Abstract
Purpose :
Adequate mydriasis is important during vitrectomy surgery to facilitate vitreous removal and membrane peeling. On the other hand, poor pupil dilation may lead to complications as accidental retinal tears, lens and retinal touching, and non-intentional reminiscent of cortical vitreous, both on the posterior pole and vitreous base. We designed this randomized, double-blinded trial to determine whether the use of sub-Tenon’s capsule injection of 0.2 cc 0.1% adrenaline improves the maintenance of mydriasis during vitrectomy, in comparison with placebo.
Methods :
Thirty-four eyes (34 patients) submitted to primary vitrectomy were enrolled. Informed consent was taken in all cases. All patients were preoperatively dilated with 3 drops of 0,5% tropicamide 30 minutes before procedure. They were then randomly assigned in one of two groups: adrenaline (treatment group) or saline (placebo group). In group adrenaline, 0.2 cc of 0.1% adrenaline was injected in the inferior perilimbic area, with a 27-gauge needle, under the Tenon’s capsule, immediatelly before beginning of the surgery; in group saline, 0.2 cc of Balanced Saline Solution (BSS) was injected following the same techique, as a placebo. Pupil horizontal diameter was measured with a milimetric scale prior to the initial injection and immediately after surgery, through microscope visualization. Gender, age, phakic status, duration of surgery, history of diabetes and possible complications were also recorded.
Results :
Mean preoperative pupil diameter was 6.68 mm [standard deviation (SD):1.09] in the adrenaline group and 6.5 mm (SD: 1.03) in the placebo group, with no significant difference. Postoperative measurements were 7.29 mm (SD: 0.63) in the adrenaline group and 6.17 mm (SD: 0.88) in placebo group, and this difference was significant larger (p<0.001). There was no difference between groups regarding gender, age, surgery duration, diagnosis of diabetes or phakic status. No surgical or clinical complications were reported.
Conclusions :
Sub-Tenon’s capsule adrenaline immediately before surgery was effective in maintaining mydriasis during vitrectomy. Despite the absence of complications, this procedure appears safe and may assist especially in more difficult surgical scenarios. More studies should be performed for better conclusions about other clinical outcomes.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.