Rhegmatogenous Retinal Detachment with a High Risk of Proliferative Vitreoretinopathy Treated with Episcleral Surgery and an Intravitreal Dexamethasone 0.7-mg Implant

Emergency Vitrectomies for Retinal Detachment Before and During the Coronavirus Pandemic - A Retrospective Single Centre Analysis

Background While the corona pandemic and the resulting containment measures affect the number of elective surgical procedures, the impact on emergency surgical interventions is less tangible. This analysis quantifies the frequency of emergency vitrectomies for retinal detachment and investigates underlying factors.

Methods Retrospective identification of patients who underwent primary emergency vitrectomies for retinal detachment at the Cantonal Hospital of Lucerne between 01.01.2018 – 31.12.2020. Parameters were collected, including demographics, date of hospitalisation, reported onset of symptoms, pre-operative best corrected visual acuity (BCVA), involvement of the macula, and canton of residence.

Results Overall, a total of 665 patients with 683 eyes underwent emergency surgery for primary retinal detachment in the time span of 01.01.2018 – 31.12.2020. Median monthly number of surgeries was 20. During the first Swiss national lockdown (16.03.2020 – 19.04.2020), a minimum of 9 vitrectomies was recorded in March 2020. A maximum of 36 vitrectomies was conducted in August 2020. The mean age of patients was 61.5 years. Of the 665 patients, 133 (20.0%) were residents of the canton of Ticino. Median pre-operative BCVA was 0.25 over all three years, and no significant reduction in pre-operative BCVA was observed during or after the lockdown. The proportion of eyes with involvement of the macula was 52.2%. In 2018, this proportion (47.6%) was significantly lower than in 2019 and 2020 (Chi ² test, p < 0.001). However, cases with macular involvement in post lockdown months were not more frequent. Median time in days from reported symptom onset to hospitalisation was 5 days. In April 2020, the proportion of patients with > 14 days symptom duration was significantly higher (Chi ² test, p < 0.001). During the lockdown, there was a significant reduction in cases from Ticino. Also, patients from Ticino showed proportionally longer symptom duration after the lockdown.

Conclusion A significant reduction in the number of emergency vitrectomies was observed for the initial period of the coronavirus pandemic. Delayed emergency presentation is not assumed, since there was no increase in severity (i.e. macular involvement) or prolonged symptoms in the months following the lockdown. More protracted symptoms were only observed in patients from Ticino. The initial low numbers were generally made good later in the year.

The impact of the COVID-19 Pandemic on rhegmatogenous retinal detachment treatment patterns

Backgrounds

To describe changes in rhegmatogenous retinal detachment (RRD) surgical procedures in Beijing during the COVID-19 Pandemic.

Methods

A retrospective cohort of RRD patients was analyzed. Patients were divided into the COVID-19 pandemic group and pre-COVID-19 group according to their presentation. The presurgery characteristics, surgical procedures, and surgery outcomes were collected. The potential factors related to the choice of pars plana vitrectomy (PPV) or scleral buckling (SB) were analyzed using logistic regression. The differences in the procedure choice under specific conditions were compared. Surgery outcomes were compared between the two groups.

Results

In the COVID-19 pandemic group, less patients received SB (27.8, 41.3%, p = 0.02) while more patients received PPV (72.2, 58.6%, p = 0.02); in patients who received SB, fewer patients received subretinal fluid drainage (45.4,75.7%, p = 0.01); in patients who received PPV, fewer patients received phacovitrectomy (7.0, 21.0%, p = 0.02). The choice of PPV was related to older age (1.03, p = 0.005), the presence of RRD with choroidal detachment (RRD-CD) (2.92, p = 0.03), pseudophakia (5.0, p = 0.002), retinal breaks located posterior to the equator (4.87, p < 0.001), macular holes (9.76, p = 0.005), and a presurgery visual acuity (VA) less than 0.02 (0.44, p = 0.03). Fewer phakia patients with retinal breaks located posterior to the equator (1/28, 11/30, p = 0.01) and fewer patients with chronic RRD and subretinal strand (1/9, 9/16, p = 0.03) received SB in the COVID-19 pandemic group. There were more patients with improved VA (55.7, 40.2%, p = 0.03) in the COVID-19 pandemic group. The overall single-surgery retinal attachment rate was similar in the two groups (94.9, 94.5%, p = 0.99).

