Ellipsoid Zone Integrity and Visual Acuity Changes during Diabetic Macular Edema Therapy: A Longitudinal Study

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.

Advances in Structural and Functional Retinal Imaging and Biomarkers for Early Detection of Diabetic Retinopathy

Diabetic retinopathy (DR), a vision-threatening microvascular complication of diabetes mellitus (DM), is a leading cause of blindness worldwide that requires early detection and intervention. However, diagnosing DR early remains challenging due to the subtle nature of initial pathological changes. This review explores developments in multimodal imaging and functional tests for early DR detection. Where conventional color fundus photography is limited in the field of view and resolution, advanced quantitative analysis of retinal vessel traits such as retinal microvascular caliber, tortuosity, and fractal dimension (FD) can provide additional prognostic value. Optical coherence tomography (OCT) has also emerged as a reliable structural imaging tool for assessing retinal and choroidal neurodegenerative changes, which show potential as early DR biomarkers. Optical coherence tomography angiography (OCTA) enables the evaluation of vascular perfusion and the contours of the foveal avascular zone (FAZ), providing valuable insights into early retinal and choroidal vascular changes. Functional tests, including multifocal electroretinography (mfERG), visual evoked potential (VEP), multifocal pupillographic objective perimetry (mfPOP), microperimetry, and contrast sensitivity (CS), offer complementary data on early functional deficits in DR. More importantly, combining structural and functional imaging data may facilitate earlier detection of DR and targeted management strategies based on disease progression. Artificial intelligence (AI) techniques show promise for automated lesion detection, risk stratification, and biomarker discovery from various imaging data. Additionally, hematological parameters, such as neutrophil-lymphocyte ratio (NLR) and neutrophil extracellular traps (NETs), may be useful in predicting DR risk and progression. Although current methods can detect early DR, there is still a need for further research and development of reliable, cost-effective methods for large-scale screening and monitoring of individuals with DM.

Ellipsoid Zone Integrity and Visual Function in Dry Age-Related Macular Degeneration

In this longitudinal retrospective image analysis, conducted on patients diagnosed with dry age-related macular degeneration (AMD) and 5 years of follow-up imaging data, the study aimed to investigate the relationship between ellipsoid zone (EZ) integrity on spectral domain optical coherence tomography (SD-OCT) and visual acuity (VA). Using a machine learning-enabled feature extraction tool, quantitative EZ parameters were derived from SD-OCT images. The analysis revealed significant correlations between EZ integrity metrics and VA. Eyes with excellent VA (≥20/25 Snellen) exhibited higher EZ integrity, including less EZ attenuation, thicker ellipsoid zone-retinal pigment epithelium (EZ-RPE) thickness, and higher EZ intensity, in contrast to eyes with worse VA (≤20/40 Snellen). Additionally, eyes with geographic atrophy (GA) in the foveal region displayed compromised EZ integrity compared to those without GA. Notably, baseline EZ integrity metrics were predictive of future VA loss. These findings suggest that quantitative SD-OCT measurements of EZ integrity could potentially detect early changes in dry AMD and serve as valuable indicators for predicting future functional outcomes. Furthermore, these measurements hold promise for use in clinical trial screenings, offering insights into the progression of the disease and its impact on visual acuity. This study underscores the importance of EZ integrity assessment in understanding and managing dry AMD.

ESASO classification relevance in the diagnosis and evolution in diabetic macular edema patients after dexamethasone implant treatment

PURPOSE

To assess the clinical relevance of The European School for Advanced Studies in Ophthalmology (ESASO) classification in patients with diabetic macular edema (DME) after their first dexamethasone implant (DEXI) treatment.

METHODS

Retrospective real-world study conducted on consecutive DME patients who underwent DEXI treatment and were controlled at month-2. Subjects were initially classified according to the ESASO classification stages. The outcomes were anatomical biomarkers with spectral-domain optical coherence tomography (SD-OCT) and best-corrected visual acuity (BCVA).

