Glaucoma Publications

Baniasadi N, Wang M, Wang H, Mahd M, Elze T. Associations between Optic Nerve Head-Related Anatomical Parameters and Refractive Error over the Full Range of Glaucoma Severity. Transl Vis Sci Technol 2017;6(4):9.Abstract
PURPOSE: To evaluate the associations between optic disc (OD)-related anatomical parameters (interartery angle [IAA] between superior and inferior temporal retinal arteries, OD tilt [TL], rotation [ROT], and torsion [TO], OD surface curvature [CUR], and central retinal vessel trunk entry point location [CRVTL] on OD) and the spherical equivalent of refractive error (SE), and to assess the impact of glaucoma severity on these relationships. METHODS: Cirrus optical coherence tomography (OCT) fundus images and 24-2 visual fields of 438 patients were included. Ellipses were fitted to OD borders. IAA was calculated between marked retinal artery locations on a circle around OD. Blood vessel entry point on OD was marked to locate CRVTL. TL was measured as the angle between the lines fitted to OD clinical boundary and the Bruch's membrane edges on the horizontal B-scans. Ellipse rotation relative to the vertical axis defined ROT. Angle between the long axis of OD and the interartery line defined TO. CUR was determined by the inner limiting membrane on the horizontal B-scans. Linear regression models evaluated by Bayes Factors (BF) were used to determine the covariance structure between the parameters and SE as well as possible impacts of mean deviation (MD). RESULTS: Our results showed that CRVTL had the strongest relationship with SE, followed by ROT, TL, and IAA (BFs: 3.59 × 10(7), 2645, 1126, and 248, respectively). MD did not significantly modulate the relationship between ONH parameters and SE. CONCLUSION: Our results suggest that SE should be considered when interpreting the OD and its circumpapillary region for diagnostic purposes. TRANSLATIONAL RELEVANCE: The reported relationships between OD-related parameters and ametropia may help to decrease false-positive clinical diagnoses of optic neuropathies.
Zhou EH, Paolucci M, Dryja TP, Manley T, Xiang C, Rice DS, Prasanna G, Chen A. A Compact Whole-Eye Perfusion System to Evaluate Pharmacologic Responses of Outflow Facility. Invest Ophthalmol Vis Sci 2017;58(7):2991-3003.Abstract
Purpose: To discover novel therapies that lower IOP by increasing aqueous humor outflow facility, ex vivo ocular perfusion systems provide a valuable tool. However, currently available designs are limited by their throughput. Here we report the development of a compact, scalable perfusion system with improved throughput and its validation using bovine and porcine eyes. Methods: At a fixed IOP of 6 mm Hg, flow rate was measured by flow sensors. We validated the system by measuring the outflow responses to Y-39983 (a Rho kinase inhibitor), endothelin-1 (ET-1), ambrisentan (an antagonist for endothelin receptor A [ETA]), sphigosine-1-phosphate (S1P), JTE-013 (antagonist for S1P receptor 2 [S1P2]), S-nitroso-N-acetylpenicillamine (SNAP, a nitric oxide [NO] donor), and 3-Morpholino-sydnonimine (SIN-1, another NO donor). Results: The instrument design enabled simultaneous measurements of 20 eyes with a footprint of 1 m2. Relative to vehicle control, Y-39983 increased outflow by up to 31% in calf eyes. On the contrary, ET-1 decreased outflow by up to 79%, a response that could be blocked by pretreatment with ambrisentan, indicating a role for ETA receptors. Interestingly, the effect of ET-1 was also inhibited by up to 70% to 80% by pretreatment with NO donors, SNAP and SIN-1. In addition to testing in calf eyes, similar effects of ET-1 and ambrisentan were observed in adult bovine and porcine eyes. Conclusions: The compact eye perfusion platform provides an opportunity to efficiently identify compounds that influence outflow facility and may lead to the discovery of new glaucoma therapies.
