Adjunctive use of intravitreal dexamethasone in presumed bacterial endophthalmitis: a randomised trial

Consensus and controversies in the science of endophthalmitis management: Basic research and clinical perspectives

Infectious endophthalmitis is a severe intraocular infection caused by bacteria, or less commonly by fungi. It can occur after penetrating eye procedures, trauma, or the spread of infection from contiguous structures or via emboli from distant organs. Because of the time-critical nature of the treatment, endophthalmitis is treated with the clinical diagnosis and modified by the microbiological report of the intraocular contents. The current strategy for managing endophthalmitis relies on pre-clinical literature, case series, and one large multi-center randomized clinical trial on post-cataract surgery endophthalmitis. Culture-susceptibility of the microorganisms from undiluted vitreous guides the definitive treatment in non-responsive cases. Strategies to reduce the incidence of endophthalmitis after penetrating eye procedures have been developed concurrently with refined means of treatment. Despite these advances, outcomes remain poor for many patients. Although consensus articles have been published on managing endophthalmitis, treatment patterns vary, and controversies remain. These include (1) the use of newer methods for early and precise microbiological diagnosis; (2) the choice of intravitreal antibiotics; (3) the need for systemic therapy; (4) early and complete vitrectomy. Here, we review the current consensus and address controversies in diagnosing and managing endophthalmitis. This review is intended to familiarize physicians and ophthalmologists with different aspects of endophthalmitis management to make informed decisions.

ALTERNATIVE INTRAVITREAL ANTIBIOTICS: A Systematic Review for Consideration in Recalcitrant or Resistant Endophthalmitis

PURPOSE

To organize, categorize, and create a quick reference guide for the use of intravitreal antibiotic alternatives to the standard combination of vancomycin and ceftazidime for the treatment of endophthalmitis.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. The authors searched for all available information regarding intravitreal antibiotics in the last 21 years. Manuscripts were selected according to relevance, level of information, and the available data regarding intravitreal dose, potential adverse effects, bacterial coverage, and relevant pharmacokinetic information.

RESULTS

The authors included 164 of 1810 manuscripts. The antibiotics were classified according to their class into fluoroquinolones, cephalosporins, glycopeptide and lipopeptide, penicillins and beta-lactams, tetracyclines, and miscellaneous. The authors also included information regarding intravitreal adjuvants for the treatment of endophthalmitis and one ocular antiseptic.

CONCLUSION

The treatment of infectious endophthalmitis is a therapeutic challenge. The current review summarizes the properties of possible intravitreal antibiotic alternatives that should be considered in cases of suboptimal response to initial treatment.

Exogenous Endophthalmitis

PURPOSE

Exogenous endophthalmitis (ExE) results from microbial infection as a complication of ocular surgery, penetrating ocular trauma, and intraocular foreign bodies. We herein review the classification of ExE, etiological agents, differential diagnosis and therapeutic challenges.

METHODS

Narrative Literature Review.

RESULTS

Identification of the causative agent through ocular fluid analysis is central in the diagnostic work-up of ExE. Prompt intravitreal antimicrobial therapy is key to successful management of ExE and vitrectomy is essential in severe cases. In culture-negative cases, and in the presence of specific features, a diagnosis of sterile intraocular inflammation or toxic syndrome should be suspected.

CONCLUSION

Strict adherence to treatment guidelines may improve outcomes of ExE, however the ultimate prognosis, especially in severe cases, may depend more on the virulence of the causative organism and associated ocular complications. Accurate differential diagnosis and effective treatment are crucial elements in the management and prognosis of non-infectious masquerades of ExE.

Clinical Practice Update: Management of Infectious Endophthalmitis After Intravitreal Anti-VEGF Injection

Although infectious endophthalmitis after intravitreal antivascular endothelial growth factor injections is rare, it is the most feared and potentially devastating complication of this procedure. There is no high-level evidence to provide definitive guidance on the management of endophthalmitis occurring after intravitreal injection (IVI). This clinical practice update reviews the published literature regarding post-IVI endophthalmitis and highlights areas in which further research is needed to better guide its management.

Visual outcomes of acute bacterial endophthalmitis treated with adjuvant intravitreal dexamethasone: A meta-analysis and systematic review

Adjunctive treatment of bacterial endophthalmitis with intravitreal steroids is a topic of controversy among many ophthalmologists. The objective of this study is to evaluate the effects of intravitreal dexamethasone on the visual outcomes of patients with acute bacterial endophthalmitis through a systematic review and meta-analysis. A literature search of PubMed, Scopus, and Cochrane Library databases was performed to include studies on the visual outcomes of adjuvant intravitreal dexamethasone in patients with acute bacterial endophthalmitis. The review is based on the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) protocol. A total of 1545 articles met our search criteria and after further review, two randomized controlled trials and three retrospective case series were included in the final analysis. A total of 126 eyes were treated with intravitreal dexamethasone combined with antibiotics, and another 139 eyes were treated with antibiotics alone. All cases of endophthalmitis were post-operative or post-intravitreal injection, with pooled results demonstrating no visual benefit with supplementation of intravitreal dexamethasone. Our meta-analysis does not show any visual benefit from steroid supplementation and yet, considering a relatively small number of patients included in each study, larger randomized controlled trials are required to further clarify the role of steroids in the treatment of acute bacterial endophthalmitis.

Adjunctive steroid therapy versus antibiotics alone for acute endophthalmitis after intraocular procedure

BACKGROUND

Endophthalmitis refers to severe infection within the eye that involves the aqueous humor or vitreous humor, or both, and that threatens vision. Most cases of endophthalmitis are exogenous (i.e. due to inoculation of organisms from an outside source), and most exogenous endophthalmitis is acute and occurs after an intraocular procedure. The mainstay of treatment is emergent administration of broad-spectrum intravitreous antibiotics. Due to their anti-inflammatory effects, steroids in conjunction with antibiotics have been proposed as being beneficial in endophthalmitis management.

