Rhegmatogenous Retinal Detachment: A Reappraisal of Its Pathophysiology and Treatment

Abstract

This article represents a synthesis of an extensive literature review and the authors' decades-long personal experience with both scleral buckling (SB) and vitrectomy for rhegmatogenous retinal detachment (RD). Presenting a coherent understanding of the pathophysiology and treatment of RD, the authors confirm numerous findings described in earlier publications but also challenge certain long-standing dogmas. The key argument made here is that it is extremely rare for the chain of events leading to an RD to start with a retinal pathology. Rather, the initial pathology is syneresis of the vitreous, which then allows gel movement (intraocular currents). At the point of vitreoretinal adhesion, dynamic traction is exerted on the retina, which may be sufficient to tear it. If the tear is operculated and the dynamic traction overcomes the forces keeping the neuroretina and retinal pigment epithelium (RPE) together, the heretofore virtual subretinal space becomes accessible through the retinal tear. The intraocular currents allow the free (nonbound) intravitreal fluid to enter the subretinal space, and once the amount of the incoming fluid overwhelms the draining capacity of the RPE, an RD ensues. Detachment of the posterior cortical vitreous (PVD) is not a necessary prerequisite to RD development; furthermore, PVD cannot be diagnosed preoperatively with adequate certainty with current technology such as biomicroscopy, ultrasonography or optical coherence tomography. The surgeon should expect no or only partial (anomalous) PVD at the time of surgical repair in over half of eyes. The treatment's primary goal must thus be weakening (pneumatic retinopexy, SB) or eliminating (vitrectomy) this dynamic traction. If vitrectomy is employed, it must be a truly complete vitreous removal. This includes a surgically induced PVD if one is not present, close shaving at the periphery, and removing the vitreous immediately behind the lens. The vitrectomy is followed by the creation of a chorioretinal scar around the tear and aided by some form of intraocular tamponade. The main function of the tamponade is not to temporarily cover the break but to significantly reduce the intraocular currents and thus prevent fluid entry through the break until the chorioretinal adhesion will have become sufficiently strong to seal the retinal edge around the tear; postoperative positioning is therefore not as important as currently assumed.

Ageing of the vitreous: From acute onset floaters and flashes to retinal detachment

“…Byer (1994) found in the natural history study of PVD that 6% of patients had photopsiae as presenting symptom of PVD, 40% had floaters and 54% reported both. Flashes are a warning sign of dynamic traction on the retina and are much more threatening phenomenon than floaters (Kuhn and Aylward, 2014). According to Hikichi et al, the appearance of floaters in patients under the age of 50 were related to opacities on the plicated membranes in the posterior portion of the Cloquet's canal and to other intravitreous opacities, which is in contrast to patients aged 50 and older, where the main reason for the occurrence of floaters is PVD (Hikichi et al, 1995).…”

“…Trans-conjuctival injection of gas bubble intravitreally is performed with a proper head posturing after the procedure. Indications for pneumatic retinopexy are RRDs with a traction that is not too advanced and rather limited syneretic changes in the vitreous body (Kuhn and Aylward, 2014). The chances of new retinal break occurrence during this procedure are up to 30% (Poliner et al, 1987).…”

“…Scleral buckling technique is performed with the help of scleral sponges as a buckling element which is sutured extrasclerally over the breaks, indenting the eye wall and modifying the direction of the force that is pulling on the edges of the retinal break, thus counter-balancing its strength (Kuhn and Aylward, 2014). Scleral buckling is the most appropriate surgical procedure for uncomplicated RRD with final anatomic success rates of greater than 94% (Sodhi et al, 2008).…”

Anatomical success rate of pars plana vitrectomy for treatment of complex rhegmatogenous retinal detachment

“…There are three critical pre-conditions for the development of RRD: liquefied vitreous, tractional forces that produce a retinal break, and fluid access into the subretinal space through the retinal break [2, 3]. Several major risk factors that might predispose to RRD have been described [4].…”

Cytopathology of Vitreous Humor Samples in Routine Practice

“…Several afflictions may impair vision by damaging vitreous fluid transparency or vitreo/retinal interface integrity. In these cases, the surgical removal of all or part of the vitreous fluid, called therapeutic vitrectomy, can be performed to remove the elements causing intraocular opacity such as blood, fibrovascular membranes, lens fragments and inflammatory debris, or to reattach a detached retina [2]. …”