Wiggs JL, Pasquale LR. Genetics of Glaucoma. Hum Mol Genet 2017;Abstract
Genetic and genomic studies, including genome-wide association studies (GWAS) have accelerated the discovery of genes contributing to glaucoma, the leading cause of irreversible blindness world-wide. Glaucoma can occur at all ages, with Mendelian inheritance typical for rare early onset disease (before age 40) and complex inheritance evident in common adult-onset forms of disease. Recent studies have suggested possible therapeutic targets for some patients with early-onset glaucoma based on the molecular and cellular events caused by MYOC, OPTN and TBK1 mutations. Diagnostic genetic tests using early-onset glaucoma genes are also proving useful for pre-symptomatic disease detection and genetic counseling. Recent GWAS completed for three types of common adult-onset glaucoma have identified novel loci for POAG (primary-open-angle glaucoma) (ABCA1, AFAP1, GMDS, PMM2, TGFBR3, FNDC3B, ARHGEF12, GAS7, FOXC1, ATXN2, TXNRD2); PACG (primary angle-closure glaucoma (EPDR1, CHAT, GLIS3, FERMT2, DPM2-FAM102); and exfoliation syndrome (XFS) glaucoma (CACNA1A). In total sixteen genomic regions have been associated with POAG (including the normal tension glaucoma (NTG) subgroup), 8 with PACG and 2 with XFS. These studies are defining important biological pathways and processes that contribute to disease pathogenesis.
Aung T, Ozaki M, Lee MC, Schlötzer-Schrehardt U, Thorleifsson G, Mizoguchi T, Igo RP, Haripriya A, Williams SE, Astakhov YS, Orr AC, Burdon KP, Nakano S, Mori K, Abu-Amero K, Hauser M, Li Z, Prakadeeswari G, Bailey JCN, Cherecheanu AP, Kang JH, Nelson S, Hayashi K, Manabe S-I, Kazama S, Zarnowski T, Inoue K, Irkec M, Coca-Prados M, Sugiyama K, Järvelä I, Schlottmann P, Lerner FS, Lamari H, Nilgün Y, Bikbov M, Park KH, Cha SC, Yamashiro K, Zenteno JC, Jonas JB, Kumar RS, Perera SA, Chan ASY, Kobakhidze N, George R, Vijaya L, Do T, Edward DP, de Juan Marcos L, Pakravan M, Moghimi S, Ideta R, Bach-Holm D, Kappelgaard P, Wirostko B, Thomas S, Gaston D, Bedard K, Greer WL, Yang Z, Chen X, Huang L, Sang J, Jia H, Jia L, Qiao C, Zhang H, Liu X, Zhao B, Wang Y-X, Xu L, Leruez S, Reynier P, Chichua G, Tabagari S, Uebe S, Zenkel M, Berner D, Mossböck G, Weisschuh N, Hoja U, Welge-Luessen U-C, Mardin C, Founti P, Chatzikyriakidou A, Pappas T, Anastasopoulos E, Lambropoulos A, Ghosh A, Shetty R, Porporato N, Saravanan V, Venkatesh R, Shivkumar C, Kalpana N, Sarangapani S, Kanavi MR, Beni AN, Yazdani S, Lashay A, Naderifar H, Khatibi N, Fea A, Lavia C, Dallorto L, Rolle T, Frezzotti P, Paoli D, Salvi E, Manunta P, Mori Y, Miyata K, Higashide T, Chihara E, Ishiko S, Yoshida A, Yanagi M, Kiuchi Y, Ohashi T, Sakurai T, Sugimoto T, Chuman H, Aihara M, Inatani M, Miyake M, Gotoh N, Matsuda F, Yoshimura N, Ikeda Y, Ueno M, Sotozono C, Jeoung JW, Sagong M, Park KH, Ahn J, Cruz-Aguilar M, Ezzouhairi SM, Rafei A, Chong YF, Ng XY, Goh SR, Chen Y, Yong VHK, Khan MI, Olawoye OO, Ashaye AO, Ugbede I, Onakoya