Enhanced Optic Nerve Expansion and Altered Ultrastructure of Elastic Fibers Induced by Lysyl Oxidase Inhibition in a Mouse Model of Marfan Syndrome.

Two major constituents of exfoliation material, fibrillin-1 and lysyl oxidase-like 1 (encoded by FBN1 and LOXL1), are implicated in exfoliation glaucoma, yet their individual contributions to ocular phenotype are minor. To test the hypothesis that a combination of FBN1 mutation and LOXL1 deficiency exacerbates ocular phenotypes, the pan-lysyl oxidase inhibitor ß-aminopropionitrile (BAPN) was used to treat adult wild-type (WT) mice and mice heterozygous for a missense mutation in Fbn1 (Fbn1C1041G/+) for 8 weeks and their eyes were examined. Although intraocular pressure did not change and exfoliation material was not detected in the eyes, BAPN treatment worsened optic nerve and axon expansion in Fbn1C1041G/+ mice, an early sign of axonal damage in rodent models of glaucoma. Disruption of elastic fibers was detected only in Fbn1C1041G/+ mice, which increased with BAPN treatment, as shown by histologic and immunohistochemical staining of the optic nerve pia mater. Transmission electron microscopy showed that Fbn1C1041G/+ mice had fewer microfibrils, smaller elastin cores, and a lower density of elastic fibers compared with WT mice in control groups. BAPN treatment led to elastin core expansion in both WT and Fbn1C1041G/+ mice, but an increase in the density of elastic fiber was confined to Fbn1C1041G/+ mice. LOX inhibition had a stronger effect on optic nerve and elastic fiber parameters in the context of Fbn1 mutation, indicating the Marfan mouse model with LOX inhibition warrants further investigation for exfoliation glaucoma pathogenesis.

Differentially expressed microRNAs in the aqueous humor of patients with exfoliation glaucoma or primary open-angle glaucoma.

Both exfoliation glaucoma (XFG) and primary open-angle glaucoma (POAG) have been linked to decreased conventional outflow of aqueous humor (AH). To better understand the molecular changes in the AH content under such conditions, we analyzed the miRNA profiles of AH samples from patients with POAG and XFG compared to non-glaucoma controls. Individual AH samples (n = 76) were collected from POAG and XFG patients and age-matched controls during surgical procedure. After RNA extraction, the miRNA profiles were individually determined in 12 POAG, 12 XFG and 11 control samples. We identified 205, 295 and 195 miRNAs in the POAG, XFG and control samples, respectively. Our differential expression analysis identified three miRNAs (miR-125b-5p, miR-302d-3p and miR-451a) significantly different between POAG and controls, five miRNAs (miR-122-5p, miR-3144-3p, miR-320a, miR-320e and miR-630) between XFG and controls and one miRNA (miR-302d-3p) between POAG and XFG. While none of these miRNAs have been previously linked to glaucoma, miR-122-5p may target three glaucoma-associated genes: OPTN, TMCO1 and TGF-ß1. Pathway analysis revealed that these miRNAs are involved in potential glaucoma pathways, including focal adhesion, tight junctions, and TGF-ß signaling. Comparison of the miRNA profile in AH to unrelated human serum (n = 12) exposed potential relationships between these two fluids, although they were not significantly correlated. In summary, we have successfully profiled the miRNA expression without amplification in individual human AH samples and identified several POAG or XFG-associated miRNAs. These miRNAs may play a role in pathways previously implicated in glaucoma and act as biomarkers for disease pathogenesis.

Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.

Importance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures: Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results: A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-ß A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.

Consensus recommendations for trabecular meshwork cell isolation, characterization and culture.

Cultured trabecular meshwork (TM) cells are a valuable model system to study the cellular mechanisms involved in the regulation of conventional outflow resistance and thus intraocular pressure; and their dysfunction resulting in ocular hypertension. In this review, we describe the standard procedures used for the isolation of TM cells from several animal species including humans, and the methods used to validate their identity. Having a set of standard practices for TM cells will increase the scientific rigor when used as a model, and enable other researchers to replicate and build upon previous findings.

Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) study: twelve-month findings.

PURPOSE: To report 1-year outcomes of the Prospective Retinal and Optic Nerve Vitrectomy Evaluation study. DESIGN: Prospective, controlled, observational study. PARTICIPANTS: Eighty eyes of 40 participants undergoing pars plana vitrectomy for epiretinal membrane (ERM), macular hole (MH), or vitreous opacities. METHODS: Enrolled participants underwent baseline evaluation of the study (surgical) and fellow (control) eyes by a masked fellowship-trained glaucoma specialist; evaluation included intraocular pressure (IOP; Goldmann applanation and Tono-Pen), central corneal thickness, gonioscopy, and cup-to-disc ratio measurement. Baseline testing included bilateral color fundus and optic disc photography, fundus autofluorescence, automated perimetry, and optical coherence tomography (OCT) of the macula and optic nerve. Evaluations were repeated at 3 months and 1 year after surgery. MAIN OUTCOME MEASURES: The primary outcome measure was changes in peripapillary retinal nerve fiber layer (pRNFL) thickness. Secondary outcomes included changes in macular thickness and IOP. RESULTS: Thirty-eight of 40 patients completed 1 year of follow-up. Mean visual acuity (VA) improved in study eyes from baseline (P = 0.003) but remained worse than fellow eyes (P<0.001). Study eyes had thinner inferior pRNFL thickness (114±16.8 µm) compared with fellow eyes (123±14.7 µm; P = 0.004). Mean IOP difference between study eyes and fellow eyes increased from baseline to 1 year. At 1 year, MH study eyes had higher mean IOP (16.0±3.7 mmHg) compared with fellow eyes (14.8±3.4 mmHg; P = 0.08). Mean IOP for pseudophakic study eyes increased from 14.5±3.2 mmHg at baseline to 16.0±2.8 mmHg at 1 year (P = 0.04). Central subfield thickness (CST) and cube volume decreased in study eyes at 1 year but remained greater than that of fellow eyes (P<0.05). Reduction in CST from baseline correlated with degree of VA improvement (P<0.05). Mean deviation (MD) improved in ERM study eyes at 1 year when compared with baseline (-2.2 vs. -4.0; P = 0.02) but remained worse than fellow eyes (-1.2; P = 0.002). CONCLUSIONS: One year after vitrectomy, VA, CST, and MD improved in study eyes but not to the level of fellow eyes. Inferior pRNFL thickness decreased in study eyes. Reduction in CST from baseline correlated with degree of VA improvement. Pseudophakic study eyes demonstrated increased IOP when compared with baseline.

Acute myopia and angle closure glaucoma from topiramate in a seven-year-old: a case report and review of the literature.

BACKGROUND: A case is reported of acute bilateral myopia and angle closure glaucoma in a 7-year-old patient from topiramate toxicity. This is the second known reported case of topiramate induced acute angle closure glaucoma and third known reported case of topiramate induced acute myopia in a pediatric patient. CASE PRESENTATION: This case presents a 7-year-old who had recently begun topiramate therapy for seizures and headache. She developed painless blurred vision and acute bilateral myopia, which progressed to acute bilateral angle closure glaucoma. After a routine eye exam where myopia was diagnosed, the patient presented to the emergency room with symptoms of acute onset blurry vision, tearing, red eyes, swollen eyelids, and photophobia. The symptoms, myopia, and angle closure resolved with topical and oral intraocular pressure lowering medications, topical cyclopentolate, and discontinuation of topiramate. CONCLUSION: Acute angle closure glaucoma is a well-known side effect of topiramate, but is rarely seen in children. It cautions providers to the potential ophthalmic side effects of commonly used medications in the pediatric population. It highlights the need to keep a broad differential in mind when encountering sudden onset blurry vision in the primary care clinic, the need for careful consideration of side effects when starting topiramate therapy in a child, and the need for parental counseling of side effects.

Mapping of the disease locus and identification of ADAMTS10 as a candidate gene in a canine model of primary open angle glaucoma.

