scholarly journals Corneal Densitometry in Bilateral Keratoconus Patients with Unilateral Corneal Vogt's Striae: A Contralateral Eye Study

2021 ◽  
Author(s):  
Shengsheng Wei ◽  
Jing Li ◽  
Yong Li ◽  
Yaohua Zhang ◽  
Yan Cai ◽  
...  
Keyword(s):  
Central Region ◽  
Corneal Stroma ◽  
Morphological Parameters ◽  
Cross Sectional ◽  
Central Cornea ◽  
Corneal Densitometry ◽  
Intermediate Layers ◽  
Contralateral Eye ◽  
Peripheral Cornea

Abstract BackgroundWe aimed to investigate corneal densitometry and correlations with corneal morphological parameters in bilateral keratoconus (KCN) patients with unilateral Vogt's striae.MethodsOne hundred and-twelve patients (224 eyes) with bilateral KCN and unilateral Vogt's striae were enrolled in this cross-sectional contralateral eye study. Corneal densitometry and morphological parameters were measured using Pentacam HR.ResultsOur study revealed that corneal densitometry values of the anterior 0–2 mm and 2–6 mm, intermediate 0–2 mm and 2–6 mm, posterior 2–6 mm, and total cornea 2–6 mm in eyes with Vogt’s striae were significantly higher than those in eyes without Vogt's striae (P < 0.05). The corneal densitometry values of the anterior 6–10 mm, posterior 0–2 mm, and total cornea 6–10 mm were significantly lower in eyes with Vogt's striae (P < 0.05). The corneal densitometry values in the anterior 0–2 mm and total cornea 2–6 mm were positively correlated with K1, K2, Km, Kmax, ACE, and PCE (P < 0.05) and negatively correlated with CCT and TCT in eyes with Vogt's striae (P < 0.05). K2, Km, and Kmax were significantly correlated with densitometry values of the anterior 0–2 mm and the intermediate 0–2 mm in eyes without Vogt’s striae (P < 0.05). Corneal densitometry values of the anterior and intermediate layers in the central cornea were higher in KCN eyes with Vogt's striae than in eyes without Vogt's striae, and the densitometry values of the anterior corneal stroma in the central region of the cornea were higher than those of the peripheral cornea in KCN eyes with and without Vogt's striae.ConclusionsIn conclusion, these results indicate that Vogt's striae mainly occur on the anterior and intermediate layers during the progression of KCN.

scholarly journals Evaluation of Ocular Surface Epithelial and Stromal Thicknesses in Psoriasis Using Anterior Segment Optical Coherence Tomography

2022 ◽  
Author(s):  
Ismail Ersan ◽  
Sevilay Kılıc ◽  
Selda Isık
Keyword(s):  
Optical Coherence Tomography ◽  
Anterior Segment ◽  
Corneal Stroma ◽  
Cross Sectional Study ◽  
Bulbar Conjunctiva ◽  
Optical Coherence ◽  
Control Groups ◽  
Cross Sectional ◽  
Central Cornea ◽  
And Control

Abstract Purpose: To evaluate the epithelial and stromal thicknesses of conjunctiva and cornea in psoriatic patients with anterior segment optical coherence tomography (AS-OCT),Methods: In this cross-sectional study, 61 patients with psoriasis and 42 age-matched, healthy individuals were enrolled. The epithelial and stromal thicknesses of both inferotemporal bulbar conjunctiva and central cornea were measured using AS-OCT. Results: Both the Tear break-up time and Schirmer-1 test values were significantly lower in the psoriasis group compared with the controls (p<0.05). The epithelial thickness of conjunctiva and cornea did not differ between psoriasis and control groups. (p>0.05) The central corneal stroma was significantly thicker in the psoriasis group (p=0.04). PASI was positively correlated with the thickness of central cornea stroma (r=0.442, p=0.006) in the nail psoriasis group. Conclusions: Psoriasis is not associated with altered epithelial thicknesses of the cornea and conjunctiva. It is accompanied by the stromal thickening of the cornea without conjunctival stromal involvement.

scholarly journals Measuring the Ocular Morphological Parameters of Guinea Pig Eye with Edge Detection and Curve Fitting

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yue Di ◽  
Ying Huang ◽  
Ya-jing Yang ◽  
Xing-Tao Zhou ◽  
Wen-ting Luo ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Edge Detection ◽  
Central Region ◽  
Tilt Angle ◽  
Curve Fitting ◽  
Morphological Parameters ◽  
Sectional Area ◽  
Cross Sectional

