975 resultados para REFRACCION OCULAR
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PURPOSE: To determine the types and incidence of caruncular lesions and to investigate the correlation between clinical and histologic diagnosis. DESIGN: Retrospective, observational case series. METHODS: Records of patients with a lesion of the caruncle that was excised and submitted to our ocular pathology department between January 1979 and May 2005 were reviewed. Lesions were classified by histologic type and correlated with patient age, gender, and preoperative clinical diagnosis. RESULTS: A total of 195 consecutive caruncular lesions from 191 patients were identified. Twenty-four different types of lesions were identified; the most common were nevi (n = 92, 47%) and papillomas (n = 29, 15%). One keratoacanthoma was identified. One hundred eighty-three lesions (93.8%) were benign, six (3.1%) were premalignant, and five (2.6%) were malignant. Preoperative clinical diagnosis corresponded to postexcision histologic diagnosis in 73 cases (37.4%). Suspected malignancy was a common reason for excision (61 cases, 31.3%), but malignancy was confirmed in only three (4.9%) of 61 cases. Two of the five malignant lesions were clinically thought to be benign. CONCLUSIONS: We hereby report the first caruncular keratoacanthoma. The rarity and variety of caruncular lesions make clinical diagnosis difficult. Malignancy is clinically overestimated, and some malignant lesions can take a benign aspect, justifying close photographic follow-up of all lesions. Because caruncular malignant melanoma is associated with poor prognosis, pigmented lesions should be monitored carefully. In the absence of clear criteria for malignancy, any change in color, size, or vascularization of a caruncular lesion should hasten excision.
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Even 30 years after its first publication the Glasgow Coma Scale (GCS) is still used worldwide to describe and assess coma. The GCS consists of three components, the ocular, motor and verbal response to standardized stimulation, and is used as a severity of illness indicator for coma of various origins. The GCS facilitates information transfer and monitoring changes in coma. In addition, it is used as a triage tool in patients with traumatic brain injury. Its prognostic value regarding the outcome after a traumatic brain injury still lacks evidence. One of the main problems is the evaluation of the GCS in sedated, paralysed and/or intubated patients. A multitude of pseudoscores exists but a universal definition has yet to be defined.
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Purpose: In vitro studies in porcine eyes have demonstrated a good correlation between induced intraocular pressure variations and corneal curvature changes, using a contact lens with an embedded microfabricated strain gauge. Continuous 24 hour-intraocular pressure (IOP) monitoring to detect large diurnal fluctuation is currently an unmet clinical need. The aims of this study is to evaluate precision of signal transmission and biocompatibility of 24 hour contact lens sensor wear (SENSIMED Triggerfish®) in humans. Methods: After full eye examination in 10 healthy volunteers, a 8.7 mm radius contact lens sensor and an orbital bandage containing a loop antenna were applied and connected to a portable recorder. Best corrected visual acuity and position, lubrication status and mobility of the sensor were assessed after 5 and 30 minutes, 4, 7 and 24 hours. Subjective comfort was scored and activities documented in a logbook. After sensor removal full eye examination was repeated, and the registration signal studied. Results: The comfort score was high and did not fluctuate significantly, except at the 7 hour-visit. The mobility of the contact lens was minimal but its lubrication remained good. Best corrected visual acuity was significantly reduced during the sensor wear and immediately after its removal. Three patients developed mild corneal staining. In all but one participant we obtained a registration IOP curve with visible ocular pulse amplitude. Conclusions: This 24 hour-trial confirmed the functionality and biocompatibility of SENSIMED Triggerfish® wireless contact lens sensor for IOP-fluctuation monitoring in volunteers. Further studies with a range of different contact lens sensor radii are indicated.
