The correlation of anterior segment structures in primary congenital glaucoma by ultrasound biomicroscopy with disease severity and surgical outcomes.

PURPOSE: To evaluate the anterior segment structures using ultrasound biomicroscopy (UBM) in primary congenital glaucoma (PCG) and explore their correlation with disease severity and surgical outcomes. METHODS: Clinical information of PCG patients who underwent UBM prior to their first glaucoma surgeries from September 2014 to March 2021 were reviewed. The study included 214 UBM images of 154 PCG eyes and 60 fellow unaffected eyes. Anterior segment characteristics were analyzed. UBM parameters, including the iris thickness (IT) at variant distances from the pupil edge and iris root, anterior chamber depth (ACD), and pupil diameter (PD), were compared between two groups and their relationship with clinical factors and surgical outcomes were analyzed in PCG eyes. RESULTS: PCG eyes had unclear scleral spur, thin iris, wide anterior chamber angle, deep anterior chamber, rarefied ciliary body, elongated ciliary processes, and abnormal anterior iris insertion. ITs were thinner, ACD was deeper, and PD was larger in PCG eyes than fellow unaffected eyes (all P < 0.001). In PCG eyes, thinner ITs correlated with bilateral involvement and earlier age at presentation, and larger PD correlated with earlier age at presentation (P = 0.030) and higher intraocular pressure (P < 0.001). Thinner IT2 (P = 0.046) and larger PD (P = 0.049) were identified as risk factors for surgical failure. CONCLUSION: UBM is a powerful technique to exam anterior segment structures in PCG. The anatomical features are associated with disease severity and surgical outcomes, providing essential clinical insights.

Distribution of TGFBI variants in patients with early onset glaucoma.

Purpose: To describe a novel association of TGFBI variants with congenital glaucoma in a family with GAPO (growth retardation, alopecia, pseudoanodontia, and progressive optic atrophy) syndrome, as well as among other unrelated cases of juvenile onset open-angle glaucoma (JOAG) and primary congenital glaucoma (PCG). Methods: This study of one family of GAPO with congenital glaucoma and three unrelated patients with JOAG analyzed a common link to glaucoma pathogenesis. Three girls with GAPO syndrome born to consanguineous parents in a multi-generation consanguineous family were identified. Two of the girls had congenital glaucoma in both eyes, while the elder sibling (a 10-year-old female) had features of GAPO syndrome without glaucoma. Results: A genetic evaluation using whole exome sequencing revealed a novel homozygous ANTXR1 mutation in all three affected siblings with GAPO. No other mutations were detected in the genes associated with glaucoma. A rare missense variant in the TGFBI gene was shared in the two siblings with congenital glaucoma and GAPO syndrome. We found three other unrelated patients with JOAG and one patient with primary congenital glaucoma with no known glaucoma causing gene mutations, but having four different missense variants in the TGFBI gene. One of these patients with JOAG had familial granular corneal dystrophy. Molecular dynamic simulations of TGFBI and 3-D structural models of three of its variants showed significant alterations that could influence TGFBI protein function. Conclusions: The possibility that variations in the TGFBI gene could have a possible role in the pathogenesis of congenital and juvenile onset open-angle glaucomas needs further evaluation.

Congenital glaucoma in a tiger (Panthera tigris).

OBJECTIVE: To describe a case of congenital glaucoma in atiger (Panthera tigris). ANIMAL STUDIED: An 8-month-old intact female tiger wasreferred for suspected glaucoma of the right eye. The right eye was buphthalmicwith moderate episcleral injection, circumferential superficial cornealneovascularization, moderate corneal edema, and a fixed dilated pupil. Tapetalreflection was absent due to a mature cataract. Rebound tonometry under generalanesthesia revealed 70 mmHg and 21 mmHg in the right and left eye, respectively. PROCEDURE: A trans-conjunctival enucleation was performedand the globe was submitted for histopathology. RESULTS: Histopathology revealed a thin sclera, amorphousmaterial contouring an imperforate and hypoplastic iridocorneal angle, ahypoplastic lens with severe anterior-posterior compression, subcapsularepithelial hyperplasia, and Morganian globules, and segmental moderate retinalatrophy. Periodic acid-Schiff stain highlighted segmental dilations of theDescemet's membrane. Masson trichrome stain highlighted a pre-irido collagenmembrane. CONCLUSION: The tiger's age and histopathologic findingsare consistent with congenital goniodysgenesis. This is the first known reportof congenital glaucoma in a tiger.

