a clinical case controled trial for the intraocular tamponade in the vitrectomy for rhegmatogenous retinal detachment(RRD)

INTERVENTION: We replace vitreous with air at the end of surgery. The air tamponade will disappear applex 7 days. We replace vitreous with SF6 at the end of surgery. The air tamponade will disappear applex 14 days. CONDITION: Rhegmatogenous retinal detachment PRIMARY OUTCOME: we try to compare the improvement of the retio of reattachment and BCVA after vitrectomy at the point of 1.3.6.12 months postoperatively. INCLUSION CRITERIA: The RRD patients who consulted this hospital and meet following criterion. .A clinical record at the time of study entry contains no definiency for essential points. .20 yearsold or older. .The affected eye caan be evaluated of the retinal tear at the upper of retina and the RRD is not old RRD. .The affected eye shuld have no other clinically significant abnormality which may cause loss of vision. .The affected eye does noy have the record of votreous surgery. .The eye length oh affected eye is not 26mm or over 26mm.