Surgery For Proliferative Vitreoretinopathy Research Articles

INTRAOPERATIVE OPTICAL COHERENCE TOMOGRAPHY OBSERVATION WITH PERFLUOROCARBON TAMPONADE FOR SUBRETINAL MEMBRANES IN PROLIFERATIVE VITREOUS RETINOPATHY.

To report the efficacy of intraoperative optical coherence tomography in locating proliferative membranes or strands subretinally or preretinally during pars plana vitrectomy for proliferative vitreoretinopathy or old rhegmatogenous retinal detachment. After removing the vitreous and apparent epiretinal membranes, vitreous fluid was exchanged for perfluorocarbon. Lesions of the retinal folds or persistently detached retinas, suspected to be subretinal membrane lesions, were examined using intraoperative optical coherence tomography in three eyes with proliferative vitreoretinopathy. Intraoperative optical coherence tomography showed subretinal or preretinal structures in all three patients. A subretinal structure with underlying fluid was removed through an intentional hole in a patient. In another patient, a subretinal structure without underlying fluid was not removed. In the remaining patient, the preretinal membranes detected with intraoperative optical coherence tomography could be peeled successfully. Intraoperative optical coherence tomography examination with perfluorocarbon tamponade effectively identified the correct location of proliferative membranes or strands, namely, preretinal or subretinal. This imaging technique helps surgeons determine whether an intentional hole should be made to remove the subretinal structure during vitrectomy. Intraoperative optical coherence tomography, combined with perfluorocarbon tamponade, leads to safer and more effective surgery for proliferative vitreoretinopathy.

Low-Dose Intravitreal Methotrexate for Proliferative Vitreoretinopathy

Proliferative vitreoretinopathy (PVR) has been mitigated by intravitreal methotrexate (MTX) 400 μg/0.1 mL in several studies. Here, we evaluate the results from a lower dose of MTX, 200 μg/0.05 mL. We identified and reviewed records of patients with grade ≥C1 PVR who were treated with 200 μg/0.05 mL MTX injections: during PVR surgery and every 2 weeks thereafter. Twenty-four eyes met inclusion criteria with a mean of 5.6 injections and follow-up ranging 6 to 56 months. The retina was reattached in 19 of 24 eyes (79%) after a single surgery and in 5 of 24 eyes (21%) after one additional PVR surgery. Visual acuity improved from baseline logMAR 1.63 to 0.97 at 12 months (P < .001), with 5 of 20 achieving 20/60 or better and 16 of 20 achieving 20/200 or better. One eye developed a transient corneal abrasion that resolved within 1 week. Low-dose MTX (200 μg/0.05 mL) during and after PVR surgery resulted in good rates of retinal reattachment and visual acuity recovery. [Ophthalmic Surg Lasers Imaging Retina 2023;54(3):139-146.].

Mechanisms of Epithelial-Mesenchymal Transition and Prevention of Dispase-Induced PVR by Delivery of an Antioxidant αB Crystallin Peptide.

