Elevated intraocular pressure (IOP) is an important risk factor in developing glaucoma, and variability in IOP might herald glaucomatous development or progression. We report the results of a genome-wide association study meta-analysis of 18 population cohorts from the International Glaucoma Genetics Consortium (IGGC), comprising 35,296 multi-ancestry participants for IOP. We confirm genetic association of known loci for IOP and primary open-angle glaucoma (POAG) and identify four new IOP-associated loci located on chromosome 3q25.31 within the FNDC3B gene (P = 4.19 × 10(-8) for rs6445055), two on chromosome 9 (P = 2.80 × 10(-11) for rs2472493 near ABCA1 and P = 6.39 × 10(-11) for rs8176693 within ABO) and one on chromosome 11p11.2 (best P = 1.04 × 10(-11) for rs747782). Separate meta-analyses of 4 independent POAG cohorts, totaling 4,284 cases and 95,560 controls, showed that 3 of these loci for IOP were also associated with POAG.

While mean intraocular pressure (IOP) has long been known to correlate with glaucomatous damage, the role of IOP fluctuation is less clearly defined. There is extensive evidence in the literature for and against the value of short-term and long-term IOP fluctuation in the evaluation and prognosis of patients with glaucoma. We present here the arguments made by both sides, as well as a discussion of the pitfalls of prior research and potential directions for future studies. Until a reliable method is developed that allows for constant IOP monitoring, many variables will continue to hinder us from drawing adequate conclusions regarding the significance of IOP variation.

PURPOSE: To compare visual acuity outcomes and diabetic retinopathy progression after pars plana vitrectomy (PPV) versus combined pars plana vitrectomy and phacoemulsification (PPVCE) in patients with diabetes. METHODS: Retrospective review of 222 consecutive diabetic patients undergoing PPV or PPVCE. RESULTS: A total of 251 eyes of 222 patients were evaluated (PPV = 122, PPVCE = 129). Four-year follow-up was 64% (161 eyes). Overall, patients undergoing PPVCE had better preoperative visual acuity (PPVCE = 20/80, PPV = 20/160, P = 0.03). At 4-year follow-up, visual acuity improved (PPV = +22, PPVCE = +11 letters) compared with baseline in both groups. After correcting for baseline differences in visual acuity, no statistically significant difference in final visual acuity was observed (PPVCE = 20/32, PPV = 20/50, P = 0.09). Results did not differ substantially by surgical indication (vitreous hemorrhage, traction retinal detachment, epiretinal membrane, and/or diabetic macular edema). Cataract progression occurred in 64%, and cataract surgery was performed in 39% of phakic eyes undergoing PPV. Rates of diabetic retinopathy progression, vitreous hemorrhage, and retinal detachment were not statistically different. Neovascular glaucoma developed in 2 patients (2%) after PPV and 6 patients (8%) after PPVCE (P = 0.07). CONCLUSION: In diabetic patients, equivalent visual acuity improvement over 4 years was observed after PPV or PPVCE. Visual outcomes and retinopathy progression rates were not significantly different after either intervention, suggesting that PPVCE may be appropriate when indicated in patients with diabetes.

Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene-FBN2-can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

