Intravitreal injections at the Massachusetts Eye and Ear Infirmary: analysis of treatment indications and postinjection endophthalmitis rates

Risk of Endophthalmitis Based on Cumulative Number of Anti-VEGF Intravitreal Injections

PURPOSE

To determine the risk of endophthalmitis in eyes undergoing intravitreal injections (IVIs) of anti-VEGF based on cumulative number of injections per eye.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Patients from a single center undergoing IVIs of ranibizumab, aflibercept, or bevacizumab.

METHODS

Eyes were divided into quartiles based on injection number causative of endophthalmitis between January 1, 2011, and June 1, 2022.

MAIN OUTCOME MEASURES

Interquartile clinical outcomes and cumulative risk of endophthalmitis per injection and per eye.

RESULTS

A total of 43 393 eyes received 652 421 anti-VEGF injections resulting in 231 endophthalmitis cases (0.035% per injection, 1 in 2857), of which 215 were included. The cumulative endophthalmitis risk increased from 0.0018% (1 in 55 556) after 1 injection to 0.013% (1 in 7692) after 11 injections (0.0012 percentage point change), versus 0.014% (1 in 7143) after 12 injections to 0.025% (1 in 4000) after 35 injections (0.00049 percentage point change), versus 0.025% (1 in 4000) after 36 injections to 0.031% (1 in 3226) after 66 injections (0.00017 percentage point change), versus 0.031% (1 in 3226) after 63 injections to 0.033% (1 in 3030) after 126 injections (0.000042 percentage point change) (P < 0.001). Likewise, the cumulative endophthalmitis risk per eye increased from 0.028% (1 in 3571) to 0.20% (1 in 500) between injections 1 and 11 (0.018 percentage point change), versus 0.21% (1 in 476) to 0.38% (1 in 263) between injections 12 and 35 (0.0075 percentage point change), versus 0.38% (1 in 263) to 0.46% (1 in 217) between injections 36 and 66 (0.0026 percentage point change), versus 0.46% (1 in 217) to 0.50% (1 in 200) between injections 67 and 126 (0.00063 percentage point change) (P < 0.001).

CONCLUSIONS

The cumulative endophthalmitis risk per injection and per eye increased with greater number of injections received but appeared to do so at a higher rate during earlier injections and at a lower rate further into the treatment course.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Sustained Inhibition of VEGF and TNF-α Achieves Multi-Ocular Protection and Prevents Formation of Blood Vessels after Severe Ocular Trauma

PURPOSE

This study aimed to develop a clinically feasible and practical therapy for multi-ocular protection following ocular injury by using a thermosensitive drug delivery system (DDS) for sustained delivery of TNF-α and VEGF inhibitors to the eye.

METHODS

A thermosensitive, biodegradable hydrogel DDS (PLGA-PEG-PLGA triblock polymer) loaded with 0.7 mg of adalimumab and 1.4 mg of aflibercept was injected subconjunctivally into Dutch-belted pigmented rabbits after corneal alkali injury. Control rabbits received 2 mg of IgG-loaded DDS or 1.4 mg of aflibercept-loaded DDS. Animals were followed for 3 months and assessed for tolerability and prevention of corneal neovascularization (NV), improvement of corneal re-epithelialization, inhibition of retinal ganglion cell (RGC) and optic nerve axon loss, and inhibition of immune cell infiltration into the cornea. Drug-release kinetics was assessed in vivo using an aqueous humor protein analysis.

RESULTS

A single subconjunctival administration of dual anti-TNF-α/anti-VEGF DDS achieved a sustained 3-month delivery of antibodies to the anterior chamber, iris, ciliary body, and retina. Administration after corneal alkali burn suppressed CD45+ immune cell infiltration into the cornea, completely inhibited cornea NV for 3 months, accelerated corneal re-epithelialization and wound healing, and prevented RGC and optic nerve axon loss at 3 months. In contrast, anti-VEGF alone or IgG DDS treatment led to persistent corneal epithelial defect (combined: <1%; anti-VEGF: 15%; IgG: 10%, of cornea area), increased infiltration of CD45+ immune cells into the cornea (combined: 28 ± 20; anti-VEGF: 730 ± 178; anti-IgG: 360 ± 186, cells/section), and significant loss of RGCs (combined: 2.7%; anti-VEGF: 63%; IgG: 45%) and optic nerve axons at 3 months. The aqueous humor protein analysis showed first-order release kinetics without adverse effects at the injection site.

CONCLUSIONS

Concomitant inhibition of TNF-α and VEGF prevents corneal neovascularization and ameliorates subsequent irreversible damage to the retina and optic nerve after severe ocular injury. A single subconjunctival administration of this therapy, using a biodegradable, slow-release thermosensitive DDS, achieved the sustained elution of therapeutic levels of antibodies to all ocular tissues for 3 months. This therapeutic approach has the potential to dramatically improve the outcomes of severe ocular injuries in patients and improve the therapeutic outcomes in patients with retinal vascular diseases.

Preventive factors, diagnosis, and management of injection-related endophthalmitis: a literature review

BACKGROUND

Intravitreal medication injections represent the gold standard treatment for a variety of potentially blinding chorioretinal vascular diseases. Despite their excellent safety profile, they are associated with the feared complication of injection-related endophthalmitis (IRE). Though the overall incidence of IRE is low, due to the ever-increasing number of injections being performed, it is a complication that all retina specialists are likely to encounter. This article reviews various factors that could potentially influence the risk of IRE and discusses evidence-based strategies for management.

METHOD

PubMed was searched for keywords "intravitreal injection" and "endophthalmitis" from the period of 1995-2021. Relevant articles were reviewed and selected articles were analyzed with respect to the incidence, potential preventive factors, clinical presentation, microbial profile, management, and outcomes for IRE.

RESULTS

There is strong consensus supporting the use of povidone iodine topical antiseptic, eyelid retraction away from the injection site, and avoiding treatment of eyes with active surface or eyelid disease, but there is less agreement on the use of face masks versus "no-talking" policies and optimal anesthetic technique. Current evidence comparing tap and inject or early vitrectomy for treatment of IRE is inadequate to determine an optimal treatment strategy.

CONCLUSION

Intravitreal injections are sight saving, but even using established prophylactic measures there remains a small but real risk of infectious injection-related complications. Further investigations comparing tap and inject versus vitrectomy may help to establish optimal treatment, although the rarity of IRE makes designing adequately powered prospective trials a difficult task.

