Repeatability of nerve fiber layer thickness measurements in patients with glaucoma and without glaucoma using spectral-domain and time-domain OCT

Background: The aim of this work is to assess the repeatability of spectral-domain-OCT (SD-OCT) retinal nerve fiber layer thickness (RNFL) thickness measurements in a non-glaucoma group and patients with glaucoma and to compare these results to conventional time-domain-OCT (TD-OCT). Methods: In a prospective, comparative, observational case-control study, 50 eyes of 25 non-glaucoma and 22 eyes of 11 patients with primary open angle glaucoma (POAG) were included. SD-OCT and TD-OCT circle scans were centered on the optic disc. In each eye, OCT scans were performed three times by two independent observers. RNFL thickness was measured in four quadrants around the optic disc. In addition, the overall mean RNFL thickness was assessed. Intraclass correlation coefficients (ICC) and coefficients of variation (COV) were calculated. Inter-observer and inter-OCT repeatability was visualized by using Bland-Altman analysis. Results: Intra-observer repeatability for TD- OCT was good with an ICCmean RNFL thickness of 0.939 in non-glaucomas and 0.980 in glaucomatous eyes. For SD-OCT, intra-observer repeatability was higher with an ICC of 0.989 for non-glaucomas and 0.997 for glaucomatous eyes. COVs for TD-OCT ranged from 2.9-7.7% in non-glaucomas and from 6.0-13.3% in glaucoma patients. COVs for SD-OCT ranged from 0.3-1% in non-glaucomas and from 0.9-2.3% in glaucomatous eyes. COVs were influenced by various factors. In the glaucoma group, COVs were significantly higher (p < 0.001) compared to the non-glaucoma group. COVs increased by a mean of 5.1% when TD-OCT was used instead of SD-OCT (p < 0.001). Conclusions: SD-OCT RNFL thickness measurements in healthy volunteers and glaucoma patients showed good intra- and inter-observer repeatability. Especially in glaucomatous eyes, repeatability of SD-OCT was superior to TD-OC

Reproducibility of Nerve Fiber Layer Thickness Measurements Using 3D Fourier-Domain OCT