Proliferative Vitreoretinopathy (PVR) is a refractory retinal disease whose primary pathogenesis involves the epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells. At present, there is no effective treatment other than surgery for PVR. The purpose of this study was to investigate the effect of αB crystallin peptide (αBC-P) on EMT in PVR. We have previously shown that this peptide is antiapoptotic and regulates RPE redox status. Subconfluent primary human RPE (hRPE) cells were stimulated by TGFβ2 (10 ng/mL) with or without αBC-P (50 or 75 μg/mL) for 48 h and expression of EMT/mesenchymal to epithelial transition (MET) markers was determined. Mitochondrial ROS (mtROS) generation in hRPE cells treated with TGFβ2 was analyzed. The effect of TGFβ2 and αBC-P on oxidative phosphorylation (OXPHOS) and glycolysis in hRPE was studied. RPE cell migration was also assessed. A PVR-like phenotype was induced by intravitreal dispase injection in C57BL/6J mice. PVR progression and potential therapeutic efficiency of αBC-Elastin-like polypeptides (ELP) was studied using fundus photography, OCT imaging, ERG, and histologic analysis of the retina. αSMA, E-cadherin, Vimentin, Fibronectin and, RPE65, and CTGF were analyzed on Day 28. Additionally, the amount of VEGF-A in retinal cell lysates was measured. The EMT-associated αSMA, Vimentin, SNAIL and SLUG showed a significant upregulation with TGFβ2, and their expression was significantly suppressed by cotreatment with αBC-P. The MET-associated markers, E-cadherin and Sirt1, were significantly downregulated by TGFβ2 and were restored by αBC-P. Incubation of hRPE with TGFβ2 for 24 h showed a marked increase in mitochondrial ROS which was noticeably inhibited by αBC-ELP. We also showed that after TGFβ2 treatment, SMAD4 translocated to mitochondria which was blocked by αBC-ELP. Mitochondrial oxygen consumption rate increased with TGFβ2 treatment for 48 h, and αBC-P co-treatment caused a further increase in OCR. Glycolytic functions of RPE were significantly suppressed with αBC-P (75 μg/mL). In addition, αBC-P significantly inhibited the migration from TGFβ2 treatment in hRPE cells. The formation of proliferative membranes was suppressed in the αBC-ELP-treated group, as evidenced by fundus, OCT, and H&E staining in dispase-induced PVR in mice. Furthermore, ERG showed an improvement in c-wave amplitude. In addition, immunostaining showed significant suppression of αSMA and RPE65 expression. It was also observed that αBC-ELP significantly reduced the expression level of vimentin, fibronectin, and CTGF. Our findings suggest that the antioxidant αBC-P may have therapeutic potential in preventing PVR by reversing the phenotype of EMT/MET and improving the mitochondrial function in RPE cells.

Managing PVR in the Era of Small Gauge Surgery.

Proliferative vitreoretinopathy (PVR) is the leading cause of failed rhegmatogenous retinal detachment (RRD) surgery. Based upon the presence of clinical features and due to associated underlying risk factors, it is classified into various grades based upon its severity and extent of involvement. Despite excellent skills, flawless techniques, and high-end technology applied in the management of RRD, PVR still occurs in 5–10% of cases. Due to the advancements in wide angle viewing systems, advance vitrectomy machines and fluidics, early identification, use of long-term heavy silicon oil tamponades, high-speed cutters, small-gauge vitrectomies, use of perfluorocarbon liquid (PFCL), and small-gauge forceps and scissors, the success rate in the management of PVR has increased leading to improved anatomical outcomes. However, functional outcomes do not correlate well with improved anatomical outcomes. Various complications occur after RRD repair that are responsible for re-retinal detachment and recurrence of PVR. This article highlights causes, risk factors, classification, grading, diagnosis, and approach to management of PVR and post-PVR surgery complications.

Management of Cystoid Macular Edema After Vitrectomy for Proliferative Vitreoretinopathy

To assess therapies for cystoid macular edema (CME) following pars plana vitrectomy for proliferative vitreoretinopathy (PVR). Retrospective analysis of 42 eyes developing CME after PVR surgery. Treatments included topical therapy, sub-Tenon's triamcinolone acetonide (STTA), intravitreal bevacizumab and combinations thereof. Best-corrected visual acuity (BCVA) as well as central subfield thickness (CST) were tracked. Mean Snellen BCVA improved from 20/598 to 20/297 (logMAR change -0.21; confidence interval [CI], -0.39 to -0.03; P = .03). Mean CST improved from 448 µm to 260 µm (CI, -248.70 to -126.06; P < 0.01). There was no difference in efficacy between treatment subgroups (analysis of variance, P = 0.16, 0.43), but STTA yielded statistically significant improvement in both categories (CI, -0.79 to -0.11; P = 0.01; and CI, -333.74 to 166.51; P < .01). Treatment of CME following PVR surgery is possible with a variety of different options. STTA appears to yield anatomical and visual improvement. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:436-443.].