A, Kizor-Akaraiwe N, Teekhasaenee C, Suwan Y, Supakontanasan W, Okeke S, Uche NJ, Asimadu I, Ayub H, Akhtar F, Kosior-Jarecka E, Lukasik U, Lischinsky I, Castro V, Grossmann RP, Megevand GS, Roy S, Dervan E, Silke E, Rao A, Sahay P, Fornero P, Cuello O, Sivori D, Zompa T, Mills RA, Souzeau E, Mitchell P, Wang JJ, Hewitt AW, Coote M, Crowston JG, Astakhov SY, Akopov EL, Emelyanov A, Vysochinskaya V, Kazakbaeva G, Fayzrakhmanov R, Al-Obeidan SA, Owaidhah O, Aljasim LA, Chowbay B, Foo JN, Soh RQ, Sim KS, Xie Z, Cheong AWO, Mok SQ, Soo HM, Chen XY, Peh SQ, Heng KK, Husain R, Ho S-L, Hillmer AM, Cheng C-Y, Escudero-Domínguez FA, González-Sarmiento R, Martinon-Torres F, Salas A, Pathanapitoon K, Hansapinyo L, Wanichwecharugruang B, Kitnarong N, Sakuntabhai A, Nguyn HX, Nguyn GTT, Nguyn TV, Zenz W, Binder A, Klobassa DS, Hibberd ML, Davila S, Herms S, Nöthen MM, Moebus S, Rautenbach RM, Ziskind A, Carmichael TR, Ramsay M, Álvarez L, García M, González-Iglesias H, Rodríguez-Calvo PP, Cueto LF-V, Oguz Ç, Tamcelik N, Atalay E, Batu B, Aktas D, Kasım B, Wilson RM, Coleman AL, Liu Y, Challa P, Herndon L, Kuchtey RW, Kuchtey J, Curtin K, Chaya CJ, Crandall A, Zangwill LM, Wong TY, Nakano M, Kinoshita S, den Hollander AI, Vesti E, Fingert JH, Lee RK, Sit AJ, Shingleton BJ, Wang N, Cusi D, Qamar R, Kraft P, Pericak-Vance MA, Raychaudhuri S, Heegaard S, Kivelä T, Reis A, Kruse FE, Weinreb RN, Pasquale LR, Haines JL, Thorsteinsdottir U, Jonasson F, Allingham RR, Milea D, Ritch R, Kubota T, Tashiro K, Vithana EN, Micheal S, Topouzis F, Craig JE, Dubina M, Sundaresan P, Stefansson K, Wiggs JL, Pasutto F, Khor CC. Genetic association study of exfoliation syndrome identifies a protective rare variant at LOXL1 and five new susceptibility loci. Nat Genet 2017;Abstract
Exfoliation syndrome (XFS) is the most common known risk factor for secondary glaucoma and a major cause of blindness worldwide. Variants in two genes, LOXL1 and CACNA1A, have previously been associated with XFS. To further elucidate the genetic basis of XFS, we collected a global sample of XFS cases to refine the association at LOXL1, which previously showed inconsistent results across populations, and to identify new variants associated with XFS. We identified a rare protective allele at LOXL1 (p.Phe407, odds ratio (OR) = 25, P = 2.9 × 10(-14)) through deep resequencing of XFS cases and controls from nine countries. A genome-wide association study (GWAS) of XFS cases and controls from 24 countries followed by replication in 18 countries identified seven genome-wide significant loci (P < 5 × 10(-8)). We identified association signals at 13q12 (POMP), 11q23.3 (TMEM136), 6p21 (AGPAT1), 3p24 (RBMS3) and 5q23 (near SEMA6A). These findings provide biological insights into the pathology of XFS and highlight a potential role for naturally occurring rare LOXL1 variants in disease biology.
Pasquale LR, Hyman L, Wiggs JL, Rosner BA, Joshipura K, McEvoy M, McPherson ZE, Danias J, Kang JH. Reply. Ophthalmology 2017;124(5):e50-e51.