Safety of Receiving Anti-Vascular Endothelial Growth Factor Intravitreal Injection in Office-Based vs Operating Room Settings: A Meta-analysis

Importance

Compared with the operating room (OR), office-based intravitreal injection (IVI) is considered a more cost-effective and convenient approach, yet clinical outcomes of IVIs with anti-vascular endothelial growth factor (VEGF) agents in different settings (office-based vs OR) have not been systematically evaluated.

Objective

To evaluate the safety outcomes of IVI with anti-VEGF agents in the OR vs office-based setting.

Data Sources

PubMed, Embase, Cochrane Library, Web of Science, and ClinicalTrials.gov were searched from inception to July 2020.

Study Selection

Eligible studies reporting on patients who received IVIs with anti-VEGF drugs with a clearly stated injection setting of the office or OR.

Data Extraction and Synthesis

Two reviewers independently screened studies, extracted data, and assessed risk of bias. A meta-analysis was conducted to determine the rates of endophthalmitis (EO) and culture-positive EO.

Main Outcomes and Measures

Rates of EO and culture-positive EO following anti-VEGF IVIs in the OR and office-based setting.

Results

Thirty-one studies with a total of 1 275 815 injections were included. Comparative analysis suggested no difference between rates of EO after IVIs performed in the office and OR settings (odds ratio, 3.06; 95% CI, 0.07-139.75; P = .57; I2 = 80%) were identified, yet a higher rate of culture-positive EO was found in the office setting (odds ratio, 21.52; 95% CI, 2.39-193.55; P = .006; I2 = 0%). The pooled rates of EO following anti-VEGF IVIs were 0.03% (95% CI, 0.03-0.04) and 0.02% (95% CI, 0.01-0.04) in office and OR settings, respectively, and the pooled rates of culture-positive EO were 0.01% (95% CI, 0.01-0.02) and 0.01% (95% CI, 0-0.02). The pooled rates of other ocular and systemic adverse events were low.

Conclusions and Relevance

The rate of clinically suspected or culture-positive EO following anti-VEGF IVIs was low whether the procedure was performed in the office or OR setting. Bacterial spectrum could differ between the 2 settings. This meta-analysis could not determine if it is more appropriate to give treatment in the OR for safety reasons in low-income compared with higher-income regions in the world.

Efficacy of a New Commercial Ocular Spray Containing Oftasecur Citrus Extract for Reducing Microbial Load in the Conjunctiva of Patients Receiving Intravitreal Injections

INTRODUCTION

The control of conjunctival microbial load is crucial for patients receiving intravitreal injections (IVTs) in order to reduce the risk of endophthalmitis. The purpose of this work was to assess the antimicrobial activity of a new commercial ocular spray containing Biosecur citrus extract (Oftasecur^®, Off Health, Florence, Italy).

METHODS

This prospective cross-sectional pilot study included patients receiving IVTs who were instructed to apply Oftasecur spray onto the eye to be injected four times daily starting 4 days before surgery. The contralateral eye was considered the control. A conjunctival swab for microbiological analysis was performed in both eyes before starting study treatment and at the time of the injection. The Brief Ocular Discomfort Inventory (BODI) questionnaire was administered to patients based on an 11-point scale (0 for no discomfort and 10 for maximum discomfort).

RESULTS

Thirty patients (15 male, 15 female; mean age 64.7 ± 11.6 [standard deviation, SD] years) were included. Before starting treatment, 53.3% of the total eyes tested positive during the microbiological analysis. After the treatment period, only 20% of the eyes tested positive at the time of injection, showing a significant reduction in the microbial load (p < 0.01). Moreover, in the treated arm, the positive swabs before and after the prophylactic treatment with Oftasecur ocular spray showed a significant reduction (from 70.4% to 29.6%; p = 0.003, McNemar's test). Oftasecur ocular spray was well tolerated, with an average BODI score of 1.2 (± 0.70 SD).

CONCLUSION

Oftasecur ocular spray showed antimicrobial activity that significantly reduced the microbial load in patients receiving intravitreal injections. Therefore, it may have a role in the prophylaxis of infection in the setting of IVTs.

Incidence and outcomes of endophthalmitis with in-house compounded intravitreal bevacizumab injections: A multicentric study

PURPOSE

To evaluate the incidence rate and outcomes of endophthalmitis after intravitreal injection of in-house compounded bevacizumab.

METHODS

In this multicentric study performed from 2014 to 2018, patients who were injected with in-house compounded and sterilized bevacizumab were observed for endophthalmitis. In-house compounded syringes were prepared in compounding pharmacy using sterile standard operating guidelines. All cases of acute endophthalmitis following intravitreal injection were recorded and followed up for final anatomical and visual outcome after management.

RESULTS

A total of 50,361 bevacizumab injections were administered. Incidence of post-injection endophthalmitis was 0.0377%. Incidence of culture-positive endophthalmitis was 0.0178%, with 55.5% culture positivity for Staphylococcus species. A significant improvement in the final visual outcome was noted (p<0.05), and overall five patients (26.3%) achieved visual acuity of 6/18 or more.

CONCLUSIONS

In-house compounded injections of bevacizumab can reduce post-injection endophthalmitis to a minimum, with maintenance of proper asepsis and strict protocols by the compounding pharmacy.

Evaluation of Photoreceptor Transduction Efficacy of Capsid-Modified Adeno-Associated Viral Vectors Following Intravitreal and Subretinal Delivery in Sheep

Gene augmentation therapy based on subretinal delivery of adeno-associated viral (AAV) vectors is proving to be highly efficient in treating several inherited retinal degenerations. However, due to potential complications and drawbacks posed by subretinal injections, there is a great impetus to find alternative methods of delivering the desired genetic inserts to the retina. One such method is an intravitreal delivery of the vector. Our aim was to evaluate the efficacy of two capsid-modified vectors that are less susceptible to cellular degradation, AAV8 (doubleY-F) and AAV2 (quadY-F+T-V), as well as a third, chimeric vector AAV[max], to transduce photoreceptor cells following intravitreal injection in sheep. We further tested whether saturation of inner limiting membrane (ILM) viral binding sites using a nonmodified vector, before the intravitreal injection, would enhance the efficacy of photoreceptor transduction. Only AAV[max] resulted in moderate photoreceptor transduction following intravitreal injection. Intravitreal injection of the two other vectors did not result in photoreceptor transduction nor did the saturation of the ILM before the intravitreal injection. However, two of the vectors efficiently transduced photoreceptor cells following subretinal injection in positive control eyes. Previous trials with the same vectors in both murine and canine models resulted in robust and moderate transduction efficacy, respectively, of photoreceptors following intravitreal delivery, demonstrating the importance of utilizing as many animal models as possible when evaluating new strategies for retinal gene therapy. The successful photoreceptor transduction of AAV[max] injected intravitreally makes it a potential candidate for intravitreal delivery, but further trials are warranted to determine whether the transduction efficacy is sufficient for a clinical outcome.