Conclusions

During the COVID-19 Pandemic, the main reason for the increased number of PPV in RRD treatment was that more complicated cases were presented. However, the surgeons were conservative in procedure choice in specific cases. The adjustments on RRD treatments lead to comparable surgery outcomes.

Characteristics of retinal detachment associated with atopic dermatitis

BACKGROUND

To examine the characteristics of rhegmatous retinal detachment (RRD) associated with atopic dermatitis.

METHOD

Medical records of 2257 patients who underwent RD surgery at this clinic between 2008 and 2018 were retrospectively reviewed. Among them, 61 patients who were diagnosed as AD were assigned into the experimental group and 100 patients who did not have AD were randomly selected and assigned into the control group. Demographics, characteristics of detachment, initial operative method, and prognosis after surgery were investigated as main outcomes. Additionally, in pseudophakic RD patients, the period between the cataract surgery and onset of RD was measured.

RESULT

Postoperative VA and prognosis were significantly worse and bilateral involvement of RD was more common in the atopy group than in the control group. (P value = 0.005, 0.001 each) Characteristics of retinal breaks were different between the two groups. Additionally, the risk of developing RD within 1 year after cataract surgery was significantly higher in pseudophakic patients of the atopic group than in the control group. (P value = 0.013) However, there was no significant difference in mean preoperative VA or refractive index between the two groups.

CONCLUSION

Our results show that in atopic patients, RD occurs at a young age with different characteristics compared to non-atopic patients. Atopic RD has a poor visual prognosis. Thus, it requires careful management. Furthermore, the risk of developing RD within 1 year after cataract surgery is higher in atopic patients. Therefore, it is important to perform regular and extensive check-up after cataract surgery for atopic patients.

New Therapeutic Perspectives in the Treatment of Uveal Melanoma: A Systematic Review

Uveal melanoma (UM) is a rare disease, but the most common primary intraocular cancer, mostly localized in the choroid. Currently, the first-line treatment options for UM are radiation therapy, resection, and enucleation. However, although these treatments could potentially be curative, half of all patients will develop metastatic disease, whose prognosis is still poor. Indeed, effective therapeutic options for patients with advanced or metastatic disease are still lacking. Recently, the development of new treatment modalities with a lower incidence of adverse events, a better disease control rate, and new therapeutic approaches, have merged as new potential and promising therapeutic strategies. Additionally, several clinical trials are ongoing to find new therapeutic options, mainly for those with metastatic disease. Many interventions are still in the preliminary phases of clinical development, being investigated in phase I trial or phase I/II. The success of these trials could be crucial for changing the prognosis of patients with advanced/metastatic UM. In this systematic review, we analyzed all emerging and available literature on the new perspectives in the treatment of UM and patient outcomes; furthermore, their current limitations and more common adverse events are summarized.

Challenges in Management of Rhegmatogenous Retinal Detachment in a Patient With Wilson's Disease: A Case Report and Literature Review

Wilson’s disease (WD) is a rare hepatolenticular inherited disorder affecting copper transport resulting in accumulation of copper, which leads to the induction of apoptosis in different organs. Furthermore, patients with WD have elevated cytokines activity responsible for inflammation of various tissues.

Here, we report our challenges in managing a case of rhegmatogenous retinal detachment (RRD) in a one-eyed 28-year-old male with WD who had a previous history of severe intraocular inflammation that ended with phthisis bulbi after pars plana vitrectomy for RRD. After one year, he developed RRD in the seeing eye.

A decision was made to perform scleral buckling to avoid the risk of postoperative intraocular inflammation. However, a barrage laser was required for shallow retinal detachment in a subsequent follow-up, which was ultimately complicated by severe intraocular inflammation.

