Search results for "Cornea"
showing 10 items of 404 documents
Mucoadhesive PEGylated inulin-based self-assembling nanoparticles: In vitro and ex vivo transcorneal permeation enhancement of corticosteroids
2019
Abstract As transcorneal drug delivery is still a challenge, the scope of the present study was to prepare useful nanosystems able to enhance transcorneal permeation/penetration of drugs. Moreover, this work aims to evaluate the effectiveness of inulin-based nanosystems in the specific field of ocular drug delivery and the effect of PEG chains to promote mucoadhesion, stability and transcorneal penetration/permeation enhancer effect of self-assembling nanoparticles in vitro (transwell systems and HCE) and ex vivo (Franz cells and bovine cornea). In particular, inulin was chosen as the starting natural polysaccharide polymer to design a novel amphiphilic derivative named INU-EDA-RA-PEG capab…
MICELLE POLIMERICHE A BASE DI NUOVI DERIVATI ANFIFILICI DELL’INULINA PER LA SOMMINISTRAZIONE OCULARE TOPICA DI CORTICOSTEROIDI NEL TRATTAMENTO DELLE …
2016
Al giorno d’oggi, la via di somministrazione oftalmica costituisce ancora una sfida per i tecnologi farmaceutici. Si tratta, inoltre, probabilmente di uno degli ambiti che più di ogni altro potrebbe beneficiare dello sviluppo di nuovi Drug Delivery Systems basati sull’utilizzo di nanovettori. Infatti, più del 50% delle patologie oculari maggiormente debilitanti (es. degenerazione maculare legata all’età, retinopatia diabetica ed edema maculare diabetico) ha origine a livello del segmento oculare posteriore. Ad oggi, la terapia intravitreale costituisce il gold standard per garantire il raggiungimento del sito target, ovvero la retina. Tuttavia, la necessità di ricorrere a frequenti somminis…
Corneal Epithelial Stem Cells-Physiology, Pathophysiology and Therapeutic Options.
2021
In the human cornea, regeneration of the epithelium is regulated by the stem cell reservoir of the limbus, which is the marginal region of the cornea representing the anatomical and functional border between the corneal and conjunctival epithelium. In support of this concept, extensive limbal damage, e.g., by chemical or thermal injury, inflammation, or surgery, may induce limbal stem cell deficiency (LSCD) leading to vascularization and opacification of the cornea and eventually vision loss. These acquired forms of limbal stem cell deficiency may occur uni- or bilaterally, which is important for the choice of treatment. Moreover, a variety of inherited diseases, such as congenital aniridia…
Evaluation of cut quality using the Amadeus microkeratome with different settings.
2004
Abstract Purpose: To evaluate the quality of keratectomy specimens created with the Amadeus® microkeratome (AMO) using scanning electron microscopy (SEM). Setting: Johannes Gutenberg-University Hospital, Department of Ophthalmology, Mainz, and the Department of Anatomy, Justus Liebig-University, Giessen, Germany. Methods: Corneal cuts were performed in freshly enucleated pig eyes using the Amadeus microkeratome with 9 combinations of oscillation rate and head-advance speed. For the cutting trials, oscillation rates of 8000, 13000, and 18000 rpm and head-advance speeds of 1.0, 2.5, and 4.0 mm/s were chosen. Fifty-four eyes were included, resulting in 9 groups of 6 eyes for each configuration…
Mechanisms and predictors of chronic facial pain in lateral medullary infarction
2001
The purpose of this study was to identify clinical predictors and anatomical structures involved in patients with pain after dorsolateral medullary infarction. Eight out of 12 patients (67%) developed poststroke pain within 12 days to 24 months after infarction. The pain occurred in the ipsilateral face (6 patients) and/or the contralateral limbs and trunk (5 patients, 3 of whom also had facial pain). Ipsilateral facial pain was significantly correlated with lower medullary lesions, including those of the spinal trigeminal tract and/or nucleus, as documented by magnetic resonance imaging. The R2 blink reflex component was abnormal only in patients with facial pain. Likewise, pain and temper…
Phake Intraokularlinsen
2004
Phakic intraocular lenses (PIOLs), which are located closer to the eye's nodal points than the anterior corneal surface, can provide superior optical quality for higher corrections because of retention of normal prolate corneal asphericity and larger effective optical zones. Improvements in the material and design of phakic intraocular lenses and their insertion devices combined with advances in the understanding of the anatomical and physiological interactions of the PIOLs with intraocular structures, have increased safety and efficacy. Safety of these implants over the long term remains a concern, but in several situations PIOLs are the refractive correction of choice. The purpose of this…
Short-Term Changes in Light Distortion in Orthokeratology Subjects
2015
Purpose. Quantifying adaptation to light distortion of subjects undergoing orthokeratology (OK) for myopia during the first month of treatment. Methods. Twenty-nine healthy volunteers (age: 22.34 ± 8.08 years) with mean spherical equivalent refractive error −2.10 ± 0.93D were evaluated at baseline and days 1, 7, 15, and 30 of OK treatment. Light distortion was determined using an experimental prototype. Corneal aberrations were derived from corneal topography for different pupil sizes. Contrast sensitivity function (CSF) was analyzed for frequencies of 1.50, 2.12, 3.00, 4.24, 6.00, 8.49, 12.00, 16.97, and 24.00 cpd under photopic conditions. Results. Average monocular values of all light di…
Trifocal toric intraocular lenses in eyes with low amount of corneal astigmatism.
2020
Aim To evaluate the refractive and visual outcomes following cataract surgery and implantation of a trifocal toric intraocular lens (IOL) in eyes with low degrees of corneal astigmatism. Methods Twenty-six eyes of 22 patients who underwent implantation a trifocal toric IOL (FineVision PODFT, PhysIOL s.a., Liege, Belgium) were enrolled. Phacoemulsification with femtosecond laser, capsular tension ring insertion and intraoperative aberrometry were performed in all cases. All IOLs used showed a cylinder power of 1.00 D. Main outcome measures were refractive error and corrected-distance visual acuity (CDVA) and uncorrected-distance visual acuity (UDVA) values. Eyes were evaluated at 4mo post-su…
Keratoconus apex positions impact on visual acuity and contrast sensitivity
2020
The change of corneal shape in keratoconus subjects can impact the optical quality of the eye on the retina and it reduces the contrast sensitivity by light scattering. The aim of our study was to estimate the keratoconus subjects’ contrast sensitivity and visual acuity depending on keratoconus apex position. We included 45 keratoconus subjects (77 eyes), which have keratoconus in the first to the third stage, in our study. There were 33 eyes with keratoconus apex in the central part of the cornea and 46 eyes with keratoconus apex in the periphery of the cornea. Contrast sensitivity and visual acuity were measured at 3 m with and without the best possible spectacle correction using the FrAC…
Conjunctival Sac Fluid Contains Elevated Levels of Soluble TRAIL: Implications for the Anti-Tumoral Surveillance of the Anterior Surface of the Eye
2008
Little is known on the ability of different epithelia to release soluble TNF-related apoptosis-inducing ligand (TRAIL) and the relevance of TRAIL secretion by epithelial cells is still incompletely understood. On these bases, we have measured the concentration of soluble TRAIL by ELISA in the conjunctival sac fluid. It was the highest ever detected in a biological fluid (mean value of 26,800 pg/ml), being approximately 20-fold greater than that found in human saliva and >200-fold greater than that detected in human serum. On the other hand, osteoprotegerin, the soluble decoy receptor of TRAIL, was almost undetectable in the conjunctival sac fluid. Of note, the levels of soluble TRAIL measur…