OBJECTIVES

To assess the effects of antibiotics combined with steroids versus antibiotics alone for the treatment of acute endophthalmitis following intraocular surgery or intravitreous injection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2021, Issue 8), MEDLINE Ovid (1946 to August 2021), Embase Ovid (1980 to August 2021), LILACS (Latin American and Caribbean Health Sciences Literature database) (1982 to August 2021), the ISRCTN registry; searched August 2021, ClinicalTrials.gov; searched August 2021, and the WHO International Clinical Trials Registry Platform; searched August 2021. We did not use any date or language restrictions in the electronic searches for trials.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing the effectiveness of adjunctive steroids with antibiotics alone in the management of acute, clinically diagnosed endophthalmitis following intraocular surgery or intravitreous injection. We excluded trials with participants with endogenous endophthalmitis unless outcomes were reported by source of infection. We imposed no restrictions on the method or order of administration, dose, frequency, or duration of antibiotics and steroids.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology, and graded the certainty of the body of evidence for six outcomes using the GRADE classification.

MAIN RESULTS

We included four RCTs with a total of 264 eyes of 264 participants in this review update. The studies were conducted in South Africa, India, and the Netherlands. All studies used intravitreous dexamethasone for adjunctive steroid therapy and a combination of two intravitreous antibiotics that provided gram-positive and gram-negative coverage for the antibiotic therapy. We judged two trials to be at overall low risk of bias, and the other two studies to be at overall unclear risk of bias due to lack of reporting of study methods. Only one study was registered in a clinical trial register.  While none of the included studies reported the primary outcome of complete resolution of endophthalmitis as defined in our protocol, one study reported combined anatomical and functional success (i.e. proportion of participants with intraocular pressure of at least 5 mmHg and visual acuity of at least 6/120). Very low certainty evidence suggested no difference in combined success when comparing adjunctive steroid to antibiotics alone (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.80 to 1.45; 32 participants). Low certainty evidence from two studies suggested that adjunctive dexamethasone may result in having a good visual outcome (Snellen visual acuity 6/6 to 6/18) at 3 months compared with antibiotics alone (RR 1.95, 95% CI 1.05 to 3.60; 60 participants); however, the evidence was less conclusive at 12 months (RR 1.12, 95% CI 0.92 to 1.37; 2 studies; 195 participants; low certainty evidence). Investigators of one study reported improvement in visual acuity, but we could not estimate the effect of adjunctive steroid therapy because the study investigators did not provide any estimates of precision. Only one study examined intraocular pressure (IOP). The evidence suggests that adjunctive dexamethasone may reduce IOP slightly after 12 months of interventions (mean difference -1.90, 95% CI -3.78 to 0.07; 1 study; 167 participants; low certainty evidence). Three studies reported adverse events (retinal detachment, hypotony, proliferative vitreoretinopathy, seclusion of pupil, floaters, and pucker). The total numbers of adverse events were 14 out of 111 (12.6%) for those who received dexamethasone versus 12 out of 116 (10.3%) for those who did not. We could only perform a pooled analysis for the occurrence of retinal detachment: any difference between the two treatment groups was uncertain (RR 1.41, 95% CI 0.53 to 3.74; 227 participants; low certainty evidence). No study reported cost-related outcomes.

AUTHORS' CONCLUSIONS

The currently available evidence on the effectiveness of adjunctive steroid therapy versus antibiotics alone in the management of acute endophthalmitis after intraocular surgery is inadequate. We found no studies that had enrolled cases of acute endophthalmitis following intravitreous injection. A combined analysis of two studies suggests that use of adjunctive steroids may provide a higher chance of having a good visual outcome at three months than not using adjunctive steroids. However, considering that most of the confidence intervals crossed the null, and that this review was limited in scope and applicability to clinical practice, it is not possible to conclude whether the use of adjunctive steroids is effective at this time. Any future trials should examine whether adjunctive steroids may be useful in certain clinical settings such as type of causative organism or etiology. These studies should include outcomes that take patients' symptoms and clinical examination into account; report outcomes in a uniform and consistent manner; and follow up at short- and long-term intervals.

Dexamethasone: Insights into Pharmacological Aspects, Therapeutic Mechanisms, and Delivery Systems

Dexamethasone (DEX) has been widely used to treat a variety of diseases, including autoimmune diseases, allergies, ocular disorders, cancer, and, more recently, COVID-19. However, DEX usage is often restricted in the clinic due to its poor water solubility. When administered through a systemic route, it can elicit severe side effects, such as hypertension, peptic ulcers, hyperglycemia, and hydro-electrolytic disorders. There is currently much interest in developing efficient DEX-loaded nanoformulations that ameliorate adverse disease effects inhibiting advancements in scientific research. Various nanoparticles have been developed to selectively deliver drugs without destroying healthy cells or organs in recent years. In the present review, we have summarized some of the most attractive applications of DEX-loaded delivery systems, including liposomes, polymers, hydrogels, nanofibers, silica, calcium phosphate, and hydroxyapatite. This review provides our readers with a broad spectrum of nanomedicine approaches to deliver DEX safely.

Global Preferred Practice Patterns for the Management of Exogenous Endophthalmitis: A Survey by the American Society of Ophthalmic Trauma

OBJECTIVE

: To investigate the global practice patterns for the management of exogenous endophthalmitis.

METHODS

: This cross-sectional study was conducted to assess global practice patterns for the management of exogenous endophthalmitis. An online survey comprised of questions regarding the management of exogenous endophthalmitis was distributed to institutions who are members of International Globe and Adnexal Trauma Epidemiology Study Group (IGATES) or invited affiliates of the American Society of Ophthalmic Trauma and the Asia Pacific Ophthalmic Trauma Society. Responses were gathered from August 2020 to January 2021.

RESULTS

Of 42 institutions, 36 responses were received (86% response rate), of which 33 (79%) were included in the analysis. Included centers were from Asia (36%), North America (36%), South America (12%), Africa (9%), Europe (3%), and Australia (3%). Oral antibiotics were administered in 19 (58%) institutions, with moxifloxacin as the preferred agent (n=9, 27%). The preferred method for obtaining cultures was vitreous tap (n=25, 76%). Most institutions (n=26, 79%) routinely administered intravitreal vancomycin and ceftazidime, while intravitreal steroids were routinely administered at 11 centers (33%). Indications for performing vitrectomy included; decreased visual acuity (n=14, 39%); all cases of exogenous endophthalmitis (n=4, 12%); non-response to medical therapy (n=4, 12%); or no view of the fundus (n=4, 12%), indicating significant variation in surgical indications. More than half (n=17, 52%) of responding institutions routinely admitted patients with exogenous endophthalmitis to the hospital. Institutions in the United States were less likely to administer oral antibiotics (27% vs. 73%, P = 0.024) and to admit patients (9% vs. 73%, P < 0.001) compared to other countries.