Aim. To identify the guinea pig eyeball with edge detection and curve fitting and devise a noncontact technology of measuring ocular morphological parameters of small experimental animal. Methods. Thirty-nine eyeballs of guinea pig eyeballs were photographed to obtain the anterior and posterior surface; transverse and sagittal planes after the eyeballs were eviscerated. Next, the eyeball photos were input into digital image analysis software; the corresponding photo pixels-actual length ratio was acquired by a proportional scale. The contour lines of the eyeballs were identified by edge detection technology; conic curve fitting was applied to fit the contour line of the eyeball. The maximum and minimum diameters, the horizontal and vertical diameters, eccentricity, tilt angle, cross-sectional area, equatorial circumference, retrobulbar equatorial maximum length, corneal radius of curvature (CRC) in central region, and the whole cornea were calculated according to the geometric principles. The corneal data of in vitro study were compared with the in vivo results. Results. The contour line of the selected guinea pig eye was identified correctly by edge detection. There were no significant differences between anterior and posterior surfaces of one eyeball in the maximum diameters, eccentricity, cross-sectional area, equatorial circumference, and tilt angle ( P > 0.01 ). There were significant differences of eccentricity and CRC between central region and the whole cornea ( P < 0.01 ). There were no significant differences between keratometer in vivo and cornea in vitro. Conclusion. It was feasible to measure an experimental animal eye in a noncontact way. Edge detection and curve fitting technology could accurately evaluate the ocular morphological parameters.

Mechanical load-dependent regulation of satellite cell and fiber size in rat soleus muscle

2006 ◽  
Vol 290 (4) ◽  
pp. C981-C989 ◽  
Author(s):  
X. D. Wang ◽  
F. Kawano ◽  
Y. Matsuoka ◽  
K. Fukunaga ◽  
M. Terada ◽  
...  
Keyword(s):  
Satellite Cell ◽  
Muscle Fiber ◽  
Satellite Cells ◽  
Central Region ◽  
Sarcomere Length ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fiber Properties ◽  
Rat Soleus Muscle ◽  
The Mean

The effects of mechanical unloading and reloading on the properties of rat soleus muscle fibers were investigated in male Wistar Hannover rats. Satellite cells in the fibers of control rats were distributed evenly throughout the fiber length. After 16 days of hindlimb unloading, the number of satellite cells in the central, but not the proximal or distal, region of the fiber was decreased. The number of satellite cells in the central region gradually increased during the 16-day period of reloading. The mean sarcomere length in the central region of the fibers was passively shortened during unloading due to the plantarflexed position at the ankle joint: sarcomere length was maintained at <2.1 μm, which is a critical length for tension development. Myonuclear number and domain size, fiber cross-sectional area, and the total number of mitotically active and quiescent satellite cells of whole muscle fibers were lower than control fibers after 16 days of unloading. These values then returned to control values after 16 days of reloading. These results suggest that satellite cells play an important role in the regulation of muscle fiber properties. The data also indicate that the satellite cell-related regulation of muscle fiber properties is dependent on the level of mechanical loading, which, in turn, is influenced by the mean sarcomere length. However, it is still unclear why the region-specific responses, which were obvious in satellite cells, were not induced in myonuclear number and fiber cross-sectional area.

A Clinical Case of Fitting Scleral Lens for Correction of Pellucid Marginal Degeneration

The Eye ◽  
2021 ◽  
Vol 23 (4) ◽  
pp. 17-20
Author(s):  
N. Yu. Pyltsina ◽  
E. A. Bezbabnova ◽  
A. A. Selezneva ◽  
M. S. Shmelkova
Keyword(s):  
Corneal Stroma ◽  
Corneal Dystrophy ◽  
Good Choice ◽  
Corneal Ectasia ◽  
Narrow Angle ◽  
Social Rehabilitation ◽  
The Right ◽  
Corneal Leukoma ◽  
Peripheral Cornea ◽  
Corneal Thinning

