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Dew points have been measured for eight ethane + carbon dioxide + water + methanol mixtures at pressures from 0.11 to 2.17 MPa and temperatures from 249.0 to 288.7 K. The results are analysed in terms of a predictive excess-function equation of state (EF-EOS) method based on the zeroth approximation of Guggenheim's reticular model. This method can be used to adequately predict the dew points of the mixtures in the temperature and pressure ranges used in the present study. In fact, the model reproduces the experimental dew point temperature data with [less than or equal to] 3.1 K average absolute deviation. Key words: dew point, equation of state, excess function.

Objectives: To evaluate visual dysfunction and its correlation with structural changes in the retina in patients with Parkinson's disease (PD). Methods: Patients with PD (n=37) and controls (n=37) were included in an observational crosssectional study, and underwent visual acuity (VA), colour vision (using the Farnsworth and Lanthony desaturated D15 colour tests) and contrast sensitivity vision (CSV; using the Pelli-Robson chart and CSV 1000E test) evaluation to measure visual dysfunction. Structural measurements of the retinal nerve fibre layer (RNFL), and macular and ganglion cell layer (GCL) thicknesses, were obtained using spectral domain optical coherence tomography (SD-OCT). Comparison of obtained data, and correlation analysis between functional and structural results were performed. Results: VA (in all different contrast levels) and all CSV spatial frequencies were significantly worse in patients with PD than in controls. Colour vision was significantly affected based on the Lanthony colour test. Significant GCL loss was observed in the minimum GCL+inner plexiform layer. A clear tendency towards a reduction in several macular sectors (central, outer inferior, outer temporal and superior (inner and outer)) and in the temporal quadrant of the RNFL thickness was observed, although the difference was not significant. CSV was the functional parameter most strongly correlated with structural measurements in PD. Colour vision was associated with most GCL measurements. Macular thickness was strongly correlated with macular volume and functional parameters (r>0.70, p<0.05). Conclusions: Patients with PD had visual dysfunction that correlated with structural changes evaluated by SD-OCT. GCL measurements may be reliable indicators of visual impairment in patients with PD. [ABSTRACT FROM AUTHOR]

BackgroundTo evaluate and compare the ability of two Fourier-domain optical coherence tomography (OCT) devices to detect retinal and retinal nerve fibre layer (RNFL) atrophy in patients with Alzheimer's disease (AD) compared with healthy subjects; to test the intra-session reliability of two OCT devices in AD patients and healthy subjects.MethodsAD patients (n=75) and age-matched healthy subjects (n=75) underwent three Macular Cube 200 × 200 protocols using the Cirrus and Spectralis OCT devices and three 360° circular scans centred on the optic disc using the Cirrus OCT device, the classic glaucoma application, and the new Nsite Axonal Analytics application of the Spectralis OCT instrument. Differences between healthy and AD eyes were compared, and measurements provided by each OCT protocol were compared. Reliability was measured using intraclass correlation coefficients and coefficients of variation. Correlations between OCT measurements and disease duration and severity were also analysed.ResultsRetinal thinning was observed in AD eyes in all areas except the fovea using both OCT devices. RNFL atrophy was detected in AD eyes with all three protocols, but the Nsite Axonal application was the most sensitive. Measurements by the two OCT devices were correlated, but differed significantly. Reliability was good using all protocols, but better with the glaucoma application of Spectralis. Mean RNFL thickness provided by the Nsite Axonal application correlated with disease duration.ConclusionsFourier-domain OCT is a valid and reliable technique for detecting subclinical RNFL and retinal atrophy in AD, especially using the Nsite Axonal application. RNFL thickness decreased with disease duration. [ABSTRACT FROM AUTHOR]