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Corneal integrity and transparency are indispensable for good vision. Cornea homeostasis is entirely dependent upon corneal stem cells, which are required for complex wound-healing processes that restore corneal integrity following epithelial damage. Here, we found that leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) is highly expressed in the human holoclone-type corneal epithelial stem cell population and sporadically expressed in the basal cells of ocular-surface epithelium. In murine models, LRIG1 regulated corneal epithelial cell fate during wound repair. Deletion of Lrig1 resulted in impaired stem cell recruitment following injury and promoted a cell-fate switch from transparent epithelium to keratinized skin-like epidermis, which led to corneal blindness. In addition, we determined that LRIG1 is a negative regulator of the STAT3-dependent inflammatory pathway. Inhibition of STAT3 in corneas of Lrig1-/- mice rescued pathological phenotypes and prevented corneal opacity. Additionally, transgenic mice that expressed a constitutively active form of STAT3 in the corneal epithelium had abnormal features, including corneal plaques and neovascularization similar to that found in Lrig1-/- mice. Bone marrow chimera experiments indicated that LRIG1 also coordinates the function of bone marrow-derived inflammatory cells. Together, our data indicate that LRIG1 orchestrates corneal-tissue transparency and cell fate during repair, and identify LRIG1 as a key regulator of tissue homeostasis.
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Background: To compare the different schemes that have been proposed during the last thirteen years to explain the renewal of the corneal epithelium. Material and Methods:We analyzed all the data present in the literature to explain the renewal of the corneal epithelium in mammals. According to the schemes proposed in the literature we developed a 3D animation to facilitate the understanding of the different concepts. Results:Three different schemes have been proposed to explain the renewal of the corneal epithelium in mammals during the last thirteen years. 1950-1981: the corneal epithelium was thought being renewed by mitosis of cells located in the basal layer. At this time scientist were not talking about stem cells. 1981-1986 was the period of the "XYZ hypothesis" or the transdifferentiation paradigm. At this time the conjunctival epithelium renewed the corneal epithelium in a centripetal migration. 1986-2008: the limbal stem cell paradigm, there were no stem cells in the corneal epithelium, all the corneal stem cells were located in the limbus and renewed the central cornea after a migration of 6 to 7 mm of transient amplifying cells toward the centre of the cornea. 2008, epithelial stem cells were found in the central cornea in mammals (Nature, Majo et al. November 2008). Discussion:We thought that the renewal of the corneal epithelium was completely defined. According to the last results we published in Nature, the current paradigm will be revisited. The experiments we made were on animals and the final demonstration on human has still to be done. If we find the same results in human, a new paradigm will be define and will change the way we consider ocular surface therapy and reconstruction.
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Cone photoreceptors mediate visual acuity under daylight conditions, so loss of cone-mediated central vision of course dramatically affects the quality of life of patients suffering from retinal degeneration. Therefore, promoting cone survival has become the goal of many ocular therapies and defining the stage of degeneration that still allows cell rescue is of prime importance. Using the Rpe65(R91W/R91W) mouse, which carries a mutation in the Rpe65 gene leading to progressive photoreceptor degeneration in both patients and mice, we defined stages of retinal degeneration that still allow cone rescue. We evaluated the therapeutic window within which cones can be rescued, using a subretinal injection of a lentiviral vector driving expression of RPE65 in the Rpe65(R91W/R91W) mice. Surprisingly, when applied to adult mice (1 month) this treatment not only stalls or slows cone degeneration but, actually, induces cone-specific protein expression that was previously absent. Before the intervention only part of the cones (40% of the number found in wild-type animals) in the Rpe65(R91W/R91W) mice expressed cone transducin (GNAT2); this fraction increased to 64% after treatment. Correct S-opsin localization is also recovered in the transduced region. In consequence these results represent an extended therapeutic window compared to the Rpe65(-/-) mice, implying that patients suffering from missense mutations might also benefit from a prolonged therapeutic window. Moreover, cones are not only rescued during the course of the degeneration, but can actually recover their initial status, meaning that a proportion of altered cones in chromophore deficiency-related disease can be rehabilitated even though they are severely affected.
