Presumed ocular histoplasmosis syndrome

Infectious eye disease in the 21st century-an overview

Infectious diseases affecting the eye often cause unilateral or asymmetric visual loss in children and people of working age. This group of conditions includes viral, bacterial, fungal and parasitic diseases, both common and rare presentations which, in aggregate, may account for a significant portion of the global visual burden. Diagnosis is frequently challenging even in specialist centres, and many disease presentations are highly regional. In an age of globalisation, an understanding of the various modes of transmission and the geographic distribution of infections can be instructive to clinicians. The impact of eye infections on global disability is currently not sufficiently captured in global prevalence studies on visual impairment and blindness, which focus on bilateral disease in the over-50s. Moreover, in many cases it is hard to differentiate between infectious and immune-mediated diseases. Since infectious eye diseases can be preventable and frequently affect younger people, we argue that in future prevalence studies they should be considered as a separate category, including estimates of disability-adjusted life years (DALY) as a measure of overall disease burden. Numbers of ocular infections are uniquely affected by outbreaks as well as endemic transmission, and their control frequently relies on collaborative partnerships that go well beyond the remit of ophthalmology, encompassing domains as various as vaccination, antibiotic development, individual healthcare, vector control, mass drug administration, food supplementation, environmental and food hygiene, epidemiological mapping, and many more. Moreover, the anticipated impacts of global warming, conflict, food poverty, urbanisation and environmental degradation are likely to magnify their importance. While remote telemedicine can be a useful aide in the diagnosis of these conditions in resource-poor areas, enhanced global reporting networks and artificial intelligence systems may ultimately be required for disease surveillance and monitoring.

Epidemiology and Clinical Characteristics of Presumed Ocular Histoplasmosis in Olmsted County, Minnesota

Purpose: To describe the incidence, prevalence, and clinical characteristics of presumed ocular histoplasmosis syndrome (POHS) in a Histoplasma endemic region.Methods: The International Classification of Diseases, 9^th and 10^th Revision codes were used to search the Rochester Epidemiology Project, a record-linkage system for medical care provided in Olmsted County, MN. Medical records were reviewed to confirm POHS diagnoses in county residents from January 1, 2006, to December 31, 2015. Age- and sex-adjusted incidence rates were calculated and adjusted to the 2010 U.S. White population.Results: There were 18 incident cases (30 eyes) and 87 prevalent cases (131 eyes). The incidence rate was 1.35 per 100,000 per year. The mid-study prevalence rate was 0.064%. Choroidal neovascularization (CNV) occurred in 17.4% of the affected eyes. At the last follow-up, 16.8% of the affected eyes had POHS-related decreased visual acuity (<20/40).Conclusion: This study assesses the epidemiology and clinical features of POHS in a Midwestern U.S. county.ABBREVIATIONS/ACRONYMS; POHS = Presumed ocular histoplasmosis syndrome; ICD = International Classification of Diseases; CI = Confidence interval; VA = Visual acuity; Anti-VEGF = Anti-vascular endothelial growth factor; REP = Rochester Epidemiology Project, CNV = Choroidal neovascularization.

Prolonged Cone b-Wave on Electroretinography Is Associated with Severity of Inflammation in Noninfectious Uveitis

PURPOSE

This study sought to investigate retinal function in patients with noninfectious uveitis by using full-field electroretinography (ERG) and correlate the ERG to disease duration and severity of inflammation.

DESIGN

Prospective cohort study.

METHODS

Patients (n = 200) with noninfectious uveitis and a disease duration of <1 year (group A [n = 80]) and those with a disease duration of >5 years (group B [n = 120]) were included. ERGs of the total 355 uveitis eyes were measured according to an extended International Society for Clinical Electrophysiology of Vision protocol. ERG abnormalities were related to demographics and uveitis characteristics, including anatomical classification, duration of uveitis, severity of inflammation, best corrected visual acuity (BCVA), cystoid macular edema (CME), and the highest fluorescein angiography (FA) score during the course of the disease.

RESULTS

ERGs showed abnormalities in 235 eyes (66.2%). The most frequent and pronounced ERG abnormality was a prolonged implicit time of the cone b-wave (151 eyes [42.5%]), which was associated with vitritis (P = .005); cells in the anterior chamber (P = .007); the highest fluorescein angiography score (P = .011); age (P < 0.001); and pupil diameter (P < 0.001). BCVA was relatively good (0.05 logMAR [interquartile range {IQR}, 0.011, 0.22]) and not associated with this ERG abnormality. There were no differences between the ERG abnormalities in group A and those in group B and no significant associations between ERG abnormalities and anatomical classification or specific diagnoses.

