Purpose: The purpose of the study to determine whether ciliary body thickness increased in the presence of diabetic macular edema (DME) and whether it changed after pars plana vitrectomy.
Methods: A DME group consisted of 26 diabetic patients who underwent pars plana vitrectomy for diffuse DME. An epiretinal membrane group, a surgical control group, consisted of 23 nondiabetic patients with epiretinal membrane who underwent pars plana vitrectomy. A healthy control was also included for the comparison of preoperative ciliary body thickness. Ciliary body thickness was measured using ultrasound biomicroscopy, and central macular thickness was determined using optical coherence tomography. The visual acuity, ciliary body thickness, and central macular thickness were compared between groups before and 1, 2, and 4 months after pars plana vitrectomy, and the correlations between the central macular thickness and ciliary body thickness and best-corrected visual acuity were determined.
Results: The preoperative ciliary body thickness was increased significantly in the DME group compared with the epiretinal membrane and healthy control groups (both P < 0.001). The ciliary body thickness decreased significantly 1 and 2 months after surgery in the DME group (both P < 0.001) but not in the epiretinal membrane group. In the DME group, the postvitrectomy changes in the ciliary body thickness and central macular thickness showed similar trends and persisted significantly, until 4 months postoperatively (P = 0.027 and P = 0.010, respectively). The correlations between the preoperative central macular thickness and ciliary body thickness and between changes in central macular thickness and ciliary body thickness before and 2 months after surgery were not significant.
Conclusion: Ciliary body thickness was increased in patients with DME, and vitrectomy was effective in decreasing ciliary body edema as well as macular edema in those patients during the 4-month follow-up period.