PurposeTo demonstrate axonal loss in the retinal nerve fiber layer (RNFL) of patients with Parkinson's disease (PD) and to evaluate the ability of Fourier-domain optical coherence tomography (OCT) to detect RNFL degeneration and retinal thinning in these patients.MethodsPD patients (n=100) and healthy subjects (n=100) were included in the study and underwent visual acuity, color vision, and OCT examinations using two next-generation Fourier-domain devices (Spectralis and Cirrus). Differences in the RNFL thicknesses were compared between patients and controls.ResultsRNFL thicknesses were significantly reduced in PD patients compared with healthy subjects, especially those obtained using the Spectralis OCT, in the inferotemporal quadrant (155.6±16.5 μm in healthy eyes vs 142.1±24.9 μm in patients, P=0.040) and in the superotemporal quadrant (142.6±20.9 μm in healthy eyes vs 132.77±18.6 μm in PD patients, P=0.046). Significant differences were observed between controls and patients in relation to mean macular thickness (P=0.031), foveal thickness (P=0.030), and inferior outer thickness (P=0.019).ConclusionPD is associated with RNFL loss and retinal thinning, which is detectable by Fourier-domain OCT measurements. [ABSTRACT FROM AUTHOR]

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The preforming of interlock reinforcement is analysed in the present paper. Interlocks are 3D textile reinforcements that prevent the delamination that can occur in the case of laminate composites. A 3D semi-discrete finite element that allows to model the deformation of an interlock perform is described. Each three-dimensional element contains some fibres that contribute to the element stiffness. The material parameters are identified from mechanical tests and the simulation is validated by comparison with experiment. [ABSTRACT FROM AUTHOR]

Purpose To test the diagnostic ability of optical coherence tomography (OCT) for the detection of Parkinson's disease (PD). Retinal thickness depends in part on the retinal pigment epithelium, one of the principal tissues producing levodopa. Methods PD patients (n=111) and healthy subjects (n=200) were enrolled. The Axonal application of the Spectralis OCT was used to obtain the circumpapillary RNFL thickness and retinal measurements in each participant. Two linear discriminant functions (LDF) were developed, one using RNFL parameters and another LDF using retinal thickness. A validating set (120 eyes from healthy individuals and 66 eyes from PD patients) was used to test the performance of both LDFs in an independent population. Receiver operating characteristic (ROC) curves were plotted and compared between both LDFs and with the standard parameters provided by OCT. Sensitivity and specificity were used to evaluate diagnostic performance. Results The Retinal LDF combines only retinal parameters and provided the best performance: 31.1 + 0.02 x Temporal Outer ‐ 0.2 x Superior Outer + 0.16 x Nasal Outer ‐ 0.2 x Inferior Outer ‐ 0.06 x Superior Inner + 0.05 x Foveal thickness. The largest areas under ROC curve were 0.902 for Retinal LDF and 0.845 for RNFL LDF. At 95% fixed specificity, the Retinal LDF yielded the highest sensitivity values. Conclusion Measurements of retinal thickness obtained with Spectralis OCT had a very good ability to differentiate between healthy and PD individuals. Based on the area under the ROC curve, the Retinal LDF performed better than any single parameter or diagnostic test used for PD. [ABSTRACT FROM AUTHOR]

Purpose To represent and interpret the three‐dimensional geometry and distribution of the axonal damage to the retinal nerve fiber layer (RNFL) in patients with multiple sclerosis (MS) compared with healthy subjects. To analyze alterations in RNFL morphology in eyes of MS patients with or without previous episodes of optic neuritis (ON). Methods MS patients (n=122) and age‐matched healthy subjects (n=108) were enrolled in this observational cross‐sectional study. The Spectralis OCT system (Heidelberg Engineering) was used to determine the circumpapillary RNFL thickness in both eyes of each participant. The 768 RNFL thickness measurements provided by the Spectralis OCT were used to evaluate thickness measurements in MS patients with or without antecedent ON and to design a three‐dimensional reconstruction of the RNFL thickness representing the mechanobiologic tissue response to neurodegeneration caused by MS and ON episodes. Results RNFL thickness was decreased in MS patients, and higher in the MS group with previous ON. Statistical analysis and three‐dimensional RNFL reconstruction revealed greater damage to the ganglionar cells in the superonasal RNFL area in MS eyes (101.77 µm in MS vs 125.47 µm in healthy subjects) and in the inferotemporal RNFL (119.05 µm in healthy eyes vs. 149.26 previous‐ON MS eyes) in MS eyes with previous ON. Conclusion The three‐dimensional representation of RNFL thickness based on measurements provided by the Spectralis OCT allows physicians to better observe damage in the temporal areas, especially in patients with previous ON. [ABSTRACT FROM AUTHOR]