CONCLUSIONS

: This study highlights the global variations in the management of exogenous endophthalmitis, especially as it pertains to surgical indications. Further establishment of evidence-based guidelines may be beneficial to provide more uniform guidance to optimize outcomes.

Systemic Immunosuppression and Risk of Endophthalmitis After Intravitreal Anti-Vascular Endothelial Growth Factor Injections

BACKGROUND AND OBJECTIVE

To evaluate the impact of systemic immunosuppressive therapy on the rates and outcomes of endophthalmitis following intravitreal anti-vascular endothelial growth factor (VEGF) injections.

PATIENTS AND METHODS

A retrospective, single-center, comparative cohort study examining eyes undergoing intravitreal anti-VEGF injections from January 2016 to September 2019. Cohorts were created based on concurrent immunosuppressive therapy at time of injection.

RESULTS

Of 270,347 anti-VEGF injections administered, 1,300 injections (0.48%) were administered while on systemic immunosuppressive therapy. The odds of endophthalmitis occurring in the immunosuppression group was 9.86 (95% confidence interval [CI], 4.0-24.3; P < .001) times higher than the no-immunosuppression group. Symptom onset occurred 2.51 (95% CI, 0.15-4.870; P = .040) days earlier in the immunosuppression cohort; visual acuity at 6 months after treatment was similar in both groups.

CONCLUSIONS

Patients on systemic immunosuppressive medications undergoing intravitreal injections may be at increased risk for post-injection endophthalmitis and may have earlier symptom onset. However, visual outcomes were similar between the two groups. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:S17-S22.].

Endophthalmitis management study. Report #1. Protocol

To date, the Endophthalmitis Vitrectomy Study (EVS) has remained the hallmark of evidence-based management of acute bacterial endophthalmitis after cataract surgery with an intraocular lens. In the last quarter-century since its publication, several studies have reported that the microbiological spectrum of endophthalmitis is not the same across the world; there is emerging antibiotic resistance of gram-negative microorganisms to the EVS recommended antibiotics; there are newer molecules that could cross the blood-retinal barrier; the advances in vitreous surgery have become safer than before, and there are newer methods of microbiological evaluation. One of the often-mentioned drawbacks of the EVS was not recruiting grossly infected eyes with poor visibility of the iris and vitreous. Keeping these factors in mind, a new prospective multi-centered randomized study, the Endophthalmitis Management Study (EMS), is designed. The EMS will recruit all post-cataract surgery endophthalmitis patients irrespective of severity (including suspected fungal infection); the EMS will use quantifiable inflammatory score instead of the presenting vision to allocate for surgery, randomize the eyes to two different combinations of intravitreal antibiotics and use the newer microbiological diagnostic techniques. We believe the EMS findings will complement the EVS recommendations.

Effectiveness of immediate vitrectomy and intravitreal antibiotics for post-injection endophthalmitis

PURPOSE

To show that an immediate vitrectomy with an intravitreal injection of antibiotics can be an effective approach for the treatment of acute endophthalmitis following intravitreal injections.

METHODS

We reviewed all cases of clinical endophthalmitis caused by an intravitreal injection that were treated in our department between March 2012 and November 2019. Only patients that underwent a vitrectomy within 6 h after presentation to the clinic and with a documented visual acuity shortly before the causative event were included. Baseline best-corrected visual acuity (BCVA) before the causative event was compared to BCVA measured within a follow-up period of 8 months (up to 14 months).

RESULTS

In total, 30 eyes of 30 patients were included. The BCVA before the intraocular infection was a mean value of 0.55 logMAR, and the BCVA on the day of the endophthalmitis decreased significantly to 1.66 logMAR. Within 2 months following the pars plana vitrectomy (PPV), the mean BCVA improved to 0.83 logMAR. Eight months following PPV (mean value, 8.20 months; SD, 3.59 months), the mean BCVA was 0.63 logMAR. In the last follow-up interval most of the eyes recovered, and the BCVA did not differ significantly from baseline. Two eyes underwent further pars plana surgery during the follow-up period. No enucleation was required.

CONCLUSION

In this study, we have shown that an immediate vitrectomy with subsequent intravitreal injection of antibiotics is an effective option for treating post-injection endophthalmitis and frequently results in recovery of vision; thus, it should be performed as early as possible, where available.

Long-term visual outcomes of endophthalmitis and the role of systemic steroids in addition to intravitreal dexamethasone

Background

The purpose of this study was to evaluate the role of systemic steroids in post-procedural endophthalmitis as the role of intravitreal steroids in treatment algorithms of endophthalmitis remain controversial.

Methods

This is a retrospective analysis from a single tertiary referral center of all patients older than 18 years old that developed presumed post-procedure endophthalmitis and were treated at our center from 2009 to 2018.

Results

Eighty-three patients were followed after being treated for post-procedural endophthalmitis that either received systemic steroids or did not around the time of diagnosis. Almost 30 % of all patients regained a final visual acuity of 20/40 or better, while 31.2% had poor visual outcomes of count fingers or worse. Non-clearing debris was the most significant long-term complication. Visual improvement plateaued in 67.7% by 1 month after diagnosis and initial treatment in both groups. There was no difference in visual outcomes when comparing the sixteen patients that received systemic steroids and the sixty-seven that did not; however, no enucleation or evisceration was required in patients receiving systemic steroids. Five patients that did not receive systemic steroids required an enucleation or evisceration due to a blind, painful eye.

Conclusions

The use of systemic steroids does not seem to worsen long-term outcomes of endophthalmitis compared to those patients that did not receive them and they may prove beneficial in the most severe cases by reducing the risk of losing the globe altogether.