CONCLUSIONS

ERG results are frequently affected in cases of noninfectious uveitis of all anatomic subtypes, including anterior uveitis without apparent inflammation of the posterior segment. ERG abnormalities appear to be associated with the severity of inflammation from both the present and the past and therefore may be seen even when signs of retinal inflammation have disappeared.

Punctate inner choroidopathy: A review

Punctate inner choroidopathy (PIC), an idiopathic inflammatory multifocal chorioretinopathy that predominantly affects young myopic women, appears to be relatively rare, but there are limited data to support accurate estimates of prevalence, and it is likely that the condition is underdiagnosed. The etiological relationship between PIC and other conditions within the "white dot syndromes" group remains uncertain. We, like others, would suggest that PIC and multifocal choroiditis with panuveitis represent a single disease process that is modified by host factors (including host immunoregulation) to cause the range of clinical phenotypes seen. The impact of PIC on the patient is highly variable, with outcome ranging from complete spontaneous recovery to bilateral severe sight loss. Detection and monitoring have been greatly facilitated by modern scanning techniques, especially optical coherence tomography and autofluorescence imaging and may be enhanced by coregistration of sequential images to detect change over time. Depending on the course of disease and nature of complications, appropriate treatment may range from observation to systemic immunosuppression and antiangiogenic therapies. PIC is a challenging condition where treatment has to be tailored to the patient's individual circumstances, the extent of disease, and the risk of progression.

A Case of Orbital Histoplasmosis

Histoplasma capsulatum var capsulatum is a dimorphic fungus endemic to the Ohio and Mississippi River Valleys of the United States. In this case report, a 33-year-old woman who presented with a right orbital mass causing progressive vision loss, diplopia, and facial swelling is described. Lateral orbitotomy with lateral orbital wall bone flap was performed for excisional biopsy of the lesion. The 1.5 × 1.8 × 2.3 cm cicatricial mass demonstrated a granulomatous lesion with necrosis and positive staining consistent with Histoplasma capsulatum var capsulatum infection. To the authors' knowledge, this is the first case of orbital histoplasmosis to be reported in the United States and the first case worldwide of orbital histoplasmosis due to Histoplasma capsulatum var capsulatum.

Improvement and optimization of standards for a preclinical animal test model of laser induced choroidal neovascularization

Background

As the murine model of laser-induced choroidal neovascularization (CNV) is becoming the most established and commonly utilized model worldwide for studying the pathogenesis of CNV and its response to treatment, specific operating standards are yet to be clarified. The purpose of this study is to compare the lesion size of CNV in mice with different ages, sex, durations of CNV process, and treated positions of laser spots, to make recommendations that may improve and optimize the quality of the model.

Methods and Results

C57/BL6 mice of different ages were treated with diode laser photocoagulation per eye and perfused with PBS containing fluorescein-labeled dextran at different time of observation. Choroid flat mounts, were then examined by fluorescence microscopy for the measurement of CNV area. Messenger-RNA expression levels of several angiogenic cytokines in eye cups of male and female C57BL/6 mice at 5–8 and 16–20 week-old were analyzed by real-time RT-PCR assay. The results showed significantly more CNV area in eyes of female mice compared to male mice with the expression level of several angiogenic cytokines elevated. 16–20-week-old female mice developed the biggest area of CNV. The mean area of CNV increased significantly at the 14^th day after photocoagulation. Laser spots delivered 1PD away from the optic disc induced the biggest area of CNV compared to those 2PD or 3PD away. Interaction of NV was observed in laser spots delivered less than 1PD away from each other.

Conclusion

The current results suggest that 16–20-week-old female C57BL/6 mice developed the most distinct CNV lesion size with laser spots delivered 1PD away from the optic disc. The best time to observe and analyze is the 14^th day after photocoagulation.

Acute systemic histoplasmosis associated with chorioretinitis in an immunocompetent adolescent

Histoplasmosis is an endemic, systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum. A minority of patients develop asymptomatic chorioretinitis known as presumed ocular histoplasmosis syndrome (POHS), which is typically associated with chorioretinal scarring and peripapillary atrophy and occasionally with choroidal neovascularization secondary to maculopathy. We report a case of acute severe bilateral chorioretinitis associated with disseminated H. capsulatum in an immunocompetent adolescent boy living in an endemic area. The chorioretinitis did not respond to systemic antifungal therapy, but both his systemic illness and ocular lesions resolved with the addition of systemic steroids.

