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.

Microenvironmental regulation by fibrillin-1.

Fibrillin-1 is a ubiquitous extracellular matrix molecule that sequesters latent growth factor complexes. A role for fibrillin-1 in specifying tissue microenvironments has not been elucidated, even though the concept that fibrillin-1 provides extracellular control of growth factor signaling is currently appreciated. Mutations in FBN1 are mainly responsible for the Marfan syndrome (MFS), recognized by its pleiotropic clinical features including tall stature and arachnodactyly, aortic dilatation and dissection, and ectopia lentis. Each of the many different mutations in FBN1 known to cause MFS must lead to similar clinical features through common mechanisms, proceeding principally through the activation of TGFß signaling. Here we show that a novel FBN1 mutation in a family with Weill-Marchesani syndrome (WMS) causes thick skin, short stature, and brachydactyly when replicated in mice. WMS mice confirm that this mutation does not cause MFS. The mutation deletes three domains in fibrillin-1, abolishing a binding site utilized by ADAMTSLIKE-2, -3, -6, and papilin. Our results place these ADAMTSLIKE proteins in a molecular pathway involving fibrillin-1 and ADAMTS-10. Investigations of microfibril ultrastructure in WMS humans and mice demonstrate that modulation of the fibrillin microfibril scaffold can influence local tissue microenvironments and link fibrillin-1 function to skin homeostasis and the regulation of dermal collagen production. Hence, pathogenetic mechanisms caused by dysregulated WMS microenvironments diverge from Marfan pathogenetic mechanisms, which lead to broad activation of TGFß signaling in multiple tissues. We conclude that local tissue-specific microenvironments, affected in WMS, are maintained by a fibrillin-1 microfibril scaffold, modulated by ADAMTSLIKE proteins in concert with ADAMTS enzymes.

Variants in ASB10 are associated with open-angle glaucoma.

The molecular events responsible for obstruction of aqueous humor outflow and the loss of retinal ganglion cells in glaucoma, one of the main causes of blindness worldwide, remain poorly understood. We identified a synonymous variant, c.765C>T (Thr255Thr), in ankyrin repeats and suppressor of cytokine signaling box-containing protein 10 (ASB10) in a large family with primary open angle glaucoma (POAG) mapping to the GLC1F locus. This variant affects an exon splice enhancer site and alters mRNA splicing in lymphoblasts of affected family members. Systematic sequence analysis in two POAG patient groups (195 US and 977 German) and their respective controls (85 and 376) lead to the identification of 26 amino acid changes in 70 patients (70 of 1172; 6.0%) compared with 9 in 13 controls (13 of 461; 2.8%; P = 0.008). Molecular modeling suggests that these missense variants change ASB10 net charge or destabilize ankyrin repeats. ASB10 mRNA and protein were found to be strongly expressed in trabecular meshwork, retinal ganglion cells and ciliary body. Silencing of ASB10 transcripts in perfused anterior segment organ culture reduced outflow facility by ∼50% compared with control-infected anterior segments (P = 0.02). In conclusion, genetic and molecular analyses provide evidence for ASB10 as a glaucoma-causing gene.

Novel glaucoma procedures: a report by the American Academy of Ophthalmology.

OBJECTIVE: To review the published literature and summarize clinically relevant information about novel, or emerging, surgical techniques for the treatment of open-angle glaucoma and to describe the devices and procedures in proper context of the appropriate patient population, theoretic effects, advantages, and disadvantages. DESIGN: Devices and procedures that have US Food and Drug Administration clearance or are currently in phase III clinical trials in the United States are included: the Fugo blade (Medisurg Ltd., Norristown, PA), Ex-PRESS mini glaucoma shunt (Alcon, Inc., Hunenberg, Switzerland), SOLX Gold Shunt (SOLX Ltd., Boston, MA), excimer laser trabeculotomy (AIDA, Glautec AG, Nurnberg, Germany), canaloplasty (iScience Interventional Corp., Menlo Park, CA), trabeculotomy by internal approach (Trabectome, NeoMedix, Inc., Tustin, CA), and trabecular micro-bypass stent (iStent, Glaukos Corporation, Laguna Hills, CA). METHODS: Literature searches of the PubMed and the Cochrane Library databases were conducted up to October 2009 with no date or language restrictions. MAIN OUTCOME MEASURES: These searches retrieved 192 citations, of which 23 were deemed topically relevant and rated for quality of evidence by the panel methodologist. All studies but one, which was rated as level II evidence, were rated as level III evidence. RESULTS: All of the devices studied showed a statistically significant reduction in intraocular pressure and, in some cases, glaucoma medication use. The success and failure definitions varied among studies, as did the calculated rates. Various types and rates of complications were reported depending on the surgical technique. On the basis of the review of the literature and mechanism of action, the authors also summarized theoretic advantages and disadvantages of each surgery. CONCLUSIONS: The novel glaucoma surgeries studied all show some promise as alternative treatments to lower intraocular pressure in the treatment of open-angle glaucoma. It is not possible to conclude whether these novel procedures are superior, equal to, or inferior to surgery such as trabeculectomy or to one another. The studies provide the basis for future comparative or randomized trials of existing glaucoma surgical techniques and other novel procedures.

