Variability of contour line alignment on sequential images with the Heidelberg Retina Tomograph

•Background: The influence of the contour line alignment software algorithm on the variability of the Heidelberg Retina Tomograph (HRT) parameters remains unclear. •Methods: Nine discrete topographic images were acquired with the HRT from the right eye in six healthy, emmetropic subjects. The variability of topometric data obtained from the same topographic image, analyzed within different samples of images, was evaluated. A total of four mean topographic images was computed for each subject from: all nine discrete images (A), the first six of those images (B), the last six of those nine images (C), and the first three combined with the last three images (D). A contour line was computed on the mean topographic image generated from the nine discrete topographic images (A). This contour line was then applied to the three other mean topographic images (B, C, and D), using the contour line alignment in the HRT software. Subsequently, the contour line on the mean topographic images was applied to each of the discrete members of the particular images subsets used to compute the mean topographic image, and the topometric data for these discrete topographic images was computed successively for each subset. Prior to processing each subset, the contour line on the discrete topographic images was deleted. This strategy provided a total of three analyses on each discrete topographic image: as a member of the nine images (mean topographic image A), and as a member of two subsets of images (mean topographic image B, C, and/or D). The coefficient of variation (100×SD/mean) of the topographic parameters within those three analyses was calculated for each discrete topographic image in each subject ("intraimage” coefficient of variation). In addition, a coefficient of variation between the nine discrete topographic images ("interimage” coefficient of variation) was calculated. •Results: The "intraimage” and "interimage” variability for the various topographic parameters ranged between 0.03% and 3.10% and between 0.03% and 24.07% respectively. The "intraimage” coefficients of variation and "interimage” coefficients of variation correlated significant (r 2=0.77;P<0.0001). •Conclusion: A high "intraimage” variability, i.e. a high variability in contour line alignment between sequential images, might be an important source of test re-test variability between sequential image

Retinal vascular diameter in young subjects with a vasospastic propensity

Purpose: Retinal vascular diameters have recently been shown not to be related to an increased risk of open-angle glaucoma. Because vasospastic propensity has been suggested to represent a risk factor for various ocular diseases, especially glaucoma, the steady-state retinal vascular diameter in subjects with a propensity for systemic vascular dysregulation was compared with a group of age-matched gender-matched controls. Methods: Thirty healthy non-smoking individuals [female/male 26/4; mean±SD age 22.8±3.4 (range 18-31) years] were enrolled into the study. Subjects were classified as having vasospasm (15 subjects) if they related a clear history of frequently cold hands and as healthy subjects (15 subjects) if they denied such a history. Vasospastic propensity or the absence of it had to be confirmed by nail-fold capillaroscopy. Vascular diameter of retinal vessels was measured repeatedly on two days with the retinal vessel analyser and corrected for perfusion pressure, age, and refraction. Results: Neither retinal arteriole diameter (P=0.30) or retinal venule diameter (P=0.49), nor retinal arteriole-to-venule ratio (P=0.96), differed between the two experimental groups. Conclusions: Although vasospastic propensity has been suggested to represent a risk factor in various ocular diseases, the steady-state retinal vessel diameters are not altered in healthy vasospastic subjects. It is probable that the steady-state retinal vessel diameters are no adequate risk indicators for the haemodynamic risk in diseases such as glaucom

Vasospastic individuals demonstrate significant similarity to glaucoma patients as revealed by gene expression profiling in circulating leukocytes

PURPOSE: There is growing evidence that vasospatic individuals could be predisposed to develop glaucoma. Vasospastic deregulation is ensuing in activation of circulating leukocytes. In previous studies using "gene-hunting" strategies, we demonstrated stable alterations in gene expression profiles of circulating leukocytes isolated from glaucoma patients with vascular deregulation when compared to healthy individuals with no history of glaucomatous damage. The goal of this study was to look for possible similarities in gene expression profiles of circulating leukocytes in vasospastic individuals and glaucoma patients. METHODS: Normal-tension (NTG) and high-tension (HTG) glaucoma patients as well as individuals with vascular deregulation (VD) and healthy controls were recruited for the gene expression analysis. The methodology of comparative Expression Array analysis followed by highly sensitive quantitative real-time PCR has been used. RESULTS: Compared to the control group the expression of 146, 68, and 60 genes was found to be altered in NTG, HTG, and VD groups respectively. Thirty-four genes demonstrated similar expressional alterations in NTG, HTG, and VD groups versus controls, and only 21 genes demonstrated similar expressional alterations in NTG and HTG groups, having no overlap with the VD group. CONCLUSIONS: This result indicates a potential predisposition of vasospastic individuals to glaucomatous optic nerve atrophy. The targeted expression profiles might be further considered for early/predictive glaucoma diagnosis