Zhao J, Chen W, Huang X, Peng S, Zhu T, Deng Z, Liang P, Chang H, Fan BJ. Serum Th1 and Th17 related cytokines and autoantibodies in patients with Posner-Schlossman syndrome. PLoS One 2017;12(4):e0175519.Abstract

Posner-Schlossman syndrome (PSS) shares some clinical features with uveitis and open angle glaucoma. Cytokines and autoantibodies have been associated with uveitis and open angle glaucoma. However, the role of serum cytokines and autoantibodies in the pathogenesis of PSS remains unknown. This study aimed to evaluate the associations of type 1 T helper (Th1) and Th17 related cytokines and autoantibodies with PSS. Peripheral blood serum samples were collected from 81 patients with PSS and 97 gender- and age-matched healthy blood donors. Th1 and Th17 related cytokines, including interleukin-1β (IL-1β), IL-12, tumor necrosis factor-α (TNF-α), interferon- γ (IFN-γ), IL-6 and IL-17, and glucose-6-phosphate isomerase (GPI) were determined by double antibody sandwich ELISA. Anti-nuclear antibody (ANA), anti-keratin antibody (AKA) and anti-neutrophil cytoplasmic antibody (ANCA) were detected by indirect immunofluorescence assay. Anti-cardiolipin antibody (ACA)-IgG, ACA-IgM, ACA-IgA, anti-double stranded DNA (anti-dsDNA) and anti-cyclic citrullinated peptide antibody (anti-CCP) were detected by indirect ELISA. Serum levels of IL-1β, IL-12 and IL-6 in PSS patients were significantly lower than those in controls (P < 0.003), and these associations survived the Bonferroni correction (Pc < 0.018). There was no significant difference in serum levels of TNF-α, IFN-γ and IL-17 between the PSS and control groups (Pc > 0.12). Positive rate of serum anti-dsDNA in PSS patients was significantly higher than that in the control group (P = 0.002, Pc = 0.018), while positive rates of serum ANA, AKA, ANCA, ACA-IgG, ACA-IgM, ACA-IgA, GPI and anti-CCP in the PSS group were not significantly different from those in the control group (Pc > 0.09). These results suggest that anti-dsDNA may contribute to the pathogenesis of PSS, while Th1 and Th17 related cytokines and other autoantibodies may not be major contributors to PSS.

Wilsey L, Gowrisankaran S, Cull G, Hardin C, Burgoyne CF, Fortune B. Comparing three different modes of electroretinography in experimental glaucoma: diagnostic performance and correlation to structure. Doc Ophthalmol 2017;134(2):111-128.Abstract

PURPOSE: To compare diagnostic performance and structure-function correlations of multifocal electroretinogram (mfERG), full-field flash ERG (ff-ERG) photopic negative response (PhNR) and transient pattern-reversal ERG (PERG) in a non-human primate (NHP) model of experimental glaucoma (EG). METHODS: At baseline and after induction of chronic unilateral IOP elevation, 43 NHP had alternating weekly recordings of retinal nerve fiber layer thickness (RNFLT) by spectral domain OCT (Spectralis) and retinal function by mfERG (7F slow-sequence stimulus, VERIS), ff-ERG (red 0.42 log cd-s/m(2) flashes on blue 30 scotopic cd/m(2) background, LKC UTAS-E3000), and PERG (0.8° checks, 99% contrast, 100 cd/m(2) mean, 5 reversals/s, VERIS). All NHP were followed at least until HRT-confirmed optic nerve head posterior deformation, most to later stages. mfERG responses were filtered into low- and high-frequency components (LFC, HFC, >75 Hz). Peak-to-trough amplitudes of LFC features (N1, P1, N2) and HFC RMS amplitudes were measured and ratios calculated for HFC:P1 and N2:P1. ff-ERG parameters included A-wave (at 10 ms), B-wave (trough-to-peak) and PhNR (baseline-to-trough) amplitudes as well as PhNR:B-wave ratio. PERG parameters included P50 and N95 amplitudes as well as N95:P50 ratio and N95 slope. Diagnostic performance of retinal function parameters was compared using the area under the receiver operating characteristic curve (A-ROC) to discriminate between EG and control eyes. Correlations to RNFLT were compared using Steiger's test. RESULTS: Study duration was 15 ± 8 months. At final follow-up, structural damage in EG eyes measured by RNFLT ranged from 9% above baseline (BL) to 58% below BL; 29/43 EG eyes (67%) and 0/43 of the fellow control eyes exhibited significant (>7%) loss of RNFLT from BL. Using raw parameter values, the largest A-ROC findings for mfERG were: HFC (0.82) and HFC:P1 (0.90); for ff-ERG: PhNR (0.90) and PhNR:B-wave (0.88) and for PERG: P50 (0.64) and N95 (0.61). A-ROC increased when data were expressed as % change from BL, but the pattern of results persisted. At 95% specificity, the diagnostic sensitivity of mfERG HFC:P1 ratio was best, followed by PhNR and PERG. The correlation to RNFLT was stronger for mfERG HFC (R = 0.65) than for PhNR (R = 0.59) or PERG N95 (R = 0.36), (p = 0.20, p = 0.0006, respectively). The PhNR flagged a few EG eyes at the final time point that had not been flagged by mfERG HFC or PERG. CONCLUSIONS: Diagnostic performance and structure-function correlation were strongest for mfERG HFC as compared with ff-ERG PhNR or PERG in NHP EG.

