Doppler imaging measurements are repeatable in OAG patients

The repeatability of colour Doppler imaging (CDI) measurements in open-angle glaucoma (OAG) patients has been confirmed by a study published in Journal of Glaucoma.

Dr Rita Ehrlich et al., Department of Ophthalmology, Indiana School of Medicine, Indianapolis, Indiana, USA, conducted a cross-sectional, observational study on 116 OAG patients involved in the Indianapolis Glaucoma Progression Study. At the same time of day to baseline measurements were recorded 1 to 2 weeks apart on all patients. CDi measurements of retrobulbar blood flow velocities and Pourcelot's vascular resistance index (RI) were analysed.

Intraclass correlation coefficient (ICC) between the 2 baseline measurements was determined. Other measurements included the calculation of RI and peak systolic and end diastolic blood flow velocities (PSV/EDV) in the ophthalmic (OA), central retinal (CRA), and nasal and temporal short posterior ciliary arteries (N/TPCA).

Measurements in the OA were all above 0.82 in the intraobserver ICC for the PSV, EDV and RI. Measurements in the CRA were both above 0.8 in the intraobserver ICC PSV and RI. EDV in the CRA was found to be 0.64.

Intraobserver ICC in the N/TPCA for the PSV, EDV, and RI measurements varied between 0.71 and 0.88. It was generally similar to the intraobsever ICC for the OA and the CRA, but lower than 0.7 in the EDV and RI.

If performed on OAG patients within 2 weeks the blood flow velocities and calculated vascular resistance of the OA, CRA and PCA are repeatable.