RESULTS

A total of 128 patients were classified according to ESASO classification stages as early (7; 5.5%), advanced (100; 78.1%), and severe (21; 16.4%). At baseline, there were significant differences between stages in BCVA, central macular thickness (CMT), and tomography anatomical biomarkers (p < 0.05). Initial BCVA (logMAR) was 0.33 ± 0.10, 0.58 ± 0.34, and 0.71 ± 0.35 in the early, advanced, and severe stages, respectively (p < 0.05). At month-2, BCVA was 0.17 ± 0.15, 0.46 ± 0.29, and 0.69 ± 0.27 in those classified as early, advanced, and severe stages, respectively. At month-2, DME was resolved or improved in 6 (85.7%), 60 (60%), and 12 (60%) patients classified as early, advanced, and severe stages, respectively.

CONCLUSIONS

There was a good correlation between BCVA and ESASO classification stages. Patients in the severe stage did not achieve visual acuity improvement over the study period.

Association between choroidopathy and photoreceptors during the early stage of diabetic retinopathy: a cross-sectional study

PURPOSE

To explore the role of choroidopathy in diabetic retinopathy (DR) by investigating the correlation between alterations of choroidal vessel and photoreceptors during the early stage of DR.

METHODS

We performed a cross-sectional comparison of diabetic patients without DR (NDR group; n=16) and those with mild nonproliferative diabetic retinopathy (NPDR group; n=39). Optical coherence tomography (OCT) images of choroidal vessel alterations and photoreceptor structures were evaluated using the choroidal vascularity index (CVI) and adjusted ellipsoid zone (EZ) reflectivity, respectively. To evaluate the function of cone photoreceptors, the fundamental, harmonic amplitudes, the parameters S and Rmp3 were calculated from the electroretinogram (ERG). These factors were compared between groups. The correlation between the CVI and parameters describing the function and structure of the photoreceptors was evaluated.

RESULTS

The significant decrease was observed in the CVI in the NPDR group compared to the NDR group (0.67 ± 0.04 vs. 0.70 ± 0.06; p = 0.028), but not in the adjusted EZ reflectivity or ERG parameters. In NPDR group and merging the 2 groups, CVI was moderately positively correlated with the fundamental amplitude obtained by the flicker ERG (NPDR only: r = 0.506; p = 0.001; merge the 2 groups: r = 0.423; p = 0.001), which was regulated by the response of the cone photoreceptors. The CVI was positively and moderately correlated with the logS (NPDR only: r = 0.462; p = 0.003; merge the 2 groups: r = 0.355; p = 0.008), indicating the sensitivity of cone cell light transduction.

CONCLUSION

Compared to eyes without DR, CVI decreased representing choroidal vascular changes in eyes with mild NPDR. These changes may be related to the functional impairment of cone photoreceptors, especially phototransduction sensitivity, as the DR develops.

Biomarkers determining treatment interval of diabetic macular edema after initial resolution by anti-vascular endothelial growth factor

PURPOSE

To identify predictive factors that help determine the interval of intravitreal anti-vascular endothelial growth factor (anti-VEGF) injection after the initial resolution of diabetic macular edema (DME).

METHODS

This retrospective case-control study enrolled treatment-naïve DME patients who had achieved DME resolution after intravitreal anti-VEGF injections. Patients were classified into the recurrence and no-recurrence groups, depending on the development of recurrent DME after deferring intravitreal anti-VEGF injection. The demographics and clinical features, including optical coherence tomography findings, were compared between the two groups.

RESULTS

We enrolled 105 eyes. Sixty eyes (57.1%) belonged to the no-recurrence group, and 45 (42.9%), belonged to the recurrence group. The severity of diabetic retinopathy at baseline was related to early DME recurrence (P = 0.009). At the treatment deferring point, the non-recurrence group had both thinner central subfield thickness (289.5 ± 27.2 μm vs. 307.0 ± 38.2 μm, P = 0.011) and thinner central retinal thickness (214.9 ± 41.4 μm vs. 231.8 ± 41.2 μm, P = 0.043) compared to the recurrence group. Intraretinal cyst was observed in 34 eyes (56.7%) in the no-recurrence group and 42 eyes (93.3%) in the recurrence group at the deferring point (P < 0.001).

CONCLUSION

A low risk of early DME recurrence is anticipated in the eyes with foveal thinning and no intraretinal cyst when anti-VEGF injection is deferred. These predictive biomarkers can be useful for patient monitoring and determining treatment strategies for DME patients.

