Comparison of postoperative ciliary body changes associated with the use of 23-gauge and 20-gauge system for pars plana vitrectomy

Background: To compare the ciliary body changes associated with the use of 23-gauge (23G) and 20-gauge (20G) systems for pars plana vitrectomy. Methods: A total of 60 patients (60 eyes) with idiopathic epiretinal membrane who were scheduled for surgical treatment were selected and randomly assigned to 20G group or 23G group. Time required for incision making, vitrectomy, and incision closure was compared between the two groups. Changes in ciliary body were evaluated by ultrasound microscopy (UBM). Anterior chamber inflammation was assessed with laser flare meter instrument. Results: Incision-making time (4.5 +/- 0.9 min) and incision-closure time (2.8 +/- 0.7 min) in the 23G group were significantly shorter than those in the 20G group (10.1 +/- 1.5 min and 11.3 +/- 2.2 min, respectively). No significant intergroup difference was observed with respect to time required for vitrectomy (21.6 +/- 3.3 min and 20.7 +/- 3.2 min, respectively). Ciliary body thickness in the 23G group recovered back to preoperative levels after 4 weeks, as against 8 weeks in the 20G group. Postoperative ciliary body thickness in the 20G group was significantly higher than that in the 23G group (p < 0.05). The aqueous protein concentration in 23G group recovered back to preoperative levels after 2 weeks, as against 4 weeks in the 20G group. Postoperative aqueous protein concentration in the 20G group was significantly higher than that in the 23G group (p < 0.05). Conclusions: The use of 23G system was associated with significantly milder injury to the ciliary body as compared to that associated with the use of 20G system.