Central subfield thickness and cube average thickness as bioimaging biomarkers for ellipsoid zone disruption in diabetic retinopathy

Correlation of limited-early-response status with 12-month CST, BVA, and machine learning-quantified retinal fluid in diabetic macular oedema in routine clinical practice

BACKGROUND/OBJECTIVES

Anti-VEGF treatment response in DMO has been measured by changes in the central subfield thickness (CST) and best visual acuity (BVA) outcomes at 3 months after initial treatment, termed early or limited early response (ER/LER). This study correlates LER with 12-month BVA, CST, and retinal fluid volumes quantified by a machine learning algorithm on optical coherence tomography (OCT).

SUBJECTS/METHODS

The study included treatment naïve DMO patients ≥ 18 years with OCT scans at baseline (M0), M3, M6, and M12. The 220 patients were categorized as limited early responders (LER) if they had ≤ 10% CST reduction and/or < 5 ETDRS letter gain at M3. BVA, CST, and subretinal (SRF), intraretinal (IRF), and total retinal (TRF) fluid volumes quantified by a machine learning algorithm were compared between groups and across time.

RESULTS

At M12, the anatomic LER (aLER), defined solely by CST, had significantly worse BVA and CST versus the anatomic ER (aER) group (p < 0.001). Retinal fluid M12 outcomes did not significantly vary between all LER and ER groups. No significant BVA, CST, TRF, and IRF variance across time for LER was found (p > 0.1).

CONCLUSIONS

BVA and CST M12 outcomes vary by aLER/aER status indicating that CST may be a strong predictor of treatment outcomes, while retinal fluid volumes were not predicted by LER status.

QUANTITATIVE OPTICAL COHERENCE TOMOGRAPHY REVEALS ROD PHOTORECEPTOR DEGENERATION in EARLY DIABETIC RETINOPATHY

PURPOSE

This study is to test the feasibility of optical coherence tomography (OCT) detection of photoreceptor abnormality and to verify that the photoreceptor abnormality is rod predominated in early diabetic retinopathy (DR).

METHODS

OCT images were acquired from normal eyes, diabetic eyes with no DR, and mild nonproliferative DR (NPDR). Quantitative features, including thickness measurements quantifying band distances and reflectance intensity features among the external limiting membrane, inner segment ellipsoid, interdigitation zone, and retinal pigment epithelium were determined. Comparative OCT analysis of central fovea, parafovea, and perifovea were implemented to verify that the photoreceptor abnormality is rod predominated in early DR.

RESULTS

Thickness abnormalities between the inner segment ellipsoid and interdigitation zone also showed a decreasing trend among cohorts. Reflectance abnormalities of the external limiting membrane, interdigitation zone, and inner segment ellipsoid were observed between healthy, no DR, and mild NPDR eyes. The normalized inner segment ellipsoid/retinal pigment epithelium intensity ratio revealed a significant decreasing trend in the perifovea, but no detectable difference in central fovea.

CONCLUSION

Quantitative OCT analysis consistently revealed outer retina, i.e., photoreceptor changes in diabetic patients with no DR and mild NPDR. Comparative analysis of central fovea, parafovea, and perifovea confirmed that the photoreceptor abnormality is rod-predominated in early DR.

Increased serum cortisol is associated with alterations in cross-sectional and topographic OCT parameters in diabetic retinopathy: a preliminary study

PURPOSE

Cortisol, a steroid hormone, plays an essential role in metabolic processes of diabetes mellitus. This study for the first time evaluated the association of serum cortisol with spectral domain optical coherence tomography (SD-OCT)-based cross-sectional and topographic parameters with severity of diabetic retinopathy (DR).

METHODS

A tertiary care center-based preliminary study was undertaken. Fourteen consecutive cases of DR and fifteen healthy controls were included. Cases were graded according to ETDRS classification: non-proliferative DR (NPDR, n = 8) and proliferative DR (PDR, n = 6). All study subjects underwent complete ophthalmological evaluation. Serum cortisol was analyzed using chemiluminescence microparticle assay method. Central subfield thickness (CST), cube average thickness (CAT), cube volume (CV), retinal nerve fiber layer (RNFL) thickness, disorganization of inner retinal layers (DRIL), grade of retinal photoreceptor ellipsoid zone (EZ) disruption and grade of retinal pigment epithelium (RPE) alterations were evaluated using SD-OCT. Statistical analysis was done using ANOVA and Pearson's correlation analysis.