Alterations of outer retinal reflectivity in diabetic patients without clinically detectable retinopathy

PURPOSE

This study aimed to investigate alterations of outer retinal reflectivity on spectral-domain optical coherence tomography (OCT) in diabetic patients without clinically detectable retinopathy (NDR).

METHODS

In this retrospective study, 64 NDR patients and 71 controls were included. Relative reflectivity (RR) of the ellipsoid zone (EZ), photoreceptor outer segment (OS) and inner segment (IS), and outer nuclear layer (ONL) at the foveola and at 500 μm, 1000 μm, and 2000 μm nasal (N), temporal (T), superior (S), and inferior (I) to the foveola was measured by cross-line OCT and ImageJ. Retinal vessel densities (VD) in fovea, parafovea, and perifovea areas were detected by OCT angiography (OCTA).

RESULTS

EZ RR in most retinal locations was significantly lower in NDR eyes compared to controls (all P < 0.05), except the foveola. Compared with controls, NDR eyes also displayed lower RR at N2000, T2000, S1000, and I1000 of OS, at S500 and I500 of IS, and at I500 of ONL (all P < 0.05). Negative correlations could be observed between retinal RR and diabetes duration, HbA1c, and best-corrected visual acuity (BCVA) (r =  - 0.303 to - 0.452). Compared to controls, EZ, OS, and IS RR of the NDR eyes showed lower correlation coefficients with whole image SCP and DCP VD of parafovea and perifovea regions.

CONCLUSION

Outer retinal reflectivity, along with the coefficients between retinal reflectivity and VD, is reduced in NDR patients and is correlated with diabetes duration, HbA1c, and BCVA. The reduction of outer retinal reflectivity may be a potential biomarker of early retinal alterations in diabetic patients.

Exploring the role of retinal fluid as a biomarker for the management of diabetic macular oedema

Anti-VEGF therapies are associated with significant gains in visual acuity and fluid resolution in the treatment of diabetic macular oedema (DMO) and have become the standard of care. However, despite their efficacy, outcomes can be unpredictable, vary widely between individual eyes, and a large proportion of patients have persistent fluid following initial treatment, with a negative impact on visual outcomes. Anatomical parameters measured by optical coherence tomography (OCT), in addition to visual acuity, are key to monitoring treatment effectiveness and guiding retreatment decisions; however, existing guidelines on the management of DMO lack clear recommendations for interpretation of OCT parameters, or proposed thresholds of various markers to guide retreatment decisions. Although central subfield thickness (CSFT) has been widely used as a marker for retreatment decisions in clinical trials in DMO, and a reduction in CSFT has generally been shown to accompany improvements in best-corrected visual acuity with treatment, analyses of the relationship between these parameters show that the correlation is small to moderate. A more direct relationship can be seen between an increased magnitude of CSFT fluctuations over time and poorer visual acuity, suggesting that control of CSFT could be important in maximising visual outcomes. The relationship between visual outcomes and qualitatively assessed intraretinal fluid and subretinal fluid is also unclear, although quantitative assessments of fluid parameters suggest that untreated intraretinal fluid and subretinal fluid negatively impact visual outcomes. These findings highlight a need for clearer guidelines on the management of retinal fluid to improve visual outcomes for patients with DMO.

Functional and Morphological Responses to Fluocinolone Acetonide 0.19 mg in Noninfectious Uveitic Macular Edema Evaluated as the Area-Under-the-Curve