Primary open angle glaucoma (POAG) is a leading cause of blindness worldwide, with elevated intraocular pressure as an important risk factor. Increased resistance to outflow of aqueous humor through the trabecular meshwork causes elevated intraocular pressure, but the specific mechanisms are unknown. In this study, we used genome-wide SNP arrays to map the disease gene in a colony of Beagle dogs with inherited POAG to within a single 4 Mb locus on canine chromosome 20. The Beagle POAG locus is syntenic to a previously mapped human quantitative trait locus for intraocular pressure on human chromosome 19. Sequence capture and next-generation sequencing of the entire canine POAG locus revealed a total of 2,692 SNPs segregating with disease. Of the disease-segregating SNPs, 54 were within exons, 8 of which result in amino acid substitutions. The strongest candidate variant causes a glycine to arginine substitution in a highly conserved region of the metalloproteinase ADAMTS10. Western blotting revealed ADAMTS10 protein is preferentially expressed in the trabecular meshwork, supporting an effect of the variant specific to aqueous humor outflow. The Gly661Arg variant in ADAMTS10 found in the POAG Beagles suggests that altered processing of extracellular matrix and/or defects in microfibril structure or function may be involved in raising intraocular pressure, offering specific biochemical targets for future research and treatment strategies.

IN SEARCH OF MOUSE MODELS FOR EXFOLIATION SYNDROME.

PURPOSE: Exfoliation syndrome (XFS) is a systemic connective tissue disorder with elusive pathophysiology. We hypothesize that a mouse model with elastic fiber defects caused by lack of lysyl oxidase like 1 (LOXL1 encoded by Loxl1), combined with microfibril deficiency due to Fbn1 mutation (encoding fibrillin-1, Fbn1C1041G/+) will display ocular and systemic phenotypes of XFS. METHODS: Loxl1-/- was crossed with Fbn1C1041G/+ to create double mutant (dbm) mice. Intraocular pressure (IOP), visual acuity (VA), electroretinogram (ERG) and biometry were characterized in 4 genotypes (wt, Fbn1C1041G/+, Loxl1-/-, dbm) at 16 weeks old. Optic nerve area was measured by ImageJ and axon counting was achieved by AxonJ. Deep whole-body phenotyping was performed in wt and dbm mice. Two-tailed Student's t-test was used for statistical analysis. RESULTS: There was no difference in IOP between the 4 genotypes. VA was significantly reduced only in dbm mice. The majority of biometric parameters showed significant differences in all 3 mutant genotypes compared to wt, and dbm had exacerbated anomalies compared to single mutants. Dbm mice showed reduced retinal function and significantly enlarged ON area when compared with wt. Dbm mice exhibited severe systemic phenotypes related to abnormal elastic fibers, such as pelvic organ prolapse, cardiovascular and pulmonary abnormalities. CONCLUSIONS: Ocular and systemic findings in dbm mice support functional overlap between fibrillin-1 and LOXL1, two prominent components of exfoliation material. Although no elevated IOP or reduction of axon numbers was detected in dbm mice at 16-week-old, their reduced retinal function and enlarged ON area indicate early retinal ganglion cell dysfunction. Dbm mice also provide insight on the link between XFS and systemic diseases in humans.

Marfan syndrome caused by a novel FBN1 mutation with associated pigmentary glaucoma.

Mutations in fibrillin-1 (FBN1) cause a wide spectrum of disorders, including Marfan syndrome, which have in common defects in fibrillin-1 microfibrils. Ectopia lentis and myopia are frequently observed ocular manifestations of Marfan syndrome. Glaucoma is also associated with Marfan syndrome, though the form of glaucoma has not been well-characterized. In this report, ocular examination of a patient diagnosed with Marfan syndrome based on family history and aortic dilatation was performed, including measurement of facility of aqueous humor outflow by tonography. The patient did not have ectopia lentis at the age of 42 years. Based on optic nerve appearance, reduced outflow facility, elevated IOP with open angles and clear signs of pigment dispersion, the patient was diagnosed with pigmentary glaucoma. The patient was heterozygous for a novel truncating mutation in FBN1, p.Leu72Ter. Histology of normal human eyes revealed abundant expression of elastic fibers and fibrillin-1 in aqueous humor outflow structures. This is the first report of a patient with Marfan syndrome that is caused by a confirmed FBN1 mutation with associated pigmentary glaucoma. In addition to identifying a novel mutation of FBN1 and broadening the spectrum of associated ocular phenotypes in Marfan syndrome, our findings suggest that pigmentary glaucoma may involve defects in fibrillin-1 microfibrils.

