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Search Results: 1 - 10 of 402424 matches for " Tariq M Aslam "
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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
Isolation of cellulolytic activities from Tribolium castaneum (red flour beetle)
FU Rehman, M Aslam, MI Tariq, A Shaheen, AJ Sami, NH Naveed, AI Batool
African Journal of Biotechnology , 2009,
Abstract: Cellulolytic enzymes have immense potential to convert cellulosic biomass into useful products. Tribolium castaneum crude proteins were isolated to screen the cellulolytic activities. The activity was established by substrate-agar plate assay and confirmed by endoglucanase assay. Cellulolytic activity was further purified and characterized using the different chromatographic techniques and electrophoresis. Gel filtration chromatography showed the presence of multiple forms of enzyme activities with different molecular weights. Stability of enzyme activity was investigated at different temperatures and pH. Optimum pH for was found 4.8 at 40oC determined as optimum temperature. Gradually decreasing Enzyme activity remained half at 60oC. Zymography and SDS-PAGE showed the presence of multiple forms of endoglucanase activities (Cel I and Cel II) with molecular weight of 55 kDa and 35 kDa.
Effect of Scuffing Damage and Curing on Diffusion Rate of CO2 Through Citrus Fruit Peel
Muhammad Akram Tariq,Faqir Muhammad Tahir,Ali Asghar Asi,M. Aslam Pervez
Journal of Biological Sciences , 2001,
Abstract: These studies were initiated to observe the effect of curing on the shelf life of damaged citrus fruits by reducing diffusion rate of CO2. The damaged peel had a higher diffusion rate of CO2 than undamaged fruit peel before curing. The effect of curing on peel was that the diffusion rate of CO2 through damaged and undamaged peel was reduced after curing. The peel of cured fruits did not show any change in diffusion rate of CO2 after 30 days of storage. Curing could be useful to reduce respiration/exchange of gases and in extending the storage life of damaged citrus fruit.
Effect of Curing and Packaging on Damaged Citrus Fruit Quality
Muhammad Akram Tariq,Faqir Muhammad Tahir,Ali Asghar Asi,M. Aslam Pervez
Journal of Biological Sciences , 2001,
Abstract: Sealing and curing was found favourable to maintain the fruit quality and to extend its shelf life upto 6-7 weeks. The treatments also helped in healing and inhibited softening. Higher O2 and lower CO2 contents were found in sealed-cured fruit bags. The combined treatment (sealing + curing + washing) was found more effective than individual treatments.
Optimisation and Assessment of Three Modern Touch Screen Tablet Computers for Clinical Vision Testing
Humza J. Tahir, Ian J. Murray, Neil R. A. Parry, Tariq M. Aslam
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0095074
Abstract: Technological advances have led to the development of powerful yet portable tablet computers whose touch-screen resolutions now permit the presentation of targets small enough to test the limits of normal visual acuity. Such devices have become ubiquitous in daily life and are moving into the clinical space. However, in order to produce clinically valid tests, it is important to identify the limits imposed by the screen characteristics, such as resolution, brightness uniformity, contrast linearity and the effect of viewing angle. Previously we have conducted such tests on the iPad 3. Here we extend our investigations to 2 other devices and outline a protocol for calibrating such screens, using standardised methods to measure the gamma function, warm up time, screen uniformity and the effects of viewing angle and screen reflections. We demonstrate that all three devices manifest typical gamma functions for voltage and luminance with warm up times of approximately 15 minutes. However, there were differences in homogeneity and reflectance among the displays. We suggest practical means to optimise quality of display for vision testing including screen calibration.
A Comparison of Saudi Building Code with 1997 UBC for Provisions of Modal Response Spectrum Analysis Using a Real Building  [PDF]
Tariq M. Nahhas
Open Journal of Earthquake Research (OJER) , 2017, DOI: 10.4236/ojer.2017.62006
Abstract: The study uses an actual building to compare the modal response spectrum analysis results of Saudi Building Code (SBC) and the 1997 Uniform Building Code (UBC) used in Saudi Arabia before the introduction of SBC. A sample of four buildings with reported analysis of comparison between IBC and UBC is taken for confirming the comparison. Eight sample places from SBC map for Saudi Arabia together with two sample places of high seismic activity in USA were taken for the comparisons. The study used software package ETABS in this study for modeling and analysis. The results are dissimilar from the comparisons reported for test places of USA. It is concluded that at most places SBC base shear is higher for both ELFP and MRSA. However, the results cannot be generalized and considered always right. The same is factual for overturning moments. Consequently, we cannot report that SBC is more conservative than UBC for all scenarios.
Utilization of Pollen Irradiation Technique for the Improvement of G. hirsutum L.
M. Aslam
Pakistan Journal of Biological Sciences , 2000,
Abstract: Not Available
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