Circulatory response to blood gas pertubations

PURPOSE. To investigate the response of the optic nerve head and the choroidal circulation to blood gas perturbations in otherwise healthy subjects with a history of cold hands. METHODS. Thirty-five healthy subjects were selected and grouped according to the related history of cold hands. All 12 selected male subjects, aged 21 to 38 years (mean Ϯ SD ϭ 28 Ϯ 5.2 years) had a negative history of cold hands. Female subjects were almost equally divided between the groups with a negative (11 subjects, aged 18 -36 years; mean, 25.7 Ϯ 5.5) or positive (12 subjects, aged 19 -45 years; mean, 25 Ϯ 6.8) history of cold hands. Blood gas perturbations were created by having subjects breath a gas mixture consisting of 21% O 2 , 74% N 2 , and 5% CO 2 . The partial pressures pCO 2 and pO 2 were continuously monitored transcutaneously. Choroidal and optic nerve head blood flow response was evaluated by means of laser Doppler flowmetry. RESULTS. Systolic and diastolic blood pressure (SBP/DBP at baseline, three-group average: 111.2/71.9 mm Hg), heart rate (HR; 70.3 bpm), and intraocular pressure (IOP; 14.7 mm Hg) increased during the blood gas perturbation phase (123.1/77.7 mm Hg, 78.5 bpm, and 15.6 mm Hg, respectively) and returned to baseline in the recovery phase (109.9/73.4 mm Hg, 69.5 bpm, and 13.5 mm Hg, respectively). There was no difference between groups (one-way ANOVA of the percentage change from baseline for SBP, P ϭ 0.75; DBP, P ϭ 0.36; HR, P ϭ 0.95; and IOP, P ϭ 0.72). pCO 2 increased from 5.52 to 6.59 kPa and returned to 5.50 kPa. pO 2 increased from 10.64 to 13.12 kPa and returned to 10.73 kPa. Again, there was no difference between groups (one-way ANOVA for the percentage change: pCO 2 , P ϭ 0.17; pO 2 , P ϭ 0.78). In the women with vasospasm, optic nerve head blood flow increased 17.1% and the choroidal blood flow decreased Ϫ3.6%, whereas in the women and men without vasospasm the optic nerve head blood flow decreased Ϫ5.8% and -4.8%, and the choroidal blood flow increased 13.3% and 18.3%, respectively (two-way ANOVA interaction; P ϭ 0.001). CONCLUSIONS. The pCO 2 increase was accompanied by a pO 2 increase. Blood pressure and HR increased comparably in all groups, indicating sympathetic arousal. The women with vasospasm demonstrated an inverse response pattern of choroidal and optic nerve head circulation to blood gas perturbation compared with the women without vasospasm and compared with the men. (Invest Ophthalmol Vis Sci. 2005;46:3288 -3294

Relationship between gender role, anger expression, thermal discomfort and sleep onset latency in women

ABSTRACT: BACKGROUND: Women with thermal discomfort from cold extremities (hands and feet; TDCE) often suffer from prolonged sleep onset latency (SOL). Suppressed anger could contribute to the genesis of both TDCE and prolonged SOL. The aim of the study was to test the hypothesis whether stereotypic feminine gender socialization (SFGS) is related to anger suppression (experienced anger inwards, Anger-In), which in turn could affect TDCE and SOL. METHODS: 148 women, a sub-sample of a larger survey carried out in the Canton Basel-Stadt (Switzerland), sent back detailed postal questionnaires about SOL, TDCE, anger expression (STAXI, state -trait -anger -expression -inventory) and SFGS using a gender power inventory, estimating the degree of gender specific power expression explicitly within women by stereotypic feminine or male attribution. Statistics was performed by path analysis. RESULTS: A significant direct path was found from stereotypic feminine attribution to Anger-In and prolonged SOL. Additionally, a further indirect path from Anger-In via TDCE to SOL was found. In contrast, stereotypic male attribution was not related to Anger-In but was significantly associated with outwardly expressed anger. LIMITATIONS: Self-reported data, retrospective cross-sectional survey, prospective studies are required including physiological measurements. CONCLUSION: Stereotypic feminine gender socialization may play an important determinant for anger suppression, which subsequently can lead to thermal discomfort from cold extremities and prolonged sleep onset latency

Intensity-based Choroidal Registration Using Regularized Block Matching

Detecting and monitoring changes in the human choroid play a crucial role in treating ocular diseases such as myopia. However, reliable segmentation of optical coherence tomography (OCT) images at the choroid-sclera interface (CSI) is notoriously difficult due to poor contrast, signal loss and OCT artefacts. In this paper we present blockwise registration of successive scans to improve stability also during complete loss of the CSI-signal. First, we formulated the problem as minimization of a regularized energy functional. Then, we tested our automated method for piecewise Intensity-based Choroidal rigid Registration using regularized block matching (ICR) on 20 OCT 3D-volume scan-rescan data set pairs. Finally, we used these data set pairs to determine the precision of our method, while the accuracy was determined by comparing our results with those using manually annotated scans

Optical coherence tomography angiography (OCTA) as a new diagnostic tool in uveitis

