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Search Results: 1 - 10 of 503 matches for " Niall Patton "
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Pupillary anomaly masquerading as a glaucomatous visual field defect: a case report
Niall Patton, Adrian Tey
BMC Ophthalmology , 2004, DOI: 10.1186/1471-2415-4-6
Abstract: We describe a patient who was found to have a superior visual field defect on routine testing by the optician. Repeat perimetry with pharmacological dilatation of the pupil revealed that the cause of the field defect was related to an eccentric inferiorly displaced pupil, secondary to trauma some years previously.Individual patient characteristics, including both ocular, as well as facial, need to be considered, when interpreting any visual field defect.Ophthalmologists are commonly referred patients with visual field defects, possibly related to a potential diagnosis of glaucoma [1]. However, other causes for visual field defects need to be considered. We report a case of a patient with a superior visual field defect referred to a glaucoma clinic. A pupillary cause for the field defect was suspected. Repeat perimetry with pharmacogical manipulation of the pupil resulting in a normal visual field confirmed this.A 72 year old lady was referred to the glaucoma clinic by her optometrist after routine Humphrey SITA fast perimetry in both eyes revealed a superior visual field defect in her right eye. The patient was asymptomatic and was visiting the optometrist for a routine annual visit. There was no known family history of glaucoma. Past ocular history included a penetrating injury to the right eye with closure of an inferior limbal wound over 10 years ago. This had resulted in loss of iris tissue inferiorly, and an inferiorly-displaced pupil. On examination, visual acuity was 6/9 corrected in each eye. Intraocular pressure was 16 mmHg OD, and 15 mmHg OS. Examination of the anterior segment and gonioscopy of the left eye was unremarkable. Examination of the right eye revealed an inferior limbal scar due to the previous penetrating eye injury, with loss of iris tissue inferiorly and an inferiorly-displaced pupil (figure 1). Gonioscopy showed an abnormal angle over the inferior 90° but the remainder of the angle was normal. Examination of both fundi revealed healthy opti
Methods of assessment of patients for Nd:YAG laser capsulotomy that correlate with final visual improvement
Tariq M Aslam, Niall Patton
BMC Ophthalmology , 2004, DOI: 10.1186/1471-2415-4-13
Abstract: 24 patients attending for capsulotomy had pre-operative measures of glare with BAT tester, visibility of posterior pole and grading of posterior capsular pearls and fibrosis seen at slit lamp. Visual function was measured before and after standardised capsulotomy. Correlations of the various preoperative measures with eventual visual function improvements were calculated.Pearls at slit lamp and poor posterior pole visualisation were all correlated with improvements in visual acuity and contrast sensitivity after capsulotomy. Amount of fibrosis visible at slit lamp and glare assessment were not correlated with vision improvements after laser.Of the various measures that are taken prior to Nd : YAG capsulotomy, some correlate with eventual visual improvement but for others no clinical utility was found. Practitioners should note these findings as they are especially of use in more questionable or high-risk cases to help determine whether referral for PCO treatment by Nd: YAG capsulotomy is likely to benefit the patient.Posterior capsular opacification (PCO) remains one of the most common post operative morbidities in modern day cataract surgery [1,2] and Nd:YAG posterior capsulotomy is one of the most commonly performed surgical procedures.However, the Nd: YAG capsulotomy procedure has been associated with complications such as damage to intraocular lenses [3], post operative intraocular pressure increases [4], cystoid macular oedema [4], disruption of the anterior vitreous face [5] and increased incidence of retinal detachment [6].Until recently Nd:YAG laser treatments have cost the U.S healthcare system up to $250 million annually [7]. Apart from exposing a patient to unnecessary risk, unqualified capsulotomies worsen this burden to the developed and developing world [8].PCO is an extremely common development in patients after cataract extraction and in many mild cases it may not be immediately obvious whether it is visually significant. Patients may have reduced vi
