58 research outputs found
Open-angle glaucoma
No full textOpen-angle glaucoma (OAG) is an important cause of irreversible blindness. In OAG, loss of retinal ganglion cells leads to damage of the optic nerve. This causes visual field loss and eventually blindness. Changes in the optic nerve head (ONH) can be examined with confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph [HRT]), scanning laser polarimetry (GDx) or Optical Coherence Tomography (OCT). Important risk factors for OAG are elevated intraocular pressure (IOP), high age, myopia, ethnicity, thin central corneal thickness, and a positive family history for OAG. However, the pathophysiology still remains largely unknown.
In order to improve the diagnosis and learn more about the pathophysiology of this blinding disease, the main objectives of the research described in this thesis were to: 1) address the diagnostic utility of the OCT scan for OAG, 2) elucidate new risk factors for OAG or IOP, 3) identify novel genetic variants associated with OAG or its endophenotypes, and 4) assess the functional consequences of genetic variants associated with OAG. Our study populations included the population-based Rotterdam Study, the Erasmus Rucphen Family (ERF) Study, population-based studies from the European Eye Epidemiology (E3) Consortium and population-based and OAG case-control studies from the International Glaucoma Genetics
Consortium (IGGC)
Age-related macular degeneration and primary open-angle glaucoma: genetics and gene-environment interaction
No full textAge-related macular degeneration and primary open-angle glaucoma: genetics and gene-environment interaction
No full textNew insights into the genetics of primary open-angle glaucoma based on meta-analyses of intraocular pressure and optic disc characteristics
No full textPrimary open-angle glaucoma (POAG), the most common optic neuropathy, is a highly heritable disease (h2 = 0.42 ± 0.09). 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. 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 ris
Age-Related Macular Degeneration and Primary Open-Angle Glaucoma: Genetics and Gene-Environment Interaction
No full textAuthor correction: Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases
No full textEmmanuelle Souzeau, who contributed to analysis of data, was inadvertently omitted from the author list in the originally published version of this Article. This has now been corrected in both the PDF and HTML versions of the Article
Validity of Automated Choroidal Segmentation in SS-OCT and SD-OCT
No full textPURPOSE. To evaluate the validity of a novel fully automated three-dimensional (3D) method capable of segmenting the choroid from two different optical coherence tomography scanners: swept-source OCT (SS-OCT) and spectral-domain OCT (SD-OCT). METHODS. One hundred eight subjects were imaged using SS-OCT and SD-OCT. A 3D method was used to segment the choroid and quantify the choroidal thickness along each A-scan. The segmented choroidal posterior boundary was evaluated by comparing to manual segmentation. Differences were assessed to test the agreement between segmentation results of the same subject. Choroidal thickness was defined as the Euclidian distance between Bruch's membrane and the choroidal posterior boundary, and reproducibility was analyzed using automatically and manually determined choroidal thicknesses. RESULTS. For SS-OCT, the average choroidal thickness of the entire 6- by 6-mm(2) macular region was 219.5 mu m (95% confidence interval [CI], 204.9-234.2 mu m), and for SD-OCT it was 209.5 mu m (95% CI, 197.9-221.0 mu m). The agreement between automated and manual segmentations was high: Average relative difference was less than 5 lm, and average absolute difference was less than 15 lm. Reproducibility of choroidal thickness between repeated SS-OCT scans was high (coefficient of variation [CV] of 3.3%, intraclass correlation coefficient [ICC] of 0.98), and differences between SS-OCT and SD-OCT results were small (CV of 11.0%, ICC of 0.73). CONCLUSIONS. We have developed a fully automated 3D method for segmenting the choroid and quantifying choroidal thickness along each A-scan. The method yielded high validity. Our method can be used reliably to study local choroidal changes and may improve the diagnosis and management of patients with ocular diseases in which the choroid is affected
Optimizing the Information Yield of 3-D OCT in Glaucoma
No full textPURPOSE. To determine, first, which regions of 3-D optical coherence tomography (OCT) volumes can be segmented completely in the majority of subjects and, second, the relationship between analyzed area and thickness measurement test-retest variability. METHODS. Three-dimensional OCT volumes (6X6 mm) centered around the fovea and optic nerve head (ONH) of 925 Rotterdam Study participants were analyzed; 44 participants were scanned twice. Volumes were segmented into 10 layers, and we determined the area where all layers could be identified in at least 95% (macula) or 90% (ONH) of subjects. Macular volumes were divided in 2 x 2, 4 x 4, 6 x 6, 8 x 8, or 68 blocks. We placed two circles around the ONH; the ONH had to fit into the smaller circle, an RESULTS. Eighty-two percent of the macular volume could be segmented in at least 95% of subjects; for the ONH, this was 65% in at least 90%. The radii of the circles were 1.03 and 1.84 mm. Depending on the analyzed area, median test-retest variability ranged from 8% to 15% for macular RNFL, 11% to 22% for macular RGCL, 5% to 11% for the two together, and 18% to 22% for ONH RNFL. CONCLUSIONS. Test-retest variability hampers a detailed analysis of 3-D OCT data. Combined macular RNFL and RGCL thickness averaged over larger areas had the best test-retest variability. (Invest Ophthalmol Vis Sci. 2012; 53: 8162-8171) DOI:10.1167/iovs.12-1055
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