PURPOSE. Conventional time-domain optical coherence tomography (OCT) has been shown to provide reproducible retinal nerve fiber layer (RNFL) measurements. Recently, high-speed, high-resolution Fourier-domain 3D-OCT has been introduced to improve OCT quality. It can provide 6-mm 2 high-density scans to provide RNFL thickness measurements. The purpose of this study was to test the reproducibility of 3D-OCT RNFL thickness measurements in healthy volunteers. METHODS. Thirty-eight eyes were included in the study. Highdensity 6-mm 2 3D scans were registered by two independent operators. RNFL thickness was calculated for eight areas corresponding to the ETDRS areas and for two ring areas. The ETDRS grid was centered on the optic disc. Intraclass correlation coefficients (ICC) and coefficients of variation (COV) were calculated. Interobserver reproducibility was visualized by using Bland-Altman analysis. RESULTS. Intrasession reproducibility was good with a mean ICC of 0.90. The mean COV for operator 1 and 2 was 4.2% and 4%, respectively (range, 1.9%-6.7%). Highest reproducibility was found for the two ring areas and the superior and inferior quadrants. Mean differences in RNFL thickness measurements for ring 1 and 2 between operator 1 and 2 were 0.9 m (limits of agreement, Ϫ11.4 to ϩ9.6 m) and 0.1 m (limits of agreement Ϫ4.1 to ϩ3.9 m), respectively. CONCLUSIONS. 3D-OCT RNFL thickness measurements in healthy volunteers showed good intra-and interobserver reproducibility. 3D-OCT provides more RNFL thickness information compared to conventional time-domain OCT measurements and may be useful for the management of glaucoma and other optic neuropathies. (Invest Ophthalmol Vis Sci. 2008;49:5386 -5391) DOI:10.1167/iovs.07-1435 E valuation of the retinal nerve fiber layer (RNFL) is fundamental for diagnosing and managing glaucoma and other optic neuropathies. In the past, RNFL could be assessed subjectively only by slit lamp examination. This method requires clinical experience and offers only qualitative data. In addition, comparisons over time are almost impossible. Successively, other techniques such as color photographs of the optic disc or red-free photographs of the RNFL have become available and have facilitated comparisons over time. Scanning laser ophthalmoscopy and scanning laser polarimetry were the first instruments to allow objective and quantitative evaluation of the RNFL and the optic disc. Studies have been conducted to investigate the reproducibility of OCT RNFL thickness measurements, to assess the value of OCT as a clinical tool for distinguishing between healthy and glaucomatous eyes. Recently, improvements in OCT technology have been introduced. 10 -11 Fourier-domain (FD)-OCT provides increased resolution and scanning speed by recording the interferometric information with a Fourier-domain spectrometric method instead of adjusting the position of a reference mirror. Resolution is up to five times higher, and imaging speed is 60 times faster than in conventional time-domain OCT. 12-13 In addition to high image quality, it is important to have reliable and reproducible software programs to analyze the data acquired by FD-OCT. Previous versions of OCT (Stratus OCT3; Carl Zeiss Meditec, GmbH, Oberkochen, Germany) mostly used a 3.4-mm diameter circle scan centered on the optic disc to generate 512 A-scans. The RNFL thickness profile showed a characteristic curve with two peaks, one in the superior and one in the inferior quadrant. FD-OCT can perform a high-density raster-scan (512 ϫ 128 axial B-scans in a 6 mm 2 area). Recently, the peripapillary nerve fiber layer thickness profile was determined with FD-OCT by using high-density scanning. 14 These raster scans provide considerably more data for RNFL thickness analysis. The purpose of this study was to test the reproducibility of RNFL thickness measurements in healthy subjects by using FD-OCT high-density raster scans (3D OCT1000; Topcon, Tokyo, Japan). METHODS Thirty-eight eyes of 19 healthy subjects (10 women) with a mean age of 26 Ϯ 3 years were included in the study. Exclusion criteria were history of glaucoma, history of any other ocular disease, intraocular pressure greater than 21 mm Hg, or a refractive error of more than Ϫ5 or ϩ5 D. FD-OCT high-density scans were performed with the 3D OCT1000 system. The 3D OCT1000 is an FD-OCT device providing OCT images up to 50 times faster than time-domain OCTs with a sweep-scan technique. The device has a field angle of 45°with a color fundus camera included. The scanning range of the device is from 3 to 6 mm 2 . Horizontal resolution is Յ20 m and depth resolution is up to 5 m. As a light source, the system uses superluminescent diodes with a wavelength of 840 nm. Pupil diameter had to be at least 4 mm for scanning. High-density raster scans (512 ϫ 128 B-scans in a 6 mm 2 area) were centered on the From th

Repeatability of nerve fiber layer thickness measurements in patients with glaucoma and without glaucoma using spectral-domain and time-domain OCT