Background. Pellucid Marginal Degeneration (PMD) is a rare bilateral degenerative corneal disease. It causes corneal ectasia with bilateral, clear, inferior (typically 4 o’clock to 8 o’clock), peripheral corneal thinning. It usually affects about 80% of corneal stroma, which leads to the corneal ectasia above the thinning area as well as provokes the irregular astigmatism and visual impairment that are difficult to correct. Purpose. To study the possibilities of correction and social rehabilitation in a patient with PMD wearing scleral lenses. Materials and methods. The study included a patient with PMD, signs of corneal dysfunction and narrow-angle subcompensated glaucoma in the right eye, and PMD of the cornea resulted in a corneal leukoma – terminal glaucoma in the left eye. In addition to standard ophthalmic methods, we performed corneal topography and optical coherence tomography (OCT). For intraocular pressure measurement, ICARE IOP tonometer was used in several areas of the intact peripheral cornea. Results. Prior to lens fitting, UCVA in the right eye amounted to 0.06. Scleral lens helped achieve a high visual acuity of 0.9–1.0. The lens was well-tolerated by the patient. Conclusion. Scleral lenses may be a good choice for patients with irregular cornea caused by corneal dystrophy. Not only they are easy to use and have a good visual effect, but they also help patients with social rehabilitation.

scholarly journals Morphological study of the vastus medialis oblique in recurrent patellar dislocation based on magnetic resonance images

2020 ◽  
Author(s):  
Lei Shu ◽  
Xu Yang ◽  
Hangyuan He ◽  
Biao Chen ◽  
Liaobin Chen ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Muscle Fibre ◽  
Tilt Angle ◽  
Area Ratio ◽  
Control Group ◽  
Vastus Medialis ◽  
Morphological Parameters ◽  
Sectional Area ◽  
Cross Sectional ◽  
Patella Tilt

Abstract Background: To investigate the morphological parameters of the vastus medialis obliquus (VMO) muscle and delineate its importance in the maintenance of patellofemoral joint stability.Methods: The magnetic resonance imaging (MRI) data of seventy-five knees (fifty-four patients) with recurrent lateral patella dislocation (LPD) and seventy-five knees (seventy patients) without recurrent LPD were retrospectively analysed. Five morphological parameters related to the VMO (elevation in the sagittal plane and coronal plane, craniocaudal extent, muscle-fibre angulation, cross-sectional area ratio) and two patella tilt parameters (patella tilt angle, bisect offset ratio) were measured in MR images. The independent-samples t test or chi-square test was used for statistical comparisons.Results: The mean ages of the patients in the recurrent LPD group and control group were 22.1 ± 9.9 years and 24.0 ± 6.5 years, respectively. Eighteen out of seventy-five (24%) patients MRI showed VMO injuries. Compared with the control group, the patients with recurrent LPD showed significantly higher sagittal VMO elevation (10.4 ± 2.3 mm vs 4.1 ± 1.9 mm), coronal VMO elevation (15.9 ± 5.7 mm vs 3.9 ± 3.7 mm), muscle-fibre angulation (35.4 ± 8.0° vs 27.9 ± 6.3°), patella tilt angle (25.9 ± 10.7° vs 9.1 ± 5.2°), and bisect offset ratio values (0.9 ± 0.3 vs 0.5 ± 0.1) and significantly lower craniocaudal extent (13.7 ± 5.3 mm vs 16.7 ± 5.1 mm) and cross-sectional area ratio values (0.05 ± 0.02 vs 0.07 ± 0.02).Conclusions: The results showed that abnormalities in the VMO and patella tilt were clearly present in recurrent LPD patients compared with normal people.

scholarly journals Characteristics and risk factors of Plasmodium falciparum malaria in Eastern and Central Nepal

1970 ◽  
Vol 7 (4) ◽  
pp. 378-382 ◽  
Author(s):  
MR Banjara ◽  
W Sirawaraporn ◽  
S Petmitr ◽  
M Imwong ◽  
AB Joshi ◽  
...  
Keyword(s):  
Risk Factors ◽  
Falciparum Malaria ◽  
Central Region ◽  
Significant Risk ◽  
Cross Sectional Study ◽  
Eastern Region ◽  
Limited Information ◽  
Laboratory Assessment ◽  
Cross Sectional ◽  
Central Nepal