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VEGF plays an essential role in ocular angiogenic diseases including the late-stage form of AMD, the primary cause of vision loss in the western world. Over-expression of VEGF leads to development of vasculature emanating from the choroid, invading the subretinal space through breaks in Bruch's membrane. Strategies leading to long-term suppression of inappropriate ocular angiogenesis are required. A panel of 10 shRNAs targeting the coding region of human VEGF165 was tested in HEK293 cells and in the human retinal pigment epithelial cell line, ARPE-19. VEGF knock-down up to 92% was achieved by co-transfecting shRNAexpressing constructs with plasmid encoding the Renilla luciferase gene fused to the VEGF165 sequence. For in vivo delivery of the most potent shRNA cassette, both single-stranded and self-complementary rAAV vectors were packaged in serotype 8 capsids. Intramuscular administration in mice led to localized expression and 96% knock-down of endogenous VEGF. Using eGFP as a marker, efficient gene transfer of retinal pigment epithelial cells, the cells thought to be responsible for the abnormal VEGF production, was obtained by subretinal delivery of rAAV2.8 vectors. The capacity of rAAV-encoded shRNAs to silence endogenous VEGF gene expression was evaluated in the laser-induced murine model of choroidal neovascularization (CNV). In this mouse model of AMD, sizes of the CNV were found to be significantly reduced following rAAV-shRNA subretinal delivery. Thus, our results indicate that gene transfer combining AAV-mediated delivery with triggering of the endogenous RNAi pathway can be used for anti-VEGF therapy and holds great promise for the treatment of AMD.
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PURPOSE: Ocular anatomy and radiation-associated toxicities provide unique challenges for external beam radiation therapy. For treatment planning, precise modeling of organs at risk and tumor volume are crucial. Development of a precise eye model and automatic adaptation of this model to patients' anatomy remain problematic because of organ shape variability. This work introduces the application of a 3-dimensional (3D) statistical shape model as a novel method for precise eye modeling for external beam radiation therapy of intraocular tumors. METHODS AND MATERIALS: Manual and automatic segmentations were compared for 17 patients, based on head computed tomography (CT) volume scans. A 3D statistical shape model of the cornea, lens, and sclera as well as of the optic disc position was developed. Furthermore, an active shape model was built to enable automatic fitting of the eye model to CT slice stacks. Cross-validation was performed based on leave-one-out tests for all training shapes by measuring dice coefficients and mean segmentation errors between automatic segmentation and manual segmentation by an expert. RESULTS: Cross-validation revealed a dice similarity of 95% ± 2% for the sclera and cornea and 91% ± 2% for the lens. Overall, mean segmentation error was found to be 0.3 ± 0.1 mm. Average segmentation time was 14 ± 2 s on a standard personal computer. CONCLUSIONS: Our results show that the solution presented outperforms state-of-the-art methods in terms of accuracy, reliability, and robustness. Moreover, the eye model shape as well as its variability is learned from a training set rather than by making shape assumptions (eg, as with the spherical or elliptical model). Therefore, the model appears to be capable of modeling nonspherically and nonelliptically shaped eyes.
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Purpose: Microphthalmia and anophthalmia are at the severe end of the spectrum of abnormalities in ocular development. A few genes (orthodenticle homeobox 2 [OTX2], retina and anterior neural fold homeobox [RAX], SRY-box 2 [SOX2], CEH10 homeodomain-containing homolog [CHX10], and growth differentiation factor 6 [GDF6]) have been implicated mainly in isolated micro/anophthalmia but causative mutations of these genes explain less than a quarter of these developmental defects. The essential role of the LIM homeobox 2 (LHX2) transcription factor in early eye development has recently been documented. We postulated that mutations in this gene could lead to micro/anophthalmia, and thus performed molecular screening of its sequence in patients having micro/anophthalmia. Methods: Seventy patients having non-syndromic forms of colobomatous microphthalmia (n=25), isolated microphthalmia (n=18), or anophthalmia (n=17), and syndromic forms of micro/anophthalmia (n=10) were included in this study after negative molecular screening for OTX2, RAX, SOX2, and CHX10 mutations. Mutation screening of LHX2 was performed by direct sequencing of the coding sequences and intron/exon boundaries. Results: Two heterozygous variants of unknown significance (c.128C > G [p.Pro43Arg]; c.776C > A [p.Pro259Gln]) were identified in LHX2 among the 70 patients. These variations were not identified in a panel of 100 control patients of mixed origins. The variation c.776C > A (p.Pro259Gln) was considered as non pathogenic by in silico analysis, while the variation c.128C > G (p.Pro43Arg) considered as deleterious by in silico analysis and was inherited from the asymptomatic father. Conclusions: Mutations in LHX2 do not represent a frequent cause of micro/anophthalmia.