Neck Extension and Intraocular Pressure Elevation During Palatoplasty in a Patient with Patau Syndrome and Congenital Glaucoma: A Case Report.

Patau syndrome (trisomy 13) is a severe disorder associated with multiple systemic defects. Patau syndrome is commonly associated with ocular abnormalities but rarely associated with congenital glaucoma. To obtain a better surgical view, palatoplasty requires neck extension during surgery. The intraocular pressure (IOP) of patients with Patau syndrome can increase owing to the neck extension position while undergoing palatoplasty, particularly in those with congenital glaucoma. Here, we describe a case with increased IOP measured using a rebound tonometer during palatoplasty in a pediatric patient with Patau syndrome and congenital glaucoma. This case shows that it may be important to reduce the degree of neck extension and shorten the operation time to minimize any increase in the IOP during palatoplasty in pediatric patients with Patau syndrome accompanied by congenital glaucoma.

Unilateral buphthalmos, corneal staphyloma and corneal fistula caused by pathogenic variant in the PITX3 gene: a case report.

INTRODUCTION: PITX3 has been reported to be associated with congenital cataracts, anterior segment mesenchymal dysgenesis, Peters' anomaly, and microphthalmia. In this case, an infant with unilateral buphthalmos, corneal staphyloma and corneal fistula carrying a variant in PITX3 was reported. CASE DESCRIPTION: We describe a 4-month-old female infant who was referred to our Eye Clinic because of gradual enlargement of the eyeball in the right eye and whitish opacity in both eyes. Buphthalmos with long axial length (22.04 mm), macrocornea with diffuse corneal oedema and opacity (14.50 mm*14.50 mm) and high intraocular pressure (23.78 mmHg) were detected in the right eye. Microphthalmia with short axial length (16.23 mm), microcornea with diffuse corneal oedema and opacity (7.50 mm*6.50 mm) were detected in the left eye. A 360° trabeculotomy was performed for the right eye. However, corneal staphyloma and corneal fistula in the right eye were detected 6 months after the surgery. A variant in exon 4 of PITX3 (c.640_656dup (p. Gly220Profs*95)) was identified in the proband but was not detected in her healthy parents. CONCLUSION: A novel phenotype characterized by unilateral buphthalmos, corneal staphyloma and corneal fistula in an infant were reported to be associated with PITX3 in our study. Our study expands the scope of the clinical heterogeneity of PITX3 variants. It also improves our understanding and increases the attention given to patients with PITX3 variants.

Quantification and image-derived phenotyping of retinal ganglion cell nuclei in the nee mouse model of congenital glaucoma.

The nee mouse model exhibits characteristic features of congenital glaucoma, a common cause of childhood blindness. The current study of nee mice had two components. First, the time course of neurodegeneration in nee retinal flat-mounts was studied over time using a retinal ganglion cell (RGC)-marker, BRN3A; a pan-nuclear marker, TO-PRO-3; and H&E staining. Based on segmentation of nuclei using ImageJ and RetFM-J, this analysis identified a rapid loss of BRN3A+ nuclei from 4 to 15 weeks of age, with the first statistically significant difference in average density compared to age-matched controls detected in 8-week-old cohorts (49% reduction in nee). Consistent with a model of glaucoma, no reductions in BRN3A- nuclei were detected, but the combined analysis indicated that some RGCs lost BRN3A marker expression prior to actual cell loss. These results have a practical application in the design of experiments using nee mice to study mechanisms or potential therapies for congenital glaucoma. The second component of the study pertains to a discovery-based analysis of the large amount of image data with 748,782 segmented retinal nuclei. Using the automatedly collected region of interest feature data captured by ImageJ, we tested whether RGC density of glaucomatous mice was significantly correlated to average nuclear area, perimeter, Feret diameter, or MinFeret diameter. These results pointed to two events influencing nuclear size. For variations in RGC density above approximately 3000 nuclei/mm2 apparent spreading was observed, in which BRN3A- nuclei-regardless of genotype-became slightly larger as RGC density decreased. This same spreading occurred in BRN3A+ nuclei of wild-type mice. For variation in RGC density below 3000 nuclei/mm2, which only occurred in glaucomatous nee mutants, BRN3A+ nuclei became smaller as disease was progressively severe. These observations have relevance to defining RGCs of relatively higher sensitivity to glaucomatous cell death and the nuclear dynamics occurring during their demise.

