Optic Angle Research Articles

Optico-Chiasmatic Distortions in Pituitary Adenomas: Correlation Between Postoperative Morphological Reversal and Follow-Up Functional Visual Recovery

PurposeTo objectively correlate distortions of optic apparatus morphology in patients with visual outcomes in patients with pituitary adenomas (PAs) undergoing trans-sphenoidal surgery. MethodsIn this retrospective analysis, visual acuity (VA), visual field (VF) and total visual (TV) function was objectively scored in patients selected from an institutional cohort of PAs The following imaging measures of optico-chiasmatic morphology were recorded preoperatively, and at 3 months after surgery: chiasm area (CA), mid-chiasm height (CH), optic nerve-canal bending angle (BA), and optic nerve kinking angle (ONKA). Receiver operator characteristic (ROC) analysis was performed to establish optimal thresholds for achieving a ‘normal’ TV score of 200 at 1-year follow-up. ResultsSeventy-one eyes were individually studied. VA, VF and TV scores significantly improved after surgery, both at the 3-month and at the 1-year follow-up visits (p<0.001). Cranio-caudal tumor dimension was significantly associated with VA, VF and TV scores, both pre- and post-operatively. There were significant changes in CH (p<0.001), BA (p<0.001) and ONKA (p<0.001) at 3 months after surgery, but not in CA (p=0.061). Baseline VA, VF and TVS scores were positively correlated with preoperative CH and ONKA, while VF and TV scores also demonstrated significant negative correlations with preoperative BA. VF scores at 1-year follow-up were significantly correlated with preoperative and change in BA values, as well as with preoperative and change in ONKA values. ROC analysis revealed that only the preoperative ONKA was found to have acceptable discrimination (AUC>0.7) for predicting ‘normal’ TV score. Chiasm sag was noted in 45.8% of patients at one year follow-up, but was not associated with delayed visual deterioration in any case. ConclusionsAnatomic realignment of the optic apparatus 3 months following trans-sphenoidal surgery predicts VF scores, but not VA or TV scores at 1 year follow-up. Patients with preoperative ONKA values of more than 139.3° have a 76% chance of achieving normal TV scores one year after surgery. Postoperative chiasm sag appears to be clinically irrelevant at short term follow-up.

Bobfinchite, Na[(UO2)8O3(OH)11]·10H2O, a new Na-bearing member of the schoepite family

Abstract The new mineral bobfinchite (IMA2020-082), Na[(UO2)8O3(OH)11]·10H2O, was found in the Burro mine, Slick Rock district, San Miguel County, Colorado, U.S.A., where it occurs as an oxidation product of uraninite on asphaltite matrix in intimate association with gypsum, natrozippeite, metaschoepite, and uranopilite. Bobfinchite crystals are transparent to translucent, yellow, lozenge-shaped disks up to 0.3 mm wide. Crystals are flattened on [100] and exhibit the forms {100}, {011}, {021}, {021}, and {011}. Bobfinchite has a pale-yellow streak and emits very dim yellow fluorescence under 365 nm ultraviolet illumination. The crystals are brittle with very good {100} cleavage and irregular, stepped fracture. The Mohs hardness is ca. 2 based on scratch tests. The calculated density is 5.044 g/cm3 based on the empirical formula and 5.036 g/cm3 for the ideal formula. Bobfinchite is optically biaxial (–), with α = 1.690(5), β = 1.7205(5), and γ = 1.730(5) (white light). The measured 2V, estimated from the interference figure, is 55(5)° and the calculated value is 59.1°. Dispersion is moderate, r &amp;gt; v; orientation: X = a, Y = b, Z = c; pleochroism: X nearly colorless, Y yellow, Z yellow; X &amp;lt; Y ≈Z. Electron microprobe analysis provided the empirical formula (Na0.99Pb0.02)[(UO2)7.99O3(OH)11]·10H2O. The five strongest X-ray powder diffraction lines are [dobs in Å(I)(hkl)]: 7.34(100)(200), 3.59(50)(024), 3.23(60)(224), 3.18(36)(240), and 2.01(23)(624,551,208,640,346). Bobfinchite is orthorhombic, Pbcn, a = 14.6249(9), b = 14.0389(10), c = 16.6923(10) Å, V = 3427.2(4) Å3, and Z = 4. The structure of bobfinchite (R1 = 0.0330 for 3770 I &amp;gt; 4σI) is built from uranyl oxide-hydroxide sheets that adopt the fourmarierite topology, with interlayer Na+ and H2O groups. Both the sheet and interlayer topology mimic those observed in natural and synthetic Na-metaschoepites studied previously, and as seen in other uranyl oxide hydrate minerals, charge balance is achieved at specific sites in the sheet through the substitution O2– ↔ (OH)–.