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BACKGROUND: The preservation of globe integrity has always been a major concern during the treatment of retinoblastoma for fear of extraocular or metastatic spread. Intravitreal chemotherapy has been attempted as a desperate salvage therapy only for eyes with refractory retinoblastoma. Published data on the safety and efficacy of this route are, however, limited. METHODS: A modified technique of intravitreal injection in eyes with retinoblastoma is described. All children with retinoblastoma who received one or more intravitreal injections using this technique were retrospectively reviewed concerning ocular complications of the injection procedure as well as clinical or histopathological evidence of tumour spread. RESULTS: 30 eyes of 30 children with retinoblastoma received a total of 135 intravitreal injections, with a median follw-up duration of 13.5 months. No extraocular spread was seen on clinical follow-up in any patients and there was no tumour contamination of the retrieved entry sites histopathologically analysed among the five enucleated eyes. No significant ocular side effects were observed except transient localised vitreous haemorrhage (3/135). CONCLUSION: This technique is potentially safe and effective at a low cost and may play a promising role, especially in the treatment of recurrent and/or resistant vitreous disease in retinoblastoma, as an alternative to enucleation and/or external beam radiotherapy. However, this treatment should not replace the primary standard of care of retinoblastoma and should not be considered in group E eyes. Its application should be approved by an ophthalmological-oncological team and it should be performed by an experienced eye surgeon in a tertiary referral centre after careful selection of a tumour-free injection site.
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Ocular neovascularizations are responsible for irreversible loss of vision in various diseases, including age-related macular degeneration. Treatments have changed greatly, and photodynamic therapy with verteporfin has come into common use. However, the visual prognosis remains poor. The recent approval of new antiangiogenic molecules such as ranibizumab and pegaptanib should allow for new therapeutical possibilities. The unapproved ophthalmological use of bevacizumab requires further studies. This paper updates what is known about old and new neovascularization treatments: their mechanism of action, their efficacy, and their toxicity. It reviews the principal clinical studies, and concludes with the recognized recommendations. For the first time, ophthalmologists can hope not only to stabilize loss of vision, but also to improve visual acuity. Complementary treatments can now be tested in associations, concomitantly or not, with the hope of improving visual results.
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Due to its small size and particular isolating barriers, the eye is an ideal target for local therapy. Recombinant protein ocular delivery requires invasive and painful repeated injections. Alternatively, a transfected tissue might be used as a local producer of transgene-encoded therapeutic protein. We have developed a nondamaging electrically mediated plasmid delivery technique (electrotransfer) targeted to the ciliary muscle, which is used as a reservoir tissue for the long-lasting expression and secretion of therapeutic proteins. High and long-lasting reporter gene expression was observed, which was restricted to the ciliary muscle. Chimeric TNF-alpha soluble receptor (hTNFR-Is) electrotransfer led to elevated protein secretion in aqueous humor and to drastic inhibition of clinical and histological inflammation scores in rats with endotoxin-induced uveitis. No hTNFR-Is was detected in the serum, demonstrating the local delivery of proteins using this method. Plasmid electrotransfer to the ciliary muscle, as performed in this study, did not induce any ocular pathology or structural damage. Local and sustained therapeutic protein production through ciliary muscle electrotransfer is a promising alternative to repeated intraocular protein administration for a large number of inflammatory, degenerative, or angiogenic diseases.