Laser trabeculoplasty for open-angle glaucoma: a report by the american academy of ophthalmology.

OBJECTIVE: To provide an evidence-based summary of the outcomes, repeatability, and safety of laser trabeculoplasty for open-angle glaucoma. METHODS: A search of the peer-reviewed literature in the PubMed and the Cochrane Library databases was conducted in June 2008 and was last repeated in March 2010 with no date or language restrictions. The search yielded 637 unique citations, of which 145 were considered to be of possible clinical relevance for further review and were included in the evidence analysis. RESULTS: Level I evidence indicates an acceptable long-term efficacy of initial argon laser trabeculoplasty for open-angle glaucoma compared with initial medical treatment. Among the remaining studies, level II evidence supports the efficacy of selective laser trabeculoplasty for lowering intraocular pressure for patients with open-angle glaucoma. Level III evidence supports the efficacy of repeat use of laser trabeculoplasty. CONCLUSIONS: Laser trabeculoplasty is successful in lowering intraocular pressure for patients with open-angle glaucoma. At this time, there is no literature establishing the superiority of any particular form of laser trabeculoplasty. The theories of action of laser trabeculoplasty are not elucidated fully. Further research into the differences among the lasers used in trabeculoplasty, the repeatability of the procedure, and techniques of treatment is necessary. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Assessment of visual function in glaucoma: a report by the American Academy of Ophthalmology.

OBJECTIVE: To review the published literature to summarize and evaluate the effectiveness of visual function tests in diagnosing glaucoma and in monitoring progression. METHODS: Literature searches of the PubMed and Cochrane Library databases were conducted last on May 7, 2010, and were restricted to citations published on or after January 1, 1994. The search yielded 1063 unique citations. The first author reviewed the titles and abstracts of these articles and selected 185 of possible clinical relevance for further review. The panel members reviewed the full text of these articles and determined that 85 met inclusion criteria. They conducted data abstraction of the 85 studies, and the panel methodologist assigned a level of evidence to each of the selected articles. One study was rated as level I evidence. The remaining articles were classified broadly as providing level II evidence. Studies deemed to provide level III evidence were not included in the assessment. RESULTS: Standard white-on-white automated perimetry remains the most commonly performed test for assessing the visual field, with the Swedish interactive threshold algorithm (SITA) largely replacing full-threshold testing strategies. Frequency-doubling technology and its refinement into Matrix perimetry, as well as short-wavelength automated perimetry, now available with SITA, have been evaluated extensively. Machine learning classifiers seem to be ready for incorporation into software to help distinguish glaucomatous from nonglaucomatous fields. Other technologies, such as multifocal visual-evoked potential and electroretinography, which were designed as objective measures of visual function, provide testing free of patient input, but issues prevent their adoption for glaucoma management. CONCLUSIONS: Advances in technology and analytic tools over the past decade have provided us with more rapid and varied ways of assessing visual function in glaucoma, but they have yet to produce definitive guidance on the diagnosis of glaucoma or its progression over time. Further research on an objective measure of visual function is needed.

Myocilin variations and familial glaucoma in Taxiarchis, a small Greek village.