Local delivery of corticosteroids in clinical ophthalmology: A review

Locally administered steroids have a long history in ophthalmology for the treatment of inflammatory conditions. Anterior segment conditions tend to be treated with topical steroids whilst posterior segment conditions generally require periocular, intravitreal or systemic administration for penetration. Over recent decades, the clinical applications of periocular steroid delivery have expanded to a wide range of conditions including macular oedema from retino-vascular conditions. Formulations have been developed with the aim to provide practical, targeted, longer-term and more efficacious therapy whilst minimizing side effects. Herein, we provide a comprehensive overview of the types of periocular steroid delivery, their clinical applications in ophthalmology and their side effects.

Dexamethasone Provides Effective Immunosuppression for Improved Survival of Retinal Organoids after Epiretinal Transplantation

We investigated the efficacy of the immunosuppressants rapamycin (RAP) and dexamethasone (DEX) in improving the survival of retinal organoids after epiretinal transplantation. We first compared the immunosuppressive abilities of DEX and RAP in activated microglia in an in vitro setting. Following this, we used immunofluorescence, real-time polymerase chain reaction, and flow cytometry to investigate the effects of DEX and RAP on cells in the retinal organoids. Retinal organoids were then seeded onto poly(lactic-co-glycolic) acid (PLGA) scaffolds and implanted into rhesus monkey eyes (including a healthy individual and three monkeys with chronic ocular hypertension (OHT) induction) and subjected to different post-operative immunosuppressant treatments; 8 weeks after the experiment, histological examinations were carried out to assess the success of the different treatments. Our in vitro experiments indicated that both DEX and RAP treatments were equally effective in suppressing microglial activity. Although both immunosuppressants altered the morphologies of cells in the retinal organoids and caused a slight decrease in the differentiation of cells into retinal ganglion cells, the organoid cells retained their capacity to grow and differentiate into retinal tissues. Our in vivo experiments indicate that the retinal organoid can survive and differentiate into retinal tissues in a healthy rhesus monkey eye without immunosuppressive treatment. However, the survival and differentiation of these organoids in OHT eyes was successful only with the DEX treatment. RAP treatment was ineffective in preventing immunological rejection, and the retinal organoid failed to survive until the end of 8 weeks. DEX is likely a promising immunosuppressant to enhance the survival of epiretinal implants.

Targets of immunomodulation in bacterial endophthalmitis

Bacterial infection of the posterior segment of the eye (endophthalmitis) leads to a robust host response that often results in irreversible damage to the layers of the retina, significant vision loss, and in some patients, enucleation of the globe. While a great deal of effort has gone into understanding the role of bacterial virulence factors in disease initiation and propagation, it is becoming increasingly clear that the host response to infection plays a major role in causing the damage associated with endophthalmitis. Researchers have identified the host receptors which detect infecting organisms and initiate the cascade of events that result in inflammation. This inflammation may damage nonregenerative tissues of the eye while attempting to clear the infection. Both Gram-positive and Gram-negative bacteria can cause endophthalmitis. These organisms initiate an immune response by activating toll-like receptor (TLR) pathways. Once an inflammatory response is initiated, the expression of immunomodulators, such as proinflammatory chemokines and cytokines, affect the recruitment of PMNs and other inflammatory cells into the eye. We and others have reported that knockout mice that do not express specific inflammatory pathways and molecules have an attenuated response to infection and retain significant retinal function. These findings suggest that host immune mediators are important components of the response to infections in the posterior segment of the eye, and the timing and level of their production may be related to the severity of the damage and the ultimate visual outcome. If that is the case, a better understanding of the complex and often redundant role of these pathways and inflammatory mediators may identify host molecules as potential anti-inflammatory therapeutic targets. This review highlights potential anti-inflammatory targets during acute inflammation in endophthalmitis, compares and contrasts those with findings in other models of ocular inflammation, and translates current immunomodulatory strategies for other types of infection and inflammation to this blinding disease. Given the poor visual outcomes seen in patients treated with antibiotics alone or in combination with corticosteroids, immunomodulation in addition to antibiotic therapy might be more effective in preserving vision than current regimens.

Prognostic Factors and Visual Outcomes of Pyogenic Liver Abscess-Related Endogenous Klebsiella pneumoniae Endophthalmitis: A 20-year retrospective review

Endogenous K. pneumoniae endophthalmitis (EKE) has a higher incidence among East Asians, and the most common infectious source of EKE is pyogenic liver abscess (PLA). We investigate the risk factors for poor visual outcomes in patients with PLA-related EKE. The retrospective medical records of 104 patients (120 eyes) diagnosed with PLA-related EKE between 1996 and 2015. In univariate logistic regression analysis, the risk factors for poor visual outcomes were initial visual acuity (VA) worse than counting fingers (CF) (p < 0.001), eye pain (p = 0.013), hypopyon (p = 0.003), ocular hypertension (p = 0.003), positive intraocular fluids cultures (p < 0.001), subretinal abscess (p = 0.025), unilateral involvement (p = 0.017), delayed ophthalmologic visit (p = 0.022), initially presented with ocular symptoms ahead of systemic symptoms (p < 0.001), and corneal edema (p < 0.001). Intravitreal dexamethasone reduced the requirement of enucleation or evisceration (p = 0.01). The multivariate logistic regression revealed that poor initial VA worse than CF (p = 0.004) and initially presented with ocular symptoms ahead of systemic symptoms (p = 0.007) were the significant independent factors for poor visual outcomes. Early diagnosis and prompt treatment may salvage useful vision in some eyes.

Nanofluidic microsystem for sustained intraocular delivery of therapeutics

Globally, 145.2 million people suffer from moderate to severe vision impairment or blindness due to preventable or treatable causes. However, patient adherence to topical or intravitreal treatment is a leading cause of poor outcomes. To address this issue, we designed an intraocularly implantable device called the nanofluidic Vitreal System for Therapeutic Administration (nViSTA) for continuous and controlled drug release based on a nanochannel membrane that obviates the need for pumps or actuation. In vitro release analysis demonstrated that our device achieves sustained release of bimatoprost (BIM) and dexamethasone (DEX) at concentrations within clinically relevant therapeutic window. In this proof of concept study, we constructed an anatomically similar in silico human eye model to simulate DEX release from our implant and gain insight into intraocular pharmacokinetics profile. Overall, our drug-agnostic intraocular implant represents a potentially viable platform for long-term treatment of various chronic ophthalmologic diseases, including diabetic macular edema and uveitis.

