Grant M. Comer

Treatment of Endogenous Fungal Endophthalmitis: Focus on New Antifungal Agents

Endogenous fungal endophthalmitis, involving only the chorioretinal structures or extending to involve the vitreous (vitritis), is a sight-threatening infection requiring early appropriate therapy. Endophthalmitis is a relatively frequent complication of candidemia and less commonly occurs in patients who have invasive aspergillosis. Because the eye is a protected compartment, penetration of systemically administered antifungal agents is highly variable. In the posterior segment of the eye, amphotericin B (AmB) achieves very poor concentrations, but fluconazole concentrations are high. Among newer antifungal agents, voriconazole shows the most promise, because therapeutic concentrations for most Candida and Aspergillus species are achieved in the vitreous, and its antifungal activity is broad. In contrast, neither posaconazole nor the 3 echinocandins achieve adequate therapeutic concentrations in the vitreous. For sight-threatening macular involvement and vitritis, intravitreal injection of either AmB or voriconazole is helpful to achieve high local antifungal activity as quickly as possible. We review the available evidence regarding the most appropriate use of antifungal agents for endogenous fungal endophthalmitis, with the emphasis on treatment of infections due to Candida species.

Fully automated detection of diabetic macular edema and dry age-related macular degeneration from optical coherence tomography images

We present a novel fully automated algorithm for the detection of retinal diseases via optical coherence tomography (OCT) imaging. Our algorithm utilizes multiscale histograms of oriented gradient descriptors as feature vectors of a support vector machine based classifier. The spectral domain OCT data sets used for cross-validation consisted of volumetric scans acquired from 45 subjects: 15 normal subjects, 15 patients with dry age-related macular degeneration (AMD), and 15 patients with diabetic macular edema (DME). Our classifier correctly identified 100% of cases with AMD, 100% cases with DME, and 86.67% cases of normal subjects. This algorithm is a potentially impactful tool for the remote diagnosis of ophthalmic diseases.

Vitreous Penetration of Orally Administered Famciclovir

PURPOSE To determine the vitreous penetration of penciclovir (Denavir; GlaxoSmithKline, Philadelphia, Pennsylvania, USA) after oral administration of the prodrug famciclovir (Famvir; Novartis Pharmaceuticals Corp, East Hanover, New Jersey, USA). DESIGN Prospective interventional case series. METHODS Ten patients undergoing elective pars plana vitrectomy at a single institution were enrolled to take 3 oral doses of famciclovir 500 mg the day preceding surgery and a fourth dose on the morning of surgery. Blood and undiluted vitreous samples were acquired from each patient during surgery. High-performance liquid chromatography was used to determine the concentration of penciclovir in each sample. Exclusion criteria included prior vitrectomy, compromised blood-retina barrier, renal or hepatic disease, human immunodeficiency virus infection, bone marrow or renal transplantation, pregnancy or breastfeeding, history of adverse reaction or allergy to famciclovir or penciclovir, and antiviral, probenecid, or cimetidine use within 1 month of surgery. RESULTS Ten eyes of 10 patients ranging in age from 26 to 82 were included. All patients had normal renal and hepatic function as determined by history and laboratory values. Mean serum penciclovir concentration +/- standard deviation was 4.45 +/- 1.31 microg/ml (range, 2.51 to 6.34 microg/ml). Mean vitreous penciclovir concentration was 1.21 +/- 0.38 microg/ml (range, 0.39 to 1.88 microg/ml). Mean vitreous-to-serum concentration ratio of penciclovir was 0.28 +/- 0.09 (range, 0.16 to 0.41). CONCLUSIONS Oral administration of famciclovir results in vitreous concentrations of penciclovir within the inhibitory ranges for herpes simplex 1, herpes simplex 2, and varicella zoster virus. Oral famciclovir may be a reasonable alternative to intravenous acyclovir (Zovirax; GlaxoSmithKline) in the treatment of acute retinal necrosis, especially in cases of acyclovir resistance or patient inability to tolerate prolonged intravenous treatment.