Worsening angle closure glaucoma and choroidal detachments subsequent to closure of a carotid cavernous fistula.

BACKGROUND: Carotid cavernous fistulas are abnormal communications between the cavernous sinus and the external or internal carotid arteries. Although rare, closure of carotid cavernous fistulas can lead to immediate ocular complications. To our knowledge, our case represents the first report of worsening angle closure glaucoma and choroidal detachments over an extended period of two months subsequent to closure of a carotid cavernous fistula. CASE PRESENTATION: A 70-year-old female with a history of primary angle closure glaucoma presented with 4 mm of proptosis, resistance to retropulsion, tortuous corkscrew blood vessels and an orbital bruit of the right eye. Diagnostic cerebral angiogram showed a small indirect Barrow type D right carotid cavernous fistula. Transarterial embolization was planned but repeat cerebral angiography prior to the procedure demonstrated spontaneous partial closure of the carotid cavernous fistula and the procedure was aborted. One month later, our patient was noted to have worsening vision and choroidal detachments of the right eye. She declined further testing and was thus started on self-administered manual carotid jugular compressions. One month later, she developed progressive worsening of her choroidal detachments and angle closure. She eventually opted for surgical intervention but repeat cerebral angiography showed significant thrombosis of the carotid cavernous fistula and no intervention was warranted. Examination two months later showed complete resolution of the choroidal detachments and open angles of both eyes. CONCLUSIONS: Our patient demonstrated worsening angle closure glaucoma and choroidal detachments after spontaneous closure of her carotid cavernous fistula had been noted. Ocular complications, including acute angle closure, have been reported to occur immediately after closure of carotid cavernous fistulas, but not over months as in our patient. It is imperative that individuals who have undergone apparent closure of a carotid cavernous fistula be carefully monitored for worsening ocular complications.

Optic neuropathy associated with TGFß dysregulation in mice with a glaucoma-causative mutation of ADAMTS10.

Glaucoma is a neurodegenerative disease that causes irreversible blindness due to loss of retinal ganglion cells (RGCs) and their axons. We previously identified a G661R mutation of ADAMTS10 (A Disintegrin And Metalloproteinase with ThromboSpondin type 1 motif 10) as the disease-causing mutation in a beagle model of glaucoma. ADAMTS10 is a secreted matrix metalloproteinase that belongs to the ADAMTS family which is involved in extracellular matrix (ECM) turnover. Previous studies have shown that ADAMTS10 binds fibrillin microfibrils, promotes their formation, and influences their fibrillin isoform composition. Here, we established a mouse model carrying the G661R mutation of ADAMTS10 (ADAMTS10G661R/G661R) to investigate its ocular phenotypes related to glaucoma and to explore possible functions of ADAMTS10. We found that ADAMTS10 was expressed in the inner retina and along RGC axons in the optic nerve. However, ADAMTS10 was not colocalized with fibrillin microfibrils in these tissues, suggesting fibrillin-independent function for ADAMTS10. In electroretinogram experiments, we found that ADAMTS10G661R/G661R mice had reduced amplitude of retinal responses to dim light stimulus, indicating RGC dysfunction. The reduced RGC function coincided with RGC axon structural changes manifested as smaller optic nerves and fewer optic nerve axons, which may contribute to glaucoma. The reduced number of optic nerve axons found for ADAMTS10G661R/G661R mice occurred early, suggesting developmental deficits. Subsequent experiments found increased apoptosis in the retina of ADAMTS10G661R/G661R mice during postnatal development, which could result in fewer RGCs produced, accounting for fewer optic nerve axons in adulthood. Consistent with a protective effect of transforming growth factor ß (TGFß) signaling against apoptosis during retinal development as shown previously by others, we found increased apoptosis accompanied by decreased TGFß signaling in the developing retina of ADAMTS10G661R/G661R mice, suggesting a novel role for ADAMTS10 in regulating TGFß signaling which could involve direct interaction between ADAMTS10 and latent TGFß.

