The purpose of this study was to determine the appropriate timing of pars plana vitrectomy after pretreatment with intravitreal bevacizumab (IVB) for proliferative diabetic retinopathy using histopathological examination of epiretinal membrane biopsies.

Material & Methods:

This prospective study was conducted in Maghrabi Eye Hospital & Kuwait University Hospital, Sana, between January 2009 – May 2010. Forty patients suffering of proliferative diabetic retinopathy (PDR) with tractional retinal detachment were included with an age range of 30 to 70 years. Fluorescein angiography was performed on every patient. Epiretinal membrane biopsies were obtained during pars plana vitrectomy surgery performed at either 3rd, 7th or 10th day post IVB treatment.


Minimum bleeding during pars plana vitrectomy and fibrovascular membrane delamination and a low frequency of post-operative complications were observed. Complications were lower in cases that had their surgery after a short period of IVB. We found that, on the 7th day following IVB injection there is absence of the process of angiogenesis in the center of the membrane with only small capillaries and fibroblast at the periphery, compared to biopsies taken at the 10th day where an avascular scar was demonstrated and blood vessels were not seen.


Our study determined the appropriate timing of intervention for diabetic tractional retinal detachment surgery based on histopathological examination of diabetic epiretinal membranes biopsies.