RESULTS

Mean serum cortisol levels (µg/dL) were NPDR = 11.59 ± 0.42, PDR = 14.50 ± 0.26 and controls = 8.22 ± 0.77. With increasing severity of DR, mean CST, CAT, CV showed positive correlation, whereas mean RNFL thickness showed negative correlation with serum cortisol levels (p < 0.01). DRIL, EZ disruption and RPE alterations showed positive correlation with serum cortisol levels (p < 0.001).

CONCLUSION

Serum cortisol levels are significantly associated with severity of DR and correlate positively with CST, CAT, CV, DRIL, EZ disruption and RPE alterations and negatively with RNFL thickness.

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.

Dilated retinal large vessels and capillaries associated with diabetic macular edema and photoreceptor loss respectively

PURPOSE

Previously, we measured retinal large vessels and capillaries separately on optical coherence tomography angiography (OCTA). In the present study, we aim to evaluate the role of these parameters in association to diabetic macular edema (DME) and ellipsoid zone disruption (EZD).

METHODS

In this cross-sectional study, 54 eyes from 31 patients (10 females, 31 Asians) with severe non-proliferative diabetic retinopathy (25 eyes) or proliferative diabetic retinopathy (PDR, 29 eyes) were enrolled. All eyes underwent 3 × 3 mm OCTA scans centered on the fovea. Perfusion density (PD), vessel length density (VLD), and vessel diameter index (VDI) were calculated for retinal large vessels and superficial capillaries separately. Other OCTA findings included suspended scattering particles in motion (SSPiM), number of microaneurysms (MA) in all retinal layers, and the area of foveal avascular zone (FAZ) of superficial capillary plexus. DME and EZD were evaluated on B-scans. Both univariate and multivariate analysis were performed.

RESULTS

Of the 54 study eyes, 31 (57%) had DME and 21 (40%) had EZD. Multivariate regression model showed that PDR (β = 27.8, 95% confidence interval (CI): 2.7-282.8, p = 0.005), more MA (β = 2.5, 95% CI: 1.3-4.5, p = 0.003), and increased VDI of larger vessels (β = 1.9, 95% CI: 1.0-3.5, p = 0.047) were risk factors for DME. As for EZD, presence of SSPiM (β = 5.5, 95% CI: 1.2-26.1, p = 0.032) and increased VDI of capillaries (β = 3.9, 95% CI: 1.1-13.8, p = 0.034) were risk factors.

CONCLUSIONS

In eyes with diabetic retinopathy, dilation of retinal larger vessels was associated with macular edema, while dilation of retinal capillaries was associated with ellipsoid zone disruption.

Spectral domain optical coherence tomography based imaging biomarkers for diabetic retinopathy

To evaluate the role of central subfield thickness (CST), cube average thickness (CAT), and cube volume (CV) as imaging biomarkers for severity of diabetic retinopathy within the ETDRS-based grades of retinopathy using spectral domain optical coherence tomography (SD-OCT). This study aims to evaluate the role of macular CST, CAT, and CV on SD-OCT as imaging biomarkers for severity of DR. One hundred ninety-four consecutive cases of type 2 diabetes mellitus were divided according to ETDRS classification: diabetes mellitus without retinopathy (No DR; n = 65), nonproliferative diabetic retinopathy (NPDR; n = 66), and proliferative diabetic retinopathy (PDR; n = 63). Sixty-three healthy controls were included. CST, CAT, and CV were analyzed using SD-OCT. Data were analyzed statistically. Analysis of variance revealed a significant increase in levels of CST, CAT, CV, and LogMAR visual acuity with the increase in severity of DR. Independent t-test revealed significant difference in CST, CAT, and CV between cases with DME and cases without DME. On multivariate linear regression analysis, increase in CST, CAT, and CV were found to indicate the increase in severity of DR. SD-OCT-based imaging biomarkers CST, CAT, and CV are effective tools for documenting the severity of diabetic retinopathy. These imaging biomarkers serve as significant indicators of severity of disease.