Facilitators and Barriers to Glaucoma Medication Adherence.

PRCIS: Patient education and dosing self-efficacy are important factors related to ongoing adherence to glaucoma topical treatment, and patients view their disease management as a shared effort with their provider. PURPOSE: Glaucoma affects nearly 3 million Americans, and medication adherence has been reported to be as low as 20% in this patient population; however, key limitations to our understanding of this behavior in adults with glaucoma exist. PATIENTS AND METHODS: This research used an electronic survey including validated concepts related to topical medication use and an in-person interview to investigate the influencers of and solutions for challenges to medication adherence in adults with glaucoma. Patient eligibility was determined upon arrival to a regularly-scheduled visit to the Vanderbilt Eye Institute, during which they were asked for consent to complete the survey. Responses were captured by tablet and assessed using descriptive and inferential statistics. The primary focus was instrument correlations with the Adherence to Refills and Medications Scale score and were run between Adherence to Refills and Medications Scale, and the totaled score for each individual questionnaire as well as individual items. Recorded interviews were thematically assessed by multiple study team members. RESULTS: Survey results of adults with glaucoma suggested that self-efficacy, forgetfulness, fear of side effects, and dosing ability were all related to self-reported medication adherence. Despite most having glaucoma for several years, discrepancies in disease knowledge were observed. Patient interviews uncovered 3 overall themes related to glaucoma treatment: (1) glaucoma management as a shared responsibility; (2) the importance of patient education; and (3) specific adherence facilitators and barriers. CONCLUSION: Glaucoma medication adherence interventions may benefit from focusing on developing patient medication-taking self-efficacy, disease-related education, and engagement with their provider.

Lysyl oxidase-like 1 deficiency alters ultrastructural and biomechanical properties of the peripapillary sclera in mice.

Lysyl oxidase-like 1 encoded by the LOXL1 gene is a member of the lysyl oxidase family of enzymes that are important in the maintenance of extracellular matrix (ECM)-rich tissue. LOXL1 is important for proper elastic fiber formation and mice lacking LOXL1 (Loxl1-/- ) exhibit systemic elastic fiber disorders, such as pelvic organ prolapse, a phenotype associated with exfoliation syndrome (XFS) in humans. Patients with XFS have a significant risk of developing exfoliation glaucoma (XFG), a severe form of glaucoma, which is a neurodegenerative condition leading to irreversible blindness if not detected and treated in a timely fashion. Although Loxl1-/- mice have been used extensively to investigate mechanisms of pelvic organ prolapse, studies of eyes in those mice are limited and some showed inconsistent ocular phenotypes. In this study we demonstrate that Loxl1-/- mice have significant anterior segment biometric abnormalities which recapitulate some human XFS features. We then focused on the peripapillary sclera (PPS), a critical structure for maintaining optic nerve health. We discovered quantitative and qualitive changes in ultrastructure of PPS, such as reduced elastic fibers, enlarged collagen fibrils, and transformed collagen lamella organization detected by transmission electron microscopy (TEM). Importantly, these changes corelate with altered tissue biomechanics detected by Atomic Force Microscopy (AFM) of PPS in mice. Together, our results support a crucial role for LOXL1 in ocular tissue structure and biomechanics, and Loxl1-/- mice could be a valuable resource for understanding the role of scleral tissue biomechanics in ocular disease.

Adamts10 controls transforming growth factor ß family signaling that contributes to retinal ganglion cell development.