Antemortem diagnosis of congenital glaucoma in a white-bellied caique (Pionites leucogaster).

A 34-day-old, male, white-bellied caique (Pionites leucogaster) was presented for a complaint of bilateral buphthalmos. Clinical examination was unremarkable apart from the ophthalmic findings. The ophthalmologic examination was negative for direct, consensual, and dazzle reflexes in both eyes. The intraocular pressure exceeded 40 mm Hg OU. Fluorescein stain demonstrated corneal surface lesions suggestive of exposure keratopathy subsequent to bilateral buphthalmos. Diagnostic imaging tests were conducted to perform ocular biometric measurements and investigate the intraocular structures, including the iridocorneal angle and lens, by means of high-resolution ultrasonography (HRUS). The presence of congenital glaucoma in this young parrot was strongly suspected after clinical and ophthalmological examination and the results of diagnostic imaging. Pharmacological treatment to reduce intraocular pressure was initiated using dorzolamide hydrochloride 2% and timolol maleate 0.5%. A month later, the parrot's eyes did not show any visual improvement, but the intraocular pressure had returned to normal. The parrot was unable to feed itself and died during a feeding procedure. Postmortem examination revealed ab ingestis pneumonia. Both eyes were submitted for histopathology, with severe anterior segment dysplasia and goniodysgenesis found OU. Histological findings added to the clinical presentation, the ophthalmologic examination and the imaging findings, confirmed the presence of congenital glaucoma.

The Epidemiological and Clinical Findings from the Latvian Registry of Primary Congenital Glaucoma and Evaluation of Prognostic Factors.

Background and objectives: primary congenital glaucoma (PCG) is a rare, potentially blinding disease that affects children worldwide. The aim of the study was to describe the epidemiological and clinical characteristics, outcomes for newly diagnosed patients with PCG, as well as evaluate the prognostic factors that are related to the outcomes. Materials and Methods: a retrospective cohort study was conducted at a tertiary referral centre among patients diagnosed with PCG. Evaluation of the clinical data was performed preoperatively at three, six, and 12 months after the surgery and at the last follow-up. Results: during the 15 years of follow-ups, 24 eyes of 18 patients were diagnosed with PCG. Unilateral and bilateral PCG constituted 50% of cases each. A slight male predominance was observed (55.6% vs. 44.4%), with a relative risk of 1.3. The incidence of PCG was 1:19,033 live births. The mean age of the patients at the time of diagnosis was 10.1 ± 10.0 months, with a diagnostic delay of 2.0 ± 1.9 months. Furthermore, 75% of patients indicated an enlargement of an eyeball, followed by excessive tearing (58.3%) and corneal opacity (41.7%). After 85.9 ± 51.2 months, the mean intraocular pressure (IOP) value was 14.6 ± 4.9 mmHg. Surgical treatment provided sufficient IOP control in 75% of PCG cases at the last follow-up visit. The only prognostic factor that was related to the outcome of IOP control that was statistically significant was axial length at the time of diagnosis. Conclusions: the incidence of PCG in Latvia was 5.3 patients per 100,000 live births. PCG was more common among males than females with a relative risk of 1.3. The enlargement of an eyeball was the leading clinical sign.

An Insight into Primary Congenital Glaucoma.