Microporous Drug Delivery System for Sustained Anti-VEGF Delivery to the Eye

Purpose

To describe a novel microporous drug delivery system (DDS) for sustained anti- vascular endothelial growth factor (VEGF) delivery to the eye and to evaluate its efficacy in a corneal injury model.

Methods

A macro-porous DDS (1.5 × 1.5 × 4 mm) loaded with 2 mg of bevacizumab was implanted subconjunctivally in three Dutch-belted pigmented rabbits after corneal alkali injury (2N NaOH). Three rabbits received sham DDS. Animals were followed for three months and assessed in vivo and ex vivo for corneal neovascularization (NV), epithelial defect, stromal scarring, endothelial cell loss, and expression of angiogenic and inflammatory markers in the cornea and retina.

Results

Anti-VEGF DDS treatment led to complete inhibition of superior cornea NV and complete corneal re-epithelialization by day 58 whereas sham DDS resulted in severe cornea NV and persistent epithelial defect (9%∼12% of total cornea area) through the end of the study. Histologically, anti-VEGF DDS significantly reduced CD45⁺ and F4/80 CD11b⁺ cell accumulation (79%, P < 0.05) in the cornea, ameliorated tumor necrosis factor–α expression (90%, P < 0.05), reduced corneal stromal scarring and prevented corneal endothelial cell loss, as compared to sham DDS. Moreover, anti-VEGF DDS achieved retinal penetration and reduction in retinal VEGF levels at 3 months.

Conclusions

Use of subconjunctival anti-VEGF DDS suppresses cornea NV, inflammation, stromal scarring, prevents endothelial cell loss, and abrogates retinal VEGF upregulation in a rabbit corneal alkali burn model. Moreover, it delivers anti-VEGF antibodies to the retina for three months. This delivery platform could enable antibody therapy of other corneal and retinal vascular pathologies.

Translational Relevance

We describe a method for sustained anti-VEGF delivery to the eye for the treatment of ocular injuries.

Prophylaxis measures for postinjection endophthalmitis

Intravitreal injections have become the most commonly performed ophthalmic procedure, transforming modern retina practice. Postinjection endophthalmitis, while rare, remains the most feared potential complication. Prophylaxis measures including topical antisepsis, hand hygiene, gloves, masks, and drapes have all been proposed to help prevent postinjection endophthalmitis; however, there remains significant variation in protocol, given the lack of agreement among retina specialists on which steps are crucial to prevent endophthalmitis. With millions of injections performed annually, collating data have helped us better understand risk factors for endophthalmitis after intravitreal injection. We summarize the consensus guidelines for intravitreal injection technique and comprehensively review the literature on prevention of postinjection endophthalmitis.

AAVrh-10 transduces outer retinal cells in rodents and rabbits following intravitreal administration

Recombinant adeno-associated virus (rAAV) has been widely used for gene delivery in animal models and successfully applied in clinical trials for treating inherited retinal disease. Although subretinal delivery of AAVs can effectively transduce photoreceptors and/or retinal pigmental epithelium (RPE), cells most affected by inherited retinal diseases, the procedure is invasive and complicated, and only delivers the gene to a limited retinal area. AAVs can also be delivered intravitreally to the retina, a much less invasive nonsurgical procedure. However, intravitreal administration of non-modified AAV serotypes tends to transduce only ganglion cells and inner nuclear layer cells. To date, most non-modified AAV serotypes that have been identified are incapable of efficiently transducing photoreceptors and/or RPE when delivered intravitreally. In this study, we investigate the retinal tropism of AAVrh10 vector administered by intravitreal injection to mouse, rat, and rabbit eyes. Our results demonstrate that AAVrh10 is capable of transducing not only inner retinal cells, but also outer retinal cells in all three species, though the transduction efficiency in rabbit was low. In addition, AAVrh10 preferentially transduced outer retinal cells in mouse models of retinal disease. Therefore, AAVrh10 vector could be a useful candidate to intravitreally deliver genes to photoreceptor and RPE cells.

Culture-Proven Endophthalmitis After Intravitreal Injection: A 10-Year Analysis

BACKGROUND AND OBJECTIVE

To report on the microbiology, management, and visual outcomes of intravitreal injection (IVI)-associated, culture-proven endophthalmitis.

PATIENTS AND METHODS

All patients seen at a tertiary referral center with culture-proven endophthalmitis associated with an IVI between June 2007 and July 2017 were included in this retrospective analysis.

RESULTS

Thirty-five patients with culture-positive endophthalmitis following IVI were identified. All gram-positive organisms (34 of 35) were susceptible to vancomycin. Cases due to pathogens associated with oral or respiratory flora were common (31.4%, n = 11), presented earlier (2.0 days vs. 4.6 days, P < .001), were more likely to undergo pars plana vitrectomy (81.8% vs. 25.0%, P = .002) and had worse visual acuity outcomes.

CONCLUSION

IVI-associated endophthalmitis pathogens and anti-microbial susceptibilities in the Pacific Northwest are similar to those reported from other geographic locations. Bacteria associated with the oral and respiratory flora are common isolates that result in a more aggressive course and worse visual outcomes. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:33-38.].

Strategies for modifying drug residence time and ocular bioavailability to decrease treatment frequency for back of the eye diseases

INTRODUCTION

Treating posterior eye diseases has become a major area of focus for pharmaceutical and biotechnology companies. Current standard of care for treating posterior eye diseases relies on administration via intravitreal injection. Although effective, this is not without complications and there is great incentive to develop longer-acting therapeutics and/or sustained release delivery systems. Here, we present an overview of emerging technologies for delivery of biologics to the back of the eye.

AREAS COVERED

Posterior eye diseases, intravitreal injection, age-related macular degeneration, anti-VEGF, ocular pharmacokinetics, novel technologies to extend half-life, in vivo models, translation to the clinic, and hurdles to effective patient care.