A freely accessible, evidence based, objective system of analysis of posterior capsular opacification ; Evidence for its validity and reliability
Tariq M Aslam, Niall Patton, Jim Graham
BMC Ophthalmology , 2005, DOI: 10.1186/1471-2415-5-9
Abstract: The system of PCO analysis was developed considering current published evidence on visual significance of PCO and additional investigative analysis of PCO images. Details of the image processing and analysis steps are discussed and a final system that measures an entropy score weighted toward proximity to central areas is described. In order to assess validity, the systems ability to measure PCO progression is assessed along with the visual significance of its final computerised scores. Reliability of the system is also assessed.The final system runs successfully and is simple to use. Analyses of PCO by the system show an ability to detect early progression of PCO as well as detection of visually significant PCO. Images with no clinical PCO produce very low scores in the analysis. Reliability of the system of analysis is shown to be satisfactory.This paper presents a system of PCO analysis that is evidence based, objective and clinically useful. Substantial evidence is provided for its validity and reliability.Despite advances in the practice of cataract surgery and intraocular lens implantation, posterior capsule opacification remains the most common post-operative cause of morbidity[1]. However, there is currently no consensus on an optimal PCO quantification method. The main objective systems of analysis, POCO[2] and AQUA[3] systems are not freely available. They do not incorporate whether PCO is peripheral or central into calculations and show limited evidence for validity. The EPCO system [4] has been assessed for evidence of construct validity [5] but is still subjective. The POCO system[6] is also subjective and is not convincing for analysis of PCO in terms of measuring progression or visual significance. There is clearly a need for a universally acceptable measure of PCO [7] that would be objective enough for scientific analysis and yet not exclude the majority of researchers by its lack of free availability. It should be based upon current evidence on the
OSCA: a comprehensive open-access system of analysis of posterior capsular opacification
Tariq M Aslam, Niall Patton, Christopher J Rose
BMC Ophthalmology , 2006, DOI: 10.1186/1471-2415-6-30
Abstract: Principal features of the OSCA system of analysis are discussed. Flash artefacts are automatically located in two PCO images and the images merged to produce a composite free from these artefacts. For this to be possible the second image has to be manipulated with a registration technique to bring it into alignment with the first. Further image processing and analysis steps use a location-sensitive entropy based texture analysis of PCO. Validity of measuring PCO progression of the whole new system is assessed along with visual significance of scores. Reliability of the system is assessed.Analysis of PCO by the system shows ability to detect early progression of PCO, as well as detection of more visually significant PCO. Images with no clinical PCO produce very low scores in the analysis. Reliability of the system of analysis is demonstrated.This system of PCO analysis is evidence-based, objective and clinically useful. It incorporates flash detection and removal as well as location sensitive texture analysis. It provides features and benefits not previously available to most researchers or clinicians. Substantial evidence is provided for this system's validity and reliability.Cataract extraction is the most common ophthalmic surgical procedure and posterior capsule opacification (PCO) remains the most common post-operative cause of morbidity[1]. There are many factors known to influence PCO[2] and there is abundant research into prevention and treatment of this condition. Objective research requires a reliable and valid outcome measure[3]. It is essential for unbiased and incontrovertible scientific progress to have an open, accessible system that can freely be used in the scientific community. However, there is currently no consensus on an optimal quantification method for PCO analysis. There are many competing systems with varying degrees of validity and objectivity. In particular, the POCO[4] and AQUA[5] systems demonstrate elaborate and appropriate algorithms fo
Does a small central Nd:YAG posterior capsulotomy improve peripheral fundal visualisation for the Vitreoretinal surgeon?