PURPOSE: To initiate a prospective study of glaucoma in a Greek village reported over 30 years ago to have several large families with primary open-angle glaucoma (POAG). METHODS: A random group of 126 villagers from Taxiarchis, Greece was examined in the village community center. The detailed evaluation included ophthalmic and general history, measurement of blood pressure, intraocular pressure (IOP), and central corneal thickness (CCT) as well as evaluation of the optic nerve status. RESULTS: The incidence of glaucoma approached 18% in this small isolated village. Myocilin variants were present in almost half of the individuals screened with Arg76Lys and Thr377Met being the most common finding (25% and 17%, respectively). Over half of the individuals with the Thr377Met mutation were diagnosed with glaucoma. Two of these patients were homozygous for the Thr377Met mutation. Three individuals with the Arg76Lys polymorphism had glaucoma; however, two of these individuals also had the Thr377Met mutation. Only two patients with pseudoexfoliation were identified. CONCLUSIONS: The incidence of glaucoma and the Thr377Met MYOC mutation in this population is much higher than that reported for other European populations.

Aqueous shunts in glaucoma: a report by the American Academy of Ophthalmology.

OBJECTIVE: To provide an evidence-based summary of commercially available aqueous shunts currently used in substantial numbers (Ahmed [New World Medical, Inc., Rancho Cucamonga, CA], Baerveldt [Advanced Medical Optics, Inc., Santa Ana, CA], Krupin [Eagle Vision, Inc, Memphis, TN], Molteno [Molteno Ophthalmic Ltd., Dunedin, New Zealand]) to control intraocular pressure (IOP) in various glaucomas. METHODS: Seventeen previously published randomized trials, 1 prospective nonrandomized comparative trial, 1 retrospective case-control study, 2 comprehensive literature reviews, and published English language, noncomparative case series and case reports were reviewed and graded for methodologic quality. RESULTS: Aqueous shunts are used primarily after failure of medical, laser, and conventional filtering surgery to treat glaucoma and have been successful in controlling IOP in a variety of glaucomas. The principal long-term complication of anterior chamber tubes is corneal endothelial failure. The most shunt-specific delayed complication is erosion of the tube through overlying conjunctiva. There is a low incidence of this occurring with all shunts currently available, and it occurs most frequently within a few millimeters of the corneoscleral junction after anterior chamber insertion. Erosion of the equatorial plate through the conjunctival surface occurs less frequently. Clinical failure of the various devices over time occurs at a rate of approximately 10% per year, which is approximately the same as the failure rate for trabeculectomy. CONCLUSIONS: Based on level I evidence, aqueous shunts seem to have benefits (IOP control, duration of benefit) comparable with those of trabeculectomy in the management of complex glaucomas (phakic or pseudophakic eyes after prior failed trabeculectomies). Level I evidence indicates that there are no advantages to the adjunctive use of antifibrotic agents or systemic corticosteroids with currently available shunts. Too few high-quality direct comparisons of various available shunts have been published to assess the relative efficacy or complication rates of specific devices beyond the implication that larger-surface-area explants provide more enduring and better IOP control. Long-term follow-up and comparative studies are encouraged.

Morphological differences between the trabecular meshworks of zebrafish and mammals.

PURPOSE: The zebrafish has been used as an animal model to study ocular development and diseases, including glaucoma. However, there are still many concerns about the morphological differences between zebrafish and mammals. Before using the zebrafish for glaucoma studies, we should understand the morphological differences in the trabecular meshworks (TMs) of zebrafish and other animal models. This study investigated and compared the histological morphologies and compositions of the extracellular matrices of the TMs of the zebrafish and some commonly used animal models, including the mouse, rat, rabbit, and cow. METHODS: Sections of the angular portions from the studied species (mouse, rat, rabbit, cow, zebrafish, and human) were prepared for immunohistochemical and electron microscopic analyses. Antibodies directed against cytoskeletal and extracellular matrix components (AE1/AE3, vimentin, alpha-smooth muscle actin, keratocan, and lumican) were used for immunolocalization. Reverse transcription polymerase chain reaction (RT-PCR) for keratocan and lumican was also performed. RESULTS: The TMs of the mouse, rat, and human consist of extracellular matrix organized into a network of beams covered in trabecular endothelial cells. However, no lamellate meshwork exists in the TMs of the rabbit, cow, or zebrafish. Instead, a reticular meshwork (rabbit and cow) and an annular ligament (zebrafish) develop. Immunohistological analysis revealed that vimentin is expressed in the TMs of the rat, rabbit, and human, and alpha-smooth muscle actin is expressed in the TMs of the mouse, rat, rabbit, and human. Only the annular ligament of the zebrafish stained positively with anti-AE1/AE3 antibody. The annular ligament of the zebrafish also expresses keratocan and lumican. The human TM showed weakly positive staining of lumican. A prominent distribution of mitochondria and intracellular vacuoles is observed in the trabecular cells of the mouse, rat, rabbit, and cow, but not the zebrafish. The analysis of RT-PCR shows the keratocan and lumican mRNAs are expressed in the annular ligament of zebrafish, but not in mouse, rat, rabbit, and cow. CONCLUSIONS: We conclude that the zebrafish expresses different extracellular matrix proteins and has a distinctive ultrastructure in the TM. Therefore, zebrafish should be used with caution for glaucoma studies.

