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8,707
result(s) for
"opacity"
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Suppression of lipopolysaccharide-induced corneal opacity by hepatocyte growth factor
by
Mittal, Sharad K.
,
Chauhan, Sunil K.
,
Elbasiony, Elsayed
in
692/308/2778
,
692/699/3161/3163
,
Actins - genetics
2022
Keratitis induced by bacterial toxins, including lipopolysaccharide (LPS), is a major cause of corneal opacity and vision loss. Our previous study demonstrates hepatocyte growth factor (HGF) promotes epithelial wound healing following mechanical corneal injury. Here, we investigated whether HGF has the capacity to suppress infectious inflammatory corneal opacity using a new model of LPS-induced keratitis. Keratitis, induced by two intrastromal injections of LPS on day 1 and 4 in C57BL/6 mice, resulted in significant corneal opacity for up to day 10. Following keratitis induction, corneas were topically treated with 0.1% HGF or PBS thrice daily for 5 days. HGF-treated mice showed a significantly smaller area of corneal opacity compared to PBS-treated mice, thus improving corneal transparency. Moreover, HGF treatment resulted in suppression of α-SMA expression, compared to PBS treatment. HGF-treated corneas showed normalized corneal structure and reduced expression of pro-inflammatory cytokine, demonstrating that HGF restores corneal architecture and immune quiescence in corneas with LPS-induced keratitis. These findings offer novel insight into the potential application of HGF-based therapies for the prevention and treatment of infection-induced corneal opacity.
Journal Article
Measuring corneal clouding in patients suffering from mucopolysaccharidosis with the Pentacam densitometry programme
2013
Aim To identify a means to objectively measure corneal clouding in patients with mucopolysaccharidosis in a prospective controlled clinical trial. Methods Corneal haze was assessed by slit lamp examination and measured using the densitometry programme of the Pentacam, a rotating Scheimpflug camera in 33 mucopolysaccharidoses (MPS) patients and 32 controls. Results Pentacam measurements were available in 31 right and 31 left eyes of 32 patients and in 32 left and right eyes of 32 subjects in the control group. Slit lamp findings correlated very well with corneal density measurements (Spearman correlation right eye (OD)/left eye (OS)=0.782/0.791). MPS patients had higher density units (median OD/OS=14.1/14.7) than control subjects (median OD/OS=6.7/6.9, p<0.001). In patients, the corneal centre density values (median OD/OS=13.8/14.0) did not differ from corneal periphery values (median OD/OS=14.3/14.7). Conclusions The densitometry programme of the Pentacam provides objective measurement of corneal haze in mucopolysaccharidosis patients.
Journal Article
Management of myopic shift and central corneal steepening resulting from superficial corneal opacity in a patient with previous radial keratotomy: a case report
2025
Purpose
The purpose of this study was to report a patient who developed myopic shift and anterior corneal steepening many years following radial keratotomy (RK). The etiology of this myopic shift resulted from central corneal opacity and was successfully managed with supra-stromal keratectomy.
Case presentation
A 59-year-old woman with a history of radial keratotomy and cataract surgery presented with blurred vision and ocular irritation in both eyes for years. Poor visual acuity and myopic change to -7.0 D were noted upon initial evaluation. Further ophthalmic examination revealed central corneal opacity occupying the optical axis with steepening of the anterior corneal surface. Anterior segment optical coherence tomography (ASOCT) revealed superficial corneal opacity with minimal stromal scarring. The opacity was successfully removed via supra-stromal keratectomy. After surgery, the patient’s visual acuity improved, and refraction returned to nearly plano. Postoperative corneal topography revealed flattening of the central cornea in both eyes.
Conclusion
Late-onset central corneal steepening with myopic shift following RK may be a sign of corneal ectasia disorders such as keratoconus. It is important to recognize corneal opacity as a distinct etiology of central corneal steepening, which may mimic corneal ectasia. A comprehensive evaluation of patients with corneal topography and ASOCT may reveal the etiology of central corneal steepening and further guide treatment decisions.
