Hirudo (Leech) for proliferative vitreous retinopathy: A protocol for systemic review and meta-analysis.

INTRODUCTION: Proliferative vitreous retinopathy (PVR) is characterized by proliferation of cells and contraction of membranes on either the retinal surface or in the vitreous cavity, which leads to retinal detachment and visual impairment. PVR is commonly seen in patients with rhegmatogenous retinal detachment and diabetic retinopathy, which seriously affects the patient's work and life. Previous studies indicated that Hirudo (Leech) or compound prescription containing Hirudo (Leech) for treatment of PVR would be effective. However, due to the lack of evidence, there are no specific methods or suggestions, so it is necessary to carry out systematic evaluations on Hirudo (Leech) for PVR and provide effective evidence for further research. METHODS AND ANALYSIS: The following 8 databases will be searched: Cochrane Central Register of Controlled Trials, PubMed, MEDLINE, EMBASE, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, VIP Database, and Wanfang Database. All randomized controlled trials in English or Chinese related to Hirudo (Leech) for PVR will be included. Outcomes will include change in Vitreous opacity, Vision changes, production of the anterior macular membrane, and retinal detachment again. The incidence of adverse events will be assessed for safety evaluation. Study inclusion, data extraction and quality assessment will be performed independently by 2 reviewers. Assessment of risk of bias and data synthesis will be performed using Review Manager V.5.3. RESULTS: In this systematic review and meta-analysis, we will synthesize the studies to assess the safety and efficacy of Hirudo (Leech) for PVR. CONCLUSION: The summary of our study will clarify whether Hirudo (Leech) therapy could be an efficient and safe method for PVR, which can further guide the promotion and application of it. OPEN SCIENCE FRAMEWORK OSF REGISTRATION NUMBER: 10.17605/OSF.IO/FP7VG (https://osf.io/fp7vg).

Intraocular Dexamethasone Implant as Adjunct to Silicone Oil Tamponade for Proliferative Vitreoretinopathy.

Background Proliferative vitreoretinopathy (PVR) occurs in 10 % of patients with retinal detachment and is characterized by excessive epi-, sub- or intraretinal contraction. Corticosteroids have been shown to counter this contraction. Patients and Methods Retrospective review of 5 patients (3 females, 2 males) with recurrent retinal detachment with stage C PVR. The mean age was 61.2 ± 20.5 years and myopia > - 5.0 dioptres was present in 3 eyes. Patients were treated with 23 g vitrectomy, retinectomy and endolaser, dexamethasone (Ozurdex®) injection under perfluorocarbone and 5500 cs silicone oil tamponade. Results After a total follow-up of 8.8 ± 6.4 months with silicone oil tamponade, the Ozurdex® implant was localised in the macula in 1 case, and in 4 cases behind the iris with a completely attached retina. Preoperative intraocular pressure was 11.0 ± 4.0 mmHg, which remained stable at 7.8 ± 3.5 mmHg at the end of the final follow-up. No localised adverse effects were observed of the implant on the retina or the iris. Conclusions The dexamethasone implant Ozurdex® is well tolerated in conjunction with silicone oil tamponade in eyes with retinal detachment and PVR. The implant may be a potential candidate for the prevention of PVR.

[Vitreous substitutes as drug release systems]. / Glaskörperersatz als Möglichkeit zur protrahierten Freisetzung von Medikamenten im Glaskörper.

Despite major improvements of vitreo-retinal surgical techniques proliferative vitreoretinopathy (PVR) remains a major challenge. Surgical therapy alone may not be sufficient in complicated cases of PVR. A combination of standard techniques such as pars plana vitrectomy with a vitreous substitute and a simultaneous adjuvant pharmacological treatment for the suppression of undesired proliferation of retinal cells and retinal scarring may be a promising therapeutic approach. However, due to the narrow therapeutic range and the short biological half-life of most anti-proliferative or anti-inflammatory drugs in the vitreous cavity, intravitreal slow-release systems for extended drug delivery are desirable. Vitrectomy for PVR normally requires a vitreous substitute. Consequently, a vitreous substitute that could also serve as a slow-release system for anti-proliferative or anti-inflammatory drugs would provide several advantages. This review gives an overview of recent developments of slow-release systems that may also be suitable as vitreous substitutes. Even standard internal tamponades such as silicone oils or gases may serve as extended drug-release systems under certain conditions. In the mean time polymerised hydrogels have been developed, which apart from providing an adequate tamponade effect, may facilitate an extended intravitreal release of various anti-proliferative and anti-inflammatory drugs for several weeks.

[Advantages and disadvantages of the circumferential retinal cryocoagulation before vitrectomy in proliferative diabetic vitreoretinopathy]. / Adjuvante zirkuläre Netzhautkryokoagulation bei proliferativer diabetischer Vitreoretinopathie--vor oder während der Vitrektomie?

BACKGROUND: It is unclear if a circumferential cryocoagulation 4 weeks before pars plana vitrectomy is useful for reducing the risks of surgery such as retinal detachment, secondary glaucomas or rebleeding. Otherwise it seems possible that this surgery itself, done in local anaesthesia, could be an additional risk. PATIENTS AND METHODS: We retrospectively evaluated the reports of all patients who underwent vitrectomy as primary surgery due to proliferative diabetic vitreoretinopathy between 1997 and 2000. Besides age and sex, all additional surgery (like phacoemulsification, endolaser coagulation, kind of tamponade etc.) and all intra- or postoperative complications were reported after a follow-up of at least 3 months. We created and compared 2 groups of patients, showing in group 1 patients who underwent vitrectomy 4 weeks after cryocoagulation and in group 2 patients undergoing vitrectomy combined with circumferential cryocoagulation. RESULTS: We evaluated the reports of 226 patients (103 men, 123 women, mean age 58.6 +/- 13.0 years). Follow-up was in the mean 16.3 months. Group 1 contained 150 patients (66.4 %), group 2 76 patients (33.6 %). 63.7 % received air as endotamponade, 8.0 % C(2)F(6) gas, 7.1 % silicon oil and 21.2 % BSS, 34.1 % were operated in combination with phakoemulsification. We observed 9 postoperative retinal detachments (4.0 %), with no significant difference between the two groups (6 detachments in group 1, 2 detachments in group 2). For other surgical risks like rebleeding, rubeosis iridis, secondary glaucoma etc. we also found no statistically significant differences. CONCLUSION: Circumferential retinal cryocoagulation is a useful preparation before pars plana vitrectomy, when done due to vitreous haemorrhage, because improved resorption lowers the vitrectomy rate. In all other cases it can be done during vitrectomy. Adjuvant circumferential cryocoagulation seems to decrease the risk of postoperative retinal detachments and rebleedings as documented in literature comparison.