Background: Very limited information is available on epidemiology of falciparum malaria in Nepal. Such information is very important for malaria control programmes. It is believed that malaria in Eastern region is imported from border districts of India and local transmission follows whereas it is indigenous in Central region. Therefore, the characteristics and risk factors of malaria are believed to be different in Eastern and Central Nepal. Objective: The objective of the study is to describe and compare the characteristics and risk factors of falciparum malaria in Eastern and Central Nepal. Materials and methods: This cross-sectional study was conducted in falciparum malaria endemic districts of Eastern and Central Nepal, during the period 2007 to 2008. We identified and collected information from 106 patients (62 from Eastern and 44 from Central region). Patient examination, clinical and laboratory assessment were done and patients were interviewed using structured questionnaire for malaria related characteristics, risk factors and behaviours. Results: There were significant differences in risk factors and characteristics of falciparum malaria in the Central than the Eastern region. In the Central region, male, illiteracy and thatched roof hut were significant risk factors of falciparum malaria patients as compared to the Eastern region. Visits outside within one months, previous malaria within three months, taking antimalarial before confirmatory diagnosis were significantly higher in patients of the Eastern region as compared to the Central region. Conclusion: Falciparum malaria in Nepal should not be seen as similar entity, and different strategies for prevention and control is needed for its diverse characteristics and endemicity. Key words: Eastern and Central Nepal; falciparum malaria; risk factors DOI: 10.3126/kumj.v7i4.2758 Kathmandu University Medical Journal (2009) Vol.7, No.4 Issue 28, 378-382

scholarly journals The Effect of Corneal Thickness, Densitometry and Curvature on Intraocular Pressure Measurements Obtained by Applanation, Rebound and Dynamic Contour Tonometry

Vision ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 45
Author(s):  
Marco Antonio de Castro Olyntho Junior ◽  
Lucas Bertazzi Augusto ◽  
Carolina P. B. Gracitelli ◽  
Andrew J. Tatham
Keyword(s):  
Intraocular Pressure ◽  
Prospective Study ◽  
Corneal Thickness ◽  
Applanation Tonometry ◽  
Corneal Astigmatism ◽  
Dynamic Contour Tonometry ◽  
Pressure Measurements ◽  
Cross Sectional ◽  
Corneal Densitometry ◽  
The Relationship

Evaluate the effect of corneal thickness, densitometry and curvature on intraocular pressure (IOP) measurements obtained by Goldmann applanation tonometry (GAT), non-contact tonometry (NCT), rebound tonometry (RT), and dynamic contour tonometry (DCT). A cross-sectional prospective study involving 40 participants was performed. Corneal measurements were obtained using Pentacam (Oculus GMbH, Wetzlar, Germany), densitometry was measured at annuli of 0–2, 2–6, 6–10 and 10–12 mm. The relationship between corneal thickness (central, 4 and 6 mm), corneal astigmatism and corneal densitometry and IOP was examined. There was a significant relationship between corneal thickness (central, 4 and 6 mm) and GAT180, GAT90, RT, and NCT (P < 0.001 for all comparisons) but not for DCT. Higher corneal densitometry (6–10 mm and 10–12 mm zones) was associated with higher IOP from GAT180 and GAT90, and higher densitometry in the 6–10 mm zone correlated with higher IOP from NCT, however corneal densitometry increased with age. Accounting for age, the relationship between corneal densitometry and IOP measurements was not significant. In eyes with greater corneal astigmatism there was a greater difference between GAT90 and GAT180 measurements. IOP measurements may be affected by corneal thickness, densitometry and curvature. DCT was less affected by properties of the cornea compared to other devices.

Crystallography of YBa2Cu3O6+x thin film-substrate interfaces

1989 ◽  
Vol 4 (5) ◽  
pp. 1072-1081 ◽  
Author(s):  
Lisa A. Tietz ◽  
C. Barry Carter ◽  
Daniel K. Lathrop ◽  
Stephen E. Russek ◽  
Robert A. Buhrman ◽  
...  
Keyword(s):  
High Resolution Electron Microscopy ◽  
Electron Beam Evaporation ◽  
Barium Zirconate ◽  
Orientation Relationships ◽  
Cross Sectional ◽  
Ceramic Substrates ◽  
Intermediate Layers ◽  
Oxygen Sublattices ◽  
Resolution Electron ◽  
Film Substrate

The epitactic nature of the growth of YBa2Cu3O6+x (YBCO) superconducting thin films on ceramic substrates has been studied using high-resolution electron microscopy (HREM) and selected-area diffraction (SAD) of cross-sectional specimens. The films were grown in situ on (001)-oriented MgO and (001)-oriented Y2O3-stabilized cubic ZrO2 (YSZ) single-crystal substrates by electron beam evaporation. Both of these materials have large lattice misfits with respect to YBCO. Different orientation relationships were observed for films grown on the two types of substrates. These orientation relationships are shown to provide the best matching of the oxygen sublattices across the substrate-film interfaces. A crystalline intermediate layer, 6 nm thick, between the YBCO film and YSZ substrate was observed by HREM and shown by EDS to be a Ba-enriched phase, possibly barium zirconate formed by a reaction. In contrast, the YBCO–MgO interface was found to be sharp and free of any intermediate layers.

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