Journal Article
Opacity of the Highly Ionized Lanthanides and the Effect on the Early Kilonova
2022
We investigate the effect of the presence of lanthanides (Z = 57–71) on the kilonova at t ∼ 1 hr after the neutron star merger for the first time. For this purpose, we calculate the atomic structures and the opacities for selected lanthanides: Nd (Z = 60), Sm (Z = 62), and Eu (Z = 63). We consider the ionization degree up to 10th (XI), applicable for the ejecta at t ∼ a few hours after the merger, when the temperature is T ∼ 105 K. We find that the opacities for the highly ionized lanthanides are exceptionally high, reaching κexp∼1000cm2g−1 for Eu, due to the highly dense energy levels. Using the new opacity, we perform radiative transfer simulations to show that the early light curves become fainter by a (maximum) factor of four, in comparison to lanthanide-free ejecta at t ∼ 0.1 days. However, the period at which the light curves are affected is relatively brief owing to the rapid time evolution of the opacity in the outermost layer of the ejecta. We predict that for a source at a distance of ∼100 Mpc, UV brightness for lanthanide-rich ejecta shows a drop to ∼21–22 mag at t ∼ 0.1 days and the UV peaks around t ∼ 0.2 days with a magnitude of ∼19 mag. Future detection of such a kilonova by an existing UV satellite like Swift or the upcoming UV satellite ULTRASAT will provide useful constraints on the abundance in the outer ejecta and the corresponding nucleosynthesis conditions in the neutron star mergers.
Journal Article
Ketamine/Xylazine-Induced Corneal Damage in Mice
by
Meyer, Kacie J.
,
Anderson, Michael G.
,
Koehn, Demelza
in
Anesthesia
,
Anesthesia - adverse effects
,
Animals
2015
We have observed that the commonly used ketamine/xylazine anesthesia mix can induce a focally severe and permanent corneal opacity. The purpose of this study was to establish the clinical and histological features of this deleterious side effect, its sensitivity with respect to age and anesthesia protocol, and approaches for avoiding it.
Young C57BL/6J, C57BLKS/J, and SJL/J mice were treated with permutations of anesthesia protocols and compared using slit-lamp exams, optical coherence tomography, histologic analyses, and telemetric measurements of body temperature.
Ketamine/xylazine induces corneal damage in mice with a variable frequency. Among 12 experimental cohorts, corneal damage associated with ketamine/xylazine was observed in 9 of them. Despite various treatments to avoid corneal dehydration during anesthesia, the frequency of corneas experiencing damage among responding cohorts was 42% (26% inclusive of all cohorts), which is significantly greater than the natural prevalence (5%). The damage was consistent with band keratopathy. It appeared as a white or gray horizontal band located proximal to the pupil and was positive for subepithelial calcium deposition with von Kossa stain.
The sum of our clinical and histological observations is consistent with ketamine/xylazine-induced band keratopathy in mice. This finding is relevant for mouse studies involving the eye and/or vision-dependent behavioral assays, which would both be prone to artifact without appreciation of the damage caused by ketamine/xylazine anesthesia. Use of yohimbine is suggested as a practical means of avoiding this complication.