Heritable features of the optic disc: a novel twin method for determining genetic significance.

PURPOSE: Numerous genetic diseases and environmental stimuli affect optic nerve morphology. The purpose of this study was to identify the principal heritable components of visible optic nerve head structures in a population-based sample of twins. METHODS: Fifteen optic nerve specialists viewed stereoscopic optic nerve head photographs (Stereo Viewer-II; Pentax Corp., Tokyo, Japan) from 50 randomly selected monozygotic or dizygotic twin pairs. Before viewing, each expert was questioned about which optic nerve head traits they believed were inherited. After viewing a standardized teaching set, the experts indicated which twin pairs they thought were monozygotic. Participants were then questioned about how their decisions were reached. A rank-ordered Rasch analysis was used to determine the relative weighting and value applied to specific optic nerve head traits. RESULTS: The proportion of twin pairs for which zygosity was correctly identified ranged from 74% to 90% (median, 82%) across the panel. Experts who correctly identified the zygosity in more than 85% of cases placed most weighting on shape and size of the optic disc and cup, whereas experts with the lowest scores placed greater weighting on the optic nerve head vasculature in reaching their decisions. CONCLUSIONS: In determining the genetic components of the optic nerve head, the results of this study suggest that the shape and size of the optic disc and cup are more heritable and should receive a greater priority for quantification than should vascular features.

Investigation of founder effects for the Thr377Met Myocilin mutation in glaucoma families from differing ethnic backgrounds.

PURPOSE: The aim of this study was to determine if there is a common founder for the Thr377Met myocilin mutation in primary open angle glaucoma (POAG) families with various ethnic backgrounds. METHODS: Genomic DNA of 24 POAG-affected individuals from nine pedigrees with the Thr377Met mutation and 104 unaffected family members was genotyped with six microsatellite markers and four single nucleotide polymorphisms. The families were from Greece, India, Finland, the USA, and Australia. To assess the degree of linkage disequilibrium across MYOC in the general population we also investigated data generated from the HapMap consortium. RESULTS: Three distinct haplotypes associated with the Thr377Met myocilin mutation were identified. The families from the USA and Greece, as well as the three Australian families originating from Greece and the former Yugoslavian Republic of Macedonia had one common haplotype. Interestingly, however, HapMap data suggest that linkage disequilibrium across MYOC was not strong. CONCLUSIONS: The Thr377Met myocilin mutation has arisen at least three separate times. Evidence for genetic founder effects in this prevalent age-related, yet heterogeneous, disease has important implications for future gene identification strategies.

Corneal thickness measurement in the management of primary open-angle glaucoma: a report by the American Academy of Ophthalmology.

