Displaying publications 1 - 20 of 26 in total

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  1. Omar R, Knight VF, Mohammed Z, Tholasee GM
    MyJurnal
    While the prevalence of visually impaired children constitutes a small portion of the visually impaired population, it is important to determine whether the low vision services available are utilised by these children. This is important as previous studies have shown that children have a very high rate of successful low vision device use compared to adults. This was a cross sectional retrospective study. Fifty nine low vision clinic children records were evaluated. The results showed that 25.4% of the children were categorised as with moderate low vision, 30.5% with severe low vision and 40.7% were categorised as blind. The major causes of low vision were congenital cataract, congenital nystagmus, congenital glaucoma, macular degeneration and retinitis pigmentosa. Low vision rehabilitation for near work using magnifiers improved the vision of 30.5% of the low vision children. This finding suggests that 1/3 of low vision children could benefit from low vision rehabilitation. The low vision devices most commonly prescribed to the children in this study were stand magnifiers, hand-held magnifiers and spectacles. This study illustrates the key role of optometrists in the management of visual impairment in Malaysian children. It would appear that the establishment of low vision services in government hospitals using trained optometrists is a cost effective method of service delivery. Therefore more low vision children would have access to proper low vision rehabilitation and through that rehabilitation, their quality of life can be improved.
    Key words: children, low vision
    Study site: Klinik Penglihatan Terhad Pusat Perubatana, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
  2. Omar R, Mohammed Z, Knight VF, Basrul MH
    Med J Malaysia, 2009 Dec;64(4):289-93.
    PMID: 20954552
    This study looked at the causes of vision loss, levels of distance, near vision and the use of low vision devices (LVDs) in children studying at special schools in Malaysia. A total of 139 children from two special education schools took part. Visual acuity was measured with and without LVDs. Those who required further assessment were referred to Low Vision Clinic. Near visual acuity in 71 children ranged from N4 to N64. Sixty eight children could not read the N64 chart or they were totally blind. Only eight students were using LVDs before intervention. Seventy one children were referred for low vision assessment and 48 were found to benefit from the LVDs prescribed. The major cause of visual impairment was cataract (17%). Hand held magnifier was the most preferred LVD. Majority of the children attending the blind schools had residual vision but did not have LVDs. LVDs are able to significantly improve near visual acuity and hence there is a need to prescribe and train the children to use the LVDs.
  3. Omar R, Hussin DA, Knight VF
    J Med Assoc Thai, 2012 Mar;95(3):412-7.
    PMID: 22550841
    Compare the performance of Lea Symbols and Sheridan Gardiner charts against the standard test chart used to determine reduced VA during vision screening among pre-schoolers.
  4. Omar R, Idris SS, Meng CK, Knight VF
    J Med Case Rep, 2012;6:316.
    PMID: 22992390
    A number of vision defects have been reported in association with albinism, such as photophobia, nystagmus and astigmatism. In many cases only prescription sunglasses are prescribed. In this report, the effectiveness of low-vision rehabilitation in albinism, which included prescription of multiple visual aids, is discussed.
  5. Omar R, Knight VF, Hussin DA
    Med J Malaysia, 2013 Jun;68(3):245-8.
    PMID: 23749015 MyJurnal
    This study determined the outcome of combining home based and clinic based amblyopia therapy among preschool children. A total of 479 preschool children were randomly selected for vision screening. Amblyopic therapy was prescribed to children whose visual acuity (VA) could not be improved to <0.1 LogMAR after a 6 week adaptation period with glasses. Intensive near work activities were conducted daily at home for 12 weeks, monitored by parents while weekly therapy was conducted at the optometry clinic by an optometrist. Six preschool children were diagnosed with refractive amblyopia, spherical equivalent (SE) was -11.25D to +0.75D. Significant improvement was found in the VA of right eye, t(6) = 3.07, left eye t(6) = 3.07 and both eyes t(6) = 3.42) p<0.05, at the end of the 12 week therapy. Combining home based and clinic based amblyopia therapy among preschool children showed a positive improvement in VA after 12 weeks of therapy.
    Study site: kindergarten, optometry clinic, Perak (site unclear)
  6. Omar R, Rahman MH, Knight VF, Mustaphal M, Mohammed Z
    BMC Res Notes, 2014;7:667.
    PMID: 25245590 DOI: 10.1186/1756-0500-7-667
    BACKGROUND: Vision impairment associated with diabetic retinopathy, is well known and low vision rehabilitation is always recommended. In this report, the importance of objective measure of mental health and quality of life screening in diabetic retinopathy low-vision assessment is discussed.
    CASE PRESENTATION: We describe the case of a 43-year-old Asian female who has mild vision impairment due to tractional retinal detachment secondary to diabetic retinopathy and how mental health screening and quality of life screening during low vision rehabilitation can improve in the management of this patient.
    CONCLUSION: Although vision impairment was mild, the psychological impact was enormous and affected her quality of life substantially. This case report illustrates that recognition of the mental health and quality of life impact on visual impairment is critical to the rehabilitation management of low vision patients with diabetic retinopathy.
  7. Omar R, Knight VF, Aziz Mohammed MA
    Malays Fam Physician, 2014;9(3):27-33.
    PMID: 26425302 MyJurnal
    Work-related ocular injuries and illnesses were among the major causes of job absenteeism. This study was conducted to determine if low vision rehabilitation was provided following work-related ocular problems among industrial workers in a developing country. This was a retrospective analysis of case records.
  8. Gnanou JV, Caszo BA, Khalil KM, Abdullah SL, Knight VF, Bidin MZ
    PMID: 26155596 DOI: 10.1186/s40200-015-0183-9
    BACKGROUND: Adiponectin is a hormone secreted by adipocytes during the fasting phase of the fast-fed cycle. Ramadan fasting involves prolonged fasting for up to twelve hours and thus could lead to increased secretion of adiponectin by adipocytes. However, studies on the role of adiponectin on glucose and body weight homeostasis during Ramadan fasting is still a matter of controversy. Thus the specific aim of this study was to assess the effect of fasting during Ramadan on the adiponectin levels, body weight and glucose homeostasis in healthy male Malaysian subjects.