We observed that our patient with WD had a tendency for severe intraocular inflammation, even following minor non-surgical ophthalmic procedures. For this reason, ophthalmologists need to be aware of managing similar cases and perhaps other diseases associated with elevated levels of cytokines.

Topical delivery of a small molecule RUNX1 transcription factor inhibitor for the treatment of proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) is the leading cause of retinal detachment surgery failure. Despite significant advances in vitreoretinal surgery, it still remains without an effective prophylactic or therapeutic medical treatment. After ocular injury or retinal detachment, misplaced retinal cells undergo epithelial to mesenchymal transition (EMT) to form contractile membranes within the eye. We identified Runt-related transcription factor 1 (RUNX1) as a gene highly expressed in surgically-removed human PVR specimens. RUNX1 upregulation was a hallmark of EMT in primary cultures derived from human PVR membranes (C-PVR). The inhibition of RUNX1 reduced proliferation of human C-PVR cells in vitro, and curbed growth of freshly isolated human PVR membranes in an explant assay. We formulated Ro5-3335, a lipophilic small molecule RUNX1 inhibitor, into a nanoemulsion that when administered topically curbed the progression of disease in a novel rabbit model of mild PVR developed using C-PVR cells. Mass spectrometry analysis detected 2.67 ng/mL of Ro5-3335 within the vitreous cavity after treatment. This work shows a critical role for RUNX1 in PVR and supports the feasibility of targeting RUNX1 within the eye for the treatment of an EMT-mediated condition using a topical ophthalmic agent.

Management of Cystoid Macular Edema After Vitrectomy for Proliferative Vitreoretinopathy

BACKGROUND AND OBJECTIVE

To assess therapies for cystoid macular edema (CME) following pars plana vitrectomy for proliferative vitreoretinopathy (PVR).

PATIENTS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.].

Preoperative, Intraoperative and Postoperative Corticosteroid Use as an Adjunctive Treatment for Rhegmatogenous Retinal Detachment

The treatment for rhegmatogenous retinal detachment (RRD) is surgery, including pars plana vitrectomy (PPV) and scleral buckling (SB). Despite surgical advances, degeneration of the photoreceptors and post-operative complications, such as proliferative vitreoretinopathy (PVR), often occurs as the result of inflammation, preventing complete visual recovery or causing RRD recurrence. There is increasing evidence that in the presence of RRD, the activation of inflammatory processes occurs and the surgery itself induces an inflammatory response. This comprehensive review focuses on the use of different formulations of corticosteroids (CCS), as an adjunctive treatment to surgery, either PPV or SB, for RRD repair. The purpose was to review the efficacy and safety of CCS in improving functional and anatomical outcomes and in preventing postoperative complications. This review is organized according to the timing of CCS administration: preoperative, intraoperative, and postoperative. The evidence reviewed supported the role of the pre-operative use of CCS in the treatment of combined RRD and choroidal detachment (CD), reducing CD height. No solid consensus exists on intraoperative and postoperative use of CCS to treat and prevent postoperative complications. However, a large randomized clinical trial including more than 200 eyes suggested that oral prednisone after surgery decreases the rate of postoperative grade B PVR.

Safety of 6000 intravitreal dexamethasone implants

PURPOSE

To evaluate the real-life safety profile of intravitreal dexamethasone implant injection for various retinal conditions.

METHODS

Retrospective multicenter analysis of intravitreal dexamethasone implant injections (700 µg) due to various retinal conditions including central retinal venous occlusion (1861 injections), diabetic macular oedema (3104 injections), post-surgical cystoid macular oedema (305 injections) and uveitis (381 injections). The eyes were evaluated mainly for the occurrence of adverse events such as glaucoma, cataract, retinal detachment and endophthalmitis along during the follow-up period.

