Vitreous Levels of VEGF and Surgical Outcomes after Vitrectomy in Proliferative Diabetic Retinopathy

ABSTRACT

PURPOSE: To evaluate the levels of vascular endothelial growth factor (VEGF) in the vitreous of patients with proliferative diabetic retinopathy (PDR) and to find any correlation between clinical and fundus findings, grade of PDR, post-operative complications and surgical outcomes. METHODS: Using ELISA, the vitreous concentration of VEGF was measured in 74 patients with PDR who had undergone vitrectomy and in 13 control patients. RESULTS: The pre-operative levels of VEGFin the vitreous of the PDR patients was significantly increased compared with those of the control and with the post-operative levels. The pre-operative VEGF concentration in the vitreous of the PDR patients was correlated with the duration of diabetes and the severity of proteinuria, but not with the type of diabetes, level of HbA1c, hypertension and BUN/creatinine levels. The severity of PDR was also correlated with pre-operative VEGF levels, especially in NVD, NVE and NVI, but was not correlated with vitreous hemorrhage and fibrous proliferation elsewhere. There was negative correlation with the severity of retinal detachments. The vitreous levels of VEGF in PDR were significantly lower in those who had received previous laser photocoagulation than in those who did not. The VEGF levels were also significantly elevated in patients who developed NVI or NVG in the post-operative period. The changes of visual acuity after vitrectomy in the PDR patients were not correlated with vitreous levels of VEGF. CONCLUSIONS: These results show that VEGF is related to intraocular angiogenesis, progression of PDR and post-operative complications such as NVI or NVG, and that panretinal photocoagulation could prevent the progression of PDR.