A prospective multicentre randomized placebo-controlled superiority trial in patients with suspected bacterial endophthalmitis after cataract surgery on the adjuvant use of intravitreal dexamethasone to intravitreal antibiotics

PURPOSE

We aimed to determine whether intravitreal dexamethasone as an adjuvant to intravitreal antibiotics is beneficial in the treatment of suspected bacterial endophthalmitis after cataract surgery.

METHODS

Randomized, placebo-controlled superiority trial in three tertiary referral centres in the Netherlands. Patients with suspected bacterial endophthalmitis within 6 weeks after cataract surgery were eligible. A diagnostic vitreous biopsy was taken for culture, and patients received intravitreal injections of 400 μg dexamethasone (without preservatives) or placebo, in addition to 0.2 mg vancomycin and 0.05 mg gentamicin. The vancomycin and dexamethasone or placebo injections were repeated once at day 3 or 4. Primary outcome measure was best-corrected visual acuity (BCVA) at 1 year.

RESULTS

Between 1 November 2004 and 1 March 2014 (excluding two interruptions totalling 20 months), 324 eligible patients presented. A total of 167 patients (81 dexamethasone, 86 placebo) were available for the intention-to-treat analysis. Biopsies of 114 patients (68%) were culture-positive. Final BCVA did not differ between the dexamethasone and the placebo group (logMAR 0.31 ± 0.58 versus 0.27 ± 0.50; p = 0.90), nor did the number of patients with final vision of no light perception (LP, 7 versus 13). Pain, corneal oedema, the absence of a red fundus reflex on presentation, LP on presentation and culture of virulent pathogens from biopsy were statistically significantly associated with an unfavourable visual outcome.

CONCLUSION

Intravitreal dexamethasone without preservatives as an adjuvant to intravitreal antibiotics does not improve visual acuity (VA) in patients treated for suspected bacterial endophthalmitis after cataract surgery.

Infectious Sources, Prognostic Factors, and Visual Outcomes of Endogenous Klebsiella pneumoniae Endophthalmitis

PURPOSE

To investigate the infectious sources and prognostic factors for poor visual outcome, including subjective symptoms, presenting clinical features, laboratory data, and treatments, in patients diagnosed with endogenous Klebsiella pneumoniae endophthalmitis (EKE) at a tertiary referral center in Northern Taiwan.

DESIGN

Retrospective, single-institution, consecutive case series.

PARTICIPANTS

One hundred ten consecutive patients (124 eyes) diagnosed with EKE.

METHODS

One hundred ten patients (124 eyes) were reviewed retrospectively between January 1996 and April 2013.

MAIN OUTCOME MEASURES

Visual acuity (VA), subjective symptoms, presenting clinical features, laboratory data, treatments, and requirement of evisceration or enucleation.

RESULTS

Of the 110 patients with EKE, 74 (67.3%) were men. Diabetes was the most commonly associated systemic disease (75/110 [68.2%]), and liver abscess was the major infection source (85/110 [77.3%]). In addition, 91 of 124 eyes (73.4%) had final VA worse than counting fingers (CF; poor visual outcome), and 20 eyes required evisceration or enucleation. The binary multivariate logistic regression (forward-Wald) model revealed that poor initial VA worse than CF (odds ratio [OR], 8.8; 95% confidence interval [CI], 2.2-36; P = 0.002), positive vitreous culture results (OR, 9.8; 95% CI, 1.7-56.1; P = 0.010), posterior focal EKE (OR, 0.15; 95% CI, 0.03-0.8; P = 0.027), and the presence of intravitreal dexamethasone administration (OR, 0.19; 95% CI, 0.04-0.9; P = 0.030) were the significant independent factors for visual outcomes.

CONCLUSIONS

Liver abscess was the major infection source, and EKE typically has poor visual prognosis. Early diagnosis and prompt treatment may salvage useful vision in some eyes. Early diagnosis with fair initial VA and intravitreal antibiotic and dexamethasone combination therapy may have beneficial effects on visual outcomes.

Clinical Applications of Dexamethasone for Aged Eyes

The risk of severe eye problems has been found to increase significantly with age, particularly between the fifth and sixth decades of life. Cataracts, dry eye, neovascular age-related macular degeneration, diabetic retinopathy and retinal vein occlusion (RVO) are very common and very different age-related ocular diseases that reduce the patient's quality of life. The rationale for using corticosteroids to treat anterior and posterior ocular segment diseases is driven by inflammation. Dexamethasone, one of the most powerful corticosteroids available, is widely used for topical or intravitreal administration. Topical dexamethasone has proven efficacy for the management of postoperative inflammation in the anterior segment after cataract surgery and symptom relief in dry-eye disease. A new sustained-release 700 µg dexamethasone intravitreal implant (DEX) was recently approved for the treatment of macular edema following RVO, diabetic macular edema, or non-infectious uveitis, and its use is increasing, especially when other therapeutic agents have failed. The most common side effects are increased intraocular pressure and cataract formation. The potency of DEX, alone or in combination with other agents, makes DEX a promising option for treating several retinal diseases.

VEGF-A is increased in exogenous endophthalmitis

OBJECTIVE

Exogenous endophthalmitis is an ophthalmologic emergency defined by panocular inflammation. Vascular endothelial growth factor A (VEGF-A) contributes to inflammation by promoting chemotaxis of monocytes and granulocytes and by increasing vascular permeability. The purpose of this article is to determine if VEGF-A is elevated in the vitreous samples obtained from individuals with exogenous endophthalmitis.

METHODS

Vitreous samples from individuals with exogenous endophthalmitis (n = 18) were analyzed via Luminex assay and enzyme-linked immunosorbent assay for the cytokines VEGF-A, tumor necrosis factor (TNF), interleukin 6 (IL-6), IL-8 (chemokine [CXCL]-8), IL-1β, IL-10, IL-12p70, IL-33, interferon (IFN)-γ, IFN-α, IFN-β, chemokine ligand (CCL)-3, IL-2, IL-5, IL-15, CXCL-10, CCL-2, IL-1Ra, CCL-5, IL-17, and CCL-11. Vitreous samples obtained at the time of macular hole surgery served as controls (n = 8).