The Outcomes of Primary 23-gauge Vitrectomy in Retinal Detachment Patients with Grade C Proliferative Vitreoretinopathy Surgery

The Outcomes of Primary 23-gauge Vitrectomy in Retinal Detachment Patients with Grade C Proliferative Vitreoretinopathy Surgery

Ocular Hypotension: How the Retina Surgeon Sees the Causes and Therapeutic Options

Ocular hypotension is a result of a lack of production or a loss of intraocular fluid. Intraocular inflammation, drugs, or proliferative vitreoretinopathy (PVR) with overgrowth of the ciliary body can result in reduced secretion of intraocular fluid. Loss of intraocular fluid can result from external loss, such as in fistulating surgery or trauma, or internally, e.g. from cyclodialysis clefts or retinal detachment. In this review, we discuss the causal therapy of ocular hypotension: fixation of the ciliary body, removal of ciliary body membranes, surgery for PVR, choice of tamponade, possibilities and limitations of an iris diaphragm, and pharmacological options.

INCIDENCE OF LENS TOUCH DURING PARS PLANA VITRECTOMY AND OUTCOMES FROM SUBSEQUENT CATARACT SURGERY.

To determine the incidence of lens touch during pars plana vitrectomy (PPV) and evaluate cataract surgery complications after lens touch. One thousand three hundred and ninety nine phakic patients who underwent PPV during the period from 2001 to 2013 were included in the study. Data of the PPV and lens touch (excluding lens bite) complications were reviewed from an electronic database (VITREOR). Subsequent cataract surgery data and intraoperative complications were reviewed. A control group consisted of 149 cases of phakic patients who underwent PPV with no lens touch then subsequent cataract surgery. All surgeries were performed by senior surgeons, and no cataract was present before the PPV. The incidence of lens touch was 3.7% (52 of 1,399 phakic patients). The Demographics and presenting complaints of the patients were not significantly associated with lens touch, but retinal detachment with proliferative vitreoretinopathy, the use of silicone oil and use of relaxing retinectomy were associated with more lens touch. Cataract developed in 49 patients of whom 45 underwent cataract surgery. Nuclear sclerosis developed in 22 patients, 16 had posterior subcapsular, 8 had mixed lens opacities, and 3 had white cataract. The median duration between PPV and cataract surgery was 4 months in the lens touch group, which was significantly shorter than the median of 8 months in the control group (P = 0.001). During the subsequent cataract surgery in the lens touch group, 5 patients (11%) had a posterior capsule rupture, whereas the control group had only 2 cases of posterior capsule rupture 1.4% (P = 0.008). Final visual acuity was 0.3 LogMar or better in 22 patients (44%). Lens touch is a frequent complication of PPV in a phakic eye. It is more common in patients having surgery for proliferative vitreoretinopathy. Care should be taken when performing subsequent cataract surgery on an eye with lens touch as it carries a significantly increased chance of posterior capsule rupture.