BACKGROUND: The aim of this work is to assess the repeatability of spectral-domain-OCT (SD-OCT) retinal nerve fiber layer thickness (RNFL) thickness measurements in a non-glaucoma group and patients with glaucoma and to compare these results to conventional time-domain-OCT (TD-OCT). METHODS: In a prospective, comparative, observational case-control study, 50 eyes of 25 non-glaucoma and 22 eyes of 11 patients with primary open angle glaucoma (POAG) were included. SD-OCT and TD-OCT circle scans were centered on the optic disc. In each eye, OCT scans were performed three times by two independent observers. RNFL thickness was measured in four quadrants around the optic disc. In addition, the overall mean RNFL thickness was assessed. Intraclass correlation coefficients (ICC) and coefficients of variation (COV) were calculated. Inter-observer and inter-OCT repeatability was visualized by using Bland-Altman analysis. RESULTS: Intra-observer repeatability for TD- OCT was good with an ICC(mean RNFL thickness) of 0.939 in non-glaucomas and 0.980 in glaucomatous eyes. For SD-OCT, intra-observer repeatability was higher with an ICC of 0.989 for non-glaucomas and 0.997 for glaucomatous eyes. COVs for TD-OCT ranged from 2.9-7.7% in non-glaucomas and from 6.0-13.3% in glaucoma patients. COVs for SD-OCT ranged from 0.3-1% in non-glaucomas and from 0.9-2.3% in glaucomatous eyes. COVs were influenced by various factors. In the glaucoma group, COVs were significantly higher (p < 0.001) compared to the non-glaucoma group. COVs increased by a mean of 5.1% when TD-OCT was used instead of SD-OCT (p < 0.001). CONCLUSIONS: SD-OCT RNFL thickness measurements in healthy volunteers and glaucoma patients showed good intra- and inter-observer repeatability. Especially in glaucomatous eyes, repeatability of SD-OCT was superior to TD-OCT

Female ornaments revisited - are they correlated with offspring quality?

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Functional and clinical neuroanatomy of morality

Morality is among the most sophisticated features of human judgement, behaviour and, ultimately, mind. An individual who behaves immorally may violate ethical rules and civil rights, and may threaten others' individual liberty, sometimes becoming violent and aggressive. In recent years, neuroscience has shown a growing interest in human morality, and has advanced our understanding of the cognitive and emotional processes involved in moral decisions, their anatomical substrates and the neurology of abnormal moral behaviour. In this article, we review research findings that have provided a key insight into the functional and clinical neuroanatomy of the brain areas involved in normal and abnormal moral behaviour. The 'moral brain' consists of a large functional network including both cortical and subcortical anatomical structures. Because morality is a complex process, some of these brain structures share their neural circuits with those controlling other behavioural processes, such as emotions and theory of mind. Among the anatomical structures implicated in morality are the frontal, temporal and cingulate cortices. The prefrontal cortex regulates activity in subcortical emotional centres, planning and supervising moral decisions, and when its functionality is altered may lead to impulsive aggression. The temporal lobe is involved in theory of mind and its dysfunction is often implicated in violent psychopathy. The cingulate cortex mediates the conflict between the emotional and the rational components of moral reasoning. Other important structures contributing to moral behaviour include the subcortical nuclei such as the amygdala, hippocampus and basal ganglia. Brain areas participating in moral processing can be influenced also by genetic, endocrine and environmental factors. Hormones can modulate moral behaviour through their effects on the brain. Finally, genetic polymorphisms can predispose to aggressivity and violence, arguing for a genetic-based predisposition to morality. Because abnormal moral behaviour can arise from both functional and structural brain abnormalities that should be diagnosed and treated, the neurology of moral behaviour has potential implications for clinical practice and raises ethical concerns. Last, since research has developed several neuromodulation techniques to improve brain dysfunction (deep brain stimulation, transcranial magnetic stimulation and transcranial direct current stimulation), knowing more about the 'moral brain' might help to develop novel therapeutic strategies for neurologically based abnormal moral behaviou

Synthesising 30 years of mathematical modelling of Echinococcus Transmission

Background: Echinococcosis is a complex zoonosis that has domestic and sylvatic lifecycles, and a range of different intermediate and definitive host species. The complexities of its transmission and the sparse evidence on the effectiveness of control strategies in diverse settings provide significant challenges for the design of effective public health policy against this disease. Mathematical modelling is a useful tool for simulating control packages under locally specific transmission conditions to inform optimal timing and frequency of phased interventions for cost-effective control of echinococcosis. The aims of this review of 30 years of Echinococcus modelling were to discern the epidemiological mechanisms underpinning models of Echinococcus granulosus and E. multilocularis transmission and to establish the need to include a human transmission component in such models