Variation in optic recess angle with optic chiasm position

Background: The position of the optic chiasm relative to surrounding structures is critical in planning surgical interventions for suprasellar lesions. This study explored the relationship between the angle of the optic chiasm and lamina terminalis (OC-LT) and the position of the optic chiasm. Methods: The study comprised 140 individuals who underwent midsagittal and axial MRI-T2 scans. The position of the optic chiasm was classified into three categories: sellar, prefixed, and postfixed. The OC-LT angle was measured in the midsagittal section. Results: The angle between OC-LT varied from 30 to 66 degrees with a mean of 46.6 degrees. The sellar position of the optic chiasm was predominant (85.2%), with smaller angles (30-39 degrees) significantly associated with a sellar chiasm location. Most cases with postfixed optic chiasm fell within a 40-49 degree angle range. Conclusions: The OC-LT angle variability can be linked to the position of the optic chiasm. Predominantly, smaller angles correlated with a sellar position of the optic chiasm, while larger angles were associated with a postfixed optic chiasm. This information is crucial for surgical planning in the suprasellar region.

Breed-Specific Skull Morphology Reveals Insights into Canine Optic Chiasm Positioning and Orbital Structure through 3D CT Scan Analysis.

This study's CT scan-based morphometric analysis of 50 adult dogs explored the relationship between skull shape variations (determined by the skull index, SI), optic chiasm, optic canals, and orbital shape. Dogs were classified as brachycephalic (SI ≥ 59), mesocephalic (SI ≥ 51 but <59), and dolichocephalic (SI < 51). No significant age or weight differences were observed. Skull lengths (brachycephalic: 11.39 ± 1.76 cm, mesocephalic: 15.00 ± 2.96 cm, dolichocephalic: 17.96 ± 3.44 cm) and facial lengths (brachycephalic: 3.63 ± 1.00 cm, mesocephalic: 6.46 ± 1.55 cm, dolichocephalic: 8.23 ± 1.03 cm) varied significantly, with shorter orbital depths (brachycephalic: 2.58 ± 0.42 cm, mesocephalic: 3.19 ± 0.65 cm, dolichocephalic: 3.61 ± 0.77 cm) in brachycephalic dogs. The optic chiasm-to-inion horizontal length ratio to cranial horizontal length positively correlated with the SI (r = 0.883, p < 0.001), while the ratio to neurocranial length showed no SI correlation (range: 55.5-75.0). Brachycephalic breeds had a significantly wider optic canal angle (93.74 ± 16.00°), along with broader lacrimal-zygomatic and zygomatic frontal process angles. These findings highlight the zygomatic bone's role in influencing breed-specific orbital variations by connecting the face to the neurocranium, projecting the orbital rim outward and forward with facial shortening.

Prognostic value of extraocular muscles for intraocular pressure in thyroid-associated ophthalmopathy patients.

Persistent increase in intraocular pressure (IOP) is often observed in eyes with thyroid-associated ophthalmopathy (TAO), which has irreversible effects on the visual function of patients. This retrospective cross-sectional study evaluated the value of magnetic resonance imaging (MRI) measurements of extraocular muscle (EOM) volume in prognosing IOP in patients with TAO. This single-center study was conducted in Beijing Friendship Hospital (Beijing, China), a tertiary hospital. From 35 participants, 70 eyes (normal IOP group: 50 eyes; high IOP group: 20 eyes; random samples) were enrolled in this study. Basic data from patients were collected and compared using 2-sample t-tests and chi-squared tests. The volume of the EOM, orbit fat, and whole orbit were measured by orbital MRI. Moreover, proptosis, optic nerve (ON) sheath diameter, optic nerve angle (ONA), and gaze angle were additionally measured with MRI. These parameters were compared between the two groups using 2-sample t-tests and chi-squared tests. Before and after post-methylprednisolone therapy, the MRI data of 20 eyes were obtained and compared with a paired t-test. Peripapillary retinal nerve fiber layer (RNFL) thickness was obtained using an optical coherence tomography (OCT) scan. Spearman rank correlation analysis, logistic regression analysis, and receiver operating characteristic (ROC) curves were performed to evaluate the role of these factors in IOP changes. The EOM volume and axial and sagittal ONAs in the high-IOP group were significantly increased compared to the normal-IOP group (P<0.001, P=0.001, P=0.02, respectively). Logistic regression analysis indicate that the cutoff value for EOM volume for the diagnosis of high IOP was significantly larger than that of the other parameters except orbit volume (P=0.03, P=0.004, P=0.08, respectively). Spearman correlation analysis revealed a significant correlation between EOM volume and ON sheath diameter and average RNFL thickness (P=0.01, P=0.02, respectively). A paired t-test indicated a significant decrease of EOM volume and ON sheath diameter as well as a significant enlargement of the axial ONAs after methylprednisolone therapy (P=0.002, P=0.02, P=0.05, respectively). EOM volume was an effective diagnostic factor for tracking IOP changes and ON patterns in patients with TAO. Methylprednisolone therapy is recommended for patients with TAO with secondary glaucoma to quickly reduce the EOM volume.

