Background Elevated serum vascular endothelial growth factor (VEGF) levels are associated with diabetic retinopathy (DR). Serum VEGF levels correlate with vitreous levels. Neuroretinal changes occur even before the appearance of vascular signs in DR. Role of VEGF as a biomarker for DR has not been assessed. Serum VEGF as a biomarker for severity of DR, was evaluated for the first time. Methods Consecutive cases of type 2 diabetes mellitus [without DR, (no DR, n = 38); non-proliferative DR, (NPDR, n = 38); proliferative DR, (PDR, n = 40)] and healthy controls (n = 40) were included. Serum VEGF was measured using enzyme linked immunosorbent assay. Accuracy of VEGF as a biomarker for severity of retinopathy was measured using the area under the receiver operator characteristic (ROC) curve. Results Serum VEGF levels in controls, No DR, NPDR and PDR groups showed significant incremental trend from 138.96 ± 63.37 pg/ml (controls) to 457.18 ± 165.69 pg/ml (PDR) (F = 48.47; p < 0.001). Serum VEGF levels were observed to be significantly elevated even before DR had set in clinically. ROC for serum VEGF levels was significant in discriminating between the cases and the controls and had good accuracy in discerning between subjects with and without retinopathy. The area under curve (AUC ± SE) for discrimination was significant: (a) cases and controls (n = 156): AUC = 0.858 ± 0.029, p < 0.001; (b) DR (NPDR + PDR) and No DR (n = 116): AUC = 0.791 ± 0.044, p < 0.001; and (c) NPDR and PDR (n = 78): AUC = 0.761 ± 0.056, p < 0.001, with over 90% projected sensitivity and specificity at various cut off values. Conclusion Serum VEGF level is a simple, effective laboratory investigative test in predicting the onset of DR in eyes showing no evidence of DR and serves as a reliable biomolecular biomarker for severity of DR.

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BackgroundTo evaluate the association of central subfield thickness (CST) and cube average thickness (CAT) with ellipsoid zone (EZ) disruption on spectral domain optical coherence tomography (SD-OCT) in patients of diabetic retinopathy (DR).MethodsCross sectional study including consecutive patients of type 2 diabetes mellitus [without DR (No DR, n = 97); non-proliferative DR (NPDR, n = 91); proliferative DR (PDR, n = 83)] and healthy controls (n = 82) was undertaken. CST and CAT values were measured using SD-OCT. Data was analyzed using Chi square test, ANOVA and multivariate analysis. Discriminant values of CST and CAT for EZ disruption were evaluated using receiver operator characteristic curve. Area under curve (AUC) was computed.ResultsMean CAT and CST values in the study subjects showed an incremental trend. Multivariate ordinal logistic regression analysis showed increase in CST (OR = 1.022, p < 0.001) and CAT (OR = 1.029, p < 0.001) as significant independent predictors of EZ disruption. Area under curve showed excellent predictive results of CST (AUC = 0. 943 ± 0.021, 95% CI, 0.902–0.984, p < 0.05) and CAT (AUC = 0.959 ± 0.012, 95% CI 0.936–0.982, p < 0.05), as bioimaging biomarkers, for EZ disruption.ConclusionIncrease in CST and CAT is associated with increased odds of EZ disruption and these macular parameters serve as bioimaging biomarkers for EZ disruption in DR.

Aim: To study the arterial blood flow changes in the orbit in thyroid associated ophthalmopathy (TAO) and compare the blood flow parameters with disease activity. Design: Observational study Patients: Fifty consecutive patients of TAOMeasurements: Blood flow parameters in the ophthalmic artery (OA) and central retinal artery (CRA) were measured in fifty consecutive patients of moderate-severe stage TAO (EUGOGO classification), irrespective of disease activity using Color Doppler Imaging. Resistive index (RI) was calculated by the formula: RI= (Pre-Systolic Velocity-End Diastolic Velocity)/ Pre-Systolic Velocity. Discriminant function of RI of OA and CRA to determine the activity of TAO was measured using the area under curve (AUC) values of receiver operator characteristics curve (ROC curve).Results: Resistive index of OA and CRA was higher in patients of active stage than inactive stage. ROC curve analysis showed excellent predictive accuracy of RI for activity of TAO (AUC of OA=0. 993 ± 0.007, p<0.05 and AUC of CRA =1.00 ± 0.00, p<0.05). Conclusion:A significant compromise of arterial vasculature occurs in the active stage of TAO, which only partially resolves in the inactive phase. Resistive index can be used to distinguish between active and inactive stages of the disease, providing proof of additional threat to vision as a result of ischemic compromise.