Chirurgische Behandlung vitreoretinaler Erkrankungen in Oman

Vitreoretinal diseases in Middle Eastern countries currently rank in importance behind cataract, trachoma and glaucoma. This study reports on the most frequent causes of vitreoretinal diseases and the results of vitreoretinal surgery in Oman in order to gain insights into requirements in training and equipment. Demographic data and biomicroscopic examinations were performed over a 5-year period. Pars plana vitrectomies were carried out with the Accurus 800CS (Alcon) and EyeLite® 532 nm Laser (Alcon), endotamponade with silicone oil 5600 cs (adatomed) or C₃F₈ Ispan (Alcon), oval silicone sponge scleral buckles 5.5 x 7.5 mm type 507 (Geuder®) in adults and oval silicone sponge scleral buckles 3.0 × 5.0 mm type 506 (Geuder®) in children (up to 12 years) were sutured with Mersilene parallel to the limbus. Patients were followed after 4 weeks and 1 year. Evaluation of data was done by descriptive statistics (Fisher exact and χ²-tests). From 2002 to 2006, 2,910 vitreoretinal surgeries were performed on 784 adult and 101 pediatric eyes. Main indications were proliferative diabetic vitreoretinopathy (PDVR) (229/784 eyes=29%), followed by trauma (166/784=21%), and PVR retinal detachment (112/784=14.3%) in adults and in children the main indication was trauma (73/101 eyes=73%). The postoperative vision in adults with trauma, PVR retinal detachment, epiretinal gliosis and IOL extraction was significantly different and better (p=0.003, p=0.044, p=0.029, p=0.001, respectively) and the postoperative vision in PDVR with uncontrolled diabetes mellitus II significantly different and worse (p=0.001). Of the eyes with PDVR in uncontrolled diabetes mellitus 165 out of 229 (72%) lost distance vision (p=0.00014). All patients with serious macular edema and an HbA(1c) of ≥9.5% lost 5 m distance in vision. The mean HbA(1c) in all patients who experienced postoperative blindness was 13.5%. Postoperative vision was significantly better in children operated for trauma complications (p=0.046) whereby patients with contusion of the globe had a significantly better final result (p=0.0302) than patients with penetrating injuries. Revision surgery was indicated most frequently after surgery for proliferative vitreoretinopathy due to prior retinal detachment surgery. The most frequent causes of preventable retinal blindness in Oman are pediatric trauma and advanced diabetic vitreoretinopathy. Eyes operated for trauma had a better outcome than PDVR in patients with uncontrolled diabetes mellitus. The large number of eyes with PDVR in the final stages and sequelae of trauma legitimates preventive medical measures and an expansion of vitreoretinal services with supportive external training of specialists and allied health professions.

Triamcinolone Acetonide in Silicone-Filled Eyes as Adjunctive Treatment for Proliferative Vitreoretinopathy: A Randomized Clinical Trial

To evaluate the effect of adjunctive intraocular triamcinolone acetonide (TA) in silicone-filled eyes on outcomes of vitreoretinal surgery for proliferative vitreoretinopathy (PVR). Prospective, randomized, controlled clinical trial. Seventy-five eyes with rhegmatogenous retinal detachment and PVR grade C (posterior, anterior, or both) undergoing vitrectomy combined with silicone oil tamponade were included. Of these, 38 eyes were assigned randomly to the adjunctive treatment, whereas 37 eyes served as controls. All eyes underwent pars plana vitrectomy, membrane peeling, and silicone oil exchange, with or without relaxing retinotomy or retinectomy. In the treatment group, 4 mg TA was injected into the silicone-filled vitreous cavity at the end of the procedure. Silicone oil was removed 3 months after surgery in eyes with attached retinas. The primary outcome measure was retinal reattachment rate at 6 months. Secondary outcome measures included visual acuity, rate of recurrent PVR, reoperation rate, and rise of intraocular pressure. Retinal reattachment without any reoperation was achieved in 32 eyes (84.2%) and 29 eyes (78.4%) in the adjunctive treatment and control groups, respectively, at 6 months (P = 0.5). No statistically significant difference was observed between the 2 groups in terms of any of the secondary outcome measures (P>0.05). The outcomes of vitreoretinal surgery for established PVR are not improved significantly by adjunctive TA injection in silicone-filled eyes.

Blockade of Endothelinergic Receptors Prevents Development of Proliferative Vitreoretinopathy in Mice

Proliferative vitreoretinopathy (PVR) is characterized by severe glial remodeling. Glial activation and proliferation that occur in brain diseases are modulated by endothelin-1 (ET-1) and its receptor B (ETR-B). Because retinal astrocytes contain ET-1 and express ETR-B, we studied the changes of these molecules in an experimental mouse model of PVR and in human PVR. Both ET-1 and ETR-B immunoreactivities increased in mouse retina after induction of PVR with dispase. Epi- and subretinal outgrowths also displayed these immunoreactivities in both human and experimental PVR. Additionally, myofibroblasts and other membranous cell types showed both ET-1 and ETR-B immunoreactivities. In early stages of experimentally induced PVR, prepro-ET-1 and ETR-B mRNA levels increased in the retina. These mRNA levels also increased after retinal detachment (RD) produced by subretinal injection. Treatment of mice with tezosentan, an antagonist of endothelinergic receptors, reduced the histopathological hallmarks of dispase-induced PVR: retinal folding, epiretinal outgrowth, and gliosis. Our findings in human and in dispase-induced PVR support the involvement of endothelinergic pathways in retinal glial activation and the phenotypic transformations that underlie the growth of membranes in this pathology. Elucidating these pathways further will help to develop pharmacological treatments to prevent PVR. In addition, the presence of ET-1 and ETR-B in human fibrous membranes suggests that similar treatments could be helpful after PVR has been established.

