level. AI-based fluid analysis opens the way for precision medicine in real-world practice of the leading retinal diseases of modern times.

Patterns of ellipsoid zone change associated with visual outcome for diabetic macular oedema

Clinical relevance: Optical coherence tomography biomarkers are dynamic and possibly change over time. The dynamic biomarkers may better predict improvement of final vision than those at baseline for diabetic macular oedema after treatment.Background: To investigate predictors for ellipsoid zone (EZ) dynamics and the association with visual acuity after treatment for diabetic macular oedemaMethods: A total of 135 eyes from 135 patients with anti-vascular endothelial growth factor treatment for diabetic macular oedema were retrospectively enrolled in this study. EZ status was evaluated by optical coherence tomography at baseline, 1, 3, 6, and 12 months post-operatively. Macular perfusion status was analysed by fluorescein angiography. Duration of EZ disruption was quantified by giving scores from 0 to 5 based on the sum of visits with evidence of EZ disruption. Linear regression models were used to predict factors for scores of EZ disruption. Binary logistic regression was used to predict various EZ biomarkers for final visual acuity improvement.Results: Thirty of 87 eyes (34.4%) with intact EZ at baseline developed subsequent EZ disruption. For those with EZ disruption at baseline, 17 of 48 (35.4%) patients had restoration of disrupted EZ over time. Non-perfused macula was associated with both earlier development of EZ disruption and poor restoration (p < 0.001 and p = 0.011, respectively). Non-perfused macula, absence of epiretinal membrane, and EZ disruption at baseline predicted higher EZ scores (p < 0.001, p = 0.022 and p < 0.001, respectively). Higher EZ scores (p = 0.016), but not baseline EZ disruption (p = 0.56), were less likely to have improvement of final vision 5 letters or more.Conclusion: Macular perfusion status played an independent role in EZ dynamics. Duration of EZ disruption could be more predictive than baseline status for improvement of vision over 12 months.

Optical Coherence Tomography Biomarkers in Bilateral Diabetic Macular Edema Patients with Asymmetric anti-VEGF Response

Background: This study aimed to identify optical coherence tomography (OCT) biomarkers for predicting response to anti-VEGF treatment in diabetic macular edema (DME)Methods: Bilateral DME patients with asymmetric response to a loading dose of anti-VEGF (ranibizumab/aflibercept) treatment were retrospectively studied. The morphologic response criterion was central subfield thickness (CST) ≤300 µm; asymmetric response was defined as ≥10% difference in CST reduction between the eyes. The functional response criterion was an increase in logMAR acuity of ≥3 lines, with an increase below this threshold in the fellow eye considered asymmetric response. Relationships between final morphologic and functional responses to anti-VEGF therapy and baseline values of the following OCT-derived biomarkers were evaluated: DME subtype, CST, vitreoretinal interface anomalies, disorganization of the inner retinal layers (DRIL), external limiting membrane (ELM) disruption, ellipsoid zone (EZ) disruption, and subretinal fluid (SRF).Results: After a loading dose of anti-VEGF, 31 eyes that met both morphologic and functional response criteria were classified as responders (RR) and 27 eyes that did not respond morphologically or functionally based on the defined criteria were classified as resistant (RT). Eyes that showed only functional (n = 5) or morphological response (n = 1) were excluded due to their small number. The presence of SRF or simple epiretinal membrane (ERM) was not associated with any difference in treatment responses (p > .05), while tractional ERM, extensive DRIL (≥500 µm), and ELM and EZ disruptions in the fovea-centered 1000-µm zone were important OCT biomarkers in predicting resistance (p < .001). A multilayer perceptron model ranked predictive power as 100% for ELM disruption, 51.7% for tractional ERM, 25.4% for DRIL, and 24.5% for EZ disruption.Conclusion: Extensive ELM disruption was the strongest OCT biomarker to predict anti-VEGF resistance, followed by tractional ERM. EZ disruption and DRIL had relatively lower predictive value.