Niall Patton, Tariq M Aslam, Harry G Bennett, Baljean Dhillon
BMC Ophthalmology , 2004, DOI: 10.1186/1471-2415-4-8
Abstract: Patients undergoing Nd:YAG capsulotomy for PCO were examined pre- and four weeks post- Nd:YAG capsulotomy. In order to give a quantitative measure of visualisation of the peripheral retina, a novel scalar measurement was developed. Changes in the degree of visualisation following Nd:YAG capsulotomy were calculated.There was a significant improvement in fundal visualisation of the retinal periphery with scleral indentation following Nd:YAG capsulotomy (p = 0.001).Peripheral fundal visualisation with scleral indentation improves following a small central Nd:YAG capsulotomy. This finding is important in relation to the detection of peripheral pseudophakic retinal breaks, particularly in those patients deemed at high risk following Nd:YAG capsulotomy.Posterior capsular opacification (PCO) is the commonest complication of cataract surgery [1]. It has implications not only for the immediate visual function of the patient, but also for the ophthalmologists' diagnostic ability, as PCO may have a significant impact on the ability of the vitreoretinal surgeon to visualise the peripheral fundus. This may be particularly important for patients at risk of retinal detachment.After uneventful extracapsular cataract surgery, Nd:YAG capsulotomy has been shown to increase the risk of developing a retinal detachment [2-11]. Proposed mechanisms include liquefaction of the vitreous[12] and interruption of the anterior hyaloid face[13]. Whilst some authors consider the increased risk to be as a result of opening the capsule and not a specific complication of the laser procedure itself[10,12,14], minimising the energy used to create the capsulotomy is generally considered advisable to minimise the associated risk of retinal detachment[15]. It has been suggested that current practise should be wary of performing Nd:YAG capsulotomy on high risk patients, such as high myopes. However when making this decision, one must also consider that there may be an increased difficulty in fundal visuali
Is the Remediation at Parys Mountain Successfully Reducing Acid Mine Drainage?  [PDF]
Niall Marsay
Journal of Environmental Protection (JEP) , 2018, DOI: 10.4236/jep.2018.95034
Abstract: Metal ion concentrations and acidity were used as indicators of acid mine drainage (AMD) at Parys Mountain, a large abandoned copper mine on An-glesey, Wales. Water samples were collected in two sessions and taken from a linear stream flowing from the northern side of the mine, and a stream flowing from the south side of the mine that has two settling ponds and long stretches of wetland along its path. pH measurements were taken to measure acidity levels and metal ions (Fe, Al, Zn, Cu, Mn, and Pb) were quantified by inductively coupled plasma (ICP-OES) spectrometry. The pH values at the settling ponds and northern stream were between 2 and 3 while the wetlands had pH values of 5 - 6 implying that it was the wetlands that reduced acidity, and not the distance downstream. Both streams showed a reduction in concentrations of all elements with distance downstream. The decrease was linear for the northern stream and exponential for the southern stream, suggesting that the reed beds and settling ponds were successful at removing metal ions; potentially, through slower flow rates allowing more time for redox reactions to occur, thus precipitating metal hydroxides and pure metals and removing them from solution. In November, the northern stream had substantially higher concentrations of Fe, Al, Zn, Cu, and Mn, but not Pb (126, 34.0, 29.1, 14.6, 10.4, and 0.064 mg/L respectively) in solution when compared to the southern stream, which had concentrations of 10.2, 12.2, 11.9, 2.43, 6.11, and 0.706 mg/L for Fe, Al, Zn, Cu, Mn, and Pb respectively. However, in January the first sample site had higher concentrations of all elements except Mn; (107, 22.0, 26.1, 10.3, 1.48, and 0.506 mg/L for Fe, Al, Zn, Cu, Mn, and Pb respectively) when compared to the northern stream (55.0, 10.6, 7.55, 6.10, 1.59, and 0.041 mg/L for Fe, Al, Zn, Cu, Mn, and Pb respectively): but by the second sample site, the southern stream concentrations had dropped to concentrations present in the northern stream. This data indicates less AMD was produced on the southern side during low rainfall periods. Remediation was measured by calculating the percentage reduction in concentration (PRC) between sample sites. PRCs were higher in January for most of the sites; possibly due to dilution by surface runoff from surrounding farmland. The northern stream had consistently lower PRCs between 15% - 55%. The settling ponds had higher PRCs but did not maintain consistent levels with a range of 5% - 90%, while the bogs had consistently high PRCs of 40% - 100%. The combination of the high PRC and pH in the