Expression and localisation of BDNF, NT4 and TrkB in proliferative vitreoretinopathy

Exogenous brain derived neurotrophic factor (BDNF) is known to rescue ganglion cell death after optic nerve injury. Its mechanism of action is believed to be indirect via glial cells in the retina. In this study we investigated the changes in expression and localisation of BDNF, neurotrophin-4 (NT4) and their common receptor (TrkB) in retinectomy sections of patients with proliferative vitreoretinopathy (PVR). Nine full-thickness retinectomy specimens obtained at retinal reattachment surgery for PVR were fixed in 4% paraformaldehyde immediately after excision and compared to similarly processed normal donor retinas (4 eyes). Agarose-embedded sections (100μm thick) were double labelled for immunohistochemistry by confocal microscopy, with antibodies against BDNF, NT4, TrkB, rod opsin, glial fibrillary acidic protein (GFAP), cellular retinaldehyde binding protein (CRALBP) and Brn3. This study demonstrates expression of NT4 by ganglion cells and shows expression of BDNF and NT4 in the outer photoreceptor segments is downregulated during PVR, whilst NT4 is markedly upregulated throughout the retina during this condition. The findings here suggest that NT4 may play a neural protective role during the development of PVR. It also shows that upregulation of NT4 in PVR is localised to Müller glial cells, indicating either over-expression of this factor by Müller cells or that Müller cells internalise NT4 for trafficking across the retina. TrkB expression was not observed in PVR retina. The observations that Müller glia demonstrate upregulation of NT4 suggests that retinal injury may lead to activation of this neurotrophin by Müller cells as part of their neuroprotective functions.

Optical Coherence Tomography in Patients With Decreased Visual Acuity After Successful Surgery for Proliferative Vitreoretinopathy—Reply

Optical Coherence Tomography in Patients With Decreased Visual Acuity After Successful Surgery for Proliferative Vitreoretinopathy—Reply

Optical Coherence Tomography in Patients With Decreased Visual Acuity After Successful Surgery for Proliferative Vitreoretinopathy

Optical Coherence Tomography in Patients With Decreased Visual Acuity After Successful Surgery for Proliferative Vitreoretinopathy

Intraretinal and periretinal pathology in anterior proliferative vitreoretinopathy

To determine the intraretinal and periretinal pathological changes in early anterior proliferative vitreoretinopathy (APVR). Observational case series. Eighteen patients undergoing retinectomy for APVR. Retinectomy specimens removed at vitrectomy surgery were analysed by (a) semithin light microscopy, (b) immunohistochemistry and (c) electron microscopy. The specimens showed consistent outer retinal degenerative changes, marked Muller cell hypertrophy and glial continuity to epiretinal membranes. Photoreceptor outer and inner segments were markedly disrupted and occasional photoreceptor nuclear had pyknosis and chromatin clumping consistent with apoptosis. Muller cells expressed upregulated levels of glial fibrillary acid protein (GFAP) and extended through glial bridges to complex epiretinal membranes which in some areas had a bilaminar structure with a glial-negative inner lamina. Retinal degeneration and photoreceptor apoptosis occur in retinal detachment complicated by proliferative vitreoretinopathy (PVR), although during the early stages of the process neural retinal cells remain present, suggesting potential for recovery. The intraretinal glial response appears to be centrally involved in the formation of contractile epiretinal membranes. The retina retains the capacity for a degree of functional recovery following surgery for PVR. Surgical separation of anterior epiretinal membranes in PVR may be difficult and incomplete and alternative surgical strategies may be necessary to prevent recurrence.