RESULTS

A total of 6015 injections in 2736 eyes of 1441 patients (mean age of 65.7±12.9 years) were in total analysed over an average period of 18 months (range 6 months to 102 months). A total of 576 eyes (32.5% of the phakic eyes) developed cataract requiring surgical intervention. However, visually insignificant cataract progression was observed in another 259 phakic eyes (14.6%) which did not require surgical removal. A total of 727 eyes (26.5%) experienced an intraocular pressure (IOP) rise of >25 mm Hg, with 155 eyes (5.67%) having a prior history of glaucoma and 572 eyes (20.9%) having new onset IOP rise. Overall, more than 90% of eyes with IOP rise were managed medically, and 0.5% eyes required filtering surgery. Endophthalmitis (0.07%), retinal detachment (0.03%) and vitreous haemorrhage (0.03%) were rare. There was no significant change in visual acuity (p=0.87) and central macular thickness (p=0.12) at the last follow-up.

CONCLUSION

This is the largest real-life study assessing the safety of intravitreal dexamethasone implant injections in various retinal conditions. Cataract progression and intraocular pressure rise are the most common side effects, but are often rather easily manageable.

Utility of Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium for an In Vitro Model of Proliferative Vitreoretinopathy

The advent of stem cell technology, including the technology to induce pluripotency in somatic cells, and direct differentiation of stem cells into specific somatic cell types, has created an exciting new field of scientific research. Much of the work with pluripotent stem (PS) cells has been focused on the exploration and exploitation of their potential as cells/tissue replacement therapies for personalized medicine. However, PS and stem cell-derived somatic cells are also proving to be valuable tools to study disease pathology and tissue-specific responses to injury. High-throughput drug screening assays using tissue-specific injury models have the potential to identify specific and effective treatments that will promote wound healing. Retinal pigment epithelium (RPE) derived from induced pluripotent stem cells (iPS-RPE) are well characterized cells that exhibit the phenotype and functions of in vivo RPE. In addition to their role as a source of cells to replace damaged or diseased RPE, iPS-RPE provide a robust platform for in vitro drug screening to identify novel therapeutics to promote healing and repair of ocular tissues after injury. Proliferative vitreoretinopathy (PVR) is an abnormal wound healing process that occurs after retinal tears or detachments. In this chapter, the role of iPS-RPE in the development of an in vitro model of PVR is described. Comprehensive analyses of the iPS-RPE response to injury suggests that these cells provide a physiologically relevant tool to investigate the cellular mechanisms of the three phases of PVR pathology: migration, proliferation, and contraction. This in vitro model will provide valuable information regarding cellular wound healing responses specific to RPE and enable the identification of effective therapeutics.

Crocetin inhibits PDGF-BB-induced proliferation and migration of retinal pigment epithelial cells

In proliferative vitreoretinopathy (PVR), the proliferation and migration of retinal pigment epithelial (RPE) cells are important to pathogenesis. Platelet-derived growth factor (PDGF) is an important factor in the underlying mechanism. Several studies have shown that PDGF induced the proliferation and migration effects on RPE cells in PVR. Crocetin-anantioxidant carotenoid that is abundant in saffron-has been shown to suppress the migration and proliferation of many cell types, but studies of the effects on RPE cell migration and proliferation are incomplete. Therefore, we investigated the inhibitory effect of crocetin on the proliferation and migration of ARPE-19 cells induced by PDGF-BB, an isoform of PDGF. The proliferation of cells was assessed by Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays. The apoptosis of cells was assessed by flow cytometric analysis. The migration of RPE cells was detected by a Transwell migration assay and an in vitro scratch assay. The levels of main regulatory proteins for apoptosis and the PDGF-BB-induced signaling pathway were determined by western blot analysis. The proliferation and migration of ARPE-19 cells treated with crocetin (100-400 μM) and PDGF-BB (20 ng/ml) were significantly inhibited in a concentration- and time-dependent manner. Crocetin exhibited potent inducing effects on the apoptosis of PDGF-BB-induced ARPE-19 cells via the modulation of Bcl-2 family regulators in a concentration-dependent manner. The inhibitory effects of crocetin on PDGF-BB-induced platelet-derived growth factor receptor β (PDGFRβ) and the underlying pathways of PI3K/Akt and ERK, p38, JNK activation were identified. The results showed that crocetin is an effective inhibitor of PDGF-BB-induced proliferation and migration of ARPE-19 cell through the downregulation of regulatory signaling pathways.