A Longitudinal Analysis of Risk Factors Associated with Central Retinal Vein Occlusion

PURPOSE To identify risk factors associated with central retinal vein occlusion (CRVO) among a diverse group of patients throughout the United States. DESIGN Longitudinal cohort study. PARTICIPANTS All beneficiaries aged ≥ 55 years who were continuously enrolled in a managed care network for at least 2 years and who had ≥ 2 visits to an eye care provider from 2001 to 2009. METHODS Insurance billing codes were used to identify individuals with a newly diagnosed CRVO. Multivariable Cox regression was performed to determine the factors associated with CRVO development. MAIN OUTCOME MEASURES Adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of being diagnosed with CRVO. RESULTS Of the 494 165 enrollees who met the study inclusion criteria, 1302 (0.26%) were diagnosed with CRVO over 5.4 (± 1.8) years. After adjustment for known confounders, blacks had a 58% increased risk of CRVO compared with whites (HR, 1.58; 95% CI, 1.25-1.99), and women had a 25% decreased risk of CRVO compared with men (HR, 0.75; 95% CI, 0.66-0.85). A diagnosis of stroke increased the hazard of CRVO by 44% (HR, 1.44; 95% CI, 1.23-1.68), and hypercoagulable state was associated with a 145% increased CRVO risk (HR, 2.45; 95% CI, 1.40-4.28). Individuals with end-organ damage from hypertension (HTN) or diabetes mellitus (DM) had a 92% (HR, 1.92; 95% CI, 1.52-2.42) and 53% (HR, 1.53; 95% CI, 1.28-1.84) increased risk of CRVO, respectively, relative to those without these conditions. CONCLUSIONS This study confirms that HTN and vascular diseases are important risk factors for CRVO. We also identify black race as being associated with CRVO, which was not well appreciated previously. Furthermore, we show that compared with patients without DM, individuals with end-organ damage from DM have a heightened risk of CRVO, whereas those with uncomplicated DM are not at increased risk of CRVO. This finding may provide a potential explanation for the conflicting reports in the literature on the association between CRVO and DM. Information from analyses such as this can be used to create a risk calculator to identify possible individuals at greatest risk for CRVO.

Use of intravitreal rituximab for treatment of vitreoretinal lymphoma

Aim Vitreoretinal lymphoma is a diffuse large B cell non-Hodgkin lymphoma. Targeting malignant cells with rituximab is being used increasingly as local chemotherapy, but information on this treatment is scant. We aimed to describe current therapeutic approaches, as well as responses to and complications of, intravitreal rituximab in patients with vitreoretinal lymphoma. Methods Clinical data were collected in a standardised manner retrospectively on patients with vitreoretinal lymphoma treated with intravitreal rituximab. Results 48 eyes (34 patients) with vitreoretinal lymphoma were treated with a median of 3.5 intravitreal injections of rituximab (1 mg/0.1 mL) for new diagnosis (68.8%), progressive disease (29.9%) and maintenance therapy (2.1%). Intravitreal rituximab±methotrexate was the sole treatment in 19 eyes (39.6%). 31 eyes (64.6%) eyes achieved complete remission, after a median of 3 injections; 7 of these eyes developed recurrent disease. 11 eyes (22.9%) achieved partial remission. Although rituximab may have contributed to complications reported in 12 eyes (25.0%), a 2-line loss of Snellen visual acuity occurred in only 2 of those eyes (4.2%). Conclusions Approaches in rituximab-based intravitreal chemotherapy vary widely, but our findings suggest that this treatment may be safe and effective in inducing remission in a majority of eyes with vitreoretinal lymphoma.

Diffusion of technologies for the care of older adults with exudative age-related macular degeneration.