Influence of Relaxing Retinotomy on Surgical Outcomes in Proliferative Vitreoretinopathy

This study sought to determine the influence of relaxing retinotomy (RR) incisions upon surgical outcomes in the repair of recurrent retinal detachment (RD) attributable to proliferative vitreoretinopathy (PVR). Retrospective, consecutive, nonrandomized, single-center series. Eighty-one eyes with recurrent RD attributable to PVR were retrospectively reviewed. Exclusion criteria were giant retinal tear, uveitis, trauma, proliferative diabetic retinopathy, and age under 18 years. A total of 52 eyes underwent RR at the time of surgery (64.2%); 29 eyes were repaired without this technique. Perfluorocarbon gas (n = 34) or silicone oil (n = 47) was used as postoperative tamponade. Statistical analyses were performed using the Fisher exact test. Eyes that received RR had significantly higher rates of anterior PVR (P = .009). Eyes receiving silicone oil for postoperative tamponade had worse baseline characteristics compared with those receiving gas. The use of RR in eyes receiving gas tamponade had no marked influence on the initial anatomic outcomes, with recurrent retinal detachment occurring in five of 14 eyes that received an RR and seven of 20 eyes that did not receive an RR (P = .62). Eyes in which silicone oil was used as a postoperative tamponade had a significantly lower rate of recurrent RD requiring additional surgery when RR was employed (one of 38 eyes) when compared with eyes that did not receive an RR (three of nine eyes, P = .02). Ultimately, surgical reattachment was attained in all eyes except one. Eyes that received gas tamponade without RR had significantly better median vision (P = .008). Surgical management of PVR often results in ultimate retinal reattachment. An RR incision does not appear to influence initial anatomic repair when gas tamponade is used after vitrectomy surgery for PVR. However, RR may increase the initial surgical success rate in eyes receiving silicone oil tamponade for PVR. In eyes undergoing RR for the treatment of severe PVR, the use of silicone oil may increase the initial rate of reattachment compared with the use of gas tamponade.

Glial Remodeling and Neural Plasticity in Human Retinal Detachment with Proliferative Vitreoretinopathy

To investigate glial remodeling and neuronal plasticity in adult human retinal detachment complicated by proliferative vitreoretinopathy (PVR) and to grade pathologic changes with a severity scoring system. Sixteen full-thickness retinectomy specimens obtained at retinal relaxing surgery for PVR were fixed in 4% paraformaldehyde immediately after excision and compared to similarly processed normal donor retinas. Agarose-embedded sections (100-microm-thick) were double labeled for immunohistochemistry by confocal microscopy, with antibodies against rod opsin and GFAP; vimentin and M/L-cone opsin; calbindin D and S-cone opsin; and cytochrome oxidase and synaptophysin. These staining patterns formed the basis of a retinal pathology scoring system, and immunohistochemistry was also used to detect CD68, neurofilaments, protein kinase C, growth-associated protein-43, and a pan-cone-specific enzymatic marker. Morphology was also assessed by light microscopy of resin-embedded semithin sections. Prolonged detachment was characterized by photoreceptor degeneration and intracellular redistribution of opsin proteins to the plasma membrane in the outer nuclear layer (ONL). Remodeling of rod synaptic terminals was characterized by terminal retraction and also by axon extension to the inner retina in most specimens. Rod bipolar cell dendrites extended into the ONL, as did fine, horizontal cell processes. Large ganglion cells showed upregulated neurofilament and GAP-43 expression, with neurites sprouting from somata and axon collaterals. Anti-cytochrome oxidase labeling of surviving inner segments was reduced but detectable in all specimens, as was anti-calbindin D labeling of horizontal and amacrine cells. All specimens demonstrated a marked upregulation of Muller cell and astrocyte expression of GFAP and vimentin. More severe degenerative changes correlated with trauma and prolonged detachment duration when scored according to this system. The neural and glial components of detached neurosensory retina complicated by PVR exhibit pathology that changes characteristically with increasing detachment severity. Even in advanced degeneration, most of the structural motifs necessary for functional recovery are retained. Evidence of remodeling in the first-, second-, and third-order neurons of detached adult human retina may represent an attempt to re-establish synaptic connectivity.

