884 resultados para Undergraduate Ophthalmology


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Purpose: IOL centration and stability after cataract surgery is of high interest for cataract surgeons and IOL-producing companies. We present a new imaging software to evaluate the centration of the rhexis and the centration of the IOL after cataract surgery.Methods: We developed, in collaboration with the Biomedical Imaging Group (BIG), EPFL, Lausanne, a new working tool in order to assess precisely outcomes after IOL-implantation, such as ideal capsulorhexis and IOL-centration. The software is a plug-in of ImageJ, a general-purpose image processing and image-analysis package. The specifications of this software are: evaluation of the rhexis-centration and evaluation the position of the IOL in the posterior chamber. The end points are to analyze the quality of the centration of a rhexis after cataract surgery, the deformation of the rhexis with capsular bag retraction and the centration of the IOL after implantation.Results: This software delivers tools to interactively measure the distances between limbus, IOL and capsulorhexis and its changes over time. The user is invited to adjust nodes of three radial curves for the limbus, rhexis and the optic of the IOL. The radial distances of the curves are computed to evaluate the IOL implantation. The user is also able to define patterns for ideal capsulorhexis and optimal IOL-centration. We are going to present examples of calculations after cataract surgery.Conclusions: Evaluation of the centration of the rhexis and of the IOL after cataract surgery is an important end point for optimal IOL implantation after cataract surgery. Especially multifocal or accommodative lenses need a precise position in the bag with a good stability over time. This software is able to evaluate these parameters just after the surgery but also its changes over time. The results of these evaluations can lead to an optimizing of surgical procedures and materials.

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Purpose: To investigate the effect of incremental increases in intraocular straylight on threshold measurements made by three modern forms of perimetry: Standard Automated Perimetry (SAP) using Octopus (Dynamic, G-Pattern), Pulsar Perimetry (PP) (TOP, 66 points) and the Moorfields Motion Displacement Test (MDT) (WEBS, 32 points).Methods: Four healthy young observers were recruited (mean age 26yrs [25yrs, 28yrs]), refractive correction [+2 D, -4.25D]). Five white opacity filters (WOF), each scattering light by different amounts were used to create incremental increases in intraocular straylight (IS). Resultant IS values were measured with each WOF and at baseline (no WOF) for each subject using a C-Quant Straylight Meter (Oculus, Wetzlar, Germany). A 25 yr old has an IS value of ~0.85 log(s). An increase of 40% in IS to 1.2log(s) corresponds to the physiological value of a 70yr old. Each WOFs created an increase in IS between 10-150% from baseline, ranging from effects similar to normal aging to those found with considerable cataract. Each subject underwent 6 test sessions over a 2-week period; each session consisted of the 3 perimetric tests using one of the five WOFs and baseline (both instrument and filter were randomised).Results: The reduction in sensitivity from baseline was calculated. A two-way ANOVA on mean change in threshold (where subjects were treated as rows in the block and each increment in fog filters was treated as column) was used to examine the effect of incremental increases in straylight. Both SAP (p<0.001) and Pulsar (p<0.001) were significantly affected by increases in straylight. The MDT (p=0.35) remained comparatively robust to increases in straylight.Conclusions: The Moorfields MDT measurement of threshold is robust to effects of additional straylight as compared to SAP and PP.