Purpose: This study investigated the impact of baseline clinical and optical coherence tomography (OCT) factors on the response to a 0.19-mg fluocinolone acetonide (FAc) implant in patients with noninfectious uveitic macular edema evaluated by the area under the curve over 24 months. Methods: A retrospective study was conducted of eyes of patients with noninfectious uveitic macular edema undergoing FAc treatment, with follow-up from baseline to 24 months. The area under the curve (AUC) of best-corrected visual acuity (BCVA) and the central macular thickness (CMT) were calculated using the trapezoidal rule. Clinical and OCT data at the time of FAc administration were collected, and associations with AUC of BCVA and CMT changes were investigated. Results: Twenty-three patients were enrolled. BCVA and CMT significantly improved after FAc implantation (P < 0.05). AUCBCVA and AUCCMT were 0.41 ± 0.33 logarithm of minimal angle of resolution/6 months and 320.15 ± 321.64 μm/6 months, respectively. Better baseline BCVA (coefficient [coef.] = 0.83, P < 0.001) and macular thickness reduction after FAc administration (coef. = -0.0001, P < 0.05) were associated with better BCVA after FAc treatment. In contrast, baseline OCT biomarkers such as ellipsoid zone reflectivity and choroidal vascularity index, sex, or disease duration before FAc injection showed no correlation with AUCBCVA and AUCCMT (P > 0.05). The younger the patient at the time of FAc injection, the greater the reduction in CMT (coef. = 1.76, P < 0.05). Conclusions: Among all clinical and morphological baseline factors, Baseline BCVA was the strongest predictor for AUCBCVA, while no association with baseline OCT features was observed. Overall, improvement of BCVA and CMT after FAc injection was maintained over 24 months. This study is registered in the German Clinical Trials Register under the DRKS-ID: DRKS00024399.

Longitudinal Quantitative Ultrawide-field Fluorescein Angiography Dynamics in the RUBY Diabetic Macular Edema Study

OBJECTIVE

The purpose of this study was to evaluate the longitudinal change in quantitative ultrawide-field angiographic (UWFA) parameters and correlate them with functional outcomes and spectral domain-OCT metrics.

DESIGN

This study is a post hoc analysis of the phase II RUBY study: a prospective, randomized trial of patients with diabetic macular edema (DME) treated with either intravitreal aflibercept injection (IAI) or combined IAI/nesvacumab (antiangiopoietin 2 mAb).

SUBJECTS

Subjects with DME that underwent UWFA across all treatment groups (n = 44).

METHODS

A machine learning-enabled feature extraction system generated panretinal quantitative UWFA metrics, including leakage, ischemia, and microaneurysm (MA) burden. Zonal assessments were performed corresponding to the macula, midperiphery, and far periphery.

MAIN OUTCOME MEASURES

Changes in ischemic area and index (proportion of nonperfusion in analyzable retina), leakage area and index (proportion of leakage in analyzable retina), and MA count at baseline, week 12, week 24, and week 36 were analyzed. Spectral-domain-OCT quantitative metrics, such as central subfield thickness, ellipsoid zone (EZ) integrity parameters, intraretinal fluid (IRF) volume, and subretinal fluid (SRF) volume were extracted via a machine learning-enhanced OCT feature extraction platform and analyzed. Additionally, the effect of these changes on best-corrected visual acuity (BCVA) was evaluated.

RESULTS

Mean panretinal leakage index, zonal leakage area, and panretinal MA count improved significantly between baseline and week 36. Panretinal ischemic index decreased between baseline and week 36, with some aspects showing significant improvement. Mean BCVA significantly improved from baseline to week 36. There was a significant inverse correlation between change in BCVA and change in macular leakage area. A direct correlation was observed between both baseline macular leakage area and panretinal leakage index with IRF volume, SRF volume, and EZ disruption on OCT.

CONCLUSIONS

Assessment of UWFA parameters demonstrates a significant improvement in panretinal leakage index, leakage area, and MA burden in eyes treated with IAI with or without nesvacumab. A numeric reduction in panretinal ischemic index and area was noted. The analysis also shows the critical association of leakage with visual and OCT features. This highlights the potential role of UWFA in disease burden assessment, with leakage parameters serving as a primary end point.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

The Role of Intravitreal Corticosteroids in the Treatment of DME: Predictive OCT Biomarkers