EXPERT OPINION

Posterior eye diseases are a worldwide public health issue. Although anti-VEGF molecules represent a major advance for treating diseases involving choroidal neovascularization, frequent injection can be burdensome for patients and clinicians. There is a need for effective and patient-friendly treatments for posterior eye diseases. Many technologies that enable long-acting delivery to the back of the eye are being evaluated. However, successful development of novel therapies and delivery technologies is hampered by a multitude of factors, including patient education, translatability of in vitro/in vivo preclinical data to the clinic, and regulatory challenges associated with novel technologies.

Safety of 5914 intravitreal ziv-aflibercept injections

Purpose

To analyse the pooled safety data of intravitreal ziv-aflibercept (IVZ) therapy for various retinal conditions.

Methods

This was a retrospective, observational study which included patients from 14 participating centres who received IVZ. The medical records of patients who received IVZ from March 2015 through October 2017 were evaluated. Patient demographics and ocular details were compiled. Ocular and systemic adverse events that occurred within 1 month of IVZ injections were recorded and defined as either procedure-related or drug-related.

Results

A total of 1704 eyes of 1562 patients received 5914 IVZ injections (mean±SD: 3.73±3.94) during a period of 2.5 years. The age of patients was 60.6±12.8 years (mean±SD) and included diverse chorioretinal pathologies. Both ocular (one case of endophthalmitis, three cases of intraocular inflammation, and one case each of conjunctival thinning/necrosis and scleral nodule) and systemic adverse events (two cases of myocardial infarction, one case of stroke and two deaths) were infrequent.

Conclusion

This constitutes the largest pooled safety report on IVZ use and includes patients from 14 centres distributed across the globe. It shows that IVZ has an acceptable ocular and systemic safety profile with incidences of adverse events similar to those of other vascular endothelial growth factor inhibitory drugs. The analysis supports the continued use of IVZ in various retinal disorders.

Nanotechnology in retinal drug delivery

Retinal diseases, including age-related macular degeneration (AMD) and diabetic retinopathy (DR) are the leading causes of blindness in adults over the age of 50 years in the US. While most of those conditions do not have a cure, currently available treatment options attempt to prevent further vision loss. For many ophthalmic drugs, an efficient delivery system to provide maximum therapeutic efficacy and promote patient compliance remains an unmet medical need. An exploration of literature via PubMed spanning from 2007 to 2017 was conducted to identify studies that have evaluated nanotechnology as platforms for delivering therapeutic agents to the posterior segment of the eye where the retina is located. Until now, four routes that have been utilized for retinal drug delivery are the intravitreal, periocular, subretinal, and systemic routes. Intravitreal injections are now widely used in clinical practice due to their ability to directly target the back of the eye but are highly invasive procedures that may cause several complications, particularly with repeated uses over a short timespan. Nanotechnology shows great promise to revolutionize retinal drug delivery, offering many advantages such as a targeted delivery system towards the specific site of the retina as well as sustained delivery of therapeutic agents. In this review, specific eye anatomy and constraints on ocular drug administration are illustrated. Further, we list and highlight several examples of nanosystems, such as hydrogels, liposomes, dendrimers, and micelles, used via different drug delivery routes to treat various retinal diseases.

Choosing wisely and the use of antibiotics in ophthalmic surgery: There is more than meets the eye

BACKGROUND:

One of the directions of modern ophthalmology is toward an odontoiatric model, and new settings of eye care are becoming the standard of care: one day surgery and also office-based therapies.

METHODS:

Retrospective analysis of three tertiary-care centers in Italy and analysis of the literature.

RESULTS:

We provide readers with state-of-the-art measures of prophylaxis in ophthalmic surgery.

DISCUSSION AND CONCLUSION:

Role of antibiotics is criticized in the light of stewardship antimicrobial paradigm.

Incidence of endophthalmitis after intravitreal injections at a tertiary care hospital

OBJECTIVE

To report the incidence of endophthalmitis after the use of intravitreal injection for anti-vascular endothelial growth factor therapy.

METHODS

This was a single-centre retrospective study conducted at the Aga Khan University Hospital, Pakistan. A total of 11 128 injections were administered to 2054 patients between January 2013 and December 2015. All procedures were performed in an operating room setting, and postinjection antibiotics were prescribed.

RESULTS

Three cases of endophthalmitis occurred during the study period, with the per-injection risk of endophthalmitis being 0.027%.

CONCLUSION

The results highlight the benefit of administering intravitreal injections in a surgical setting in addition to enforcing quality protocols. We also recommend further investigation to scrutinize the role of antibiotics prescribed after deploying intravitreal injections so that unnecessary use of such may be curtailed.

In vitro and ex vivo models to study drug delivery barriers in the posterior segment of the eye

Many ocular disorders leading to blindness could benefit from efficient delivery of therapeutics to the retina. However, despite extensive research into drug delivery vehicles and administration techniques, efficacy remains limited because of the many static and dynamic barriers present in the eye. Comprehension of the various barriers and especially how to overcome them can improve our ability to estimate the potential of existent drug delivery vectors and support the design of new ones. To this end, this review gives an overview of the most important ocular barriers for each administration route to the back of the eye. For each barrier, its biological composition and its role as an obstacle towards macromolecules, nanoparticles and viral vectors will be discussed; special attention will be paid to the influence of size, charge and lipophilicity of drug(s) (carrier) on their ability to overcome each barrier. Finally, the most significant available in vitro and ex vivo methods and models to test the potential of a therapeutic to cross each barrier are listed.

Incidence of Endophthalmitis after Intravitreal Injections: Risk Factors, Microbiology Profile, and Clinical Outcomes

PURPOSE

To report the incidence and characteristics of endophthalmitis after intravitreal injections (IVI) of antivascular endothelial growth factor agents and triamcinolone acetonide.

METHODS

Patients' medical records were retrospectively reviewed from January 2009 to June 2016, and the incidence, risk factors, clinical and microbiological characteristics of post-IVI endophthalmitis were evaluated.

RESULTS

The total number of intravitreal injections given, which included ranibizumab, bevacizumab, and triamcinolone acetonide, was 20,566, of which 27 cases developed endophthalmitis, giving an overall incidence of 0.131%. Significant reduction (p < 0.003) in incidence of endophthalmitis was observed in patients who received prefilled compounded bevacizumab injections (0.050%) compared to multiple bevacizumab injections from a single vial (0.235%). In the triamcinolone acetonide group, the incidence was 0.26%. Staphylococcus species were isolated from 18 cases (67%), and all strains were sensitive to vancomycin.