Glaucoma is the second most prominent cause of impaired vision in the world. Over 60 million individuals are presently affected, and 12 million are sightless as a result. Primary congenital glaucoma (PCG) is a childhood disease that can lead to blindness in newborns and very young children. The rate of occurrence of PCG varies in different communities and across geographical boundaries, and its etiology is unknown. It is caused by genetic structural defects in the trabecular meshwork and makes its appearence in newborns and children no older than three years. PCG is most prevalent in populations with high rates of consanguineous marriages. It is categorized by inappropriate development of the eye's aqueous outflow system, causing increased intraocular pressure (IOP) and leading to swelling of the cornea, epiphora, discomfort or pain, enlargement of the eyeball (buphthalmos), corneal opacity, and optic nerve damage. PCG is classified as an autosomal recessive disorder involving four loci. The main culprit is CYP1B1, at locus GLC3A. PCG is also linked with loci GLC3B and GLC3C; however, their genetic factors have only recently been recognized. The gene LTPB2 at locus GLC3D, plays an important role in tissue healing and cell attachment. Trabeculectomy and gonioscopy are effective treatments for PCG. Additional efforts are essential to provide timely screening of children and, most important, to assign sufficient resources to allow healthcare workers to reduce the rate of avoidable blindness in developing countries.

Novel mutations in LTBP2 identified in familial cases of primary congenital glaucoma.

Purpose: Primary congenital glaucoma (PCG) is a genetically heterogeneous disorder caused by developmental defects in the anterior chamber and trabecular meshwork. This disease is an important cause of childhood blindness. In this study, we aim to identify the genetic determinants of PCG in three consanguineous families of Pakistani descent. Methods: Affected members of all three families underwent detailed ophthalmological examination including slit-lamp biomicroscopy. Blood samples were collected from affected and healthy members of all three families, and genomic DNA was extracted. Linkage analysis was performed for the known or reported loci of PCG to localize the disease interval, and logarithm of odds (LOD) scores were calculated. All protein-coding exons of the candidate gene, latent transforming growth factor-beta binding protein 2 (LTBP2), were bidirectionally sequenced to identify the disease-causing mutation. Results: Short tandem repeat (STR) marker-based linkage analysis localized the critical interval to chromosome 14q with a maximum two-point LOD score of 2.86 (PKGL076), 2.8 (PKGL015), and 2.92 (PKGL042). Bidirectional Sanger sequencing of LTBP2 revealed three novel pathogenic variants, i.e., c.3028G>A (p.Asp1010Asn), c.3427delC (p.Gln1143Argfs*35), and c.5270G>A (p.Cys1757Tyr) in PKGL076, PKGL015, and PKGL042, respectively. All three mutations segregated with the disease phenotype in their respective families and were absent in 200 ethnically matched normal chromosomes. Conclusions: We identified three novel mutations, p.D1010N, p.Q1143Rfs*35, and p.C1757Y, in LTBP2 responsible for PCG.

Surgical interventions for primary congenital glaucoma.

