Management of macular holes that develop after retinal detachment repair

To study the characteristics and management of macular holes that develop after prior rhegmatogenous retinal detachment (RD) repair. Retrospective, interventional, consecutive case series. The setting was a clinical practice. The case records of all of our patients (n = 12) who developed a new full-thickness macular hole after prior RD repair over an 8-year period were examined. Patients who developed a macular hole after prior RD repair were offered either surgical repair of the macular hole or continued observation. For eyes that underwent macular hole repair, main outcome measures included macular attachment status and postoperative visual acuity. Twelve full-thickness macular holes were detected in a series of 2,380 eyes (0.5% prevalence), which had undergone surgery for prior primary RD. Ten macular holes developed after scleral buckling surgery, two after pneumatic retinopexy, and none were seen after primary vitrectomy. The fovea had been detached in 11 of the 12 eyes at the time of RD. The median time to macular hole diagnosis after RD repair was 3.4 months (range, 0.3–161 months). Eight of the eight eyes (100%) undergoing surgical repair achieved macular reattachment with a median of 3.5 lines of visual improvement at a median of 14.8 months of follow-up. Seven of these eight eyes had an improvement in visual acuity of at least 3 Snellen lines, and four of the eight had at least 20/40 visual acuity postoperatively. Four eyes with macular holes were observed. Macular holes developed in less than 1% of eyes that had previously undergone repair of rhegmatogenous RD. In our series, these atypical holes were seen predominantly after macula-off detachments, most commonly occurring after scleral buckling procedures. They were effectively repaired using conventional pars plana vitrectomy with long-acting gas tamponade and a variety of adjuvant therapies. A good visual outcome is possible with this approach

N-Acetylcysteine Suppresses Retinal Detachment in an Experimental Model of Proliferative Vitreoretinopathy

Proliferative vitreoretinopathy (PVR) is a complication that develops in 5% to 10% of patients who undergo surgery to correct a detached retina. The only treatment option for PVR is surgical intervention, which has a limited success rate that diminishes in patients with recurring PVR. Our recent studies revealed that antioxidants prevented intracellular signaling events that were essential for experimental PVR. The purpose of this study was to test whether N-acetyl-cysteine (NAC), an antioxidant used in a variety of clinical settings, was capable of protecting rabbits from PVR. Vitreous-driven activation of PDGFRα and cellular responses intrinsic to PVR (contraction of collagen gels and cell proliferation) were blocked by concentrations of NAC that were well below the maximum tolerated dose. Furthermore, intravitreal injection of NAC effectively protected rabbits from developing retinal detachment, which is the sight-robbing phase of PVR. Finally, these observations with an animal model appear relevant to clinical PVR because NAC prevented human PVR vitreous-induced contraction of primary RPE cells derived from a human PVR membrane. Our observations demonstrate that antioxidants significantly inhibited experimental PVR, and suggest that antioxidants have the potential to function as a PVR prophylactic in patients undergoing retinal surgery to repair a detached retina

Coexisting Domains in the Plasma Membranes of Live Cells Characterized by Spin-Label ESR Spectroscopy

The importance of membrane-based compartmentalization in eukaryotic cell function has become broadly appreciated, and a number of studies indicate that these eukaryotic cell membranes contain coexisting liquid-ordered (L(o)) and liquid-disordered (L(d)) lipid domains. However, the current evidence for such phase separation is indirect, and so far there has been no direct demonstration of differences in the ordering and dynamics for the lipids in these two types of regions or their relative amounts in the plasma membranes of live cells. In this study, we provide direct evidence for the presence of two different types of lipid populations in the plasma membranes of live cells from four different cell lines by electron spin resonance. Analysis of the electron spin resonance spectra recorded over a range of temperatures, from 5 to 37°C, shows that the spin-labeled phospholipids incorporated experience two types of environments, L(o) and L(d), with distinct order parameters and rotational diffusion coefficients but with some differences among the four cell lines. These results suggest that coexistence of lipid domains that differ significantly in their dynamic order in the plasma membrane is a general phenomenon. The L(o) region is found to be a major component in contrast to a model in which small liquid-ordered lipid rafts exist in a ‘sea’ of disordered lipids. The results on ordering and dynamics for the live cells are also compared with those from model membranes exhibiting coexisting L(o) and L(d) phases