CONCLUSIONS

Adherence to strict aseptic protocols and use of prefilled compounded bevacizumab injections reduces the rate of post-IVI endophthalmitis.

Stenotrophomonas maltophilia: An emerging entity for cluster endophthalmitis

PURPOSE

This was a study of acute cluster endophthalmitis along with clinical features, culture results, and visual outcomes of 10 eyes of 10 patients after intravitreal injection of Avastin (bevacizumab) in one sitting from a single vial.

METHODS

Retrospective review of intravitreal injection of 1.25 mg/0.05 ml bevacizumab that was given to 10 eyes of 10 patients on the same day from a freshly opened vial. All patients manifested with endophthalmitis the next day. Vitreous tap for direct smear and culture was done. Intravitreal antibiotics and steroids were injected and appropriate treatment begun. The injection vial of the same batch was sent for VITEKTM identification and antimicrobial susceptibility of isolates.

RESULTS

Endophthalmitis presented within 24 h of intravitreal injection. There was a remarkable absence of posterior pupillary synechia. Two cases were culture-positive (20%), showing pseudomonoid growth. The vial of the same batch revealed a pseudomonoid bacilli Stenotrophomonas maltophilia using VITEKTM, which was resistant to multiple drugs. Hence, the contaminated vial was identified as the source of infection in our case. Among 10 patients, two underwent pars plana vitrectomy. Visual acuity returned to preendophthalmitis levels in 9/10 eyes after 1 month. One patient was lost to follow-up. Late complications included retinal detachment in one case and neovascular glaucoma in another.

CONCLUSION

Early recognition and treatment are key factors in improving outcomes. Causative etiology could be microbial contamination of the drug vial. S. maltophilia should be considered a pathogenic organism of postintravitreal endophthalmitis.

Lid splinting eyelid retraction technique: a minimised sterile approach for intravitreal injections

BACKGROUND/AIMS

To describe an alternative technique for avoiding contact with the lids and lashes, without the use of a lid speculum, during intravitreal anti-vascular endothelial growth factor injections.

METHODS

Retrospective case series of all patients undergoing intravitreal injections of bevacizumab and ranibizumab, with the lid splinting retraction technique from January 2010 to December 2015. Injections performed by six vitreoretinal specialists were included. The key preinjection ocular surface preparation includes topical anaesthetic, 5% povidone-iodine and a subconjunctival injection of 2% lidocaine with epinephrine. A second instillation of 5% povidone-iodine is given and the intravitreal injection is then performed. No lid speculum is used. A search of the electronic medical records identified patients diagnosed with postinjection endophthalmitis and charts were reviewed to ensure inclusion criteria were met. The main outcome measure was incidence of postinjection endophthalmitis.

RESULTS

A total of 78 009 consecutive intravitreal injections were performed, of which 22 207 were bevacizumab and 55 802 were ranibizumab. In this cohort of patients (n=6320), 12 cases of endophthalmitis developed, corresponding to a rate of 0.015%.

CONCLUSIONS

The technique of eyelid retraction for intravitreal injection has a low rate of endophthalmitis, similar to the reported rates using a metal lid speculum. This is beneficial for both the physician and the patient as it minimises patient discomfort as well as the duration of the procedure. To our knowledge, this is one of the largest studies performed to date evaluating intravitreal injection-related endophthalmitis.

Toward smart design of retinal drug carriers: a novel bovine retinal explant model to study the barrier role of the vitreoretinal interface

Retinal gene delivery via intravitreal injection is hampered by various physiological barriers present in the eye of which the vitreoretinal (VR) interface represents the most serious hurdle. In this study, we present a retinal explant model especially designed to study the role of this interface as a barrier for the penetration of vectors into the retina. In contrast to all existing explant models, the developed model is bovine-derived and more importantly, keeps the vitreous attached to the retina at all times to guarantee an intact VR interface. After ex vivo intravitreal injection into the living retinal explant, the route of fluorescent carriers across the VR interface can be tracked. By applying two different imaging methods on this model, we discovered that the transfer through the VR barrier is size-dependent since 40 nm polystyrene particles are more easily taken up in the retina than 100 and 200 nm sized particles. In addition, we found that removing the vitreous, as commonly done for culture of conventional explants, leads to an overestimation of particle uptake, and conclude that the ultimate barrier to overcome for retinal uptake is undoubtedly the inner limiting membrane. Damaging this matrix resulted in a massive increase in particle transfer into the retina. In conclusion, we have developed a highly relevant ex vivo model that maximally mimics the human in vivo physiology which can be applied as a representative test set-up to assess the potential of promising drug delivery carriers to cross the VR interface.

The peptidomimetic Vasotide targets two retinal VEGF receptors and reduces pathological angiogenesis in murine and nonhuman primate models of retinal disease

Blood vessel growth from preexisting vessels (angiogenesis) underlies many severe diseases including major blinding retinal diseases such as retinopathy of prematurity (ROP) and aged macular degeneration (AMD). This observation has driven development of antibody inhibitors that block a central factor in AMD, vascular endothelial growth factor (VEGF), from binding to its receptors VEGFR-1 and mainly VEGFR-2. However, some patients are insensitive to current anti-VEGF drugs or develop resistance, and the required repeated intravitreal injection of these large molecules is costly and clinically problematic. We have evaluated a small cyclic retro-inverted peptidomimetic, D(Cys-Leu-Pro-Arg-Cys) [D(CLPRC)], and hereafter named Vasotide, that inhibits retinal angiogenesis by binding selectively to the VEGF receptors VEGFR-1 and neuropilin-1 (NRP-1). Delivery of Vasotide via either eye drops or intraperitoneal injection in a laser-induced monkey model of human wet AMD, a mouse genetic knockout model of the AMD subtype called retinal angiomatous proliferation (RAP), and a mouse oxygen-induced model of ROP decreased retinal angiogenesis in all three animal models. This prototype drug candidate is a promising new dual receptor inhibitor of the VEGF ligand with potential for translation into safer, less-invasive applications to combat pathological angiogenesis in retinal disorders.

Incidence of Endophthalmitis after Intravitreal Bevacizumab using Aliquots Prepared On-site in 2 Operating Rooms in Kuwait

Purpose:

To report the incidence of endophthalmitis after intravitreal injection of bevacizumab and the outcomes of treatment of endophthalmitis at two centers in Kuwait.