OBJECTIVE: To evaluate published literature to assess whether central corneal thickness (CCT) is a risk factor for the presence, development, or progression of glaucomatous optic nerve damage related to primary open-angle glaucoma (POAG). METHODS: A PubMed literature search limited to English language articles conducted on November 15, 2004 retrieved 195 articles. The authors reviewed these abstracts and selected 57 to review in full text to determine relevance to the assessment questions. A further 24 studies of interest were identified from periodic updates to the literature search, surveillance of the literature, and reference lists of reviewed articles. From the 81 published reports identified, the first author applied specified selection criteria that yielded 37 articles for methodological review because of relevance to the assessment questions. The articles were rated according to the strength of evidence by the panel methodologist. A level I rating was assigned to well-designed properly conducted randomized clinical trials or similar quality-validated cohort studies with appropriate reference standards. A level II rating was assigned to well-designed case-control studies, exploratory cohort studies, and other nonrandomized clinical studies lacking consistently applied reference standards. A level III rating was reserved for poorly designed case-control studies, case series, and papers consisting only of expert opinion without supporting evidence. In addition, each study was graded as positive if it supported a statistical association of CCT with the risk of having or developing glaucomatous optic nerve damage or as negative if no such association was found. RESULTS: There is strong and consistent level I and level II evidence that CCT is a risk factor for progression from ocular hypertension to POAG. Studies that were rated as providing the highest quality of evidence revealed mixed results with respect to glaucoma prevalence. One population-based study (level II) showed a positive association, another larger study (level I) revealed an association of marginal significance, and 3 studies (all level I) found no association of CCT with POAG prevalence. CONCLUSIONS: There is strong evidence that measuring CCT is an important component of a complete ocular examination, particularly for patients being evaluated for the risk of developing POAG. Therefore, CCT measurement should be included in the examination of all patients with ocular hypertension. Although the evidence supporting the necessity of measuring CCT as part of screening for POAG or as a risk factor for glaucoma progression is not as strong, intraocular pressure (IOP) is the only modifiable risk factor in the treatment of glaucoma, and CCT has the potential to significantly impact IOP measurement by applanation tonometry in all patients.

Differential expression profile prioritization of positional candidate glaucoma genes: the GLC1C locus.

OBJECTIVES: To develop and apply a model for prioritization of candidate glaucoma genes. METHODS: This Affymetrix GeneChip (Affymetrix, Santa Clara, Calif) study of gene expression in primary culture human trabecular meshwork cells uses a positional differential expression profile model for prioritization of candidate genes within the GLC1C genetic inclusion interval. RESULTS: Sixteen genes were expressed under all conditions within the GLC1C interval. TMEM22 was the only gene within the interval with differential expression in the same direction under both conditions tested. Two genes, ATP1B3 and COPB2, are of interest in the context of a protein-misfolding model for candidate selection. SLC25A36, PCCB, and FNDC6 are of lesser interest because of moderate expression and changes in expression. Transcription factor ZBTB38 emerges as an interesting candidate gene because of the overall expression level, differential expression, and function. CONCLUSIONS: Only 1 gene in the GLC1C interval fits our model for differential expression under multiple glaucoma risk conditions. The use of multiple prioritization models resulted in filtering 7 candidate genes of higher interest out of the 41 known genes in the region. CLINICAL RELEVANCE: This study identified a small subset of genes that are most likely to harbor mutations that cause glaucoma linked to GLC1C.

Relationship between foveal threshold and visual acuity using the Humphrey visual field analyzer.

PURPOSE: Evaluate Humphrey visual field (VF) analyzer central 30-2 foveal threshold test for best-corrected visual acuity. DESIGN: Consecutive case series. METHODS: Both eyes (n = 117) of 59 patients with diseased and healthy eyes presenting for VF analysis were evaluated to determine foveal threshold. This was compared with uncorrected visual acuity converted to logMAR, determined by manifest refraction, or estimated from Snellen visual acuity with pinhole. RESULTS: Foveal threshold correlated with logMAR uncorrected visual acuity for right (P < .0001) and left eyes (P < .0001) and logMAR best-corrected visual acuity for right (P < .0001) and left eyes (P < .0001). Sixty-eight percent of eyes with visual acuity <20/50 had foveal threshold of 0 to 30; 47% with visual acuity of >20/20 had foveal threshold better than 37. CONCLUSIONS: Foveal threshold measurement appears to provide a reliable estimate of best-corrected visual acuity. This method may usefully predict visual acuity in eyes with possible nonorganic visual acuity loss.

Clinical features associated with an Asp380His Myocilin mutation in a US family with primary open-angle glaucoma.