A randomized controlled trial of combined 5-fluorouracil and low-molecular-weight heparin in management of established proliferative vitreoretinopathy

To determine the efficacy of a combination of 5-fluorouracil and low-molecular-weight heparin (LMWH) to improve the outcome of surgery for established proliferative vitreoretinopathy (PVR). Double-masked, prospective, randomized, placebo-controlled clinical trial. Three tertiary-referral teaching hospital vitreoretinal surgical units. One hundred fifty-seven patients with established PVR (grade C, anterior or posterior) undergoing vitrectomy surgery. All patients underwent vitreoretinal surgery and silicone oil exchange with or without membrane peeling and/or retinectomy. Patients were randomly allocated to perioperative infusion with or without 5-fluorouracil (200 microg/ml) and LMWH (5 IU/ml) in Hartmann's solution for 1 hour. The primary outcome measure was defined as posterior retinal reattachment after removal of silicone oil without any reoperations at 6 months. Secondary outcome measures recorded were posterior retinal reattachment, localized/tractional retinal detachment, visual acuity, macular pucker, hypotony, glaucoma, keratopathy, and cataract. Removal of silicone oil and reoperations were also recorded. Overall, at 6 months 84% of patients had full retinal reattachment and 94% had stable posterior retinal reattachment. There was no significant difference in success in the primary outcome measure (56%, treatment group; 51%, placebo group; P = 0.59) or in secondary outcome measures or rates of complications. Secondary macular pucker occurred less often in the treatment group (6% vs. 17% at 6 months, P = 0.068). A perioperative infusion of combined 5-fluorouracil and LMWH does not significantly increase the success rate of vitreoretinal surgery for established PVR.

Y1 receptor of neuropeptide Y as a glial marker in proliferative vitreoretinopathy and diseased human retina.

The Y1 receptor of neuropeptide Y (NPY) has been demonstrated in glial cells of astrocytic lineage in vitro. We have studied the immunohistochemical expression of Y1 receptors in the glia of the diseased human retina, in tissue samples obtained after surgery for proliferative vitreoretinopathy. In this condition, glia and other cell types migrate and form epi- or subretinal membranes. Both diseased retinas (n = 8) and PVR membranes (n = 43) contained numerous Y1-immunoreactive cells. In the diseased retina, the Y1 antiserum labeled cells with the morphological radial pattern characteristic of Müller cells, whereas in the membranes, label appeared in a large population of elongate cells, measuring up to 250 microm. In both retina and membranes, double labeling demonstrated that the vast majority of Y1-immunoreactive cells were also labeled by a glial fibrillary acidic protein (GFAP) antibody, indicating their glial origin. Retinal regions devoid of GFAP immunoreactivity also lacked the Y1 label. None of these markers was detected in Müller cells of normal retina. Y1 immunoreactivity did not co-localize with smooth muscle actin immunoreactivity, a marker of myofibroblasts. Expression of Y1 receptors would characterize reactive and proliferating glial cells of the diseased retina and could perhaps be involved in the proliferation of injured glial cells causing regrowth of PVR membranes and the consequent secondary retinal detachments.

Proliferative vitreoretinopathy—developments in adjunctive treatment and retinal pathology

Proliferative vitreoretinopathy (PVR) remains a difficult management problem despite advances in vitreoretinal surgery. There is still a significant incidence of PVR in rhegmatogenous retinal detachment and other forms of retinal disease. Surgery for PVR now has a high anatomical success rate although visual results are often disappointing. The use of adjunctive treatments to prevent cellular proliferation holds promise for the prevention of PVR or recurrences after surgery. Control of proliferation and strategies aimed at improving visual outcome are important areas of future research in PVR and other forms of retinal disease. Studies of the intraretinal and peri-retinal pathology of PVR have demonstrated characteristic changes which may have a significant influence on visual outcome and surgical management.