RESULTS

Concentrations of VEGF-A were significantly elevated in vitreous samples from individuals with exogenous endophthalmitis compared with macular hole (p < 0.001). VEGF-A was significantly upregulated in individuals with exogenous endophthalmitis after cataract surgery (p = 0.001), vitrectomy (p = 0.024), and intravitreal injection (p = 0.012). VEGF-A concentrations were similar in both culture-positive and culture-negative populations (p > 0.05). In a linear regression model, levels of VEGF-A correlated significantly with the chemokine CXCL-8 (p = 0.028).

CONCLUSIONS

We demonstrate that VEGF-A is potently upregulated in exogenous endophthalmitis. This observation provides a foundation for future studies of targeted VEGF-A blockade in the management of endophthalmitis.

Adjunctive steroid therapy versus antibiotics alone for acute endophthalmitis after intraocular procedure

BACKGROUND

Endophthalmitis refers to severe infection within the eye that involves the aqueous humor or vitreous humor, or both, and threatens vision. Most cases of endophthalmitis are exogenous (i.e. due to inoculation of organisms from an outside source), and most exogenous endophthalmitis is acute and occurs after an intraocular procedure. The mainstay of treatment is emergent administration of broad-spectrum intravitreous antibiotics. Due to their anti-inflammatory effects, steroids in conjunction with antibiotics have been proposed to be beneficial in endophthalmitis management.

OBJECTIVES

To assess the effects of antibiotics combined with steroids versus antibiotics alone for the treatment of acute endophthalmitis following intraocular surgery or intravitreous injection.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 11), MEDLINE Ovid (1946 to 8 December 2016), Embase Ovid (1980 to 8 December 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 8 December 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch); searched 8 December 2016, ClinicalTrials.gov (www.clinicaltrials.gov); searched 8 December 2016, and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 8 December 2016. We did not use any date or language restrictions in the electronic searches for trials.

SELECTION CRITERIA

We included randomized controlled trials comparing the effectiveness of adjunctive steroids with antibiotics alone in the management of acute, clinically diagnosed endophthalmitis following intraocular surgery or intravitreous injection. We excluded trials with participants with endogenous endophthalmitis unless outcomes were reported by source of infection. We imposed no restrictions on the method or order of administration, dose, frequency, or duration of antibiotics and steroids.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, assessed risk of bias, and extracted data using methods expected by Cochrane. We contacted study authors to try to obtain missing information or information to clarify risk of bias. We conducted a meta-analysis for any outcomes that were reported by at least two studies. Outcomes reported from single studies were summarized in the text. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included three trials with a total of 95 randomized participants in this review and identified one ongoing trial. The studies were conducted in South Africa, India, and the Netherlands. Out of the 92 analyzed participants, 91 participants were diagnosed with endophthalmitis following cataract surgery. In the remaining participant, endophthalmitis was attributable to penetrating keratoplasty. All studies used intravitreous dexamethasone for adjunctive steroid therapy and a combination of two intravitreous antibiotics that provided gram-positive and gram-negative coverage for the antibiotic therapy. We judged one trial to be at overall low risk of bias and two studies to be at overall unclear risk of bias due to lack of reporting of study methods. None of the three trials had been registered in a clinical trial register.While none of the included studies reported the primary outcome of complete resolution of endophthalmitis as defined in our protocol, one study reported combined anatomical and functional success (i.e. proportion of participants with intraocular pressure of at least 5 mmHg and visual acuity of at least 6/120). Very low-certainty evidence suggested no difference in combined success when comparing adjunctive steroid antibiotics alone (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.80 to 1.45; 32 participants). Low-certainty evidence from two studies showed that a higher proportion of participants who received adjunctive dexamethasone had a good visual outcome (Snellen visual acuity 6/6 to 6/18) at three months compared with those in the antibiotics-alone group (RR 1.95, 95% CI 1.05 to 3.60; 60 participants). Similarly, low-certainty evidence from one study suggested that more participants in the dexamethasone group had a good visual outcome at 12 months compared to those who did not receive dexamethasone (RR 2.00, 95% CI 0.98 to 4.08; 28 participants). Investigators of one study reported improvement in visual acuity, but we could not estimate the effect of adjunctive steroid therapy because the study investigators did not provide standard deviations or standard errors. Two studies reported adverse events (retinal detachment, hypotony, proliferative vitreoretinopathy, and seclusion of pupil). The total numbers of adverse events were 8 out of 30 (26.7%) for those who received dexamethasone versus 6 out of 30 (20.0%) for those who did not. We could only perform a pooled analysis for the occurrence of retinal detachment; any difference between the two treatment groups was uncertain (RR 1.57, 95% CI 0.50 to 4.90; 60 participants) (very low-certainty evidence). No study reported intraocular pressure or cost outcomes.

AUTHORS' CONCLUSIONS

Current evidence on the effectiveness of adjunctive steroid therapy versus antibiotics alone in the management of acute endophthalmitis after intraocular surgery is inadequate. We found no studies that had enrolled cases of acute endophthalmitis following intravitreous injection. A combined analysis of two studies suggests adjunctive steroids may provide a higher probability of having a good visual outcome at three months than not using adjunctive steroids. However, considering that most of the confidence intervals crossed the null and that this review was limited in scope and applicability to clinical practice, it is not possible to conclude whether the use adjunctive steroids is effective at this time. Any future trials should examine whether adjunctive steroids may be useful in certain clinical settings such as type of causative organism or etiology. These studies should include outcomes that take patient's symptoms and clinical examination into account, report outcomes in a uniform and consistent manner, and follow up at short- and long-term intervals.

Intravitreal dexamethasone in the management of acute endophthalmitis: a comparative retrospective study

PURPOSE

To compare the clinical outcome of eyes with acute bacterial endophthalmitis treated with intravitreal injection of antibiotics with or without intravitreal dexamethasone.

METHODS

This was a retrospective chart review of 63 eyes diagnosed with acute bacterial endophthalmitis and treated with vitreous tap and intravitreal injection of antibiotics, 19 eyes (30.2%) with and 44 eyes (69.8%) without concurrent intravitreal dexamethasone.

RESULTS

Visual acuity had significantly improved by 1 week and was maintained long-term (p&lt;0.001). There were no differences in visual outcome or rates of ocular complications between the groups. None of the eyes treated with dexamethasone required repeated intravitreal antibiotic injection while 6 (13.6 %) of the other eyes required repeated intravitreal antibiotic injection (p = 0.09). A subset analysis of 21 eyes that presented with light perception/no light perception vision where vitrectomy was not possible demonstrated that intravitreal antibiotic injection improved vision and achieved similar visual gain as in eyes that presented with hand motion vision or better, with no higher complication rates.