Background: The broad spectrum of uveitis disorders requires a multimodal imaging approach in the daily practice of an ophthalmologist. As inflammatory conditions, they have in common an alteration in leukocyte migration. In this context, optical coherence tomography angiography (OCTA) might be of great value for diagnosing or following up patients with these disorders. To date, OCTA has rather been used as an additional tool besides the well-established diagnostic imaging tools, but its complementary diagnostic features become increasingly relevant, to follow disease activity and treatment response and for the understanding of pathomechanisms of various uveitis types. This review summarizes the possible applications of OCTA and its advantages and disadvantages as opposed to dye-based angiographies in uveitic diseases. Main body: Hitherto gold standards in the diagnostic workup of posterior or intermediate uveitis have been angiography on a dye-based method, which is fluorescein or indocyanine green. It gives information about the status of the blood-retinal barrier and the retinal and choroidal vasculature by visualizing diffuse leakage as a state of inflammation or complications as an ischemia or choroidal neovascularization. As noninvasive methods, fundus autofluorescence depicts the status of metabolic activity of the retinal pigment epithelium and OCT or enhanced depth imaging OCT, respectively, as a depth-resolving imaging method can supply additional information. OCTA as a non-invasive, depth-resolution imaging tool of retinal and choroidal vessels adds detailed qualitative and quantitative information of the status of retinal and choroidal vessels and bridges the gap between the mentioned conventional diagnostic tools used in uveitis. It is important, though, to be aware of its limitations, such as its susceptibility to motion artifacts, limited comparability among different devices, and restricted contribution of information regarding the grade of disease activity. Conclusion: OCTA as a non-invasive, depth-resolution imaging tool can give qualitative and quantitative information about the status of retinal and choroidal vessels, but also has certain limitations. Employing OCTA as a complementary rather than exclusive tool, it can give important additional information about the macro- and microvasculature under inflammatory circumstances. Thereby, it also contributes to the understanding of the pathophysiology of various uveitis entities

Thermal discomfort with cold extremities in relation to age, gender, and body mass index in a random sample of a Swiss urban population

<p>Abstract</p> <p>Background</p> <p>The aim of this epidemiological study was to investigate the relationship of thermal discomfort with cold extremities (TDCE) to age, gender, and body mass index (BMI) in a Swiss urban population.</p> <p>Methods</p> <p>In a random population sample of Basel city, 2,800 subjects aged 20-40 years were asked to complete a questionnaire evaluating the extent of cold extremities. Values of cold extremities were based on questionnaire-derived scores. The correlation of age, gender, and BMI to TDCE was analyzed using multiple regression analysis.</p> <p>Results</p> <p>A total of 1,001 women (72.3% response rate) and 809 men (60% response rate) returned a completed questionnaire. Statistical analyses revealed the following findings: Younger subjects suffered more intensely from cold extremities than the elderly, and women suffered more than men (particularly younger women). Slimmer subjects suffered significantly more often from cold extremities than subjects with higher BMIs.</p> <p>Conclusions</p> <p>Thermal discomfort with cold extremities (a relevant symptom of primary vascular dysregulation) occurs at highest intensity in younger, slimmer women and at lowest intensity in elderly, stouter men.</p

Phase relationship between skin temperature and sleep-wake rhythms in women with vascular dysregulation and controls under real-life conditions

The aim of the study was to investigate whether women with primary vascular dysregulation (VD; main symptoms of thermal discomfort with cold extremities) and difficulties initiating sleep (DIS) exhibit a disturbed phase of entrainment ( ) under everyday life conditions. The authors predicted a phase delay of the distal-proximal skin temperature gradient and salivary melatonin rhythms with respect to the sleep-wake cycle in women with VD and DIS (WVD) compared to controls (CON), similar to that found in their previous constant-routine laboratory data. A total of 41 young healthy women, 20 with WVD and 21 matched CON without VD and normal sleep onset latency (SOL), were investigated under ambulatory conditions (following their habitual bedtimes) during 7 days of continuous recording of skin temperatures, sleep-wake cycles monitored by actimetry and sleep-wake diaries, and single evening saliva collections for determining the circadian marker of dim light melatonin onset (DLMO). Compared to CON, WVD showed increased distal vasoconstriction at midday and in the evening, as indicated by lower distal (DIST; hands and feet) and foot-calf skin temperatures, and distal-proximal skin temperature gradients (p> .05). WVD manifested distal vasoconstriction before lights-off that also lasted longer after lights-off than in CON. In parallel, WVD exhibited a longer SOL (p> .05). To define internal phase-relationships, cross-correlation analyses were performed using diurnal rhythms of wrist activity and foot skin temperature. WVD showed a phase delay in foot skin temperature (CON versus WVD: 3.57 ± 17.28 min versus 38.50 ± 16.65 min; p> .05) but not in wrist activity. This finding was validated by additional within-subject cross-correlation analyses using the diurnal wrist activity pattern as reference. DLMO and habitual sleep times did not differ between CON and WVD. The authors conclude that WVD exhibit a phase delay of distal vasodilatation with respect to their habitual sleep-wake cycle and other circadian phase markers, such as DLMO. A full factorial design will have to show whether the finding is specific to primary vascular dysregulation, to DIS, or to their interaction