Vaterite Optical Petrography in Lake Sturgeon Otoliths

Abstract Vaterite occurring in fish otoliths exhibits plumose and spherulitic habits, the latter being like those grown from aqueous solutions. Vaterite spherulites are known to have sheaf-like texture and can be up to 100 μm in size. In thin section, the spherulites typically show uniaxial positive interference figures between cross-polarizers using a polarizing light microscope but without conoscopic or Bertrand lenses because the spherulites mimic the effect of these lenses. Plumose vaterite can show both uniaxial (+) and biaxial (+) interference figures with a small 2V, which suggests that crystal structural models for vaterite should have the plane of the carbonate group parallel to the optic axis or acute bisectrix. Vaterite spherulites grown from aqueous solution exhibit similar structure and growth habits.

Artificial intelligence to distinguish retinal vein occlusion patients using color fundus photographs.

Our aim is to establish an AI model for distinguishing color fundus photographs (CFP) of RVO patients from normal individuals. The training dataset included 2013 CFP from fellow eyes of RVO patients and 8536 age- and gender-matched normal CFP. Model performance was assessed in two independent testing datasets. We evaluated the performance of the AI model using the area under the receiver operating characteristic curve (AUC), accuracy, precision, specificity, sensitivity, and confusion matrices. We further explained the probable clinical relevance of the AI by extracting and comparing features of the retinal images. Our model achieved an average AUC was 0.9866 (95% CI: 0.9805-0.9918), accuracy was 0.9534 (95% CI: 0.9421-0.9639), precision was 0.9123 (95% CI: 0.8784-9453), specificity was 0.9810 (95% CI: 0.9729-0.9884), and sensitivity was 0.8367 (95% CI: 0.7953-0.8756) for identifying fundus images of RVO patients in training dataset. In independent external datasets 1, the AUC of the RVO group was 0.8102 (95% CI: 0.7979-0.8226), the accuracy of 0.7752 (95% CI: 0.7633-0.7875), the precision of 0.7041 (95% CI: 0.6873-0.7211), specificity of 0.6499 (95% CI: 0.6305-0.6679) and sensitivity of 0.9124 (95% CI: 0.9004-0.9241) for RVO group. There were significant differences in retinal arteriovenous ratio, optic cup to optic disc ratio, and optic disc tilt angle (p = 0.001, p = 0.0001, and p = 0.0001, respectively) between the two groups in training dataset. We trained an AI model to classify color fundus photographs of RVO patients with stable performance both in internal and external datasets. This may be of great importance for risk prediction in patients with retinal venous occlusion.

A new interpretation of the optical interference figures observed in a lyotropic biaxial nematic phase for a ternary mixture of DTMABr, 1-DDeOH and H2O

The lyotropic ternary mixture of dodecyltrimethylammonium bromide (DTMABr), 1-dodecanol (DDeOH) and water (H2O) was studied by optical conoscopy and Abbe refractometer techniques. The present mixture showed a large biaxial phase domain (NB) located between two different uniaxial ones in the partial phase diagram, one optically positive (ND) and the other negative (NC). The NB phase exhibits two optic signs as a function of the temperature , each of which was equal to the neighboring uniaxial phases. The temperature dependence of the refractive indices was measured along the NC-NB-ND phase transitions. In addition, we are reporting for the first time a new interpretation of the optical interference figures observed along the NB phase.