EFFICACY OF INTRAVITREAL INJECTION OF BEVACIZUMAB IN VITRECTOMY FOR PATIENTS WITH PROLIFERATIVE VITREORETINOPATHY RETINAL DETACHMENT: A Meta-analysis of Prospective Studies

PURPOSE

To evaluate the effect of intravitreal injection of bevacizumab in vitrectomy for patients with proliferative vitreoretinopathy (PVR)-related retinal detachment.

METHODS

The PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched from their earliest entries through October, 2016, to identify the studies that had evaluated the effects of intravitreal injection of bevacizumab in vitrectomy for eyes with PVR-related retinal detachment. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. The relevant data were analyzed using Stata 12.0 software. The weighted mean difference, relative risk, and their 95% confidence intervals were used to assess the strength of the association.

RESULTS

The authors' search yielded 133 records from which 3 studies that have examined the effects of intravitreal injection of bevacizumab (120 eyes with PVR-related retinal detachment) were included for review and analysis. Their meta-analyses showed that neither the best-corrected visual acuity nor retinal redetachment rate showed any clinically or statistically important difference between the nonbevacizumab and bevacizumab groups (P > 0.05). In addition, bevacizumab did not influence the interval between vitrectomy and retinal redetachment (P > 0.05).

CONCLUSION

Based on the available evidence, intravitreal injection of bevacizumab in vitrectomy for patients with PVR-related retinal detachment did not decrease retinal redetachment rate or improve visual acuity. Better-designed studies with larger simple sizes and longer follow-up periods are required to reach valid conclusions regarding benefits and harms. Moreover, evaluation of anti-vascular endothelial growth factor therapy on surgical outcomes in eyes with milder subtypes of PVR or no PVR, but deemed at high risk of PVR, may be worthy of future consideration.

Effect of Methotrexate on an In Vitro Patient-Derived Model of Proliferative Vitreoretinopathy

Purpose

The purpose of this study was to develop a method for isolating, culturing, and characterizing cells from patient-derived membranes in proliferative vitreoretinopathy (PVR) to be used for drug testing.

Methods

PVR membranes were obtained from six patients with grade C PVR. Membrane fragments were analyzed by gross evaluation, fixed for immunohistologic studies to establish cell identity, or digested with collagenase II to obtain single cell suspensions for culture. PVR-derived primary cultures were used to examine the effects of methotrexate (MTX) on proliferation, migration, and cell death.

Results

Gross analysis of PVR membranes showed presence of pigmented cells, indicative of retinal pigment epithelial cells. Immunohistochemistry identified cells expressing α-smooth muscle actin, glial fibrillary acidic protein, Bestrophin-1, and F4/80, suggesting the presence of multiple cell types in PVR. Robust PVR primary cultures (C-PVR) were successfully obtained from human membranes, and these cells retained the expression of cell identity markers in culture. C-PVR cultures formed membranes and band-like structures in culture reminiscent of the human condition. MTX significantly reduced the proliferation and band formation of C-PVR, whereas it had no significant effect on cell migration. MTX also induced regulated cell death within C-PVR as assessed by increased expression of caspase-3/7.

Conclusions

PVR cells obtained from human membranes can be successfully isolated, cultured, and profiled in vitro. Using these primary cultures, we identified MTX as capable of significantly reducing growth and inducing cell death of PVR cells in vitro.

Key Factors to Improve the Outcome of Retinal Reattachment Surgery in Proliferative Vitreoretinopathy and Proliferative Diabetic Retinopathy

INTRODUCTION

For management of complicated retinal detachments, a pars plana vitrectomy with temporary silicone oil (SO) fill is the method of choice. According to literature, the retinal redetachment rate varies between <10% and >70% with around 36% in our own group (retrospective data analysis, n = 119 eyes).

METHODS

The main goal was to reduce the retinal redetachment rate. Standard operating procedures (SOPs) and evaluation protocols (EVALPs) were developed to prospectively analyse risk factors. Lab analysis of SO was performed, and the role of surgical experience was evaluated and investigated with Eyesi®.