Sun D, Moore S, Jakobs TC. Optic nerve astrocyte reactivity protects function in experimental glaucoma and other nerve injuries. J Exp Med 2017;214(5):1411-1430.Abstract
Reactive remodeling of optic nerve head astrocytes is consistently observed in glaucoma and other optic nerve injuries. However, it is unknown whether this reactivity is beneficial or harmful for visual function. In this study, we used the Cre recombinase (Cre)-loxP system under regulation of the mouse glial fibrillary acidic protein promoter to knock out the transcription factor signal transducer and activator of transcription 3 (STAT3) from astrocytes and test the effect this has on reactive remodeling, ganglion cell survival, and visual function after experimental glaucoma and nerve crush. After injury, STAT3 knockout mice displayed attenuated astrocyte hypertrophy and reactive remodeling; astrocytes largely maintained their honeycomb organization and glial tubes. These changes were associated with increased loss of ganglion cells and visual function over a 30-day period. Thus, reactive astrocytes play a protective role, preserving visual function. STAT3 signaling is an important mediator of various aspects of the reactive phenotype within optic nerve astrocytes.
Wang R, Seifert P, Jakobs TC. Astrocytes in the Optic Nerve Head of Glaucomatous Mice Display a Characteristic Reactive Phenotype. Invest Ophthalmol Vis Sci 2017;58(2):924-932.Abstract

Purpose: Optic nerve head astrocytes, a subtype of white-matter astrocytes, become reactive early in the course of glaucoma. It was shown recently that in the DBA/2J mouse model of inherited glaucoma optic nerve astrocytes extend new longitudinal processes into the axon bundles before ganglion cell loss becomes apparent. The present study aims at testing whether this behavior of astrocytes is typical of early glaucomatous damage. Methods: Mice expressing green fluorescent protein in individual astrocytes were used to evaluate the early response of astrocytes in the glial lamina of the optic nerve head after increasing the IOP using the microbead occlusion method. Tissue sections from the glial lamina were imaged consecutively by confocal and electron microscopy. Results: Confocal and electron microscope images show that astrocytes close to the myelination transition zone in the hypertensive nerve heads extend new processes that follow the longitudinal axis of the optic nerve and invade axon bundles in the nerve head. Ultrastructurally, the longitudinal processes were largely devoid of subcellular organelles except for degenerating mitochondria. Conclusions: The longitudinal processes are a common feature of glaucomatous optic nerve astrocytes, whereas they are not observed after traumatic nerve injury. Thus, astrocytes appear to fine-tune their responses to the nature and/or timing of the injury to the neurons that they surround.

