Color Doppler imaging of retrobulbar hemodynamics after topiacal carteolol in normal tension glaucoma

Background. Carteolol is a nonselective adrenergic blocking agent. The aim of this study was to evaluate the effect of topical carteolol on retrobulbar hemodynamics in patients with normal tension glaucoma (NTG). Methods. Twelve NTG patients received twelve-week topical treatment of 2% carteolol. Color Doppler imaging (CDI) was used to evaluate the hemodynamic effects before and after drug therapy. Measurements were obtained from the central retinal artery (CRA), the lateral posterior ciliary artery (LPCA) and the medical posterior ciliary artery (MPCA). From each vessel, peak systolic velocity (PSV), end-diastolic velocity (EDV), resistance index (R1) and Gosling's pulsatility index (PI) were collected and analyzed. Results. After topical carteolol treatment for twelve weeks, mean resistance index reduced significantly from 0.83 to 0.74 in the CRA (p = 0.03), from 0.74 to 0.68 in the LPCA (p = 0.09). Moreover, mean pulsatility index of the LPCA decreased from 1.45 to 1.26 (p = 0.08). Conclusions. Twelve weeks of 2% carteoiol treatment may decrease the vascular resistance in NTG patients possibly due to the intrinsic sympathomimetic activity (ISA) of carteolol.