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PURPOSE: To evaluate functional and ultrastructural changes in the retina of scavenger receptor B1 (SR-BI) knockout (KO) mice consuming a high fat cholate (HFC) diet. METHODS: Three-month-old male KO and wild-type (WT) mice were fed an HFC diet for 30 weeks. After diet supplementation, plasma cholesterol levels and electroretinograms were analyzed. Neutral lipids were detected with oil red O, and immunohistochemistry was performed on cryostat ocular tissue sections. The retina, Bruch's membrane (BM), retinal pigment epithelium (RPE), and choriocapillaris (CC) were analyzed by transmission electron microscopy. RESULTS: Using the WT for reference, ultrastructural changes were recorded in HFC-fed SR-BI KO mice, including lipid inclusions, a patchy disorganization of the photoreceptor outer segment (POS) and the outer nuclear layer (ONL), and BM thickening with sparse sub-RPE deposits. Within the CC, there was abnormal disorganization of collagen fibers localized in ectopic sites with sparse and large vacuolization associated with infiltration of macrophages in the subretinal space, reflecting local inflammation. These lesions were associated with electroretinographic abnormalities, particularly increasing implicit time in a- and b-wave scotopic responses. Abnormal vascular endothelial growth factor (VEGF) staining was detected in the outer nuclear layer. CONCLUSIONS: HFC-fed SR-BI KO mice thus presented sub-RPE lipid-rich deposits and functional and morphologic alterations similar to some features observed in dry AMD. The findings lend further support to the hypothesis that atherosclerosis causes retinal and subretinal damage that increases susceptibility to some forms of AMD.

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Purpose:We analyzed the transcriptional activity of disease-causing NR2E3 mutant proteins in a heterologous system. NR2E3 belongs to the nuclear receptor superfamily of transcription factors, characterized by evolutionary-conserved DNA-binding (DBD) and ligand-binding (LBD) domains. NR2E3 acts in concert with the transcription factors CRX and NRL to repress cone-specific genes and activate rod-specific genes in rod photoreceptors. During development, NR2E3 is also required to suppress cone cell generation from retinal progenitor cells. In humans, mutations in NR2E3 have been associated with the recessively inherited enhanced short wavelength sensitive (S-) cone syndrome (ESCS), the Goldman-Favre syndrome, and, more recently, with autosomal dominant retinitis pigmentosa (adRP). Methods:The different NR2E3 mutants were generated by QuickChangeR mutagenesis and analyzed by transfection in heterologous HEK293T cells. Results:In transactivation assays in HEK293T cells, the adRP-linked p.G56R mutant protein exhibited a more severe effect both in activation of a rhodopsin promoter reporter construct and in repression of M-opsin promoter reporter construct, than the ESCS-linked R76Q, R76W, G88V, R97H, R104Q, R104W mutants of the DBD. In contrast, the ESCS-linked p.R311Q mutant of the LBD behaved like the NR2E3 wild-type protein in these assays. By co-expressing the corepressors atrophin-1 and -2, a differential repression of the M-opsin promoter was observed in presence of the p.R311Q, p.R385P and p.M407K. Interestingly, corepressor expression also affected the activity of CRX, but not NRL, in both rhodopsin and M-opsin transactivation assays. Conclusions:Taken together, these in vitro results suggest a distinct disease mechanism for the adRP-linked mutation, but open the possibility of different mechanisms for the development of ESCS that is clinically characterized by important phenotypic variations.

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Purpose: Crosslinking of corneal collagen with riboflavin and ultraviolet-A irradiation (CXL) induces crosslinks within and between collagen fibers. CXL increases corneal biomechanical and biochemical stability and is currently used clinically to treat keratectasia. CXL also significantly reduces the stromal swelling capacity. We investigated whether a modified CXL treatment protocol would be beneficial in early Fuchs' dystrophy with various degrees of corneal edema and diurnal variations in visual acuity. Methods: CXL was performed as published previously with the following modification: in cases where the stroma was thicker than 450 µm after abrasion and 30 minutes of instillation of isoosmolar riboflavin solution, glycerol 70% solution was applied every 5 seconds for two minutes, and central corneal thickness (CCT) was measured using ultrasound pachymetry. Glycerol 70% solution was administered repeatedly until the target corneal thickness of 370-430 µm was reached. During irradiation, CCT was monitored by ultrasound pachymetry every five minutes and glycerol 70% solution was applied, if necessary. Results: Three eyes in two patients were treated using the modified CXL protocol. Representative case: a 50-year-old woman with Fuchs' dystrophy and a history of 3 years of diurnal visual fluctuations was referred to us in March 2008. Preoperative best spectacle-corrected visual acuity (BSCVA) was 20/50. We performed modified CXL in the left eye. At one month after CXL, Scheimpflug analysis of CCT showed a reduction of more than 100 µm, and the Corneal Thickness Spatial Profile (CTSP) and Percentage of Increase in Thickness (PIT) showed a regularization of the "flattening" typical for Fuchs' dystrophy. Accordingly, diurnal analysis of corneal thickness showed a distinct postoperative reduction in CCT at all time points measured. At one month after CXL, the patient reported a reduction of diurnal visual fluctuations and we measured an increase in BSCVA to 20/32. The patient showed stable topographical and visual acuity at the three months follow-up. Conclusions: We saw a distinct reduction in CCT, an improvement of the corneal thickness spatial profile (CTSP) and an increase in BSCVA at one month after treatment, which remained stable at the three months follow-up. Patients with early Fuchs' dystrophy and disturbing diurnal visual fluctuations represent a novel application for CXL. Although CXL may not prevent the outcome of the dystrophy, it may increase the patients' visual comfort until keratoplasty becomes necessary.