PURPOSE: To determine the glaucoma phenotype of an American pedigree with the myocilin Asp380His. DESIGN: An observational case series study. METHODS: An observational case series study was used to examine a family in which an Asp380His myocilin mutation was segregating. Thirteen family members were examined and medical records were obtained on the remaining two individuals. Blood samples were collected from all 15 participants following the tenets of the Helsinki declaration under the auspices of the Oregon Health & Sciences University Institutional Review Board and screened for myocilin variants by denaturing high-performance liquid chromatography (dHPLC). Any DNA samples with dHPLC data different from the control sample were sequenced for base pair analysis. RESULTS: An Asp380His myocilin mutation was identified in eight members, seven of whom had primary open-angle glaucoma (POAG). The eighth individual had high intraocular pressures (IOPs). The disease presents in this family with extremely high IOPs requiring trabeculectomies to control the pressure. The age at diagnosis ranged from 30 to 45. CONCLUSIONS: This family with an Asp380His myocilin mutation presents with an intermediate phenotype between juvenile- and adult-onset glaucoma. The Asp380 amino acid residue appears to be important in myocilin function based on the finding that substitution of this amino acid with four different amino acids (His, Ala, Asn, or Gly) all result in a similar presentation of POAG that is intermediate between the more severe clinical presentations observed in individuals with the Pro370Leu or Lys423Glu variant and the milder findings in patients with the Gln368Stop mutation.

Aqueous humor sCD44 concentration and visual field loss in primary open-angle glaucoma.

PURPOSE: To correlate aqueous humor soluble CD44 (sCD44) concentration, visual field loss, and glaucoma risk factors in primary open-angle glaucoma (POAG) patients. METHODS: Aqueous samples were obtained by paracentesis from normal and glaucoma patients who were undergoing elective surgery and analyzed for sCD44 concentration by enzyme-linked immunosorbent assay. RESULTS: In normal aqueous (n=124) the sCD44 concentration was 5.88+/-0.27 ng/mL, whereas in POAG aqueous (n=90) the sCD44 concentration was 12.76+/-0.66 ng/mL, a 2.2-fold increase (P<0.000001). In POAG patients with prior successful filtration surgery (n=13), the sCD44 concentration was decreased by 43% to 7.32+/-1.44 (P=0.001) in comparison with POAG patients without filtration surgery; however, the sCD44 concentration in the prior successful filtration subgroup with no medications and normal intraocular pressure was 12.62+/-3.81 (P=0.05) compared with normal. The sCD44 concentration of normal pressure glaucoma patients was 9.19+/-1.75 ng/mL, a 1.6-fold increase compared with normal (P=0.02). Race and intraocular pressure pulse amplitude were significant POAG risk factors in this cohort of patients. In both normal and POAG patients with mild and moderate visual field loss, sCD44 concentration was greater in African Americans than in whites (P=0.04). CONCLUSIONS: sCD44 concentration in the aqueous of POAG patients correlated with the severity of visual field loss in all stages in white patients and in mild to moderate stages in African American patients. sCD44 concentration in aqueous is a possible protein biomarker of visual field loss in POAG.

Contrasting blue-on-yellow with white-on-white visual fields: Roles of visual adaptation for healthy peri- or postmenopausal women younger than 70 years of age.

PURPOSE: To test the hypothesis that differences between short-wavelength automated perimetry (SWAP) and white-on-white visual field sensitivities are related to between-individual variation in the visual adaptation properties of SWS cone pathways. METHODS: Twenty-six healthy amenorrheic (peri- or postmenopausal) women not using hormonal medication were tested. Subjects ranged in age from 48 to 68 years. They were tested by using foveal increment-threshold techniques and also with two types of 24-2 visual field tests: a full-threshold SWAP blue-on-yellow (B/Y) test and a white-on-white (W/W) test obtained using a Swedish Interactive Threshold Algorithm (SITA Standard). The age-corrected sensitivity differences between the two types of visual fields were compared against foveal measures of visual sensitivity and adaptation, which were obtained psychophysically using dim and bright yellow backgrounds. All measurements for each subject were made at a single testing session. The comparisons were made for the entire visual field and for separate portions of the visual field. The analyses also included pupil size data obtained during visual field testing. RESULTS: The B/Y minus W/W (B/Y - W/W) mean deviation difference was described (R = 0.80) by a multilinear model with three significant factors: (1) an adaptation factor and (2) a baseline sensitivity factor, each derived from the foveal psychophysical data for short-wavelength test stimuli, and (3) a pupil size factor, as recorded for SWAP. The total deviation differences in the periphery of the visual field (approximately 22 degrees from fixation) were described (R = 0.87) by a model with four significant factors, the fourth being an "eccentricity factor" describing the rate of change of the B/Y - W/W total deviation difference measured as a function of increasing retinal eccentricity approximately 9 degrees -17 degrees from fixation. More than 40% of the variance in the B/Y - W/W mean deviation differences was accounted for either directly or indirectly (via effects of pupil size) by variations in adaptation to the yellow background used for SWAP. CONCLUSIONS: Much of the extra variability in SWAP sensitivities for a select group of healthy women can be accounted for by differences in the degree of desensitization induced by the yellow background used for SWAP. For clinical practice, pupil status (dilated or undilated) should be altered only with caution from one SWAP testing session to another.