Improved assessment of laser-induced choroidal neovascularization

The primary objective of this study was to develop and evaluate new methods of analyzing laser-induced choroidal neovascularization (CNV), in order to make recommendations for improving the reporting of experimental CNV in the literature. Six laser burns of sufficient power to rupture Bruch's membrane were concentrically placed in each eye of 18 adult Norway rats. Eyes received intravitreal injections of either triamcinolone acetonide, ketorolac, or balanced salt solution (BSS). Fluorescein angiography (FA) was performed 2 and 3 weeks after injection, followed by choroidal flat mount preparation. Vascular leakage on FAs and vascular budding on choroidal mounts were quantified by measuring either the cross-sectional area of each CNV lesion contained within the best-fitting polygon using Adobe Photoshop (Lasso Technique or Quick Selection Technique), or the area of bright pixels within a lesion using Image-Pro Plus. On choroidal mounts, the Lasso Technique and Image-Pro Plus detected a significant difference in lesion size between either ketorolac or triamcinolone when compared to BSS, while the Quick Selection Technique did not (Lasso Technique, 0.78 and 0.64; Image-Pro Plus, 0.77 and 0.65). On FA, the Lasso Technique and Quick Selection Technique detected a significant difference in lesion size between either ketorolac or triamcinolone when compared to BSS, while Image-Pro Plus did not (Lasso Tool, 0.81 and 0.54; Quick Selection Tool, 0.76 and 0.57). Choroidal mounts and FA are both valuable for imaging experimental CNV. Adobe Photoshop and Image-Pro Plus are both able to detect subtle differences in CNV lesion size, when images are not manipulated. The combination of choroidal mounts and FA provides a more comprehensive assessment of CNV anatomy and physiology.

Anti-vascular endothelial growth factor therapy for neovascular ocular diseases other than age-related macular degeneration

PURPOSE OF REVIEW

Anti-vascular endothelial growth factor (anti-VEGF) therapies that arrest choroidal angiogenesis and reduce vascular permeability have revolutionized clinical practices for neovascular eye diseases. This review describes anti-VEGF strategies that are being evaluated in ocular diseases, other than neovascular age-related macular degeneration, in which neovascularization plays a critical role in pathogenesis.

RECENT FINDINGS

Early studies of the anti-VEGF agents, pegaptanib sodium, ranibizumab, bevacizumab, VEGF trap, and bevasiranib in the treatment of various neovascular diseases (e.g., diabetic macular edema, retinal vein occlusion, choroidal neovascularization) have shown promising results. The efficacy and safety of these agents, either alone or combined with standard treatments (e.g., laser photocoagulation), anti-inflammatory agents, or other non-VEGF-based antiangiogenic therapies, is actively investigated. Non-VEGF-driven pathways and growth factors other than VEGF may play important roles in pathogenesis and are included in certain combination therapies with VEGF inhibitors.

SUMMARY

The discovery of VEGF-A's role in the pathogenesis of neovascular ocular disease provided a strong rationale for the development of anti-VEGF-based therapies. There is now ample evidence that anti-VEGF therapies are viable treatment options for these diseases. Nevertheless, large, randomized controlled trials are still awaited to confirm early safety and efficacy findings from small, open-label prospective studies.

Intravitreal bevacizumab for choroidal neovascularization in ocular histoplasmosis

PURPOSE

To define the role of intravitreal bevacizumab in individuals with choroidal neovascularization (CNV) resulting from Ocular Histoplasmosis syndrome (OHS).

DESIGN

Retrospective chart review of a surgical therapy.

METHODS

We reviewed the course of 28 eyes of 28 patients who underwent intravitreal injection of bevacizumab for treatment of CNV secondary to OHS. Outcome was measured by pretreatment and posttreatment visual acuity (VA).

RESULTS

The average pretreatment logarithm of the minimum angle of resolution (logMAR) VA was 0.65 (Snellen equivalent of 20/88). Mean follow-up was 22.43 weeks with an average of 1.8 intravitreal injections. Average final logMAR VA was 0.43 (Snellen equivalent of 20/54). Twenty eyes (71%) experienced an increase in central VA, whereas four eyes (14%) were unchanged and four eyes (14%) experienced a decrease in vision.

CONCLUSIONS

Intravitreal bevacizumab may improve or stabilize VA in a significant majority of patients with neovascular complications of OHS (24 eyes [85.7%] in our study population).