Although mutations in ADAMTS10 have long been known to cause autosomal recessive Weill-Marchesani Syndrome which is characterized by short stature and ocular abnormalities, more recent work has shown that certain mutations in ADAMTS10 cause glaucoma in dogs. In humans, glaucoma is the leading cause of irreversible vision loss that affects tens of millions of people world-wide. Vision loss in glaucoma is a result of neurodegeneration of retinal ganglion cells that form the inner-most layer of the retina and whose axons form the optic nerve which relays visual information to the brain. ADAMTS10 contributes to the formation of microfibrils which sequester latent transforming growth factor ß (TGFß). Among its many biological functions, TGFß promotes the development of retinal ganglion cells and is also known to play other roles in glaucoma pathogenesis. The aim of this study was to test the hypothesis that ADAMTS10 plays a role in retinal ganglion cell development through regulation of TGFß signaling. To this end, Adamts10 expression was targeted for reduction in zebrafish embryos carrying either a fluorescent reporter that labels retinal ganglion cells, or a fluorescent reporter of pSmad3-mediated TGFß family signaling. Loss of adamts10 function in zebrafish embryos reduced retinal ganglion cell reporter fluorescence and prevented formation of an ordered retinal ganglion cell layer. Targeting adamts10 expression also drastically reduced constitutive TGFß signaling in the eye. Direct inhibition of the TGFß receptor reduced retinal ganglion cell reporter fluorescence similar to the effect of targeting adamts10 expression. These findings unveil a previously unknown role for Adamts10 in retinal ganglion cell development and suggest that the developmental role of Adamts10 is mediated by active TGFß family signaling. In addition, our results show for the first time that Adamts10 is necessary for pSmad3-mediated constitutive TGFß family signaling.

Altered Ocular Fibrillin Microfibril Composition in Mice With a Glaucoma-Causing Mutation of Adamts10.

Purpose: Previously, we identified a G661R mutation of ADAMTS10 (a disintegrin-like and metalloprotease with thrombospondin type 1 motif 10) as being disease causative in a colony of Beagles with inherited primary open-angle glaucoma (POAG). Mutations in ADAMTS10 are known to cause Weill-Marchesani syndrome (WMS), which is also caused by mutations in the fibrillin-1 gene (FBN1), suggesting functional linkage between ADAMTS10 and fibrillin-1, the principal component of microfibrils. Here, we established a mouse line with the G661R mutation of Adamts10 (Adamts10G661R/G661R) to determine if they develop features of WMS and alterations of ocular fibrillin microfibrils. Methods: Intraocular pressure (IOP) was measured using a TonoLab rebound tonometer. Central cornea thickness (CCT), anterior chamber depth (ACD) and axial length (AL) of the eye were examined by spectral-domain optical coherence tomography. Sagittal eye sections from mice at postnatal day 10 (P10) and at 3 and 24 months of age were stained with antibodies against fibrillin-1, fibrillin-2, and ADAMTS10. Results: IOP was not elevated in Adamts10G661R/G661R mice. Adamts10G661R/G661R mice had smaller bodies, thicker CCT, and shallower ACD compared to wild-type mice but normal AL. Adamts10G661R/G661R mice displayed persistent fibrillin-2 and enhanced fibrillin-1 immunofluorescence in the lens zonules and in the hyaloid vasculature and its remnants in the vitreous. Conclusions: Adamts10G661R/G661R mice recapitulate the short stature and ocular phenotypes of WMS. The altered fibrillin-1 and fibrillin-2 immunoactivity in Adamts10G661R/G661R mice suggests that the G661R mutation of Adamts10 perturbs regulation of the fibrillin isotype composition of microfibrils in the mouse eye.

Increased Susceptibility to Glaucomatous Damage in Microfibril Deficient Mice.