Purpose To assess the utility in clinical practice of anterior segment optical coherence tomography (OCT) in glaucoma surgery. Methods Consecutive cases review of patients diagnosed of primary open angle glaucoma, closure angle glaucoma, pseudoexfoliative glaucoma. Anterior segment 5 Line Raster OCT protocol (Cirrus HD –Spectral Domain Technology) was performed to evaluate the follow‐up of glaucoma surgeries (trabeculectomy and drainage devices) of these patients. Results Anterior segment OCT achieved a correct display of the angle anatomy after surgery. About glaucoma surgery images, it showed a correct display of structures in superficial sclera. However, it showed limitations at the evaluation of structures in deep sclera: space under sclera flap and exact location of the trabecular drainage. Conclusion Anterior segment OCT is a tool of in vivo diagnostic, that achieves an objective anterior segment evaluation in glaucomatous eyes after surgery. This device shows limitations at the evaluation of deep sclera. However, anterior segment OCT provides clinical information about glaucoma post‐surgical anatomy and its functionality. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the agreement between the Moorfields regression analysis classification (MRA) of the Heidelberg retina Tomograph 3 (HRT3; Heidelberg Engineering, Heidelberg, Germany) and the functional classification of white‐on‐white Heidelberg Edge Perimetry (HEP, Heidelberg Engineering). Methods Fifty‐seven normal subjects and 89 age‐matched glaucoma subjects were selected.Only one eye per subject was randomly included in the statistical analysis. All glaucoma patients had an intraocular pressure higher than 21 mmHg and abnormal Humphrey visual fields. The glaucoma group was divided into three subsets, according to the subject's level of visual field loss (Hodapp‐Parrish‐Anderson score). All participants underwent a comprehensive ophthalmic examination, at least a reliable Humphrey perimetry, at least a reliable HEP and imaging with the HRT3. The agreement between color‐coded classifications of both, MRA and HEP, was calculated for each sector of the optic nerve head: nasal‐superior Results Mean age was 52.9 ± 9.5 years in the control group and 55.5 ± 9.7 years in the glaucoma group (p=0.104). In the control group, the best agreement was found for NI sector (100%), while the worst agreement was observed for TI sector (93%). Patients with mild glaucoma (n=59) had the best agreement at NS sector (79.7%) while patients with moderate glaucoma (n=18) had the best agreement at NS, TS and TI sectors (88.9%), and patients with severe glaucoma (n=12) had the best agreement at NS, TS, TI and T sectors (83.3%). Conclusion In general, MRA and functional classification of HEP showed moderate to good agreement. The best agreement between both classifications was observed in healthy and patients with mild glaucoma. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the peripapillary retinal nerve fiber layer (RNFL) thickness obtained with spectral‐domain optical coherence tomography (OCT) in obstructive sleep apnea syndrome (OSA) patients, as a biological marker of neuronal damage. Methods Sixty‐four OSA patients and one hundred twenty‐nine healthy controls were prospectively selected. Only one eye per subject was randomly chosen. AOS patients were classified in three groups according to apnea/hipopnea index: mild, moderate and severe. All participants had intraocular pressure less than 21 mmHg and performed at least a reliable standard automated perimetry (SAP). Peripapillary RNFL thicknesses were measured with Cirrus OCT (Carl Zeiss Meditec, Dublin, Ca). After checking for a normal distribution of variables, differences between both groups were tested by Student t test. Results Age was 50.6 ± 9.3 years in control eyes and 47.8 ± 11.5 years in AOS patients (p = 0.09). Mean deviation of SAP was ‐0.50 ± 1.0 dB and ‐1.4± 2.3 dB, in control and AOS patients, respectively (p<0.001). Pattern standard deviation and Visual Field Index (VFI) of SAP were also different between both groups. The RNFL thickness at 7 o'clock position and the average RNFL thickness had lower thicknesses in AOS patients compared to healthy individuals Conclusion OCT detected a mild reduction of RNFL thickness in AOS patients compared with healthy subjects. Visual field indices were also different between both groups. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the relationship of retinal nerve fiber layer (RNFL) thicknesses obtained with two different optical coherence tomography (OCT) systems, time‐domain OCT (Stratus; Carl Zeiss Meditec, Dublin, Ca) and spectral‐domain OCT (Cirrus; Carl Zeiss Meditec), in healthy and glaucomatous eyes. Methods Seventy healthy and 71 glaucoma individuals were prospective and consecutively selected. Only one eye per subject was included in the study. Glaucoma patients had intraocular pressure higher than 21 mmHg and abnormal standard automated perimetry (SAP). All participants underwent a comprehensive ophthalmic examination and at least 2 reliable SAPs. Peripapillary RNFL measurements were acquired with 2 different OCT systems (Stratus and Cirrus OCTs). Kolmogorov‐Smirnov test was applied to check normality of variables. Then, Pearson´s correlations were calculated between parameters of both OCTs in the healthy and glaucoma groups. Results Mean age was 56.1 ± 12.1 and 62.2 ± 9.1 years in the healthy and glaucoma groups, respectively (p=0.07). Moderate to strong correlations were observed between equivalent parameters of both devices. The strongest correlations were found for average RNFL thickness (r=0.928; p<0.001) and RNFL thickness at inferior quadrant (r=0.925; P<0.001) in the glaucoma group. The RNFL thickness at 3 o'clock position showed the mildest correlation (r=0.435; p<0.001) in the healthy group. Conclusion Although RNFL parameters cannot be interchanged between both devices, the RNFL measurements of time‐ and spectral‐domain OCTs had strong correlations in glaucoma patients. [ABSTRACT FROM AUTHOR]