IMPORTANCE: Current treatments for cystoid macular edema (CME) in retinitis pigmentosa (RP) are not always effective, may lead to adverse effects, and may not restore visual acuity. The present research lays the rationale for evaluating whether an iodine supplement could reduce CME in RP. OBJECTIVE: To determine whether central foveal thickness (CFT) in the presence of CME is related to dietary iodine intake inferred from urinary iodine concentration (UIC) in nonsmoking adults with RP. DESIGN, SETTING, AND PARTICIPANTS: We performed a cross-sectional observational study of 212 nonsmoking patients aged 18 to 69 years referred to our institution for RP with visual acuity of no worse than 20/200 in at least 1 eye. EXPOSURE: Retinitis pigmentosa with or without CME. MAIN OUTCOMES AND MEASURES: With the eye as the unit of analysis, the relationship of log CFT measured by optical coherence tomography to UIC measured from multiple spot samples and represented as a 3-level classification variable (<100, 100-199, and ≥200 µg/L), assigning greater weight to patients with more reliable UIC estimates. RESULTS: Analyses were limited to 199 patients after excluding 11 who failed to return urine samples for measuring UIC and 2 outliers for UIC. Of the 199 patients, 36.2% had CME in 1 or both eyes. Although log CFT was inversely related to UIC based on findings from all eyes (P = .02), regression of log CFT on UIC separately for eyes with and without CME showed a strong inverse significant relationship for the former group (P < .001) and no significant relationship for the latter group (P = .66) as tested. For the eyes with CME, CFT ranged from a geometric mean of 267 µm for a median UIC of less than 100 µg/L to a geometric mean of 172 µm for a median UIC of 200 µg/L or greater. In contrast, we found no significant association between CME prevalence and UIC based on the entire sample as tested (odds ratio, 1.01 [95% CI, 0.38-2.67]; P = .99). CONCLUSIONS AND RELEVANCE: A higher UIC in nonsmoking adults with RP was significantly associated with less central foveal swelling in eyes with CME. Additional study is required to determine whether an iodine supplement can limit or reduce the extent of CME in patients with RP.

PURPOSE OF REVIEW: Although conjunctival goblet cells are a major cell type in ocular mucosa, their responses during ocular allergy are largely unexplored. This review summarizes the recent findings that provide key insights into the mechanisms by which their function and survival are altered during chronic inflammatory responses, including ocular allergy. RECENT FINDINGS: Conjunctiva represents a major component of the ocular mucosa that harbors specialized lymphoid tissue. Exposure of mucin-secreting goblet cells to allergic and inflammatory mediators released by the local innate and adaptive immune cells modulates proliferation, secretory function, and cell survival. Allergic mediators like histamine, leukotrienes, and prostaglandins directly stimulate goblet cell mucin secretion and consistently increase goblet cell proliferation. Goblet cell mucin secretion is also detectable in a murine model of allergic conjunctivitis. Additionally, primary goblet cell cultures allow evaluation of various inflammatory cytokines with respect to changes in goblet cell mucin secretion, proliferation, and apoptosis. These findings in combination with the preclinical mouse models help understand the goblet cell responses and their modulation during chronic inflammatory diseases, including ocular allergy. SUMMARY: Recent findings related to conjunctival goblet cells provide the basis for novel therapeutic approaches, involving modulation of goblet cell mucin production, to improve treatment of ocular allergies.

While growth factor-driven dimerization of receptor tyrosine kinases (RTKs) is a simple and intuitive mechanism of activating RTKs, K.-I. Arimoto et al. (Mol. Cell. Biol. 34:3843-3854, 2014, doi:10.1128/MCB.00758-14) describe a novel means of promoting the activity of RTKs. Namely, plakophilin-2 (PKP2) associates with the epidermal growth factor receptor (EGFR) and enhances its ligand-dependent and ligand-independent activity. This discovery suggests that antagonizing PKP2 may be a new therapeutic opportunity to combat tumors in which activation of EGFR contributes to pathogenesis.

Adeno-associated virus (AAV) is a helper-dependent parvovirus which has not been linked with human disease. This aspect, in combination with its broad cell and tissue tropism, and limited viral host response has made it an attractive vector system for gene therapy. The viral protein capsid, the primary interface with the host, is the main determinant for these phenotypes, is highly variable, and is most subject to pressures during replication. Here, we explore the evolutionary path of AAV and other parvoviruses in respect to these phenotypes, as well as directed evolution and engineering strategies that have exploited the lessons learned from natural selection in order to address remaining limitations of AAV as a therapeutic gene transfer platform.