RESULTS

We achieved a significant reduction of the retinal redetachment rate (to 6.80%, n = 101, p = 0.002). After surgery with SO injection, neither further membrane peeling (in 16.5%) nor retinal laser coagulation (in 100%) during revision surgery had a significant effect on the reattachment rate (p = 0.167, p = 0.23), while extensive additional laser coagulation reduced visual acuity (p = 0.01). A 3-port approach had to be set up to complete SO removal. A difference in success rate depending on surgical experience was confirmed, and the performance in Eyesi correlated with that in the patients' eye.

CONCLUSIONS

A SOP- and EVALP-based management and new strategies to secure the surgical performance seem to be essential for successful surgery.

Effect of Serial Intrasilicone Oil Bevacizumab Injections in Eyes With Recurrent Proliferative Vitreoretinopathy Retinal Detachment

PURPOSE

To investigate the effect of serial intrasilicone oil bevacizumab injections (1.25 mg/0.05 mL) on visual acuity (VA) and anatomic outcomes in eyes undergoing proliferative vitreoretinopathy (PVR)-related retinal detachment (RD) repair.

DESIGN

Prospective, nonrandomized, historical-control pilot study.

METHODS

setting: Tertiary care center.

STUDY POPULATION

Nondiabetic eyes undergoing pars plana vitrectomy (PPV) and silicone oil tamponade with or without scleral buckling procedure (SBP) for recurrent RD due to PVR.

INTERVENTION

Intrasilicone oil injection of 1.25 mg bevacizumab was performed intraoperatively and at postoperative months 1, 2, and 3.

OUTCOMES

Retinal reattachment rate, final VA, and rate of epiretinal membrane (ERM) formation at month 6.

RESULTS

Twenty eyes of 20 patients were enrolled and compared to a historical control group composed of 35 age- and sex-matched controls. In the study group, logMAR VA improved from mean 1.78 ± 0.43 (Snellen 20/1205) to 1.43 ± 0.70 (Snellen 20/538, P = .04), retinal reattachment was achieved in 14 of 20 eyes (70%), and ERM formation was observed in 7 of 20 eyes (35%) at 6 months. In the control group, logMAR VA improved from mean 1.50 ± 0.74 (Snellen 20/632) to 1.43 ± 0.58 (Snellen 20/538, P = .64), retinal reattachment was achieved in 25 of 35 eyes (71%), and ERM formation was observed in 7 of 35 eyes (20%) at 6 months. No significant difference in final VA (P = .96), retinal reattachment rate (P = .75), or ERM formation (P = .33) was observed between groups. No intrasilicone oil injection-related adverse events occurred.

CONCLUSIONS

Serial intrasilicone oil injections of bevacizumab did not improve retinal reattachment rate, improve final VA, or reduce ERM formation in patients undergoing PVR-related RD surgery.

Clinical management of proliferative vitreoretinopathy: an update

BACKGROUND

Proliferative vitreoretinopathy (PVR) remains the most significant obstacle to successful retinal reattachment surgery. Preclinical studies continue to add insights into the complex molecular events leading to PVR development, helping to identify new targets for potential prophylactic or therapeutic agents. This article reviews the recent evidence supporting surgical and medical treatments for PVR.

METHODS

PUBMED was used for literature search. Clinical studies regarding surgical management of PVR from January 1, 2000 to August 1, 2014 were included. Clinical studies regarding medical management of PVR from January 1, 2000 to August 1, 2014 were included if the design of study was a randomized controlled trial.

RESULTS

Many recent studies have evaluated surgical and medical strategies for the treatment and prevention of PVR. Newer vitreoretinal surgery technology (23- and 25-gauge vitrectomy) and tamponade agents (heavy silicone oils) have been studied. Medical therapies evaluated include antiinflammatory agents, low molecular weight heparin, 5-fluorouracil, 13-cis-retinoic acid, and daunorubicin, amongst others.