Out of Africa with Haste: Reflections on my Truncated Kenyan Elective
Dan Patton
University of Toronto Medical Journal , 2008, DOI: 10.5015/utmj.v85i3.249
Evaluation of a drug & alcohol primary health care team
Robert Patton
PeerJ , 2015, DOI: 10.7287/peerj.preprints.135v1
Abstract: As part of an ongoing assessment of the physical health needs of injecting drug users during 2005, all 167 general practices in the Lambeth, Southwark & Lewisham (LSL) area were sent a questionnaire. The results indicate that the majority of IDUs visited the surgery because of DVT, pregnancy, chest infections or skin ulceration, and the GPs themselves opportunistically identified more serious problems such as BBV’s and Liver problems. Interestingly we found significant variation in the rate of opportunistic detection between PCTs. Many practices indicated that health promotion activity would benefit their IDU clients, in particular issues related to smoking and drinking, as well as dental health, diet and exercise needed to be addressed. In general it was felt that a nurse led resource integrated into existing services, such as that offered by the Drug and Alcohol Health Care Team, would be of greatest benefit to IDU clients.
Identification and management of physical health problems among an injecting drug using population
Robert Patton
PeerJ , 2015, DOI: 10.7287/peerj.preprints.108v1
Abstract: Injecting drug use is highly prevalent in London and is associated with specific physical health problems. These problems are related to the toxicity of the substances, their mode of consumption and as a consequence of the drug taking lifestyle. Hepatitis B and C viral infections are common among drug users due to sharing of both needles and other drug taking paraphernalia. Hepatitis B infection can be prevented by immunisation. Hepatitis C infection can interact with alcohol consumption to accelerate liver damage. Sharing of drug injection equipment is high (up to 78%). Injecting drug users (IDUs) that live close to needle exchanges are significantly less likely to engage in sharing activities than those that live further away. Drug users are at particular risk of developing poor dental health, which is associated with morbidity and mortality, particularly cardio-vascular conditions and respiratory disease. Many female drug users have been involved with the commercial sex industry and are at risk of contracting blood borne viruses. Drug users who also use alcohol have an increased likelihood of physical morbidity and injury / trauma. Problem drug users have an increased likelihood of experiencing physical morbidity, but are less likely to engage with primary care services. Barriers to accessing primary care include convenience (access), apathy, procrastination and “self-medication”. Drug users are more likely to report physical health complications at an Accident & Emergency department (AED) than at a GP practice. Further investigation of local AEDs is required to ascertain their potential for assessing and referring drug users to specialist services and other primary care providers. Integration of primary care and drug treatment services may encourage drug users to engage in treatment for physical morbidity and promote retention within addictions services. Physical health of drug users may be assessed as part of a formal induction to treatment services, or opportunistically as appropriate. Drug users presenting to primary care services for prescriptions related to their addiction may not experience such an assessment. Increasing GPs knowledge and skills can lead to greater implementation of screening practices. The provision of primary care services to clients attending addiction treatment centres can lead to improvements in drug users’ physical health and enhanced treatment outcomes.
Concrete uses of XML in software development and data analysis
S. Patton
Computer Science , 2003,
Abstract: XML is now becoming an industry standard for data description and exchange. Despite this there are still some questions about how or if this technology can be useful in High Energy Physics software development and data analysis. This paper aims to answer these questions by demonstrating how XML is used in the IceCube software development system, data handling and analysis. It does this by first surveying the concepts and tools that make up the XML technology. It then goes on to discuss concrete examples of how these concepts and tools are used to speed up software development in IceCube and what are the benefits of using XML in IceCube's data handling and analysis chain. The overall aim of this paper it to show that XML does have many benefits to bring High Energy Physics software development and data analysis.
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