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We report a 14-year-old boy who presented with vision loss secondary to peripapillary neovascular membrane (PPNVM) as the initial and only symptom of papilledema secondary to idiopathic intracranial hypertension. After one lumbar puncture, visual acuity progressively recovered during the course of 1 week and further improved with the administration of oral acetazolamide. One year after the onset of vision loss, the patient's visual acuity had recovered to baseline measurements. The previously active PPNVM had involuted into a residual peripapillary fibrotic scar. To our knowledge, this is the first report of PPNVM complicating idiopathic intracranial hypertension in a child.

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Right from the beginning of the development of the medical specialty of Physical and Rehabilitation Medicine (PRM) the harmonization of the fields of competence and the specialist training across Europe was always an important issue. The initially informal European collaboration was formalized in 1963 under the umbrella of the European Federation of PRM. The European Academy of PRM and the UEMS section of PRM started to contribute in 1969 and 1974 respectively. In 1991 the European Board of Physical and Rehabilitation Medicine (EBPRM) was founded with the specific task of harmonizing education and training in PRM in Europe. The EBPRM has progressively defined curricula for the teaching of medical students and for the postgraduate education and training of PRM specialists. It also created a harmonized European certification system for medical PRM specialists, PRM trainers and PRM training sites. European teaching initiatives for PRM trainees (European PRM Schools) were promoted and learning material for PRM trainees and PRM specialists (e-learning, books and e-books, etc.) was created. For the future the Board will have to ensure that a minimal specific undergraduate curriculum on PRM based on a detailed European catalogue of learning objectives will be taught in all medical schools in Europe as a basis for the general medical practice. To stimulate the harmonization of national curricula, the existing postgraduate curriculum will be expanded by a syllabus of competencies related to PRM and a catalogue of learning objectives to be reached by all European PRM trainees. The integration of the certifying examination of the PRM Board into the national assessment procedures for PRM specialists will also have to be promoted.

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PURPOSE: The purpose of this paper is to present our data and to provide some conclusions about the attitude that has to be chosen when metastasis of the orbit is suspected. PATIENTS AND METHODS: Between 1965 and 1994, 571 patients with non-traumatic orbital diseases were controlled in the department of ophthalmology of Lausanne. Thirty-four cases of metastasis of the orbit were selected, that is 24 females and 10 males, aged from 1 to 81 years. Tumors of the breast are the most frequent origin of this metastasis, followed by cutaneous melanomas and pulmonary tumors. Orbital metastasis was the first sign of a malignant process in 7 patients. The histologic diagnosis was confirmed in 15 patients. The type of treatment is presented herein and the follow-up of more than half of the cases is given. RESULTS AND CONCLUSION: Orbital metastasis can develop after a long time in patients who were previously treated for malignant tumors. In several cases, orbital metastasis was the first sign of a malignant process which starts to become general. This diagnosis has to be taken into account when a patient was treated earlier for a malignant tumor, and it is reasonable to propose a biopsy or an excision biopsy in every orbital pathology which was not confirmed by clinical or paraclinical investigations.