Comparison of Optic Disc Ovality Index and Rotation Angle Measurements in Myopic Eyes Using Photography and OCT Based Techniques.

PurposeTo compare optic nerve head (ONH) ovality index and rotation angle measurements based on semi-automated delineation of the clinical ONH margin derived from photographs and automated BMO configuration derived from optical coherence tomography (OCT) images in healthy and glaucomatous eyes with high-, mild- and no axial myopia.MethodsOne hundred seventy-five healthy and glaucomatous eyes of 146 study participants enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) with optic disc photographs and Spectralis OCT ONH scans acquired on the same day were stratified by level of axial myopia (non-myopic [n = 56, axial length (AL) <24 mm], mild-myopic [n = 58, AL 24–26 mm] and high-myopic [n = 32, AL >26 mm]. The clinical disc margin of each photograph was manually annotated, and semi-automated measurements were recorded of the ovality index and rotation angle based on a best-fit ellipse generated using ImageJ software. These semi-automated photograph-based measurements were compared to ovality index and rotation angle generated from custom automated BMO-based analysis using segmented OCT ONH volumes. R2 values from linear mixed effects models were used to describe the associations between semi-automated, photograph-based and automated OCT-based measurements.ResultsAverage (95% CI) axial length was 23.3 (23.0, 23.3) mm, 24.8 (24.7, 25.0) mm and 26.8 (26.6, 27.0) mm in non-myopic, mild-myopic and high-myopic eyes, respectively (ANOVA, p ≤ 0.001 for all). The R2 association (95% CI) between semi-automated photograph-based and automated OCT-based assessment of ONH OI for all eyes was [0.26 (0.16, 0.36); p < 0.001]. This association was weakest in non-myopic eyes [0.09 (0.01, 0.26); p = 0.02], followed by mild-myopic eyes [0.13 (0.02, 0.29); p = 0.004] and strongest in high-myopic eyes [0.40 (0.19, 0.60); p < 0.001]. No significant associations were found between photography- and OCT-based assessment of rotation angle with R2 values ranging from 0.00 (0.00, 0.08) in non-myopic eyes to 0.03 (0.00, 0.21) in high-myopic eyes (all associations p ≥ 0.33).ConclusionsAgreement between photograph-based and automated OCT-based ONH morphology measurements is limited, suggesting that these methods cannot be used interchangeably for characterizing myopic changes in the ONH.

Analysis of visual field disturbance in patients with sellar and suprasellar lesions: relationship with magnetic resonance imaging findings and sagittal bending of the optic nerve.

Visual dysfunction due to sellar and suprasellar lesions is thought to be caused by chiasmatic compression and bending of the optic nerve at the entrance of the optic canal. We examined the relationship between visual field impairment and magnetic resonance (MR) imaging. This study reviewed 122 consecutive patients with sellar and suprasellar tumors. We have newly devised a simple visual field impairment score (SVFIS) that was divided into 12 areas. SVFIS is classified into four grades as mild (0-3 points), moderate (4-6 points), severe (7-9 points), and most severe (10-12 points) for each eye. We investigated the relationship between SVFIS grades and MR imaging, including the recently reported optic nerve-canal bending angle (ONCBA) and visual acuity. Ipsilateral visual acuity tended to deteriorate with increased SVFIS grade. Larger ONCBA was associated with increased SVFIS grades. Bitemporal hemianopia occurred in the early stage (mild case), but the central visual field within 30° was particularly likely to be impaired. The visual field disturbance progressed clockwise (counterclockwise on the left side) from the upper temporal side. Disorders of the central visual field within 5° were associated with ipsilateral large ONCBA. The newly developed SVFIS grades are closely associated with indicators of visual pathway impairment on MR imaging, and are useful as indicators of the severity and progression of visual field impairment due to sellar and suprasellar lesions. Disorders of the central visual field within 5° were found to be associated with ipsilateral large ONCBA.