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Diabetic retinopathy is associated with ocular inflammation, leading to retinal barrier breakdown, macular edema, and visual cell loss. We investigated the molecular mechanisms involved in microglia/macrophages trafficking in the retina and the role of protein kinase Cζ (PKCζ) in this process. Goto Kakizaki (GK) rats, a model for spontaneous type 2 diabetes were studied until 12 months of hyperglycemia. Up to 5 months, sparse microglia/macrophages were detected in the subretinal space, together with numerous pores in retinal pigment epithelial (RPE) cells, allowing inflammatory cell traffic between the retina and choroid. Intercellular adhesion molecule-1 (ICAM-1), caveolin-1 (CAV-1), and PKCζ were identified at the pore border. At 12 months of hyperglycemia, the significant reduction of pores density in RPE cell layer was associated with microglia/macrophages accumulation in the subretinal space together with vacuolization of RPE cells and disorganization of photoreceptors outer segments. The intraocular injection of a PKCζ inhibitor at 12 months reduced iNOS expression in microglia/macrophages and inhibited their migration through the retina, preventing their subretinal accumulation. We show here that a physiological transcellular pathway takes place through RPE cells and contributes to microglia/macrophages retinal trafficking. Chronic hyperglycemia causes alteration of this pathway and subsequent subretinal accumulation of activated microglia/macrophages.
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Antisense oligonucleotides (ODNs) specific for VEGFR-2-(17 MER) and inhibiting HUVEC proliferation in-vitro were screened. One efficient sequence was selected and incorporated in different types of nanoemulsions the potential toxicity of which was evaluated on HUVEC and ARPE19 cells. Our results showed that below 10 microl/ml, a 2.5% mid-chain triglycerides cationic DOTAP nanoemulsion was non-toxic on HUVEC and retinal cells. This formulation was therefore chosen for further experiments. In-vitro transfection of FITC ODNs in ARPE cells using DOTAP nanoemulsions showed that nanodroplets do penetrate into the cells. Furthermore, ODNs are released from the nanoemulsion after 48 h and accumulate into the cell nuclei. In both ex-vivo and in-vivo ODN stability experiments in rabbit vitreous, it was noted that the nanoemulsion protected at least partially the ODN from degradation over 72 h. The kinetic results of fluorescent ODN (Hex) distribution in DOTAP nanoemulsion following intravitreal injection in the rat showed that the nanoemulsion penetrates all retinal cells. Pharmacokinetic and ocular tissue distribution of radioactive ODN following intravitreal injection in rabbits showed that the DOTAP nanoemulsion apparently enhanced the intraretinal penetration of the ODNs up to the inner nuclear layer (INL) and might yield potential therapeutic levels of ODN in the retina over 72 h post injection.
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BACKGROUND: Dolichoectasia (elongation, dilatation and tortuosity) of the basilar artery can cause an isolated cranial neuropathy. The trigeminal nerve and facial nerve are most frequently affected. Dysfunction of one of the ocular motor cranial nerves due to basilar artery dolichoectasia is uncommon, and an isolated IVth (trochlear) nerve palsy has not been previously described in the literature. HISTORY AND SIGNS: Two men, ages 70 and 59 years, respectively, presented with vertical diplopia due to a IVth nerve palsy. In one patient, the onset of the IVth nerve palsy was painless and gradual and in the other patient, the onset was acute and associated with periorbital pain. Neuroimaging in both patients revealed pathological tortuosity of the basilar artery around the midbrain and displacement of the artery toward the side of the affected trochlear nerve. THERAPY AND OUTCOME: The patients were observed clinically. One patient had gradual worsening of his palsy for three and one-half years then suffered a stroke. The second patient whose IVth nerve palsy had an acute onset experienced spontaneous resolution of his palsy but later developed dysfunction of other cranial nerves. CONCLUSIONS: Basilar artery dolichoectasia should be considered in the differential diagnosis of an isolated IVth nerve palsy. The clinical course may be variable, and the prognosis is not always benign.