Abstract
Purpose: :
To evaluate the acute effects of local–anesthetic stellate ganglion block (SGB) on ocular blood flow (OBF), intraocular pressure (IOP) and the effect of topical ß–blockers on these parameters.
Methods: :
Twelve patients (age 24,27±4,67 years) with Raynaud Disease who underwent SGB for its treatment participated in the study. SGB was performed using bupivacaine 0.5% solution for three times consecutively with two days interval time (Day 0, Day 2, and Day 4). Ocular blood flow (OBF), IOP, blood pressure, and pulse rate were measured before and 5 and 60 minutes after SGB. OBF and IOP were measured using Langham pneumotonometer. Fundus photographs were taken with a non–mydriatic fundus camera. Temporal artery and vein diameters were measured apart one disc diameter from the optic disc. Before performing SGB for the first time (Day 0), no topical drops were administered. Placebo (0.9% NaCl) and timolol maleate 0.5 % drops were instilled 4 hours before performing SGB on day 2 and day 4, respectively.
Results: :
The IOP in the blocked side significantly decreased between 5 and 60 minutes following SGB on Day 0, 2 and 4 when compared to that of baseline. (p<0.01). The IOP in the unblocked side did not change significantly. Placebo drops showed no effect on IOP on both eyes after SGB on day 2.Timolol maleate decreased IOP in both eyes but the IOP lowering effect in the unblocked side was higher when compared to that of in the blocked side on day 4 (p<0.05). OBF increased significantly after 5 and 60 minutes in the blocked side. There was no significant change in the unblocked side. Placebo drops and timolol maleate drops have not significantly changed OBF and the temporal artery and vein diameter following SGB.
Conclusions: :
SGB increased OBF and decreased IOP in the blocked side. The IOP lowering effect of timolol decreased significantly in the blocked side following SGB. This suggests that ß–blockers' IOP lowering effect needs sympathetic tonus and this might explain why the IOP lowering effect of ß–blockers were diminished at night.
Keywords: optic flow • innervation: neural regulation