Subjects and Methods:

The aliquots of bevacizumab were prepared under aseptic precautions and administered in the operating theater on the same day at both centers. All patients received antibiotic drops after injection of bevacizumab. Data were collected on the number of cases that received intravitreal bevacizumab (IVB) and those that developed endophthalmitis were identified at the two centers. All cases of endophthalmitis received an intravitreal antibiotic injection and additional treatments as warranted. Data were collected on the outcomes of endophthalmitis treatment.

Results:

There were 5 cases of endophthalmitis among a total of 5429 injections (0.09%: Confidence interval: 0.084–0.1). The incidence was 3 cases among 4690 (0.06%) and 2 cases among 739 injections (0.027%) at each center, respectively (P = 0.08). Four cases of endophthalmitis were culture-positive and organisms isolated were, coagulase negative Staphylococcus in 2 cases, Staphylococcus lugdunensis and Streptococcus pneumoniae in 1 case each. The final visual acuity was better than pre-IVB in 3 cases, same as pre-IVB in 1 case and worse in 1 case with streptococcal infection. No eyes developed phthisis bulbi or required enucleation.

Conclusions:

The incidence of endophthalmitis after intravitreal injection of bevacizumab using aliquots prepared in the operating room is comparable to other studies. There were no clusters of endophthalmitis cases.

Current Perspectives of Prophylaxis and Management of Acute Infective Endophthalmitis

Endophthalmitis is an intraocular inflammatory condition which may or may not be caused by infective agents. Noninfectious (sterile) endophthalmitis may be attributable to various causes including postoperative retained soft lens matter or toxicity following introduction of other agents into the eye. Infectious endophthalmitis is further subdivided into endogenous and exogenous. In endogenous endophthalmitis there is hematogenous spread of organisms from a distant source of infection whereas in exogenous endophthalmitis direct microbial inoculation may occur usually following ocular surgery or penetrating eye injury with or without intraocular foreign bodies. Acute infective endophthalmitis is usually exogenous induced by inoculation of pathogens following ocular surgery, open-globe injury and intravitreal injections. More infrequently the infective source is internal and septicemia spreads to the eye resulting in endogenous endophthalmitis. Several risk factors have been implicated including immunosuppression, ocular surface abnormalities, poor surgical wound construction, complicated cataract surgery with vitreous loss and certain types of intraocular lens. Comprehensive guidelines and recommendations on prophylaxis and monitoring of surgical cases have been proposed to minimize the risk of acute endophthalmitis. Early diagnosis and prompt management of infective endophthalmitis employing appropriately selected intravitreal antibiotics are essential to optimize visual outcome.

Endophthalmitis following intravitreal injection of anti-VEGF agents: long-term outcomes and the identification of unusual micro-organisms

Background

While the development of targeted molecular therapy to inhibit vascular endothelial growth factor (VEGF) has revolutionized the treatment and visual prognosis of highly prevalent retinal diseases such as diabetic retinopathy and age-related macular degeneration, each intravitreal injection of these agents carries a small risk of endophthalmitis which can be visually devastating. In the absence of specific guidelines, current management of post-injection endophthalmitis is typically extrapolated from data regarding endophthalmitis occurring after cataract surgery despite potential differences in pathogenic organisms and clinical course. Here, we assess the contribution of intravitreal injections of anti-VEGF agents to all cases of endophthalmitis at our tertiary care referral center and characterize the clinical outcomes and microbial pathogens associated with post-injection endophthalmitis in order to inform management of this serious iatrogenic condition.

Results

During the 7-year study period analyzed, 199 cases of endophthalmitis were identified using billing records. Of these, the most common etiology was post-surgical, accounting for 62 cases (31.2 %), with bleb-associated, endogenous, and corneal ulcer-related infections representing the next most frequent causes, comprising 15.6 % (31/199), 13.1 % (26/199), and 13.6 % (27/199) of all cases, respectively. Intravitreal injections of anti-VEGF agents represented 8.5 % of endophthalmitis (17/199 cases). Intraocular cultures yielded positive results in 75 % of post-injection cases, with the majority associated with coagulase-negative Staphylococcus. Consistent with prior literature, a case of Strep viridans displayed more rapid onset and progression. We also report the first association of Enterobacter cloacae and Lactococcus garvieae with post-injection endophthalmitis. While all but one patient were treated with initial vitreous tap and intravitreal injection of antibiotics, both patients with these rare organisms exhibited persistent vitritis requiring subsequent vitrectomy. Long-term outcomes of post-injection endophthalmitis indicated visual recovery to baseline levels, even with resumption of anti-VEGF agents following resolution of the acute infection.

Conclusions

Acute endophthalmitis following intravitreal injections of anti-VEGF agents is an uncommon but potentially devastating complication which may be managed effectively with vitreous tap and injection of intravitreal antibiotics. However, persistent vitritis requiring subsequent vitrectomy should raise suspicion for unusual pathogens.

Eliminating antibiotic prophylaxis for intravitreal injections: a consecutive series of 18,839 injections by a single surgeon

PURPOSE

By optimizing the protocol for intravitreal injections, the risk of endophthalmitis can be minimized. This study assesses the incidence of endophthalmitis and other complications after a consecutive series of intravitreal injections where all antibiotics were excluded.

METHODS

Injections were performed from August 1, 1997 to October 31, 2012 in outpatient examination rooms at the Retina Center of Minnesota by a single retinal surgeon, the lead author. Most injections were performed to treat exudative age-related macular degeneration. Other reasons included diabetic macular edema, cystoid macular edema because of retinal vein occlusions, cytomegalovirus retinitis, and severe uveitis. Injections were given with topical povidone-iodine, proparacaine, and tetracaine, a sterile eyelid speculum, and clean nonsterile gloves, but without any antibiotics. Data were retrospectively analyzed using billing codes from a computer database system.

RESULTS

A total of 18,839 injections were given. Of these, the following injections were administered: bevacizumab, 15,479 (82.16%); ranibizumab, 1,669 (8.86%); triamcinolone acetonide (Kenalog-40), 1,014 (5.38%); pegaptanib sodium, 370 (1.96%); aflibercept, 148 (0.79%); dexamethasone implant, 88 (0.47%); triamcinolone acetonide (Triesence), 32 (0.17%); dexamethasone, 29 (0.15%); and ganciclovir, 10 (0.05%). There was one case of postinjection endophthalmitis. The incidence of endophthalmitis per injection was 0.0053%.

CONCLUSION

A low incidence of endophthalmitis can be achieved when topical antibiotics are omitted.

