Resistive Index

Background: In glaucoma, only one-third to half have elevated IOP at initial stages. Hemodynamic parameters measured using Colour Doppler Imaging (CDI) parameters can differentiate eyes suffering from Glaucoma compared to normal eyes early. To evaluate the role of CDI in glaucoma patients and to compare hemodynamic changes and resistive index in Ophthalmic artery (OA), Central retinal artery (CRA), Short posterior ciliary arteries (SPCA) in glaucoma patients and controls. Methods: A case control study was conducted on 30 cases of Glaucoma and 30 controls. IOP measurement, fundus examination and CDI was done. The Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV) values, Systolic/ diastolic (S/D) ratio were obtained for the OA, CRA and SPCA. Resistive Index (RI) was calculated as (PSV - EDV)/PSV. IBM SPSS version 22 was used for statistical analysis. P value < 0.05 was considered statistically significant. Chi square test/Fisher’s exact test was used for qualitative variables while independent sample t-test was used for quantitative variables. Results: The difference between the two groups was statistically significant with respect to PSV OA and EDV SPCA. The mean difference of RI OA, RI CRA, RI SPCA in the glaucoma group was statistically not significant. ROC curve analysis revealed a good predictive value (AUC = 0.647) for the PSV OA in predicting Glaucoma. Conclusions: Hemodynamic parameters measured using CDI can differentiate glaucomatous eyes from normal eyes.