Effects of sub-Tenon's anaesthesia on ocular hemodynamics.

Objective: To research the effects of sub-Tenon's anaesthesia (STA) on ocular hemodynamics in patients with cataract using colour Doppler imaging (CDI).

Design: Prospective clinical study.

Participants: Thirty-four eyes of 34 patients with age-related cataract.

Methods: Peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) values of the ophthalmic artery (OA), central retinal artery, and central retinal vein were measured by CDI before and immediately after performing sub-Tenon block using 2 mL of 2% lidocaine with adrenaline (1:200 000).

Results: Both PSV and EDV values were significantly decreased after sub-Tenon injection in all the studied vessels of the patients. However, no important changes were observed in the RI values of the vessels.

Conclusions: STA markedly reduced ocular blood flow. The reduction may be more acceptable compared with other retrobulbar block methods. Sub-Tenon block should be performed carefully to senile patients with cataract with vascular occlusive disorder.