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BACKGROUND: Collateral damage to upper eyelid margin during proton beam radiotherapy (PBR) for choroidal melanoma may cause squamous metaplasia of the tarsal conjunctiva with keratinisation, corneal irritation, discomfort and, rarely, corneal perforation. We evaluated transpalpebral PBR as a means of avoiding collateral damage to the upper eyelid margin without increasing the risk of failure of local tumour control. METHODS: Retrospective study of consecutive patients who underwent PBR for choroidal melanoma between 1992 and 2007 at the Royal Liverpool University Hospital and the Douglas Cyclotron at Clatterbridge Cancer Centre, UK. RESULTS: Sixty-three patients were included in this study. Mean basal tumour diameter and tumour thickness were 11.8 mm and 3.6 mm, respectively. PBR mean beam range and modulation were 26.5 mm and 16.9 mm respectively. The eyelid margin was included in the radiation field in 15 (24%) eyes. The median follow-up was 2.5 years. Local tumour recurrence developed in 2 (3.2%) patients. In these two cases that developed tumour recurrence the transpalpebral treatment did not involve the eyelid margin. Six (9.5%) patients died of metastatic disease. No eyelid or ocular surface problems developed in any of the 48 patients who were treated without eyelid rim involvement, while 7 of the 15 patients with unavoidable irradiation of the eyelid rim developed some degree of madarosis. These seven patients all received more than 26.55 proton Gy to the eyelid margin. Symptoms, such as grittiness occurred in 12% of 48 patients without eyelid margin irradiation as compared with 53% of 15 patients whose lid margin was irradiated. CONCLUSIONS: Transpalpebral PBR of choroidal melanoma avoids eyelid and ocular surface complications without increasing failure of local tumour control.

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Purpose: Previously we reported on a premature termination mutation in SLC16A12 that leads to dominant juvenile cataract and renal glucosuria. To assess the mutation rate and genotype-phenotype correlations of SLC16A12 in juvenile or age-related forms of cataract, we performed a mutation screen in cataract patients. Methods: Clinical data of approximately 660 patients were collected, genomic DNA was isolated and analyzed. Exons 3 to 8 including flanking intron sequences of SLC16A12 were PCR amplified and DNA sequence was determined. Selected mutations were tested by cell culture assays, in silico analysis and RT-PCR. Results: We found sequence alterations at a rate of approximately 1/75 patients. None of them was found in 360 control alleles. Alterations affect splice site and regulatory region but most mutations caused an amino acid substitution. The majority of the coding region mutations maps to trans-membrane domains. One mutation located to the 5'UTR. It affects translational efficiency of SLC16A12. In addition, we identified a cataract-predisposing SNP in the non-coding region that causes allele-specific splicing of the 5'UTR region. Conclusions: Altered translational efficiency of the solute carrier SLC16A12 and its allele-specific splicing strongly support a model of challenged homeostasis to cause various forms of cataract. In addition, the pathogenic property of the here reported sequence alterations is supported by the lack of known sequence variations within the coding region of SLC16A12. Due to the relatively high mutation rate, we suggest to include SLC16A12 in diagnostic cataract screening. Generally, our data recommend the assessment of regulatory sequences for diagnostic purposes.

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PURPOSE: To report the use of argon laser iridoplasty in the management of uveitic acute angle-closure glaucoma. METHODS: Interventional case report. RESULTS: A 46-year-old man developed uveitic acute angle-closure glaucoma with an intraocular pressure (IOP) of 65 mmHg. After unsuccessful attempts with medical treatment and two laser peripheral iridotomies, iridoplasty allowed to break posterior synechiae, open the angle, and reduce the IOP within a few hours. CONCLUSIONS: Argon laser iridoplasty allowed rapid reduction of IOP and prevented the need for emergency surgery. Therefore, the authors stipulate that it is a viable management option in active uveitic acute angle-closure glaucoma.