PURPOSE To determine patterns of diffusion of diagnostic tests and therapeutic interventions in the United States through 2010 for patients with newly diagnosed exudative macular degeneration (AMD). DESIGN Retrospective longitudinal cohort analysis. METHODS SETTING AND PATIENT POPULATION: A total of 23 941 Medicare beneficiaries with exudative AMD newly diagnosed during 1992-2009. OBSERVATION PROCEDURES Current Procedural Technology (CPT-4) billing codes were used to identify use of diagnostic tests (optical coherence tomography, fluorescein angiography, and fundus photography) and therapeutic interventions (argon laser photocoagulation, photodynamic therapy, intravitreal corticosteroids, and anti-vascular endothelial growth factor [VEGF] agents) used by these beneficiaries during the first year following diagnosis. MAIN OUTCOME MEASURES Rates of use of study diagnostic and therapeutic procedures. RESULTS Diffusion was rapid for each successive new diagnostic and treatment modality, with use of newer procedures quickly replacing existing ones. The number of beneficiaries treated with anti-VEGF agents for exudative AMD was considerably greater than for prior innovations, rising from use in 4.0% of beneficiaries in 2004-05 to 62.7% in 2009-10. In each year from first diagnosis years 2006-2009 and in different practice settings, use of bevacizumab exceeded that of ranibizumab (60%-78% vs 33%-47%, respectively). Rates of diffusion of the various therapies were relatively similar in communities throughout the United States irrespective of presence of a major teaching hospital in the vicinity. CONCLUSIONS Newer, more effective therapeutic interventions for exudative AMD diffused rapidly throughout the United States, quickly replacing older, less effective interventions. Although improving patient outcomes, rapid diffusion raises important public policy issues for Medicare and other payers to consider.

Successful salvage therapy of Fusarium endophthalmitis secondary to keratitis: An interventional case series

Purpose To describe a combination of treatment modalities used for the successful eradication of Fusarium endophthalmitis. Design Interventional case series. Participants Three consecutive patients with keratitis-associated Fusarium endophthalmitis. Methods After failure of traditional management options, a combination of intravitreal and long-term, high-dose systemic voriconazole, topical antifungal medications, and surgical intervention, with penetrating keratoplasty, lensectomy, and endoscopic-guided pars plana vitrectomy, was administered to each patient. Results All three cases achieved full resolution of the infection, with a final Snellen visual acuity score of 20/50 to 20/70. Conclusions An aggressive combination of therapeutic modalities, including the removal of subiris abscesses, might be needed for the successful resolution of Fusarium endophthalmitis.

Algorithm for the Measure of Vitreous Hyperreflective Foci in Optical Coherence Tomographic Scans of Patients With Diabetic Macular Edema

IMPORTANCE Developing a noninvasive measure of diabetic retinopathy disease progression may provide physicians with information needed for patient-specific intervention. OBJECTIVE To develop an algorithm to measure vitreous hyperreflective foci (VHRF) from standard, 3-dimensional optical coherence tomographic (OCT) images in an unbiased manner. DESIGN, SETTING, AND PARTICIPANTS We retrospectively analyzed OCT scans from 97 patients who were evaluated at the Kellogg Eye Center, University of Michigan. Patients with diabetes mellitus without signs of retinopathy (n =  9) and patients with diabetic macular edema (DME) (n = 31) were compared with healthy control participants (n = 37). The algorithm was used to determine whether the VHRF score is associated with DME and may serve as a noninvasive measure of inflammation. The study was conducted from November 14, 2011, to August 5, 2015. Data analysis was performed from May 15, 2014, to August 13, 2015. MAIN OUTCOMES AND MEASURES An algorithm was developed to enhance the vitreous imaging from OCT to allow automated quantification of VHRF and calculation of a VHRF score. This score was compared between the healthy control, diabetes without retinopathy, and DME groups. RESULTS In the 97 scans evaluated, VHRF scores, reported as mean (SD), were increased in patients with DME by 2.95-fold (5.60 [8.65]) compared with healthy controls (1.90 [3.42]; 95% CI, 0.75-7.45; P = .012) and by 6.83-fold compared with patients with diabetes without retinopathy (0.82 [1.26]; 95% CI, 1.46-8.82; P = .005). CONCLUSIONS AND RELEVANCE Scores obtained using the VHRF algorithm may be obtained from OCT images that include the vitreous and could provide a rapid, noninvasive clinical correlate for ocular inflammation. Higher VHRF scores in patients with DME compared with controls and diabetic patients without retinopathy warrant further population-based and longitudinal studies to help determine the value of the VHRF score in selecting therapeutic intervention.