A large GLC1C Greek family with a myocilin T377M mutation: inheritance and phenotypic variability.

PURPOSE: POAG is a complex disease; therefore, families in which a glaucoma gene has been mapped may carry additional POAG genes. The goal of this study was to determine whether mutations in the myocilin (MYOC) gene on chromosome 1 are present in two POAG families, which have previously been mapped to the GLC1C locus on chromosome 3. METHODS: The three exons of MYOC were screened by denaturing (d)HPLC. Samples with heteroduplex peaks were sequenced. Clinical findings were compared with genotype status in all available family members over the age of 20 years. RESULTS: A T377M coding sequence change in MYOC was identified in family members of the Greek GLC1C family but not in the Oregon GLC1C family. Individuals carrying both the MYOC T377M variant and the GLC1C haplotype were more severely affected at an earlier age than individuals with just one of the POAG genes, suggesting that these two genes interact or that both contribute to the POAG phenotype in a cumulative way.

The association of single nucleotide polymorphisms in the MMP-9 genes with susceptibility to acute primary angle closure glaucoma in Taiwanese patients.

PURPOSE: To study the relationships between single nucleotide polymorphisms (SNPs) of extracellular matrix, matrix metalloproteases (MMPs), tissue inhibitors of MMPs, and other glaucoma-associated genes and acute primary angle closure glaucoma (PACG). METHODS: We extracted DNA samples from 78 adult patients with acute PACG and 86 control subjects to study the relationships between these specific genes and acute PACG. Genotyping was performed for 35 genes by the GenomeLab SNPstream genotyping system after PCR amplification of chromosomal DNA. The association between these genetic polymorphisms and risk of primary PACG was estimated by chi2 and logistic regression. RESULTS: The genotyping success rate was 99%. Genotyping for the MMP9 site (rs2664538) was significantly different between the two groups (p=0.000001) and the odds ratio was 2.586 (95% CI: 1.715-3.898, p<0.00001). However, there were no associations of SNPs to other genes in patients with acute PACG. CONCLUSIONS: Our results reveal that SNP rs2664538, which is located at the MMP9 gene, is likely to be associated with acute PACG.

The role of the WDR36 gene on chromosome 5q22.1 in a large family with primary open-angle glaucoma mapped to this region.

OBJECTIVE: To determine whether mutations in the WD40-repeat 36 (WDR36) gene are responsible for primary open-angle glaucoma (POAG) that maps to the GLC1G locus in a family with 16 affected family members. METHODS: Ninety-two family members underwent clinical evaluation for POAG on the basis of intraocular pressures, cupping of discs, and visual fields after informed consent was obtained. All 23 exons of WDR36 were sequenced in DNA from 5 affected and 2 unaffected family members. RESULTS: Sixteen family members showed evidence of POAG. A number of sequence variations were identified in family members; most of the variations were previously described single-nucleotide polymorphisms also present in the general population. The 3 new sequence changes were all intronic; 2 were found in only 1 of the family members undergoing screening. CONCLUSIONS: Several polymorphisms, including known single-nucleotide polymorphisms, were identified; however, none of these were consistent with disease-causing mutations. A mutation in a noncoding region of WDR36 may be responsible for POAG in this family, or another gene in this region may be the actual cause of glaucoma in this family. CLINICAL RELEVANCE: The finding that the WDR36 gene is probably not the responsible gene in this family further documents the genetic heterogeneity of POAG.