Lin S-C, Wang SY, Pasquale LR, Singh K, Lin SC. The relation between exercise and glaucoma in a South Korean population-based sample. PLoS One 2017;12(2):e0171441.Abstract

PURPOSE: To investigate the association between exercise and glaucoma in a South Korean population-based sample. DESIGN: Population-based, cross-sectional study. PARTICIPANTS: A total of 11,246 subjects, 40 years and older who underwent health care assessment as part of the 2008-2011 Korean National Health and Nutrition Examination Survey. METHODS: Variables regarding the duration (total minutes per week), frequency (days per week), and intensity of exercise (vigorous, moderate exercise and walking) as well as glaucoma prevalence were ascertained for 11,246 survey participants. Demographic, comorbidity, and health-related behavior information was obtained via interview. Multivariable logistic regression analyses were performed to determine the association between the exercise-related parameters and odds of a glaucoma diagnosis. MAIN OUTCOME MEASURE(S): Glaucoma defined by International Society for Geographical and Epidemiological Ophthalmology criteria. RESULTS: Overall, 336 (2.7%) subjects met diagnostic criteria for glaucomatous disease. After adjustment for potential confounding variables, subjects engaged in vigorous exercise 7 days per week had higher odds of having glaucoma compared with those exercising 3 days per week (Odds Ratio [OR] 3.33, 95% confidence interval [CI] 1.16-9.54). High intensity of exercise, as categorized by the guidelines of the American College of Sports Medicine (ACSM), was also associated with greater glaucoma prevalence compared with moderate intensity of exercise (OR 1.55, 95% CI 1.03-2.33). There was no association between other exercise parameters including frequency of moderate exercise, walking, muscle strength exercise, flexibility training, or total minutes of exercise per week, and the prevalence of glaucoma. In sub-analyses stratifying by gender, the association between frequency of vigorous exercise 7 days per week and glaucoma diagnosis remained significant in men (OR 6.05, 95% CI 1.67-21.94) but not in women (OR 0.96 95% CI: 0.23-3.97). A U-shaped association between exercise intensity and glaucoma prevalence was noted in men (OR 1.71, 95% CI 1.09-2.69 for low intensity versus moderate intensity; OR 2.19, 95% CI 1.25-3.85 for high intensity versus moderate intensity). CONCLUSION: In a South Korean population sample, daily vigorous exercise was associated with higher glaucoma prevalence. In addition, the intensity of exercise was positively associated with glaucoma diagnosis in men but not women.

Fan KC, Tsikata E, Khoueir Z, Simavli H, Guo R, A de Luna R, Pandit S, Que CJ, de Boer JF, Chen TC. Enhanced Diagnostic Capability for Glaucoma of 3-Dimensional Versus 2-Dimensional Neuroretinal Rim Parameters Using Spectral Domain Optical Coherence Tomography. J Glaucoma 2017;26(5):450-458.Abstract
PURPOSE: To compare the diagnostic capability of 3-dimensional (3D) neuroretinal rim parameters with existing 2-dimensional (2D) neuroretinal and retinal nerve fiber layer (RNFL) thickness rim parameters using spectral domain optical coherence tomography (SD-OCT) volume scans. MATERIALS AND METHODS: Design: Institutional prospective pilot study. STUDY POPULATION: 65 subjects (35 open-angle glaucoma patients, 30 normal patients). OBSERVATION PROCEDURES: One eye of each subject was included. SD-OCT was used to obtain 2D RNFL thickness values and 5 neuroretinal rim parameters [ie, 3D minimum distance band (MDB) thickness, 3D Bruch's membrane opening-minimum rim width (BMO-MRW), 3D rim volume, 2D rim area, and 2D rim thickness]. MAIN OUTCOME MEASURES: Area under the receiver operating characteristic curve values, sensitivity, and specificity. RESULTS: Comparing all 3D with all 2D parameters, 3D rim parameters (MDB, BMO-MRW, rim volume) generally had higher area under the receiver operating characteristic curve values (range, 0.770 to 0.946) compared with 2D parameters (RNFL thickness, rim area, rim thickness; range, 0.678 to 0.911). For global region analyses, all 3D rim parameters (BMO-MRW, rim volume, MDB) were equal to or better than 2D parameters (RNFL thickness, rim area, rim thickness; P-values from 0.023 to 1.0). Among the three 3D rim parameters (MDB, BMO-MRW, and rim volume), there were no significant differences in diagnostic capability (false discovery rate >0.05 at 95% specificity). CONCLUSIONS: 3D neuroretinal rim parameters (MDB, BMO-MRW, and rim volume) demonstrated better diagnostic capability for primary and secondary open-angle glaucomas compared with 2D neuroretinal parameters (rim area, rim thickness). Compared with 2D RNFL thickness, 3D neuroretinal rim parameters have the same or better diagnostic capability.