Purpose To determine the relationship between retinal nerve fiber layer (RNFL) thickness measured with spectral‐domain optical coherence tomography (OCT) and the retinal sensitivity tested by standard automated perimetry (SAP). Methods Two hundred and five subjects (100 healthy and 105 with different levels of glaucomatous damage subjects) were prospective and consecutively recruited. Only one eye per participant was randomly chosen. Glaucoma patients had intraocular pressure higher than 21 mmHg and glaucomatous optic disc appearance. All of them underwent imaging with the Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany) and at least one reliable perimetry. SAPs were performed with a Humphrey Field Analyzer, using the 24‐2 SITA Standard strategy. Left eye data were converted to a right eye format. The Kolmogorov Smirnov test was applied to check that the data were normally distributed. Threshold values of SAP were converted to a linear scale. Pearson correlations were calculated between the 52 threshold values tested by 24‐2 algorithm of SAP and OCT parameters Results Age was not different between both groups (p=0.09). In the whole sample, the strongest correlation was found between point 15 of SAP and RNFL thickness at inferior quadrant (r=0.670; p<0.001). The healthy group showed few and mild correlations. In the glaucoma group, the strongest correlation was also found between point 15 of SAP and inferior RNFL thickness at inferior quadrant (0.664; p<0.001). Conclusion Normal individuals had mild correlations between few functional and structural parameters, while glaucoma patients showed mild to moderate correlations. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the relationship between Standard Automated Perimetry (SAP) performed with Humphrey perimeter (Carl Zeiss Meditec, EEUU) and a new white‐white perimetry tested with Heidelberg Edge Perimeter (HEP, Heidelberg Engineering, Alemania). Methods Fourty‐three subjects (healthy and with different levels of glaucomatous damage subjects) were prospectively and consecutively selected. Only one eye per subject was included in the study. All of them underwent at least one reliable perimetry with each device. 24‐2 SITA standard was used with Humphrey perimeter and 24‐2 ASTA standard algorithm was tested with HEP in all subjects. After checking the normal values of variables by Kolmogorov‐Smirnov test, Pearson's correlation coefficients were calculated between global indices of both devices: mean deviation (MD), pattern standard deviation (PSD) and visual field index (VFI). Results Mean age was of 58.41±12.4 years. Subjects had mean IOP values of 18.24±3.6 mmHg. No differences were found in mean MD values (p=0.127): ‐2.82±4.8 dB and ‐1.54±2.6 dB between Humphrey and HEP, respectively. No differences were found in mean PSD values (p=0.290) between Humphrey (3.11±3.1) and HEP (2.52±1.9). The strongest correlations were observed between PSDs (0.788; p<0.001) and between PSD with HEP and VFI (‐0.711; p<0.001). Conclusion Both perimetries showed a good correlation between their indices. HEP tends to present MD and PSD values lower than Humphrey. Further studies are required to assess the clinical usefulness of HEP. [ABSTRACT FROM AUTHOR]