Variants in LOXL1 are significantly associated with exfoliation syndrome (XFS), however the impact of the associated variants on disease development is not yet understood. Initially the associated missense changes, R141L and G153D, were considered to be pathogenic alleles. Flipping of the risk allele in certain populations for both missense variants provided strong evidence that these missense changes are not biologically significant and suggest that other LOXL1 variant(s), in linkage disequilibrium with these missense variants, predispose to exfoliation syndrome by affecting gene expression or protein function. Several lines of evidence support dysregulation of LOXL1 gene expression as a contributing factor to disease development. First, in the German population the R141L (rs1048661) risk allele reduced LOXL1 expression by 20%. Second, haplotype analysis identified a risk haplotype that includes including R141L, G153D, as well as a LOXL1 promoter region variant previously shown to reduce gene expression (rs16958477). Third, the LOXL1 risk haplotype influences gene expression induced by disease-associated factors TGF-B1, oxidative stress, UV light and hypoxia. Finally, a LOXL1 null mouse has some features of XFS suggesting that decreased enzyme activity contributes to predisposition to the disease. Collectively, these results suggest that dysregulation of LOXL1 expression is a contributing factor to exfoliation disease development.

Complex traits can be triggered by environmental factors in genetically predisposed individuals. The lysyl oxidase-like 1 gene (LOXL1) variants associated with exfoliation syndrome (XFS) are detected in >90% of cases that have been genotyped from sites around the world. Remarkably, roughly 80% of people without XFS also possess these same variants in all populations that have been tested. Nonetheless, the prevalence of XFS varies from ≤0.4% to >20%. These data suggest that other genetic variants, epigenetic modifications, or environmental factors also contribute to XFS. Furthermore, it is possible that environmental factors modify the association between LOXL1 and XFS. Interactions between LOXL1 variants and environmental factors could explain the varying prevalence of XFS seen throughout the world. At the very least, the discovery of the association between LOXL1 variants and XFS has opened the door to the discovery of environmental risk factors for this condition. Candidate gene-environment interactions in XFS will be discussed.

Age-related macular degeneration (AMD) is a multifactorial degeneration of photoreceptors and retinal pigment epithelium. The societal impact is significant, with more than 2 million individuals in the United States alone affected by advanced stages of AMD. Recent progress in our understanding of this complex disease and parallel developments in therapeutics and imaging have translated into new management paradigms in recent years. However, there are many unanswered questions, and diagnostic and prognostic precision and treatment outcomes can still be improved. In this article, we discuss the clinical features of AMD, provide correlations with modern imaging and histopathology, and present an overview of treatment strategies.

The intestinal microbial ecosystem is complex, and few of the principles that contribute to homeostasis in health are well understood. Pham et al. (2014) show that a network including the epithelial interleukin-22 receptor protects against infection with the opportunistic pathogen Enterococcus faecalis through promotion of host-microbiota mutualism.

There is currently considerable controversy about existence and classification of "lymphatic vessels" in the eye. Some of the confusion is certainly caused by inappropriate use (or nonuse) of the correct immunohistochemical markers. Many experts in the field expressed the need for a consensus statement, and, in this perspective, authors offer arguments and solutions to reliably continue with immunohistochemical ocular lymphatic research.

Purpose: To investigate bilateral tear cytokine levels in patients with unilateral bacterial keratitis (BK) as associated with in vivo confocal microscopic (IVCM) alterations in corneal nerves and dendritiform immune cells (DCs). Methods: Fifty-four (13 BK, 13 contralateral, 28 healthy controls) tear samples were collected prospectively and analyzed by multiplex microbeads assay. IVCM of the central cornea was performed on the same day and assessed for corneal nerve and DC alterations Results: Interleukin (IL)-1β, IL-6, and IL-8 were significantly elevated only in affected eyes (66.6±26.8 ρg/ml, 7,174±2,430, 810±315, P=0.04, P<0.001 and P<0.001), compared to healthy controls (13.0±4.0 ρg/ml, 171.8±32.1, 56.5±33.8). CCL-2, IL-10 and IL-17a were elevated only in contralateral eyes (813±478 ρg/ml, 86.7±38.3, 3,350±881, P=0.02, P=0.01, P=0.04), compared to controls (73.7±25.3 ρg/ml, 17.5 ±4.9, 1,350±337). Triggering receptor expressed on myeloid cells (TREM)-1 was significantly elevated in both affected (551±231 ρg/ml, P=0.02) and contralateral unaffected eyes (545±298 ρg/ml, P=0.03), compared to controls (31.3±12.4 ρg/ml). The density of DCs was significantly increased in both affected (226.9±37.3 cells/mm2, P<0.001) and unaffected eyes (122.3±23.7 cells/mm2, P<0.001) compared to controls (22.7±5.9 cells/mm2). Subbasal nerve density significantly decreased in affected eyes (3,337±1,615 μm/mm2, P<0.001) and contralateral eyes (13,230±1,635 μm/mm2, P<0.001) compared to controls (21,200±545 μm/mm2). IL-1β, IL-6 and IL-8 were significantly correlated with DC density (R=0.40, R=0.55 and R=0.31, all P<0.02) and nerve density (R=-0.30, R=-0.53 and R=-0.39, all P<0.01). Conclusions: Pro-inflammatory tear cytokines are elevated bilaterally in patients with unilateral BK, and are correlated strongly with alterations in DCs and nerve density as detected by IVCM.