Purpose: To test whether mice with microfibril deficiency due to the Tsk mutation of fibrillin-1 (Fbn1Tsk/+) have increased susceptibility to pressure-induced retinal ganglion cell (RGC) degeneration. Methods: Intraocular pressure (IOP) elevation was induced in Fbn1Tsk/+ and wild type (wt) mice by injecting microbeads into the anterior chamber. Mice were then followed up for four months, with IOP measurements every three to six days. Retinas were stained for Brn3a to determine RGC number. Optic nerve cross-sections were stained with p-phenylene diamine to determine nerve area, axon number, and caliber and thickness of the pia mater. Results: Microbead injection induced significant IOP elevation that was significantly less for Fbn1Tsk/+ mice compared with wt. The optic nerves and optic nerve axons were larger, and the elastic fiber-rich pia mater was thinner in Fbn1Tsk/+ mice. Microbead injection resulted in reduced optic nerve size, thicker pia mater, and a slight decrease in axon size. Fbn1Tsk/+ mice had significantly greater loss of RGCs and optic nerve axons compared with wt (14.8% vs. 5.8%, P = 0.002, and 17.0% vs. 7.5%, P = 0.002, respectively). Conclusions: Fbn1Tsk/+mice had altered optic nerve structure as indicated by larger optic nerves, larger optic nerve axons and thinner pia mater, consistent with our previous findings. Despite lower IOP elevation, Fbn1Tsk/+mice had greater loss of RGCs and optic nerve axons, suggesting increased susceptibility to IOP-induced optic nerve degeneration in microfibril-deficient mice.

Telmisartan Reduces Axon Degeneration in Mice With Experimental Glaucoma.

Purpose: The purpose of this study was to determine if treatment with telmisartan, an angiotensin II type 1 receptor blocker (ARB), protects against retinal ganglion cell (RGC) degeneration in a mouse glaucoma model with induced elevation of intraocular pressure (IOP). Methods: IOP elevation was induced by injection of polystyrene microbeads into the anterior chamber of the right eye of 3-month-old C57BL/6J mice, with the left eye serving as contralateral control. Starting the day of microbead injection, mice were maintained on solid food pellets with or without incorporated telmisartan. IOP was measured by Tono Lab tonometry prior to and weekly after microbead injection. Twelve weeks postinjection, mice were euthanized to obtain optic nerves for analysis of RGC axons. The total numbers of optic nerve axons were determined manually and automatedly using AxonJ. Degenerating axons were counted manually. Results: IOP elevation induced by microbead injection was similar in magnitude and duration in vehicle and telmisartan-fed mice, although IOP was reduced 5.8% in uninjected mice treated with telmisartan (P = 0.0027). Axon loss determined by manual and automated methods was greater in vehicle compared to telmisartan-treated mice (manual: 9.5% vs. 1.8%, P = 0.044; automated: 14.2% vs. 2.9%, P = 0.0375). An increase in the percent of axons undergoing degeneration was observed in nerves from microbead-injected eyes that was greater in vehicle-treated compared to telmisartan-treated mice (49.0% vs. -0.58%, P = 0.0019). Conclusions: Elevation of IOP by microbead injection led to loss of RGC axons in vehicle-treated mice that was largely prevented by telmisartan treatment, suggesting a neuroprotective effect of telmisartan.

Three-Year Findings on Intraocular Pressure Changes in The Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) Study.

BACKGROUND AND OBJECTIVE: This paper reports 3-year intraocular pressure (IOP) outcomes of the Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) study. PATIENTS AND METHODS: The prospective, controlled, observational study included 80 eyes of 40 participants undergoing routine pars plana vitrectomy. Study patients underwent preoperative evaluation and multimodal testing of the study (surgical) and fellow (control) eye. This testing was repeated at 3 months postoperatively and then annually for 3 years. RESULTS: Thirty-two of 40 patients (80%) completed 3-year follow-up. At 3 years postoperatively, there was no difference in IOP measurements in surgical eyes overall from baseline (P = .36). Subgroup analysis of pseudophakic eyes at baseline showed a significant elevation in IOP from 14.3 mm Hg ± 2.9 mm Hg at baseline to 16.8 mm Hg ± 3.2 mm Hg at 3-year follow-up (P < .029). Fellow eyes did not experience a significant change from baseline. CONCLUSION: The authors' 3-year results show that IOP is consistently and significantly elevated in pseudophakic eyes compared to baseline following routine vitrectomy. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:371-376.].

Compound Heterozygous LTBP2 Mutations Associated With Juvenile-Onset Open-Angle Glaucoma and Marfan-Like Phenotype.

This case report describes a patient diagnosed at age 13 years with glaucoma who later presented with elevated intraocular pressure, severe cupping, open iridocorneal angle, and lens dislocation.