Quantification of an oval optic disc in relation to myopic foveoschisis using swept-source optical coherence tomography

BackgroundTo investigate the relationship between an oval optic disc and the occurrence of myopic foveoschisis (MF) using swept-source optic coherence tomography (SS-OCT).MethodsFifty eyes of 25 patients with unilateral MF were included in this retrospective observational study. The biometric features of the optic disc and peripapillary structures were evaluated using SS-OCT.ResultsThe ovality index (OI) of the optic disc was significantly smaller (P = 0.003) and the optic disc tilt angle was greater (P = 0.023) in the eyes with MF than in the contralateral eyes. The optic disc tilt angle was significantly correlated with the OI (P = 0.000). Generalized estimating equation (GEE) model (linear regression) demonstrated that spherical equivalent refraction (P = 0.001), narrow macular staphyloma (P = 0.001) and the occurrence of MF (P = 0.026) were the independent factors associated with the OI. Narrow macular staphyloma was more frequent (P = 0.020) and the staphyloma was deeper (P = 0.006) in eyes with MF. GEE model (logistic regression) revealed that narrow macular staphyloma was the only independent factor related to the occurrence of MF (P = 0.013).ConclusionsAn oval optic disc in eyes with MF resulted from the increased tilt around the vertical disc axis. The optic disc tilt was related to narrow macular staphyloma, which was the only independent factor associated with the occurrence of MF. The clinical relevance needs further exploration through longitudinal analysis.

The Relationship Between Optic Disc and Retinal Artery Position and Glaucomatous Visual Field Progression

PurposeTo investigate whether retinal structural parameters, including positions of the optic disc and major retinal arteries, affect glaucomatous progression of the visual field (VF).MethodsIn this cohort study, 116 eyes of 73 patients with primary open angle glaucoma (POAG) were included. VFs were measured using the Humphrey Field Analyzer 24-2 program and the VF was divided into seven sectors according to the corresponding optic disc angle. Average total deviation (TD) was calculated in each sector. Positions of major retinal arteries in the superotemporal and inferotemporal areas were decided by identifying the points where the retinal artery intersected the 3.4-mm-diameter circle around the optic disc. The relationship between sectorial TD VF progression rate and eight variables (age, mean and standard deviation of intraocular pressure during the observation period, baseline sectorial TD value, papillomacular bundle tilt angle, and axial length, along with superior/inferior arterial angle) was investigated.ResultsThe main outcome measures were the association between retinal structural parameters and glaucomatous progression of VF. The superior retinal artery angular position was positively associated with sectorial TD progression rates in two central sectors in the inferior hemifield, which suggests faster VF progression where superior retinal artery angles are narrow. Papillomacular bundle tilt was not associated with TD progression rate in any sector.ConclusionsProgression of the inferior VF was associated with the superior retinal artery angular position in this study of POAG.

Modeling light interference figures and isogyres of uniaxial and biaxial birefringent optical elements

Using polarization fields, light interference figures and isogyres of some uniaxial and biaxial birefringent optical elements are modeled. The effects of diattenuation, and linear and circular birefringence are included, and the Airy spiral is displayed for various cases. The two branches of the Airy spiral are shown to separate and surround separately the melatopes in the case of biaxial elements with linear and circular birefringence. A connection and discussion with the aberration field of astigmatism, in particular binodal, is presented.

The influence of axial myopia on optic disc characteristics of glaucoma eyes

This study characterizes differences in glaucomatous eyes with and without high axial myopia using custom automated analysis of OCT images. 452 eyes of 277 glaucoma patients were stratified into non (n = 145 eyes), mild (n = 214 eyes), and high axial myopia (axial length (AL) > 26 mm, n = 93 eyes). Optic disc ovality index, tilt and rotation angle of Bruch´s membrane opening (BMO) and peripapillary choroidal thickness (PCT) were calculated using automated and deep learning strategies. High myopic optic discs were more oval and had larger BMO tilt than mild and non-myopic discs (both p < 0.001). Mean PCT was thinnest in high myopic eyes followed by mild and non-myopic eyes (p < 0.001). BMO rotation angle, global retinal nerve fiber layer (RNFL) thickness and BMO-minimum rim width (MRW) were similar among groups. Temporal RNFL was thicker and supranasal BMO-MRW was thinner in high myopic eyes. BMO tilt and PCT showed moderate and temporal RNFL and nasal BMO-MRW showed weak but significant associations with AL in multivariable analyses (all p < 0.05). Large BMO tilt angle and thin PCT are characteristics of highly myopic discs and were not associated with severity of glaucoma. Caution should be exercised when using sectoral BMO-MRW and RNFL thickness for glaucoma management decisions in myopic eyes.

Assessment of objective ocular cyclodeviation under monocular condition and binocular condition using fundus photography

ObjectiveThe relationship between retinal structure and function of glaucomatous eyes has attracted a great deal of research attention. However, visual field tests are conducted under monocular condition, and ophthalmic imaging...