Springelkamp H, Iglesias AI, Mishra A, Höhn R, Wojciechowski R, Khawaja AP, Nag A, Wang YX, Wang JJ, Cuellar-Partida G, Gibson J, Cooke Bailey JN, Vithana EN, Gharahkhani P, Boutin T, Ramdas WD, Zeller T, Luben RN, Yonova-Doing E, Viswanathan AC, Yazar S, Cree AJ, Haines JL, Koh JY, Souzeau E, Wilson JF, Amin N, Müller C, Venturini C, Kearns LS, Kang JH, Kang JH, Tham YC, Zhou T, van Leeuwen EM, Nickels S, Sanfilippo P, Liao J, van der Linde H, Zhao W, van Koolwijk LME, Zheng L, Rivadeneira F, Baskaran M, van der Lee SJ, Perera S, de Jong PTVM, Oostra BA, Uitterlinden AG, Fan Q, Hofman A, Tai E-S, Vingerling JR, Sim X, Wolfs RCW, Teo YY, Lemij HG, Khor CC, Willemsen R, Lackner KJ, Aung T, Jansonius NM, Montgomery G, Wild PS, Young TL, Burdon KP, Hysi PG, Pasquale LR, Wong TY, Klaver CCW, Hewitt AW, Jonas JB, Mitchell P, Lotery AJ, Foster PJ, Vitart V, Pfeiffer N, Craig JE, Mackey DA, Hammond CJ, Wiggs JL, Cheng C-Y, van Duijn CM, Macgregor S. New insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics. Hum Mol Genet 2017;Abstract

Primary open-angle glaucoma (POAG), the most common optic neuropathy, is a heritable disease. Siblings of POAG cases have a ten-fold increase risk of developing the disease. Intraocular pressure (IOP) and optic nerve head characteristics are used clinically to predict POAG risk. We conducted a genome-wide association meta-analysis of IOP and optic disc parameters and validated our findings in multiple sets of POAG cases and controls. Using imputation to the 1000 genomes (1000G) reference set, we identified 9 new genomic regions associated with vertical cup disc ratio (VCDR) and 1 new region associated with IOP. Additionally, we found 5 novel loci for optic nerve cup area and 6 for disc area. Previously it was assumed that genetic variation influenced POAG either through IOP or via changes to the optic nerve head; here we present evidence that some genomic regions affect both IOP and the disc parameters. We characterized the effect of the novel loci through pathway analysis and found that pathways involved are not entirely distinct as assumed so far. Further, we identified a novel association between CDKN1A and POAG. Using a zebrafish model we show that six6b (associated with POAG and optic nerve head variation) alters the expression of cdkn1a In summary, we have identified several novel genes influencing the major clinical risk predictors of POAG and showed that genetic variation in CDKN1A is important in POAG risk.

Simavli H, Poon LY-C, Que CJ, Liu Y, Akduman M, Tsikata E, de Boer JF, Chen TC. Diagnostic Capability of Peripapillary Retinal Volume Measurements in Glaucoma. J Glaucoma 2017;26(6):592-601.Abstract
PURPOSE: To determine the diagnostic capability of spectral domain optical coherence tomography peripapillary retinal volume (RV) measurements. MATERIALS AND METHODS: A total of 156 patients, 89 primary open-angle glaucoma and 67 normal subjects, were recruited. Spectral domain optical coherence tomography peripapillary RV was calculated for 4 quadrants using 3 annuli of varying scan circle diameters: outer circumpapillary annuli of circular grids 1, 2, and 3 (OCA1, OCA2, OCA3). Area under the receiver operating characteristic curves and pairwise comparisons of receiver operating characteristic (ROC) curves were performed to determine which quadrants were best for diagnosing primary open-angle glaucoma. The pairwise comparisons of the best ROC curves for RV and retinal nerve fiber layer (RNFL) were performed. The artifact rates were analyzed. RESULTS: Pairwise comparisons showed that the smaller annuli OCA1 and OCA2 had better diagnostic performance than the largest annulus OCA3 (P<0.05 for all quadrants). OCA1 and OCA2 had similar diagnostic performance, except for the inferior quadrant which was better for OCA1 (P=0.0033). The pairwise comparisons of the best ROC curves for RV and RNFL were not statistically significant. RV measurements had lower rates of artifacts at 7.4% while RNFL measurements had higher rates at 42.9%. CONCLUSIONS: Peripapillary RV measurements have excellent ability for diagnosing not only glaucoma patients but also a subset of early glaucoma patients. The inferior quadrant of peripapillary annulus OCA1 demonstrated the best diagnostic capability for both glaucoma and early glaucoma. The diagnostic ability of RV is comparable with that of RNFL parameters in glaucoma but with lower artifact rates.