BACKGROUND: Primary congenital glaucoma (PCG) is an optic neuropathy with high intraocular pressure (IOP) that manifests within the first few years of a child's life and is not associated with other systemic or ocular abnormalities. PCG results in considerable morbidity even in high-income countries. OBJECTIVES: To compare the effectiveness and safety of different surgical techniques for PCG. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2020, Issue 4); Ovid MEDLINE; Embase.com; PubMed; metaRegister of Controlled Trials (mRCT) (last searched 23 June 2014); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search. We last searched the electronic databases on 27 April 2020. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-RCTs comparing different surgical interventions in children under five years of age with PCG. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodology. MAIN RESULTS: We included 16 trials (13 RCTs and three quasi-RCTs) with 587 eyes in 446 children. Eleven (69%) trials were conducted in Egypt and the Middle East, three in India, and two in the USA. All included trials involved children younger than five years of age, with follow-up ranging from six to 80 months. The interventions compared varied across trials. Three trials (on 68 children) compared combined trabeculotomy and trabeculectomy (CTT) with trabeculotomy. Meta-analysis of these trials suggests there may be little to no evidence of a difference between groups in mean IOP (mean difference (MD) 0.27 mmHg, 95% confidence interval (CI) -0.74 to 1.29; 88 eyes; 2 studies) and surgical success (risk ratio (RR) 1.01, 95% CI 0.90 to 1.14; 102 eyes; 3 studies) at one year postoperatively. We assessed the certainty of evidence as very low for these outcomes, downgrading for risk of bias (-1) and imprecision (-2). Hyphema was the most common adverse outcome in both groups (no meta-analysis due to considerable heterogeneity; I2 = 83%). Two trials (on 39 children) compared viscotrabeculotomy to conventional trabeculotomy. Meta-analysis of 42 eyes suggests there is no evidence of between groups difference in mean IOP (MD -1.64, 95% CI -5.94 to 2.66) and surgical success (RR 1.11, 95% CI 0.70 to 1.78) at six months postoperatively. We assessed the certainty of evidence as very low, downgrading for risk of bias and imprecision due to small sample size. Hyphema was the most common adverse outcome (38% in viscotrabeculotomy and 28% in conventional trabeculotomy), with no evidence of difference difference (RR 1.33, 95% CI 0.63 to 2.83). Two trials (on 95 children) compared microcatheter-assisted 360-degree circumferential trabeculotomy to conventional trabeculotomy. Meta-analysis of two trials suggests that mean IOP may be lower in the microcatheter group at six months (MD -2.44, 95% CI -3.69 to -1.19; 100 eyes) and at 12 months (MD -1.77, 95% CI -2.92 to -0.63; 99 eyes); and surgical success was more likely to be achieved in the microcatheter group compared to the conventional trabeculotomy group (RR 1.59, 95% CI 1.14 to 2.21; 60 eyes; 1 trial at 6 months; RR 1.54, 95% CI 1.20 to 1.97; 99 eyes; 2 trials at 12 months). We assessed the certainty of evidence for these outcomes as moderate due to small sample size. Hyphema was the most common adverse outcome (40% in the microcatheter group and 17% in the conventional trabeculotomy group), with greater likelihood of occurring in the microcatheter group (RR 2.25, 95% CI 1.25 to 4.04); the evidence was of moderate certainty due to small sample size (-1). Of the nine remaining trials, no two trials compared the same two surgical interventions: one trial compared CTT versus CTT with sclerectomy; three trials compared various suturing techniques and adjuvant use including mitomycin C, collagen implant in CTT; one trial compared CTT versus Ahmed valve implant in previously failed surgeries; one trial compared CTT with trabeculectomy; one trial compared trabeculotomy to goniotomy; and two trials compared different types of goniotomy. No trials reported quality of life or economic data. Many of the included trials had limitations in study design, implementation, and reporting, therefore the reliability and applicability of the evidence remains unclear. AUTHORS' CONCLUSIONS: The evidence suggests that there may be little to no evidence of difference between CTT and routine conventional trabeculotomy, or between viscotrabeculotomy and routine conventional trabeculotomy. A 360-degree circumferential trabeculotomy may show greater surgical success than conventional trabeculotomy. Considering the rarity of the disease, future research would benefit from a multicenter, possibly international trial, involving parents of children with PCG and with a follow-up of at least one year.

Severity of visual field defects in primary congenital glaucoma and their risk factors.

PURPOSE: The primary objective of the study was to assess the frequency and severity of visual field defects (VFD) in primary congenital glaucoma (PCG). The secondary objective was to ascertain any associated risk factors. METHODS: An ambispective review of patients with PCG on follow-up with a 'target' intraocular pressure (IOP) of ≤ 15 mmHg. Age, sex, laterality, duration of follow-up, baseline IOP, baseline cup-disc ratio (CDR), central corneal thickness (CCT), age during filtering surgery, second surgery if any, yearly IOP, glaucoma medications and best corrected visual acuity from 2013 (year 1) to the final review and final CDR were noted down. Children ≥ 5 years of age with best corrected visual acuity ≥ 6/60 were subjected to manual kinetic Goldmann perimetry, and visual field defects (VFD) were identified. RESULTS: Seventy-one of 90 eyes completed a reliable kinetic perimetry. The mean age of children was 12.34 ± 4.86 years, and the mean follow-up duration was 10.77 ± 4.69 years. Baseline IOP and CDR were 29.07 ± 8.83 mmHg and 0.66 ± 0.22, respectively. 86.67% of eyes underwent a trabeculotomy + trabeculectomy with mitomycin-C. Thirty-one eyes (34.44%) required a second surgery, 25 of which were bleb revisions and 3 trabeculectomies. Mean IOP and CDR during last visit were 10.23 ± 2.76 mmHg and 0.52 ± 0.25, p < 0.001 as compared with baseline. On Goldmann perimetry, 19 eyes, 26.76%, had defects, arcuate scotoma being most frequent. On the Fisher exact test, a baseline/final CDR > 0.8, undergoing just a trabeculectomy with MMC, needing ≥ 2 glaucoma medications on review or a repeat trabeculectomy was associated with greater severity of VFD. On univariate logistic regression, eyes that needed a bleb revision [OR, 95% CI 9.75 (2.66-35.67), p = 0.001], a repeat trabeculectomy with mitomycin-C [OR (CI) 18 (1.31-245.58), p = 0.03] and final CDR of > 0.8 [OR (CI) 23.1 (3.7-144.21), p = 0.001] were associated with VFD. On multivariable regression analysis, female sex [OR (CI) 18 (2.01-161.04), p = 0.01] was identified as the single most important risk factor for development of a VFD. CONCLUSION: At a 'target' IOP of ≤ 15 mmHg, 26.76% of PCG eyes manifested a VFD over 10 years. Baseline and/or final CDR > 0.8, necessity for ≥2 medications or a repeat glaucoma surgery, and female sex were identified as risk factors for development and greater severity of glaucomatous VFD.