CONCLUSIONS:

No adverse effect of intravitreal dexamethasone in the acute management of infectious endophthalmitis was noted. A trend toward less need for repeat intravitreal antibiotic therapy was noted in eyes with acute bacterial endophthalmitis treated with concurrent intravitreal dexamethasone at presentation.

Modeling intraocular bacterial infections

Bacterial endophthalmitis is an infection and inflammation of the posterior segment of the eye which can result in significant loss of visual acuity. Even with prompt antibiotic, anti-inflammatory and surgical intervention, vision and even the eye itself may be lost. For the past century, experimental animal models have been used to examine various aspects of the pathogenesis and pathophysiology of bacterial endophthalmitis, to further the development of anti-inflammatory treatment strategies, and to evaluate the pharmacokinetics and efficacies of antibiotics. Experimental models allow independent control of many parameters of infection and facilitate systematic examination of infection outcomes. While no single animal model perfectly reproduces the human pathology of bacterial endophthalmitis, investigators have successfully used these models to understand the infectious process and the host response, and have provided new information regarding therapeutic options for the treatment of bacterial endophthalmitis. This review highlights experimental animal models of endophthalmitis and correlates this information with the clinical setting. The goal is to identify knowledge gaps that may be addressed in future experimental and clinical studies focused on improvements in the therapeutic preservation of vision during and after this disease.

Safety of intravitreal quinupristin/dalfopristin in an animal model

AIM

To determine whether different intravitreal doses of quinupristin/dalfopristin lead to electroretinographic or histological changes in the rabbit retina over one month period after injection.

METHODS

Eighteen New Zealand white rabbits were divided into three treatment groups (groups 1 to 3) and different intravitreal doses of quinupristin/dalfopristin were tested in each group. The right eye was injected with the drug and the left eye received intravitreal injection of 5% dextrose water and served as control eye. The doses delivered to each group were 0.1 mg/0.1 mL, 1 mg/0.1 mL and 10 mg/0.1 mL. Simultaneous, bilateral, dark-adapted electroretinography and clinical images of both eyes were obtained in all groups before injection (baseline) and after 7, 14, 21 and 28d, followed by enucleation for histological examination.

RESULTS

Subjects in the group 1 showed no signs of toxicity in the electroretinogram when compared with groups 2 and 3 (Kruskall-Wallis test, P=0.000). By day 7, no electrical response to light stimuli was recorded in the treated eyes in groups 2 and 3, consistent with severe damage due to retinal toxicity. Light microscopy revealed no significant histopathological changes in the group 1, while rabbits in groups 2 and 3 had signs of granulomatous inflammation in most cases.

CONCLUSION

Intravitreal 0.1 mg/0.1 mL doses of quinupristin/dalfopristin do not lead to electroretinographic or histological signs of retinal toxicity compared with 1 mg/0.1 mL and 10 mg/0.1 mL in this rabbit model.

Persistently Vitreous Culture-Positive Exogenous Bacterial Endophthalmitis

PURPOSE

To report the clinical settings, bacterial isolates, antibiotic sensitivities, and visual acuity outcomes of patients with persistently positive vitreous cultures after intravitreal antibiotics.

DESIGN

Consecutive, noncomparative case series.

METHODS

setting: Tertiary care center.

PATIENT POPULATION

Thirty-six eyes of 36 patients with exogenous endophthalmitis with the same bacterial organism identified on at least 2 consecutive vitreous cultures from 1981 to 2015.

OBSERVATION PROCEDURES

Vitreous cultures with intravitreal injections of antibiotics and pars plana vitrectomies with intravitreal antibiotics.

MAIN OUTCOME MEASURES

Bacterial isolates, antibiotic sensitivities, visual outcomes.

RESULTS

Thirty-six eyes of 36 patients met the study criteria. The mean follow-up was 26.5 months. The most common clinical settings were after cataract extraction (18/36, 50%) and glaucoma surgery (11/36, 31%). The mean initial visual acuity was 2.16 ± 0.77 logMAR (Snellen equivalent ≈20/2900), and there was no statistically significant change at the final evaluation (2.08 ± 0.97 logMAR, ≈20/1900, P = .72). The most common bacteria were Staphylococcus (11/36, 31%) and Streptococcus (9/36, 25%). Gram-positive bacteria were sensitive to vancomycin (27/27, 100%); gram-negative bacteria were sensitive to amikacin (5/5, 100%). The antibiotic sensitivities were the same on repeat cultures in 34 of 36 patients (94%). The initial treatment was a vitreous culture and intravitreal injection of antibiotics in 28 of 36 patients (78%). The vision at the last follow-up was 20/200 or better in 12 patients (33%) and no light perception in 11 of 36 patients (31%).

CONCLUSIONS

The most commonly identified organisms were gram-positive bacteria. There was good concordance in the antibiotic sensitivities between initial and subsequent cultures. Patients with persistently vitreous culture-positive endophthalmitis had poor visual outcomes.

Comparison of Snellen and Early Treatment Diabetic Retinopathy Study charts using a computer simulation

AIM

To compare accuracy, reproducibility and test duration for the Snellen and the Early Treatment Diabetic Retinopathy Study (ETDRS) charts, two main tools used to measure visual acuity (VA).

METHODS

A computer simulation was programmed to run multiple virtual patients, each with a unique set of assigned parameters, including VA, false-positive and false-negative error values. For each virtual patient, assigned VA was randomly chosen along a continuous scale spanning the range between 1.0 to 0.0 logMAR units (equivalent to 20/200 to 20/20). Each of 30 000 virtual patients were run ten times on each of the two VA charts.

RESULTS

Average test duration (expressed as the total number of characters presented during the test ±SD) was 12.6±11.1 and 31.2±14.7 characters, for the Snellen and ETDRS, respectively. Accuracy, defined as the absolute difference (± SD) between the assigned VA and the measured VA, expressed in logMAR units, was superior in the ETDRS charts: 0.12±0.14 and 0.08±0.08, for the Snellen and ETDRS charts, respectively. Reproducibility, expressed as test-retest variability, was superior in the ETDRS charts: 0.23±0.17 and 0.11±0.09 logMAR units, for the Snellen and ETDRS charts, respectively.