This work aims to summarize predictive biomarkers to guide treatment choice in DME. Intravitreal anti-VEGF is considered the gold standard treatment for centers involving DME, while intravitreal steroid treatment has been established as a second-line treatment in DME. However, more than 1/3 of the patients do not adequately respond to anti-VEGF treatment despite up to 4-weekly injections. Not surprisingly, insufficient response to anti-VEGF therapy has been linked to low-normal VEGF levels in the serum and aqueous humor. These patients may well benefit from an early switch to intravitreal steroid treatment. In these patients, morphological biomarkers visible in OCT may predict treatment response and guide treatment decisions. Namely, the presence of a large amount of retinal and choroidal hyperreflective foci, disruption of the outer retinal layers and other signs of chronicity such as intraretinal cysts extending into the outer retina and a lower choroidal vascular index are all signs suggestive of a favorable treatment response of steroids compared to anti-VEGF. This paper summarizes predictive biomarkers in DME in order to assist individual treatment decisions in DME. These markers will help to identify DME patients who may benefit from primary dexamethasone treatment or an early switch.

Biomarkers to Predict the Success of Treatment with the Intravitreal 0.19 mg Fluocinolone Acetonide Implant in Uveitic Macular Edema

To predict the need for additional local corticosteroids after receiving the 0.19 mg fluocinolone acetonide (FAc) implant in patients with macular edema secondary to non-infectious uveitis previously treated with local peribulbar corticosteroids. The number of corticosteroids required prior FAc, visual acuity, central retinal thickness, ellipsoid zone reflectivity ratio (EZR), and choroidal vascularity index (CVI) were compared between patients who did and did not require additional corticosteroids after FAc implantation. Pearson’s correlation coefficient (R) between putative predictors and the number of adjunctive corticosteroids after FAc implantation were measured; significant candidates were included in a generalized regression model. Patients who required additional corticosteroids after FAc had higher CVI and central retinal thickness as well as worse EZR at subsequent visits (p < 0.05). The number of corticosteroids required prior to FAc implantation (R: 0.49), CVI change from baseline to 6 months (R: −0.41), and central retinal thickness at baseline (R: −0.36) correlated to the number of additional corticosteroids (all p < 0.05). A higher number of corticosteroids per year before FAc implantation was predictive for an increase in corticosteroids required after FAc (odds ratio = 2.65), while a decrease in CVI from baseline to 6 months was inversely correlated (odds ratio = 0.82). Our results suggest that the more corticosteroids prior to FAc and the greater the short-term CVI reducing effect, the less is the chance to get additional corticosteroids after FAc.

Semi-Automated Quantification of Retinal and Choroidal Biomarkers in Retinal Vascular Diseases: Agreement of Spectral-Domain Optical Coherence Tomography with and without Enhanced Depth Imaging Mode

BACKGROUND

We compared with and without enhanced depth imaging mode (EDI) in semi-automated quantification of retinal and choroidal biomarkers in optical coherence tomography (OCT) in patients with diabetic retinopathy (DR) or retinal vein occlusion (RVO) complicated by macular edema. We chose to study three OCT biomarkers: the numbers of hyperreflective foci (HF), the ellipsoid zone reflectivity ratio (EZR) and the choroidal vascularity index (CVI), all known to be correlated with visual acuity changes or treatment outcomes.

METHODS

In a single examination, one eye of each patient (n = 60; diabetic retinopathy: n = 27, retinal vein occlusion: n = 33) underwent macular 870 nm spectral domain-OCT (SD-OCT) B-scans without and with EDI mode. Semi-automated quantification of HF, EZR and CVI was applied according to preexisting published protocols. Paired Student's t-test or Wilcoxon rank-sum test was used to test for differences in subgroups. Intraclass correlation coefficient (ICC) and Bland-Altman plots were applied to describe the agreement between quantification in EDI and conventional OCT mode. The effect of macular edema on semi-automated quantification was evaluated.

RESULTS

For the entire cohort, quantification of all three biomarkers was not significantly different in SD-OCT scans with and without EDI mode (p > 0.05). ICC was 0.78, 0.90 and 0.80 for HF, EZR and CVI. The presence of macular edema led to significant differences in the quantification of hyperreflective foci (without EDI: 80.00 ± 33.70, with EDI: 92.08 ± 38.11; mean difference: 12.09, p = 0.03), but not in the quantification of EZR and CVI (p > 0.05).

CONCLUSION

Quantification of EZR and CVI was comparable whether or not EDI mode was used. In conclusion, both retinal and choroidal biomarkers can be quantified from one single 870 nm SD-OCT EDI image.