Endophthalmitis following intravitreal anti-vascular endothelial growth factor (VEGF) injection: a comprehensive review

The purpose of this review is to report and summarize previously reported studies and assess many of the individual steps of the intravitreal injection procedure's possible effect on the prevention of endophthalmitis. The pooled endophthalmitis rate from 20 large retrospective case series of anti-VEGF injections was 144/510,396 (0.028%; 1/3,544). Injections may be performed in an office-based location or in an operating room (OR) and low rates of endophthalmitis can be achieved in either location with careful attention to asepsis. Pre- or post-injection topical antibiotics have not been shown to be effective, and could select for more virulent microorganisms. Povidone-iodine prior to injection is accepted as the gold-standard antiseptic agent, but aqueous chlorhexidine may be an alternative. Antisepsis before and after gel or subconjunctival anesthetic is suggested. The preponderance of Streptococcal infections after intravitreal injection is discussed, including the possible role of aerosolization, which can be minimized by using face masks or maintaining silence. As with other invasive procedures in medicine, the use of sterile gloves, following adequate hand antisepsis, may be considered. Control of the eyelashes and lid margin is required to avoid contamination of the needle, but this can be achieved with or without a speculum. Techniques to minimize vitreous reflux have not been shown to reduce the risk of endophthalmitis. Same day bilateral injections should be performed as two separate procedures, preferably using drug from different lots, especially when using compounded drugs.

An outbreak of Ralstonia pickettii endophthalmitis following intravitreal methotrexate injection

Purpose

To report an outbreak of endophthalmitis in three eyes of two patients following intravitreal methotrexate, caused by Ralstonia pickettii.

Design

Retrospective, noncomparative, consecutive case series.

Methods

Medical records and microbiology results of two patients who presented with acute endophthalmitis following intravitreal methotrexate injection in November 2013 were reviewed.

Results

Following intravitreal injections, the patients experienced pain and decrease in vision in the affected eye within 24 hours of receiving intravitreal methotrexate injection. The presenting visual acuity in case 1 was 20/50 in the left eye. The presenting visual acuity in case 2 was hand motions in the right eye and counting fingers at 1 m in the left eye. Both the patients received methotrexate prepared in the same manufacturing facility. Both the patients underwent vitreous biopsy and intravitreal injection of vancomycin 1 mg/0.1 mL, amikacin 400 µg/0.1 mL, and dexamethasone 400 µg/0.1 mL. Microbiology cultures from vitreous, and used and unused vials of methotrexate from the same batch grew R. pickettii. After 8 months of follow-up, both the patients had visual acuity 20/60 or better.

Conclusion

R. pickettii can be rarely associated with outbreak of endophthalmitis. Timely intervention can be associated with good visual outcome in such patients.

Complications of subspecialty ophthalmic care: endophthalmitis after intravitreal injections of anti-vascular endothelial growth factor medications

The use of medications directed against vascular endothelial growth factor (VEGF) signaling has revolutionized the treatment of age-related macular degeneration (AMD) and many other retinal diseases in the last decade. However, the rapidly increasing use of these agents has led to a rise in treatment-associated complications. One of the most feared by patients and ophthalmologists is post-injection endophthalmitis, which can result in severe vision loss and, in rare cases, loss of the eye. The aim of this article is to review the incidence, clinical findings, risk factors, management, and visual outcomes in cases of endophthalmitis following intravitreal injections of anti-VEGF medications.

Modulation of VEGF-induced retinal vascular permeability by peroxisome proliferator-activated receptor-β/δ

PURPOSE

Vascular endothelial growth factor (VEGF)-induced retinal vascular permeability contributes to diabetic macular edema (DME), a serious vision-threatening condition. Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) antagonist/reverse agonist, GSK0660, inhibits VEGF-induced human retinal microvascular endothelial cell (HRMEC) proliferation, tubulogenesis, and oxygen-induced retinal vasculopathy in newborn rats. These VEGF-induced HRMEC behaviors and VEGF-induced disruption of endothelial cell junctional complexes may well share molecular signaling events. Thus, we sought to examine the role of PPARβ/δ in VEGF-induced retinal hyperpermeability.

METHODS

Transendothelial electrical resistance (TEER) measurements were performed on HRMEC monolayers to assess permeability. Claudin-1/Claudin-5 localization in HRMEC monolayers was determined by immunocytochemistry. Extracellular signal-regulated protein kinases 1 and 2 (Erk 1/2) phosphorylation, VEGF receptor 1 (VEGFR1) and R2 were assayed by Western blot analysis. Expression of VEGFR1 and R2 was measured by quantitative RT-PCR. Last, retinal vascular permeability was assayed in vivo by Evans blue extravasation.

RESULTS

Human retinal microvascular endothelial cell monolayers treated with VEGF for 24 hours showed decreased TEER values that were completely reversed by the highest concentration of GSK0660 (10 μM) and PPARβ/δ-directed siRNA (20 μM). In HRMEC treated with VEGF, GSK0660 stabilized tight-junctions as evidenced by Claudin-1 staining, reduced phosphorylation of Erk1/2, and reduced VEGFR1/2 expression. Peroxisome proliferator-activated receptor β/δ siRNA had a similar effect on VEGFR expression and Claudin-1, supporting the specificity of GSK0660 in our experiments. Last, GSK0660 significantly inhibited VEGF-induced retinal vascular permeability and reduced retinal VEGFR1and R2 levels in C57BL/6 mice.

CONCLUSIONS

These data suggest a protective effect for PPARβ/δ antagonism against VEGF-induced vascular permeability, possibly through reduced VEGFR expression. Therefore, antagonism/reverse agonism of PPARβ/δ siRNA may represent a novel therapeutic methodology against retinal hyperpermeability and is worthy of future investigation.

Prevention and treatment of injection-related endophthalmitis

BACKGROUND

Intravitreal injections are the fastest growing cause of endophthalmitis and can result in severe vision loss. The prevention, diagnosis and management of such infections remain unclear and at times controversial.

METHODS

We searched Pubmed for keywords "prophylaxis," "endophthalmitis," "intravitreal injection." We focused on studies published in the last 2 years as well as other recent studies with particular attention to data on the incidence, microbiology, prevention, and treatment of injection-related endophthalmitis.

RESULTS

Over 20 relevant studies were found. With povidone-iodine preparation, the per-injection endophthalmitis rate is low at about 0.03%. Antibiotics do not appear to be beneficial for prevention of post-injection endophthalmitis. The best timing of vitrectomy is unclear.