Purpose To compare the main indices of flicker FDF perimetry (FDF, Heidelberg Engineering, Germany) with standard automated perimetry (SAP). Methods Twenty healthy subjects and twenty‐three glaucoma patients were prospectively and consecutively selected. Glaucomatous patients had an intraocular pressure higher than 21 mmHg and glaucomatous optic disc appearance. All of them underwent at least one reliable perimetry with each device. SAPs were performed with a FDF perimeter (24‐2 ASTA‐Standard test) and Humphrey perimeter (Carl Zeiss (24‐2 SITA standard algorithm). The Kolmogorov Smirnov test was applied to check that the data were normally distributed. Only one eye per subject was included in the study. Pearson correlations were calculated between both devices : mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI). Results Mean age was 58.41±12,4 years. MD of SAP was ‐2.82 ± 4.8 dB, and MD of FDF was ‐4.47 ± 4.8 dB (p=0.123); PSD of SAP was 3.11 ± 3.1, and PSD of FDF was 3.14 ± 1.4 (p = 0.953). The correlations between MDs were 0.521 (p<0.001) and between PSDs were 0.350 (p<0.001) Conclusion Moderate correlations were found between main visual field indices both devices. Altough no differences were found, FDF tends to present MD values lower than Humphrey. [ABSTRACT FROM AUTHOR]

Purpose To compare the results obtained between Humphrey Perimeter (Carl Zeiss Meditec, EEUU) and Heidelberg Edge Perimeter (HEP, Heidelberg Engineering, Alemania) tested in a group of glaucomatous patients. Methods A total of 23 eyes of 23 glaucomatous patients were prospectively and consecutively selected. All of them had basal IOP values higher than 20 mmHg and glaucomatous optic nerve head. They were examined with Standard Automated Perimetry (SAP) using 24‐2 SITA standard and HEP perimetry using 24‐2 ASTA standard algorithm. They performed at least one reliable perimetry with each device. Spearman's correlation coefficients were calculated between global indices of both devices: mean deviation (MD), pattern standard deviation (PSD) and visual field index (VFI). Results Mean age was of 65.07±8.67 years. Subjects had mean IOP values of 24.43±1.90 mmHg. The mean MD values were ‐6.73±6.23 and ‐2.89±3.26 measured with Humphrey and HEP perimeters respectively. And the mean PSD values were 6.07±3.62 and 3.80±2.45 measured with Humphrey and HEP perimeters respectively. The strongest correlations were observed between MDs (0.683; p=0.001) and between PSDs (0.619; p=0.003). Conclusion Humphrey and HEP perimeter correlated well in some global values. Further studies are required to evaluate the clinical usefulness of HEP perimeter in glaucoma patients. [ABSTRACT FROM AUTHOR]