State of the art management of diabetic macular edema

Macular edema following diabetic retinopathy is one of the ocular complications associated with diabetes, and it is the leading cause of visual loss in the active young and middle aged population in developed countries. While all patients with diabetes particularly those with diabetic retinopathy are at increased risk of developing eye complications, early detection and timely intervention may prevent or delay loss of visual acuity. Systemic management of diabetes through combined control of blood sugar, hypertension, and hyperlipidemia has remained the most effective method to prevent diabetic retinopathy and its progression. Development of diabetic retinopathy and related complications require, surgical and medical interventions including photocoagulation, vitrectomy, and intravitral drug injection to preserve vision. Considering recently most popular treatment of diabetic macular edema(DME) including intravitreal anti-vascular endothelial growth factor(VEGF) agents, several issues such as ideal regimen, duration of treatment, combination therapy and long-term safety have remained unanswered yet and deserve further investigations. In this review, all the articles that had investigated such treatment modalities for DME as well as pharmacokinetic, efficacy, safety, dose and frequency of intravitreal pharmacologic agents and also the effect of macular ischemia, initial macular thickness and optical coherence tomographic patterns of DME on the final outcomes of treatment with Intravitreal drugs are reviewed. In summary, literature searches reveal that almost all studies that have been published up to now provide some evidence that support the use of intravitreal anti-VEGF agents for treatment of either nve or persistent DME in short and long term up to two years.

Safety threshold of intravitreal clonidine in rabbit's eyes

AIM： To determine the safe dose of intravitreal clonidine（IVC）, a potential drug for neuroprotection and angiogenesis inhibition in rabbits. METHODS： A total of 28 rabbits were divided into four groups. Three groups received IVC with concentrations of 15（Group A）, 25（Group B）, and 50（Group C） g/0.1 m L and the control group（Group D） received 0.1 m L balanced salt solution（BSS）. To investigate IVC safety, electroretinography（ERG） was performed at baseline, then at 1, 4 and 8 wk after injection. After last ERG, all rabbits were euthanized, their eyes were enucleated and subjected to routine histopathological evaluation, immunohistochemistry for glial fibrillary acidic protein（GFAP） and terminal deoxynucleotidyl transferase d UTP nick end labeling（TUNEL） test.RESULTS： Based on ERG, histopathology, GFAP and TUNEL assay findings, 15 g IVC was determined as the safe dose in rabbit eyes. While, the results of routine histopathology and TUNEL assay were unremarkable in all groups, toxic effects attributed to 25 and 50 g IVC were demonstrated by ERG and GFAP tests. CONCLUSION： Totally 15 g clonidine is determined as the safe dose for intravitreal injection in rabbits. Contribution of IVC in neuroprotection and inhibition of angiogenesis deserve more studies.

Association between Pri-miR-34b/c rs4938723 polymorphism and bladder cancer risk

Several studies examined the impact of miR-34b/c rs4938723 polymorphism and cancer risk, but the findings are inconsistent. However, no study has been conducted to inspect the impact of miR-34b/c polymorphism on bladder cancer. This study aimed to assess possible association between rs4938723 polymorphism and bladder cancer risk.This case-control study was done on 136 pathologically proven bladder cancer patients and 144 controls. Genotyping of Pri-miR-34b/c rs4938723 polymorphism was achieved by using the polymerase chain reaction restriction fragment length polymorphism(PCR-RFLP) method. Our findings did not show any statistically significant differences in genotype and allele frequencies between bladder cancer and controls. Larger sample sizes with diverse ethnicities are required to validate our findings.

Donor cornea quality used for penetrating keratoplasty vs deep anterior lamellar keratoplasty

Deep anterior lamellar keratoplasty(DALK) has recently been introduced as an alternative procedure to penetrating keratoplasty(PK) for corneal pathologies not affecting the corneal endothelium. DALK does not rely on donor endothelium and requires less rigid criteria for donor corneal tissue quality. Therefore, DALK makes it possible to use donor corneas deemed unsuitable for PK. Furthermore, lamellar keratoplasty allows acellular corneal tissue to be transplanted. As a result, long-term preservation techniques are being revisited to increase the availability of donor corneas and subsequently alleviate constraints of availability, cost, storage, and transportation in many countries. The recent alterations in corneal transplantation techniques and hence the type of donor cornea tissues used for each technique, may require corneal surgeons and eye banks to reevaluate their selection criteria. The purpose of this systematic review is to present an updated analysis on the type and quality of donor corneas used for PK and DALK, assess the influence of donor and eye bank factors on the quality of donor corneas, and determine whether any of these donor factors affect clinical outcomes, complications, and graft survivals.