Thinner temporal peripapillary retinal nerve fibre layer in Stargardt disease detected by optical coherence tomography

PurposeTo evaluate peripapillary retinal nerve fibre layer (RNFL) thickness measured by spectral domain optical coherence tomography (OCT) in patients with Stargardt disease (STGD).MethodsA cross-sectional, monocentric, observational case-control study. Twenty patients (39 eyes) with ABCA4 mutations graded according to the Fishman STGD classification were included. RNFL measurement was performed using Heidelberg Spectralis SD-OCT. RNFL thickness in STGD patients was compared to age-matched data of healthy individuals provided by the device’s manufacturer. A manual readjustment of the optic disc-fovea angle was performed when needed.ResultsThe mean age at first diagnosis of STGD was 22.9 years (range 9 to 50) and 39.1 years (range 18 to 74) at the time of examination. Thirty-nine percent of eyes (15 eyes) needed manual adjustment of the optic disc-fovea angle due to malfixation of the patients during OCT. The temporal quadrant corresponding to the macula showed a RNFL 16% thinner than controls (mean − 12 μm, 95%CI − 9 to −15 μm). However, global RNFL thickness did not differ from controls due to increased RNFL thickness of 12% in the nasal sectors. Duration and stage of STGD were not correlated to thinner RNFL.ConclusionSTGD seems to be associated with thinner peripapillary RNFL in the sector of axons projecting to the degenerated macular area. It is yet unclear as to whether this results from anterograde transneuronal degeneration of direct injury to retinal ganglion cells.

Digital Image Analysis of the Angle and Optic Nerve: A Simple, Fast, and Low-Cost Method for Glaucoma Assessment.

Purpose To devise a simple, fast, and low-cost method for glaucoma assessment using digital image analysis of the angle and optic nerve in human subjects. Methods Images from glaucoma and fundus assessment were used in this study, including color fundus photographs, standard optic nerve optical coherence tomography (OCT), and digital slit-lamp images of the angle/gonioscopy. Digital image conversion and analysis of the angle using ImageJ (NIH, USA) and adaptive histogram equalization contrast-limited AHE (CLAHE) to prevent noise amplification were implemented. Angle and optic nerve images were analyzed separately in the red, green, and blue (RGB) channels followed by 3D volumetric analysis of the degrees of angle depth and cup volume of the optic nerve. Horizontal tomogram reconstitution and nerve fiber detection methods were developed and compared to standard OCT images. Results Digital slit-lamp angle images showed similar accuracy as standard anterior OCT measurements. Comparative analysis of RGB channels produced volumetric cup and horizontal tomogram, which closely resembled the 3D OCT appearance and B-scan of the cup, respectively. RGB channel splitting and image subtraction produced a map closely resembling that of the retinal nerve fiber layer (RNFL) thickness map on OCT. Conclusions While OCT imaging is rapidly progressing in the area of optic disc and chamber angle assessment, rising healthcare costs and lack of availability of the technology open a demand for alternative and cost-minimizing forms of image analysis in glaucoma. Volumetric, geometric, and segmentational data obtained through digital image analysis correspond well to those obtained by OCT imaging.

Force-Position Photo-Robotic Approach for the High-Accurate Micro-Assembly of Photonic Devices

Recently, micro-assembly of individual photonic elements has been highly attracting to provide new optical functionalities and products with high performances. This approach requires position control in free space and contact detection in constrained space. In both cases, getting accurate measurements remains a key lock. For this sake, the FP (Fabry-Perot) interferences happening during the active alignment of optical elements is exploited. This 1D displacement measurement is combined with multi-DoF (Degrees-of-Freedom) robotic motions and a compliant structure along a photo-robotic approach to provide high accurate estimation of both multi-DoF position and contact forces during the assembly process. This approach has been applied to the assembly of an optical lamella with respect to a fiber. An original contact detection algorithm has been proposed, which relies on correlations between the interference figure and the expected irradiance deduced from the nano-positioner internal sensors. This contact detection enables to estimate the position of the lamella with respect to the fiber along the optical axis and thus control the UV-adhesive thickness required to achieve high optical performances after assembly. Experimental investigations using this new approach shows that a positioning accuracy of 27.6 nm and 2.1 m° (standard deviation values) are reached for positions and orientations respectively. The contact detection algorithm has also been studied experimentally and results shows that the contact position can be detected with a maximum error of 80 nm, which

Optic Nerve Angle in Idiopathic Intracranial Hypertension.