PURPOSE. Canonical Wnt signaling has emerged as a critical regulator of aqueous outflow facility and intraocular pressure (IOP). In this study, we examine the role of canonical Wnt signaling on extracellular matrix (ECM) expression in the trabecular meshwork (TM) and explore the molecular mechanisms involved. METHODS. β-catenin localization in human TM tissue was examined using immunofluorescent staining. Primary human TM cells were incubated with lithium chloride (LiCl) and the effect on active β-catenin expression was assessed by immunoblot. Adenovirus expressing a dominant-negative TCF4 mutant that lacks a β-catenin binding domain was used. Changes in the levels of the microRNA-29 (miR-29) family and ECM proteins were determined by real-time quantitative PCR and immunoblot analysis, respectively. RESULTS. β-catenin was expressed throughout the TM, with localization primarily to the plasma membrane. Incubation of TM cells with lithium chloride increased the expression of active β-catenin. Lithium chloride treatment upregulated miR-29b expression, and suppressed the levels of various ECM proteins under both basal and TGF-β2 stimulatory conditions. Infection of TM cells with a dominant-negative TCF4 mutant induced ECM levels without a significant change in the expression of the miR-29 family. CONCLUSIONS. Collectively, our data identify the canonical Wnt signaling pathway as an important modulator of ECM expression in the TM and provide a mechanistic framework for its regulation of outflow facility and IOP.

PURPOSE: The aim of this study was to report the clinical, imaging, and histopathological findings of bilateral, conjunctival adult-onset xanthogranulomas that raised the prospect of a mild form of Erdheim-Chester disease. METHODS: This is a case report. RESULTS: A 35-year-old white male complaining of ocular irritation, presented with bilateral, nasal and temporal, yellow, elevated conjunctival lumps first noticed 1.5 years back, which were not associated with other ocular findings. The lesions were firm, attached to the underlying episclera, and measured 1.1 × 0.9, 1.1 × 0.8, 1.2 × 0.5, and 0.5 × 0.5 cm in the temporal and nasal right and left eyes, respectively. Each mass was fleshy with vascularity at the peripheral margin. Histopathologic evaluation after excisional biopsy revealed lipidized xanthoma cells, multiple Touton giant cells, and lymphocytes. Immunohistochemical staining was positive for adipophilin (lipid), CD68, CD163 histiocytes, CD3 T cells (with CD8 cytotoxic T cells > CD4 T-helper cells), and virtually no CD20 B cells or IgG4 plasma cells. The patient later acquired similar xanthogranulomatous subcutaneous lesions on the extremities. Positron emission tomography scans showed sclerosis in the medullary cavities of the tibia and the radius of both legs and arms, and an absence of retroperitoneal lesions. A normal serum immunoelectrophoresis and the absence of a BRAF gene mutation were demonstrated. CONCLUSIONS: Adult-onset xanthogranuloma can present as a solitary conjunctival mass without periocular or orbital involvement. The clinical, histopathologic, and radiologic findings in this case are suggestive of Erdheim-Chester disease without displaying any life-threatening lesions to date. Histopathologic and imaging studies can help in obtaining a diagnosis. Ophthalmologists should be aware that xanthogranulomatous conditions may have potential systemic implications, and a thorough systemic evaluation is recommended for lesions that initially seemed to be isolated in nature.