Journal Article
Clinicopathologic Features and Treatment Characteristics of Congenital Corneal Opacity Infants and Children Aged 3 Years or Less: A Retrospective Single Institution Analysis
by
Zhang, Ying-Nan
,
Pan, Zhi-Qiang
,
Liu, Yang
in
Anterior Eye Segment - abnormalities
,
Anterior Eye Segment - surgery
,
Cataracts
2020
Objective: In this retrospective single institution study, we investigated the clinicopathologic features and treatment characteristics of 90 patients with congenital corneal opacities (CCO) (117 eyes) who were 3 years and younger and treated at our hospital. Subject and Methods: We reviewed the clinical data of patients with CCO who presented for the first time for treatment at our hospital between January 1, 2017, and December 31, 2017. CCO were classified using the “STUMPED” (Sclerocornea, Tears in Descement’s membrane, Metabolic, Peters, Endothelial dystrophy and Dermoid) method and confirmed by pathological examination. Results: Seventy percent of the patients had unilateral CCO. Iridocorneal adhesions (61 eyes, 52.1%) and cataracts (22 eyes, 18.8%) were the 2 most common ocular abnormalities. Systemic abnormalities were present in 5 patients (5.6%), including growth retardation (4 patients) and congenital brain defects (1 patient). Eighty-five eyes (72.6%) underwent penetrating keratoplasty (PK), and lamellar keratoplasty (LK) was performed in 30 (25.6%) eyes. Forty-seven (95.9%) eyes with Peters anomaly and all 16 eyes with sclerocornea received PK, and all 24 eyes with dermoids were treated with LK. Conclusion: Our study demonstrates that CCO has varied manifestations in infants and young children in China. A thorough medical history, careful clinical examination, and the use of accessory examinations such as ultrasound biomicroscopy are critical for the accurate diagnosis and classification of CCO and to provide guidance on therapeutic choices.
Journal Article
Diversity of Early Kilonova with the Realistic Opacities of Highly Ionized Heavy Elements
2024
We investigate early (t < 1 day) kilonova from a neutron star merger by deriving atomic opacities for all the elements from La to Ra (Z = 57–88) ionized to the states V–XI. The opacities at high temperatures for the elements with open f-shells (e.g., lanthanides) are exceptionally high, reaching κexp∼3×103cm2g−1 at λ ≤ 1000 Å at T ∼ 70,000 K, whereas the opacities at the same temperature and wavelengths for the elements with open d-, p-, and s-shells reach κexp∼1 , 0.1, and 0.01 cm2 g−1, respectively. Using the new opacity data set, we derive early kilonovae for various compositions and density structures expected for neutron star merger ejecta. The bolometric luminosity of the lanthanide-rich ejecta shows distinct signatures and is fainter than that of the lanthanide-free ejecta. Early luminosity is suppressed by the presence of a thin outer layer, agreeing with the results of Kasen et al. and Banerjee et al. The early brightness in the Swift UVOT filters and in the optical g, r, i, and z filters for a source at 100 Mpc are about ∼22–19.5 and ∼21–20 mag, respectively, at t ∼ 0.1 day. Such kilonovae are ideal targets for the upcoming UV satellites, such as ULTRASAT, UVEX, and DORADO, and the upcoming surveys, e.g., the Vera Rubin Observatory. We suggest that the gray opacities that reproduce the bolometric light curves with and without lanthanides are ∼1–10 and ∼0.8 cm2 g−1.
Journal Article
Epidemiology of blindness in children
by
Solebo, Ameenat Lola
,
Teoh, Lucinda
,
Rahi, Jugnoo
in
Blindness
,
Blindness - diagnosis
,
Blindness - epidemiology
2017
An estimated 14 million of the world’s children are blind. A blind child is more likely to live in socioeconomic deprivation, to be more frequently hospitalised during childhood and to die in childhood than a child not living with blindness. This update of a previous review on childhood visual impairment focuses on emerging therapies for children with severe visual disability (severe visual impairment and blindness or SVI/BL).For children in higher income countries, cerebral visual impairment and optic nerve anomalies remain the most common causes of SVI/BL, while retinopathy of prematurity (ROP) and cataract are now the most common avoidable causes. The constellation of causes of childhood blindness in lower income settings is shifting from infective and nutritional corneal opacities and congenital anomalies to more resemble the patterns seen in higher income settings. Improvements in maternal and neonatal health and investment in and maintenance of national ophthalmic care infrastructure are the key to reducing the burden of avoidable blindness. New therapeutic targets are emerging for childhood visual disorders, although the safety and efficacy of novel therapies for diseases such as ROP or retinal dystrophies are not yet clear. Population-based epidemiological research, particularly on cerebral visual impairment and optic nerve hypoplasia, is needed in order to improve understanding of risk factors and to inform and support the development of novel therapies for disorders currently considered ‘untreatable’.
Journal Article