眼内非金属性和非磁性金属异物的手术治疗

BACKGROUND AND OBJECTIVE: To identify clinical features and evaluate outcomes of vitreoretinal surgery in eyes with retained non-metallic and non-magnetic metallic intraocular foreign bodies (IOFBs). PATIENTS AND METHODS: Retrospective chart review. Thirty-two eyes (28 patients) with non-metallic and non-magnetic metallic IOFBs underwent removal of IOFBs with intraocular forceps, either via the pars plana in 30 eyes (93.9%) or a limbal approach in 2 eyes (6.25%). The main outcome measures were postoperative visual acuity, rate of retinal break formation, development of retinal detachment, and type of IOFB. RESULTS: IOFBs were non-metallic in 22 eyes (68.7%) and non-magnetic metallic in 10 eyes (31.1%). The average follow-up period was 7.5 months. Overall, final visual acuity was 20/40 or better in 10 eyes (31.1%) and 5/200 to 20/50 in 10 eyes (31.1%). A higher incidence of retinal break formation posterior to the sclerotomy was seen with glass IOFBs (P=.02). Retinal detachment was observed preoperatively in 4 eyes (12.5%) and postoperatively in 2 eyes (6.25%). CONCLUSION: Final visual outcome was independent of size and type of IOFB. Pars plana extractions may be associated with a higher rate of retinal break formation and subsequent retinal detachment, particularly with glass IOFBs.

Electrospun Aloe Vera Extract Loaded Polycaprolactone Scaffold for Biomedical Applications:A Promising Candidate for Corneal Stromal Regeneration

Corneal diseases,the second leading cause of global vision loss affecting over 10.5 million people,underscores the unmet demand for corneal tissue replacements.Given the scarcity of fresh donor corneas and the associated risks of immune rejection,corneal tissue engineering becomes imperative.Developing nanofibrous scaffolds that mimic the natural corneal structure is crucial for creating transparent and mechanically robust corneal equivalents in tissue engineering.Herein,Aloe Vera Extract(AVE)/Polycaprolactone(PCL)nanofibrous scaffolds were primed using electrospinning.The electrospun AVE/PCL fibers exhibit a smooth,bead-free morphology with a mean diameter of approximately 340±95 nm and appropriate light transparency.Mechanical measurements reveal Young’s modulus and ultimate tensile strength values of around 3.34 MPa and 4.58 MPa,respectively,within the range of stromal tissue.In addition,cell viability of AVE/PCL fibers was measured against Human Stromal Keratocyte Cells(HSKCs),and improved cell viability was observed.The cell-fiber interactions were investigated using scanning electron microscopy.In conclusion,the incorporation of Aloe Vera Extract enhances the mechanical,optical,hydrophilic,and biological properties of PCL fibers,positioning PCL/AVE fiber scaffolds as promising candidates for corneal stromal regeneration.

Therapeutic approaches for corneal neovascularization

Angiogenesis refers to new blood vessels that originate from pre-existing vascular structures.Corneal neovascularization which can lead to compromised visual acuity occurs in a wide variety of corneal pathologies.A large subset of measures has been advocated to prevent and/or treat corneal neovascularization with varying degrees of success.These approaches include topical corticosteroid administration,laser treatment,cautery,and fine needle diathermy.Since the imbalance between proangiogenic agents and antiangiogenic agents primarily mediate the process of corneal neovascularization,recent therapies are intended to disrupt the different steps in the synthesis and actions of proangiogenic factors.These approaches,however,are only partially effective and may lead to several side effects.The aim of this article is to review the most relevant treatments for corneal neovascularization available so far.