Genetic mapping of autosomal recessive microspherophakia to chromosome 14q24.3 in a consanguineous Pakistani family and screening of exon 36 of LTBP2 gene.

Latent transforming growth factor beta binding protein 2 (LTBP2) plays a critical role in the development of connective tissue structure and function. Mutations in gene encoding LTBP2 are known to cause syndromic and a non-syndromic microspherophakia. Here, we present a 'first' report of genetic linkage of microspherophakia (MSP) to LTBP2 locus in a large consanguineous Pakistani family with four affected individuals in three loops. Using polymorphic microsatellite markers, haplotypes and linkage analysis, the diseased phenotype in MSP001 family was mapped to the LTBP2 gene. A maximum two point Logarithm of the odds (LOD) score of 4.16 was obtained with marker D14S284 at θ =0. Mutational analysis of exon 36 of LTBP2 using Sanger's sequencing did not reveal any previously reported mutations. Further analysis of the remaining exons are required to identify the causative variant.

Primary congenital and developmental glaucomas.

Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also important causes of visual disability. Primary congenital glaucoma (PCG) is isolated, non-syndromic glaucoma that occurs in the first three years of life and is a major cause of childhood blindness. Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome. Congenital and childhood glaucomas have strong genetic bases and disease-causing mutations have been discovered in several genes. Mutations in three genes (CYP1B1, LTBP2, TEK) have been reported in PCG patients. Axenfeld-Rieger syndrome is caused by mutations in PITX2 or FOXC1 and aniridia is caused by PAX6 mutations. This review discusses the roles of these genes in primary congenital glaucoma and glaucomas of childhood.

Mutation profile of glaucoma candidate genes in Mauritanian families with primary congenital glaucoma.

Purpose: Intraocular pressure leading to glaucoma is a major cause of childhood blindness in developing countries. In this study, we sought to identify gene variants potentially associated with primary congenital glaucoma (PCG) in the Mauritanian population. Methods: Using next-generation sequencing (NGS), a panel of PCG candidate genes was screened in a search for DNA mutations in four families with multiple occurrences of PCG. Results: Targeted exome sequencing analysis revealed predicted pathogenic mutations in four genes: CYP1B1 (c.217_218delTC, p.Ser73Valfs*150), MYOC (878C>A, p.T293K), NTF4 (c.601T>G, p.Cys201Gly), and WDR36 (c.2078A>G, p.Asn693Ser), each carried by a different family. Conclusions: Genetic variation associated with PCG in this study reflects the ethnic heterogeneity of the Mauritanian population. However, a larger cohort is needed to identify additional families carrying these mutations and confirm their biologic role.

Metabolomics of the aqueous humor in patients with primary congenital glaucoma.