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Through the history of Electrical Engineering education, vectorial and phasorial diagrams have been used as a fundamental learning tool. At present, computational power has replaced them by long data lists, the result of solving equation systems by means of numerical methods. In this sense, diagrams have been shifted to an academic background and although theoretically explained, they are not used in a practical way within specific examples. This fact may be against the understanding of the complex behavior of the electrical power systems by students. This article proposes a modification of the classical Perrine-Baum diagram construction to allowing both a more practical representation and a better understanding of the behavior of a high-voltage electric line under different levels of load. This modification allows, at the same time, the forecast of the obsolescence of this behavior and line’s loading capacity. Complementary, we evaluate the impact of this tool in the learning process showing comparative undergraduate results during three academic years

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PURPOSE: Afferent asymmetry of visual function is detectable in both normal and pathologic conditions. With a computerized test, we assessed the variability in measuring afferent asymmetry of the pupillary light reflex, that is, the relative afferent pupillary defect. METHODS: In ten normal subjects, pupillary responses to an alternating light stimulus were recorded with computerized infrared pupillography. The relative afferent pupillary defect for each test was determined by using a new computer analysis. The 95% confidence interval of each determination of relative afferent pupillary defect was used to represent the short-term fluctuation in its measurement. To optimize the test for clinical use, we studied the influence of stimulus intensity, duration, and number on the variability of the relative afferent pupillary defect. RESULTS: When the relative afferent pupillary defect was based on only a few light alternations (stimulus pairs), there was excessive variability in its measurement (95% confidence interval > 0.5 log units). With approximately 200 stimulus pairs, the 95% confidence interval was reduced to less than 0.1 log unit (relative afferent pupillary defect +/- 0.05 log unit). Also, there was less variability when the dark interval between alternating light stimulation was less than one second. CONCLUSIONS: Computerized infrared pupillography can standardize the alternating light test and minimize the error in quantifying a relative afferent pupillary defect. A reproducible relative afferent pupillary defect measurement is desirable for defining afferent injury and following the course of disease.

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OBJECTIVE: To determine the outcomes of vitreoretinal surgery after choroidal tumor biopsy. DESIGN: Retrospective, single-center, consecutive case series. PARTICIPANTS: A total of 739 consecutive patients undergoing choroidal tumor biopsy. METHODS: All subjects who underwent transretinal or transscleral choroidal tumor biopsy for diagnostic or prognostic purposes between May 1993 and May 2013 were identified in our database. We then reviewed patients who subsequently required secondary vitreoretinal surgery for complications arising from such biopsies. MAIN OUTCOME MEASURES: Reason for vitreoretinal surgery, association with biopsy procedure, best-corrected visual acuity (BCVA; logarithm of the minimum angle of resolution [logMAR]), intraocular or extrascleral tumor dissemination, resolution of vitreous hemorrhage, reattachment of the retina with a single vitreoretinal procedure, number of additional vitrectomies undertaken, and number of enucleations. RESULTS: A total of 20 of 739 eyes (2.7%) underwent vitreoretinal surgery for complications arising from choroidal tumor biopsy. The tumors consisted of choroidal melanoma in all 20 eyes. The reasons for the secondary surgery included persistent vitreous hemorrhage in 1.9% (14/739), rhegmatogenous retinal detachment in 0.7% (5/739), and endophthalmitis in 0.14% (1/739). Median BCVA improved from 2.0 logMAR (mean, 1.92 logMAR; range, 0.8-2.7 logMAR) before vitrectomy to 0.72 logMAR (mean, 0.88 logMAR; range, -0.14 to 2.7 logMAR) after vitrectomy and 0.76 logMAR (mean, 1.14 logMAR; range, 0.1-3.0 logMAR) at the final visit (P < 0.0001, t test). Permanent resolution of vitreous hemorrhage was achieved in 6 of 14 patients, and reattachment of the retina was achieved in 2 of 5 patients after the first vitrectomy. A median of 1 (mean, 1.5; range, 1-3) additional vitrectomy was performed. Enucleation was necessary in 3 of 20 eyes (15%). There were no cases of intraocular invasion or extrascleral extension after vitrectomy. CONCLUSIONS: Vitrectomy for complications of choroidal tumor biopsy is rare. Such corrective surgery is complex and is best undertaken by specialized ocular oncologists or vitreoretinal surgeons with experience in managing this problem.