AIM:To investigate the impact of different vitreous operations on the corneal endothelial cells counts and indicate the best time of silicon oil withdrawing. METHODS:Depending on different pathological changes, 37 patients 40 eyes with vitreoretinal disease were divided into three groups, respectively they underwent the pure vitrectomy, vitrectomy silicon oil retinal tamponade, and vitrectomy & lensectomy silicon oil tamponade. Corneal endothelium microscope was used to respectively measure the corneal endothelial cell counts of these three groups of cases according to the frequency of 1 day before operation, 1 week, 1 month, 3 months, and 6 months after operation. The changes of corneal endothelial cell counts before and after the operation were compared. RESULTS:There were no statistical differences in the corneal endothelial cell counts among these three groups 1 week after operation and 1 month after operation, compared with the preoperative observation. For the group of pure vitrectomy, there were also no statistical differences in the corneal endothelial cell counts 3 months and 6 months after operation, if compared with the preoperative observation. For the group of vitrectomy silicon oil retinal tamponade, there were also no statistical differences in the corneal endothelial cell counts 3 months after operation, compared with the preoperative observation. However, there were significant decreases in the corneal endothelial cell counts 6 months after operation, and there were statistical differences. For the group of vitrectomy & lensectomy silicon oil tamponade, there were significant decreases in the corneal endothelial cell counts in the corneal endothelial cell counts 3 and 6 months after operation, compared with the preoperative observation, and there were statistical differences. CONCLUSION:For the vitrectomy with reteniton of crystalline lens silicon oil tamponade, there are significant decreases in the corneal endothelial cell counts 6 months after operation, under the premise that the intraocular prossure is under good control. However, for the aphakia vitrectomy silicon oil tamponade, there are significant decreases in the corneal endothelial cell counts at the time of 3 months after operation. This result indicates that the long-term silicon oil tamponade inside vitreous body can significantly reduce the corneal endothelial cells counts. However, there are significant decreases in the corneal endothelial cell counts only at the time of 6 months after the long-term silicon oil tamponade in vitreoretinal surgical operation and vitreous chamber, which shows that the retention of crystalline lens has positive significance in the protection of corneal endothelium.