CONCLUSION

Surgical management with pars plana vitrectomy, with or without scleral buckle or inferior retinectomy, remains an effective treatment for PVR-related detachments. Consensus regarding a preferred surgical strategy remains controversial. Many medical therapies have been studied but fail to demonstrate a statistically significant benefit in clinical trials. Further studies to clarify the efficacy of available and novel treatment options are warranted.

Preparation and evaluation of a novel biodegradable long-acting intravitreal implant containing ligustrazine for the treatment of proliferative vitreoretinopathy

OBJECTIVES

It is challenging to deliver the therapeutic drug effectively to the posterior ocular disease location with optimized exposure and long-term effects when treating proliferative vitreoretinopathy (PVR). The objective of this study is to develop a novel biodegradable and long-acting ocular implant for PVR therapy with ligustrazine as the active ingredient.

METHODS

The ligustrazine implants were prepared with poly(DL-lactide-co-glycolide) using a hot-melting extrusion. The physicochemical properties of the implants were characterized. The effectiveness of the selected ligustrazine implants was evaluated in a PVR rabbit model. Furthermore, the in-vitro drug release profile and pharmacokinetics were compared, and in-vitro/in-vivo correlations were evaluated.

KEY FINDINGS

The optimal implants had an ideal zero-order in-vitro drug release profile, which was correlated with the in-vivo drug absorption fraction in the vitreous bodies of the rabbits. The sustained-release ligustrazine implants significantly reduced the development of PVR in the animal model.

CONCLUSIONS

Ligustrazine implants can be used to treat posterior ocular disease in rabbit animal models, and it provides more choices for medical research on posterior ocular disease.

In vitro vitamin K3 effect on conjunctival fibroblast migration and proliferation

Purpose. To evaluate the dose effect of vitamin K₃ on wound healing mechanisms. Methods. Conjunctival fibroblasts were incubated for 24 hours. An artificial wound was made and the cells were incubated with fresh medium plus doses of vitamin K₃ to be tested. Wound repair was monitored at 0, 18, 24, and 48 hours. Proliferation was measured in actively dividing cells by [³H]thymidine uptake. Six different groups were tested: group 1/no drugs added, group 2/ethanol 0.1%, group 3/vitamin K₃ 1 mg/L, group 4/vitamin K₃ 2 mg/L, group 5/vitamin K₃ 4 mg/L, and group 6/vitamin K₃ 6 mg/L. Each experiment was carried out in triplicate and 4 times. Results. There were no differences among groups at the initial time. In vitro wound repair was slower in groups 4, 5, and 6. There were no differences between control and ethanol groups and between control and vitamin K₃ 1 mg/L groups. Fibroblast mitogenic activity was statistically decreased in all vitamin K groups; statistical differences were found among vitamin K₃ 1 mg/mL and higher doses too. In groups 5 and 6, cellular toxicity was presented. Conclusions. Vitamin K₃ is able to inhibit fibroblast proliferation. Vitamin K₃ 2 mg/L or higher doses inhibit wound healing repair, exhibiting cellular toxicity at 4 and 6 mg/L.

Proliferative vitreoretinopathy after eye injuries: an overexpression of growth factors and cytokines leading to a retinal keloid

Eye injury is a significant disabling worldwide health problem. Proliferative Vitreoretinopathy (PVR) is a common complication that develops in up to 40–60% of patients with an open-globe injury. Our knowledge about the pathogenesis of PVR has improved in the last decades. It seems that the introduction of immune cells into the vitreous, like in penetrating ocular trauma, triggers the production of growth factors and cytokines that come in contact with intra-retinal cells, like Müller cells and RPE cells. Growth factors and cytokines drive the cellular responses leading to PVR's development. Knowledge of the pathobiological and pathophysiological mechanisms involved in posttraumatic PVR is increasing the possibilities of management, and it is hoped that in the future our treatment strategies will evolve, in particular adopting a multidrug approach, and become even more effective in vision recovery. This paper reviews the current literature and clinical trial data on the pathogenesis of PVR and its correlation with ocular trauma and describes the biochemical/molecular events that will be fundamental for the development of novel treatment strategies. This literature review included PubMed articles published from 1979 through 2013. Only studies written in English were included.