CONCLUSIONS

Antibiotic prophylaxis is probably not needed when giving intravitreal injections. More data is needed to help determine the proper treatment for post-injection endophthalmitis.

[Incidence of endophthalmitis after intravitreal injection: is antibioprophylaxis mandatory?]

INTRODUCTION

Endophthalmitis is the most dreaded complication after intravitreal injection. With the rise of antiangiogenics their rate is getting higher each year. The use of antibioprophylaxis is controversial. We tried to evaluate the impact of antibioprophylaxis on intravitreal injection endophthalmitis incidence.

METHODS

All patients who received intravitreal injections between January 2007 and October 2012 were included in this retrospective study. Until June 2012 all patients had antibiotics the days following the injection. From July 2012 the antibiotic was replaced by an antiseptic immediately after the injection.

RESULTS

An overall number of 11,450 injections were performed. The overall rate of endophthalmitis was 6/11,450 (0.052%). The incidence of endophthalmitis in the group with antibiotics was 3/10,144 injections (0.03%), 2 were culture proven (0.02%). The incidence in the group without antibiotics was 3/1306 (0.23%). The difference was significant (P=0.024).

CONCLUSION

The incidence of endophthalmitis post-intravitreal injections seems to be lower when using antibiotics. However, a prospective study is mandatory to draw more robust conclusions.

Burkholderia cepacia endophthalmitis, in a penicillin allergic patient, following a ranibizumab injection

Burkholderia cepacia, a Gram-negative bacterium commonly found in water and soil, is a rare cause of endophthalmitis. The authors report a case of a penicillin-allergic patient who presented 15 days after an uneventful injection of ranibizumab for neovascular age-related macular degeneration with culture-positive B cepacia endophthalmitis. Initial antibiotic therapy using non-penicillin-based medications was not successful in eradicating the bacteria. Subsequent treatment with a third-generation cephalosporin resulted in complete resolution of the infection. B cepacia should be included among the bacterial species that may cause endophthalmitis after intravitreal injections.

Endophthalmitis Associated with Intravitreal Anti-Vascular Endothelial Growth Factor Injections

The use of anti-vascular endothelial growth factor (VEGF) agents has led to a dramatic increase in the number of intravitreal injections. Endophthalmitis remains a rare but potentially vision-threatening complication of intravitreal injections. Recent large series have estimated this risk to be about one in 3,000 injections or less. Bevacizumab, which is generally prepared by a compounding pharmacy, is associated with additional risks of contamination. Although endophthalmitis cannot be prevented in all cases, certain risk reduction strategies have been proposed, including the use of an eyelid speculum, povidone iodine, avoidance of needle contact with the eyelid margin or eyelashes, and avoidance of routine post-injection antibiotics. Despite these precautions, some patients will develop endophthalmitis following intravitreal anti-VEGF injections, and outcomes may be poor despite prompt and appropriate therapy.

Tyrosine capsid-mutant AAV vectors for gene delivery to the canine retina from a subretinal or intravitreal approach

Recombinant adeno-associated viruses are important vectors for retinal gene delivery. Currently utilized vectors have relatively slow onset and for efficient transduction it is necessary to deliver treatment subretinally, with the potential for damage to the retina. Amino-acid substitutions in the viral capsid improve efficiency in rodent eyes by evading host responses. As dogs are important large animal models for human retinitis pigmentosa, we evaluated the speed and efficiency of retinal transduction using capsid-mutant vectors injected both subretinally and intravitreally. We evaluated AAV serotypes 2 and 8 with amino-acid substitutions of surface exposed capsid tyrosine residues. The chicken beta-actin promoter was used to drive green fluorescent protein expression. Twelve normal adult beagles were injected, 4 dogs received intravitreal injections, 8 dogs received subretinal injections. Capsid-mutant viruses tested included AAV2(quad Y-F) (intravitreal and subretinal), and self-complementary scAAV8(Y733F) (subretinal only). Contralateral control eyes received injections of scAAV5 (subretinal) or scAAV2 (intravitreal). Subretinally delivered vectors had a faster expression onset than intravitreally delivered vectors. Subretinally delivered scAAV8(Y733F) had a faster onset of expression than scAAV5. All subretinally injected vector types transduced the outer retina with high efficiency, and the inner retina with moderate efficiency. Intravitreally delivered AAV2(quad Y-F) had a marginally higher efficiency of transduction of both outer retinal and inner retinal cells than scAAV2. Because of their rapid expression onset and efficient transduction, subretinally delivered capsid-mutant AAV8 vectors may increase the efficacy of gene therapy treatment for rapid photoreceptor degenerative diseases. With further refinement, capsid-mutant AAV2 vectors show promise for retinal gene delivery from an intravitreal approach.

Biomarkers in diabetic retinopathy and the therapeutic implications

The main problem both in type 1 (T1DM) and type 2 (T2DM) diabetes is the development of chronic vascular complications encompassing micro- as well as macrocirculation. Chronic complications lower the quality of life, lead to disability, and are the cause of premature death in DM patients. One of the chronic vascular complications is a diabetic retinopathy (DR) which leads to a complete loss of sight in DM patients. Recent trials show that the primary cause of diabetic retinopathy is retinal neovascularization caused by disequilibrium between pro- and antiangiogenic factors. Gaining knowledge of the mechanisms of action of factors influencing retinal neovascularization as well as the search for new, effective treatment methods, especially in advanced stages of DR, puts special importance on research concentrating on the implementation of biological drugs in DR therapy. At present, it is antivascular endothelial growth factor and antitumor necrosis factor that gain particular significance.

Current and future management of diabetic retinopathy: a personalized evidence-based approach

Diabetic retinopathy (DR) is the leading cause of new-onset blindness in working-age individuals in the USA and represents a growing worldwide epidemic. Classic risk factors for onset or progression of DR include poor glycemic control, hypertension and hyperlipidemia; however, these factors account for only a small proportion of the risk of DR. New systemic risk factors are emerging, which may allow for personalized risk profiling and targeted treatment by physicians. In addition, early studies of vitreous fluid in patients with DR have resulted in a new paradigm: diabetes causes inflammation in the retina, which is mediated by multiple small signaling molecules that induce angiogenesis and vascular permeability. Future treatment of DR may involve two approaches: early vitreous analysis, followed by drug treatment targeted to the unique vitreous composition of the patient; and collaboration between ophthalmologists and primary care providers to address the unique systemic risk profile of each diabetic patient.