Purpose: Primary congenital glaucoma (PCG) is an autosomal recessive eye disorder, accounting for 0.01%-0.04% of blindness around the world. Unfortunately, the molecular characteristics concerning the pathogenic mechanisms of the disease remain poorly understood. Methods: Here, for the first time, we employed gas chromatography coupled to time-of-flight mass spectrometry (GC/TOF MS) to reveal comprehensively the metabolic characteristics of PCG. Results: First, 363 metabolites were detected in 50 aqueous humor (AH) samples from 30 patients with PCG, 10 patients with congenital cataracts (CCs), and 10 patients with aged-related cataracts (ARCs). Second, 290 metabolites in total were found in another 15 patients with PCG and 10 patients with primary open angle glaucoma (POAG). A further analysis suggested that patients with PCG had a significantly distinct metabolomics profile. Three amino acid-associated metabolites, including glycine, urea, and phenylalanine, were identified to be significantly different (p≤0.05) in relation to PCG. Meanwhile, three glaucoma-associated single nucleotide polymorphisms (SNPs), rs7114303, rs9364602, and rs2165241, were determined to be related to these three metabolites. The results here indicate that certain amino acid-associated metabolites and their metabolisms are key regulatory elements and metabolic pathways in the pathogenesis of PCG. Conclusions: Collectively, this work not only extended our understanding of the molecular characteristics of PCG, but also presented glycine as a potential biomarker for earlier diagnosis and may provide new therapeutic strategies for the disease.

Identities and frequencies of variants in CYP1B1 causing primary congenital glaucoma in Pakistan.

Purpose: Primary congenital glaucoma (PCG) is a clinically and genetically heterogeneous disease. The present study was undertaken to find the genetic causes of PCG segregating in 36 large consanguineous Pakistani families. Methods: Ophthalmic examination including fundoscopy, or slit-lamp microscopy was performed to clinically characterize the PCG phenotype. Genomic nucleotide sequences of the CYP1B1 and LTBP2 genes were analyzed with either Sanger or whole exome sequencing. In silico prediction programs were used to assess the pathogenicity of identified alleles. ClustalW alignments were performed to determine evolutionary conservation, and three-dimensional (3D) modeling was performed using HOPE and Phyre2 software. Results: Among the known loci, mutations in CYP1B1 and LTBP2 are the common causes of PCG. Therefore, we analyzed the genomic nucleotide sequences of CYP1B1 and LTBP2, and detected probable pathogenic variants cosegregating with PCG in 14 families. These included the three novel (c.542T>A, c.1436A>G, and c.1325delC) and five known (c.868dupC, c.1168C>T, c.1169G>A, c.1209InsTCATGCCACC, and c.1310C>T) variants in CYP1B1. Two of the novel variants are missense substitutions [p.(Leu181Gln), p.(Gln479Arg)], which replaced evolutionary conserved amino acids, and are predicted to be pathogenic by various in silico programs, while the third variant (c.1325delC) is predicted to cause reading frameshift and premature truncation of the protein. A single mutation, p.(Arg390His), causes PCG in six (~43%) of the 14 CYP1B1 mutations harboring families, and thus, is the most common variant in this cohort. Surprisingly, we did not find any LTBP2 pathogenic variants in the families, which further supports the genetic heterogeneity of PCG in the Pakistani population. Conclusions: In conclusion, results of the present study enhance our understanding of the genetic basis of PCG, support the notion of a genetic modifier of CYP1B1, and contribute to the development of genetic testing protocols and genetic counseling for PCG in Pakistani families.

Relationship between corneal sensitivity, corneal thickness, corneal diameter, and intraocular pressure in normal cats and cats with congenital glaucoma.

OBJECTIVE: To determine the effect of feline congenital glaucoma (FCG) on corneal sensitivity, and relationships between corneal sensitivity, central corneal thickness (CT), and corneal diameter (CD). ANIMALS AND PROCEDURES: Corneal sensitivity (estimated by corneal touch threshold [CTT] using Cochet-Bonnet esthesiometry); CT using ultrasonic pachymetry; intraocular pressure (IOP) using rebound tonometry; and maximal horizontal CD were measured in 16 normal and 14 FCG cats, both males and females, aged 7 months-3.5 years. All procedures complied with an Institutional Animal Care and Use Committee-approved protocol. Data were analyzed by linear regression: paired Student's t tests for between-eye comparisons, and unpaired Student's t tests for comparisons between groups. Relationships between parameters were evaluated by Pearson correlation coefficients and linear mixed effects modeling. For statistical tests, with the exception of values that were Benjamini-Hochberg adjusted for multiple comparisons, P-values < 0.05 were considered significant. RESULTS: Mean CTT and CT values were lower in FCG eyes relative to normal eyes, but differences were not statistically significant. Mean CD was significantly larger in FCG eyes relative to normal eyes, and there was a significant negative correlation between CD and CTT in FCG (r = -0.8564, corrected P = 0.005). These associations were confirmed in linear mixed effects models. CONCLUSIONS: Eyes with FCG have significantly larger CDs when compared with normal eyes, and larger CDs correlated with decreased corneal sensitivity in this group. Further studies are warranted to explore the effect of buphthalmos and corneal enlargement on corneal sensitivity and innervation in feline subjects with chronic glaucoma.

