Abstract
Purpose: :
To examine whether epinephrine in addition to intravitreal infusion solution affects the blood flow volume in eyes during vitrectomy, based on measurements by laser speckle flowgraphy (LSFG).
Methods: :
In this study we analyzed 11 eyes of 11 patients treated by vitrectomy, 7 of 11 with epimacular membrane and 4 of 11 with idiopathic macular hole. All procedures were in full compliance with the guidelines of the Declaration of Helsinki and were approved by the Institutional Review Board/Ethics Committee. All patients underwent micro incision vitreous surgery with a 23 gauge instrument using the Accurus® (Alcon) Vented Gas Forced Infusion (VGFI) system. After performing the core vitrectomy and posterior vitreous detachment under an epinephrine-free BSS PLUS®500 intraocular irrigating solution, the blood flow volume was measured under a stabilized infusion pressure of 10 mmHg using the VGFI system. The blood flow volume in the optic nerve head was measured by LSFG with the patient in the supine position. Next, 50 ml of 1 mg epinephrine-fortified BSS PLUS®500 intraocular irrigating solution was infused at 10 mmHg with the same VGFI system, and the blood flow volume was measured again by the same method. During the LSFG measurement, there were no significant changes noted in simultaneous measurements of the intraocular pressure, pulse rate, or systolic and diastolic blood pressure. The relative blood flow volume in the LSFG was expressed as the mean blur rate (MBR).
Results: :
The MBR, the value representing the blood flow volume of the optic nerve head, significantly decreased after the switchover to the epinephrine-fortified infusion solution from the epinephrine-free solution (average decrease of 9.8±8.9%; P=0.004; paired t-test) . There were no significant differences in the blood pressure, pulse rate, or intraocular pressure between the two measurements in any patient.
Conclusions: :
The results of this study suggest that the blood flow volume of the optic nerve head is significantly affected by epinephrine in addition to intravitreal infusion solution during vitrectomy.