Anatomic and Topographic Vitreous and Vitreoretinal Interface Features in Proliferative Diabetic Vitreoretinopathy

The role of the vitreous body and vitreomacular interface (VMI) is key in many processes including proliferative diabetic retinopathy (PDR). In PDR patients, the VMI changes can significantly influence the emergence and progression of the disease. There are multiple factors at work in the VMI including taut posterior cortical layers, vitreoschisis, posterior vitreous detachment (PVD), and vitreous adhesions. But there is no general consensus about their role in proliferative complications. Further understanding the VMI relationship in a case of PDR is warranted in order to design better treatments, to arrest and possibly even reverse progression of PDR.  Today there is no imaging techniques to determine normal vitreous and VMI interactions in different PDR stages intraoperatively. Purpose: to analyze intraoperative vitreous and vitreoretinal interface features during chromovitrectomy in patients with A-C stages of PDR. Patients and methods. Seventy-four diabetic patients (74 eyes) were included. We performed standard 25 Gauge pars plana vitrectomy using Vitreocontrast for vitreous and vitreoretinal interface (VRI) visualization. Intravitreal “Vitreocontrast” suspension is the most favored agent of those studied and it is increasingly used as an adjunct during surgery to delaminate fine tissue planes and pockets of formed vitreous and VRI structures that may not be visible with routine operative illumination systems, or using modern vital dyes. Results. “Vitreocontrast” suspension allows to visualize posterior cortex changes during different stages of PDR. We investigated vitreous and VRI anatomy, topography and structure and determined safety of retrociliary and equatorial cisterns walls in 97 % in stage A of PDR, 95 % in stage B and in 82 % of stage C. In 3–5–18 % cases, correspondently, we determined disorganization of some vitreous cisterns. In 94 % cases of PDR A and 96 % cases of PDR B we visualized preretinal vitreous layer in a central macular zone, within the boundaries of vascular arcades. It has specific topography and strong adhesion to the internal retinal membrane. It’s the first time when this new vitreous cortex layer was revealed. The presence of this layer is the result of a strong vitreomacular adhesion that causes the posterior vitreous cortex split as it attempts to detach from the inner retinal surface. Such outermost layer remains attached to the macula and can induce further proliferation process. On a stage B of PDR this area correspond with multiple vitreoschisis, on a stage C of PDR — with fibrovascular membrane. The complete PVD was revealed in 61 cases. Conclusion. In this article we analyze the results of surgical treatment in 74 patients with A-C stages of proliferative diabetic retinopathy. Newer imaging technique with new dye — suspension “Vitreocontrast” allows to detect sensitive relationships of vitreous and VRI in each stage of the disease. The role of vitreous body in this process gives us a reason to consider it as an important object for further research. Moreover, the understanding of their relations in different stages of PDR enables to develop optimal surgical approach on each stage of PDR.