CONCLUSION

A comparison of true (assigned) VA to measured VA, demonstrated, on average, better accuracy and reproducibility of the ETDRS chart, but at the penalty of significantly longer test duration. These differences were most pronounced in the low VA range. The reproducibility using a simulation approach is in line with reproducibility values found in several clinical studies.

A prospective multicenter randomized placebo-controlled trial of dexamethasone as an adjuvant in the treatment of postoperative bacterial endophthalmitis: interim safety analysis of the study drug and analysis of overall treatment results

PURPOSE

In an ongoing prospective multicenter randomised placebo-controlled trial we study the adjuvant use of intravitreal dexamethasone in the treatment of patients with suspected bacterial endophthalmitis after phacoemulsification. In accordance with the study protocol, a mid-inclusion interim analysis of the safety of the study drug was performed.

PATIENTS AND METHODS

Patients with suspected endophthalmitis after phacoemulsification were asked to participate in this study. A diagnostic vitreous biopsy was taken and the patients received intravitreal injections of 400 micrograms dexamethasone or a placebo, plus 0.2 mg vancomycin and 0.05 mg gentamicin. Injections were repeated after 3 or 4 days. The safety analysis included: the number of eyes with an evisceration; no light perception; or a visual acuity of less than 5/200. Treatment outcome was evaluated in terms of: the percentage of patients with a visual acuity of 20/40 or more and 20/100 or more.

RESULTS

The interim analysis included 81 patients with at least 1 year follow-up. Sixty-three patients (65 %) were culture-positive. Safety analysis: 7 eyes were eviscerated (3 dexamethasone, 4 placebo); 4 eyes had no light perception (2 dexamethasone, 2 placebo); and 4 eyes had less than 5/200 vision (3 dexamethasone, 1 placebo). Treatment outcome: 70 % of patients had a visual acuity of at least 20/40.

CONCLUSION

The safety analysis does not warrant premature discontinuation of the study. So far, the overall outcome of our treatment regimen, consisting of merely a diagnostic biopsy instead of a vitrectomy and an optimized antibiotic dosing, compares favourably to published literature.

Pediatric infectious endophthalmitis: a review

Infectious endophthalmitis is a rare but severe complication of septecemia, intraocular surgeries, or penetrating eye trauma. The etiology, prognosis, and management of pediatric endophthalmitis resulting from exogenous and endogenous infections are reviewed. Open-globe trauma and glaucoma surgery are the most frequent causes of endophthalmitis in children, whereas endogenous infection is the least common cause. Streptococcus and Staphylococcus species are common bacterial agents in both posttraumatic and postoperative pediatric endophthalmitis, whereas Candida albicans is a commonly reported organism in endogenous endophthalmitis. Additionally, Streptococcus pneumoniae and Haemophilus influenzae appear more likely as pathogens in children than in adults. The clinical manifestations and outcome usually correlate with the virulence of the infecting organism. The visual prognosis of endophthalmitis is generally poor.

Role of inflammation in endophthalmitis

Inflammation originating from infection of the vitreous cavity is called endophthalmitis. Attention has been focused on the epidemiologic, microbiologic reports, and treatment options; unfortunately, the role of the host immune reaction in the visual function damage is still not well understood. Endophthalmitis occurs most frequently after cataract surgery. In this paper we review the published literature regarding inflammatory mediators and apoptosis during the course of endophthalmitis. Toll-like receptors, cytokines, high-mobility group box 1 proteins, aB-crystallin and apoptosis have been studied during clinical and experimental cases of endophthalmitis. Further understanding of the host-immune reaction to vitreous infection is essential for the development of new therapies. The use of intravitreal antibiotics and corticosteroids, vitrectomy and systemic antibiotics for the preservation of visual function is still discouraging.

Bacterial endophthalmitis in the age of outpatient intravitreal therapies and cataract surgeries: host-microbe interactions in intraocular infection

Bacterial endophthalmitis is a sight threatening infection of the interior structures of the eye. Incidence in the US has increased in recent years, which appears to be related to procedures being performed on an aging population. The advent of outpatient intravitreal therapy for management of age-related macular degeneration raises yet additional risks. Compounding the problem is the continuing progression of antibiotic resistance. Visual prognosis for endophthalmitis depends on the virulence of the causative organism, the severity of intraocular inflammation, and the timeliness of effective therapy. We review the current understanding of the pathogenesis of bacterial endophthalmitis, highlighting opportunities for the development of improved therapeutics and preventive strategies.

Diagnostic dilemmas in retinitis and endophthalmitis

Visual loss in infectious posterior uveitis or panuveitis can occur if proper therapy is delayed because of diagnostic uncertainty. Some disorders, such as acute retinal necrosis and bacterial endophthalmitis, can be rapidly progressive, and therefore require prompt and accurate diagnosis to guide initial therapy. Other more slowly evolving infections, such as toxoplasmic chorioretinitis or fungal endophthalmitis, can be worsened by empiric use of corticosteroids without specific antimicrobial coverage. Key ocular diagnostic features are helpful but highly variable with overlap with both non-infectious uveitis and neoplastic masquerades, even for key signs such as hypopyon. Close examination of the fundus with attention to color, location, size, border, and opacity of lesions and associated arteriolitis or frosted branch angiitis is helpful in the diagnosis of chorioretinitis. Ultrasonography is an important tool in the evaluation of eyes with suspected endophthalmitis, especially those with intracapsular infection or focal infected deposits. Testing of intraocular fluid can be extremely useful but suffers from inaccessibility, poor sensitivity, and test selections dependent on a presumptive diagnosis, which may be wrong. The dilemma for clinician is to make the correct diagnosis of a rare, blinding, variegated disease quickly enough to intercede with specific therapy or to apply empiric therapy in a sufficiently skilled manner to avert disaster and confirm the diagnosis by response to treatment. When non-infectious uveitis is in the differential, empiric corticosteroids must sometimes be used, at great risk, if clinical examination, ancillary testing, and any available intraocular diagnostic tests have failed to confirm a diagnosis.