Prognostic factors of pediatric glaucoma: a retrospective study.

PURPOSE: To correlate the features of certain types of infantile glaucoma with the progression and the prognosis of the disease, highlighting probable risk factors. METHODS: Seventy-six patients with pediatric glaucoma were recruited in this retrospective study. All patients underwent ophthalmological examination in the Department of Ophthalmology of the Saarland University Medical Center from January 2001 to December 2012. Our pediatric patients were classified into four different categories of glaucoma: (1) primary congenital glaucoma (presenting buphthalmus), (2) aniridia-related glaucoma, (3) Peters/Rieger's anomaly-related glaucoma and (4) congenital cataract-related glaucoma. Personal data comprised age, sex, nationality, systemic diseases and gestational age. The best-corrected visual acuity (BCVA), the cup-disk ratio (CDR), the intraocular pressure (IOP), the corneal diameter and thickness, along with the Haab striae and corneal haze, were recorded. RESULTS: The majority of the children were male (58%) and suffered from aniridia-related glaucoma (38%). Children with aniridia exhibited the worst BCVA. The CDR and IOP were significantly higher in children with primary congenital glaucoma, compared to the other groups, at the first visit. Those children also were with the largest corneal diameter and prevalence of Haab striae compared to the rest groups, whereas corneal haze was found more often and was more pronounced in children with Peters/Rieger's syndrome. CONCLUSIONS: We concluded that glaucoma was earlier detected in children with primary congenital glaucoma, who exhibited increased corneal diameter and high percentage of Haab striae comparing to the other groups. However, these children responded successfully to any therapeutic intervention, exhibiting better BCVA and IOP values than the rest groups at the second visit.

Anterior segment ultrasound biomicroscopy image analysis using ImageJ software: Intra-observer repeatability and inter-observer agreement.

PURPOSE: In this novel study, we demonstrate a standardized imaging and measurement protocol of anterior segment (AS) structures with reliability analysis using ultrasound biomicroscopy (UBM) and ImageJ software. METHODS: Ten pediatric and young adult patients undergoing examination under anesthesia for AS pathology were imaged using UBM. Four trained observers analyzed 20 images using ImageJ. Forty-five structural parameters were measured. Those that relied on the trabecular-iris angle (TIA) as a reference landmark were labeled TIA-dependent (TD) and all others were labeled non-TIA dependent (NTD). Intra-observer repeatability (IOR) and inter-observer agreement (IOA) of measurements were determined using coefficient of variation (CV) and intra-class correlation (ICC) followed by assessment of Bland-Altman plots (BAP) for each pair of observers, respectively. RESULTS: For NTD parameters, non-ciliary body (CB) related measurements showed CV range 0.60-16.22% and ICC range 0.84-0.89, whereas CB-related parameters showed CV range 2.86-23.40% and ICC range 0.29-0.92. For TD parameters, parameters < 2 degrees removed from reference showed CV range 0.02-5.40% and ICC range 0.89-1.00, whereas parameters > 1 degree removed showed CV range 0.63-27.44% and ICC range 0.22-1.00. No systematic proportional bias was detected by BAPs. CONCLUSIONS: Preplaced landmarks yielded good IOR and IOA in quantitative assessment of AS structures that were NTD and non-CB-related or less removed from the reference. CB-related NTD measurements varied greatly in IOR and IOA, indicating protocol modifications or CB qualitative assessments needed to improve accuracy. Variability in TD measurements increased the further removed from the reference, which supports implementation of a reliable reference landmark to minimize variation.