The tortuosity of the optic nerve can be quantified radiologically by measuring the angle of optic nerve deformation (the "optic nerve angle" [ONA]). In patients with idiopathic intracranial hypertension (IIH), lowering the intracranial pressure (ICP) to a normal range by lumbar puncture leads to straightening of the optic nerve and an increase in the measured sagittal ONA on MRI. It is uncertain whether there is any correlation between ONA and cerebrospinal fluid (CSF) opening pressure or visual function. Retrospective study of patients with and without IIH who had MRI of the brain followed by lumbar puncture with CSF opening pressure within 24 hours of MRI. Before LP and within 24 hours of MRI of the brain, all patients with IIH had neuro-ophthalmologic assessment including visual acuity, Humphrey Visual Field (HVF), and fundus photography. Sagittal ONA was measured on multiplanar T2-SPACE images on a DICOM viewer. Papilledema on the fundus photographs was graded using the Frisén scale. Fifty-four patients with IIH and 30 unmatched controls were included. The IIH group was 6.3 years younger (95% CI 2.4-10.3, P = 0.002), had 8.7 kg/m2 higher body mass index (4.9-12.5, P < 0.001), and 26.3% more women (P = 0.011) compared with controls. In both eyes, the ONA was significantly smaller in patients with IIH by 12° compared with controls (7°-17°, P < 0.00001). In the IIH group, no correlation between ONA and the CSF opening pressure was present in either eye (right eye r = 0.19, P = 0.15; left eye r = 0.18, P = 0.19) The ONA did not correlate with logarithm of the minimum angle of resolution visual acuity (right eye r = 0.26, P = 0.063; left eye r = 0.15, P = 0.27), HVF mean deviation (right eye r = 0.0059, P = 0.97; left eye r = -0.069, P = 0.63), or Frisén grade (Spearman's rho right eye 0.058, P = 0.67; left eye 0.14, P = 0.30). The ONA is significantly smaller in patients with IIH compared to controls, but does not correlate with CSF opening pressure, severity of papilledema, or visual function. The ONA may be useful in identifying patients with raised ICP, but not necessarily those with a poor visual prognosis.

Mangani-pargasite, NaCa2(Mg4Mn3+)(Si6Al2)O22(OH)2 , a new mineral species of the amphibole

Mangani-pargasite, ideally NaCa 2 (Mg 4 Mn 3+ )(Si 6 Al 2 )O 22 (OH) 2 , is a new mineral species of the calcium amphibole subgroup of the amphibole supergroup. The type specimen was found on the mine dump of the Langban Fe-Mn-(Ba-As-Pb-Sb) deposit in Varmland, Bergslagen ore province, Sweden. Crystal chemical analyses resulted in the empirical chemical formula: A (Na 0.90 Pb 0.07 K 0.03 ) Σ1.00 B (Ca 1.93 Mn 2+ 0.07 ) Σ2.00 C (Mg 4.25 Mn 3+ 0.39 Al 0.26 Fe 3+ 0.10 ) Σ5.00 T (Si 6.35 Al 1.65 ) Σ8.00 O 22 W (OH) 2 . The mineral is biaxial positive, with a = 1.635(5), b = 1.645(5), c = 1.660(5) and the measured optic angle 2 V = 85(5)°. The dispersion is weak (r > v), and the optic orientation is: Y || b ; Z ^ c = 25(3)°. Mangani-pargasite is red to brownish red with weak pleochroism; X = pale reddish brown, Y = pale reddish brown and Z = pale brownish red; X ≈ Y > Z . The unit-cell parameters are a = 9.9448(5), b = 18.0171(9), c = 5.2829(3) A, b = 105.445(3)°, V = 912.39(9) A 3 , Z = 2, space group C 2/ m . The ten strongest reflections in the X-ray powder diffraction pattern [ d -values in A, I , ( h k l )] are: 8.420, 29, (1 1 0); 3.368, 17, (1 3 1), 3.279, 49, (2 4 0); 3.141, 100, (3 1 0); 2.817, 44, (3 3 0); 2.698, 21, (1 5 1); 2.389, 18, (3 5 0); 1.904, 29, (5 1 0); 1.650, 22, (4 6 1) and 1.448, 46, (6 6 -1).