    METHODS: Twenty healthy male (19-23 years) Muslim subjects were followed up during the fasting month of Ramadan. Anthropometry and blood samples were taken one week before and during the fourth week of fasting. Plasma glucose, insulin and adiponectin were estimated and insulin sensitivity indices were estimated using the Homeostasis Model Assessment.

    RESULTS: Subjects experienced a significant decrease in body weight (2.4 %, p 

  9. Johari HM, Zainudin HA, Knight VF, Lumley SA, Subramanium AS, Caszo BA, et al.
    J Sports Med Phys Fitness, 2017 Apr;57(4):396-401.
    PMID: 27045742 DOI: 10.23736/S0022-4707.16.06292-7
    BACKGROUND: Anthropometric and lung function characteristics of triathletes are important for the implementation of individual specific training and recovery recommendations. However, limited data are available for these parameters in triathletes. Hence, the aim of this study was to characterize and examine the gender differences of lung function and anthropometry parameters in competitive triathletes from Malaysia.

    METHODS: Body composition assessment and lung function tests were performed on sixteen competitive triathletes (nine male and seven female). The subject's body composition profile including muscle mass (kg), fat free mass (kg), and percent body fat was measured using a bio-impedance segmental body composition analyzer. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured by Quark PFT2 spirometer.

    RESULTS: The anthropometric measurements revealed that male triathletes were significantly taller than female triathletes and had significantly more protein and skeletal muscle mass. The female triathletes, however, had significantly higher percent body fat. Male triathletes had statistically significant higher FVC and FEV1 than female triathletes. Both the male and female triathletes showed a positive correlation between height, fat free mass and the lung function markers FVC and FEV1. This association was not seen with Body Mass Index (BMI) in female triathletes.

    CONCLUSIONS: The data from our study shows that anthropometric parameters are directly linked to lung function of a triathlete. We also found the relationship between BMI and lung function to be gender specific in triathletes and is dependent on the body protein and fat content. Hence, body composition characterization is essential and provides valuable information for developing individual specific training modules.
  10. Omar R, Kuan YM, Zuhairi NA, Manan FA, Knight VF
    Int J Ophthalmol, 2017;10(9):1460-1464.
    PMID: 28944208 DOI: 10.18240/ijo.2017.09.20
    AIM: To compare visual efficiency, specifically accom-modation, vergence, and oculomotor functions among athletes and non-athletes.

    METHODS: A cross-sectional study on sports vision screening was used to evaluate the visual skills of 214 elementary students (107 athletes, 107 non-athletes), aged between 13 and 16y. The visual screening assessed visual parameters such as ocular motor alignment, accommodation, and vergence functions.

    RESULTS: Mean visual parameters were compared between age-group matched athletes (mean age 14.82±0.98y) and non-athletes (mean age 15.00±1.04y). The refractive errors of all participants were corrected to maximal attainable best corrected visual acuity of logMAR 0.0. Accommodation function assessment evaluated amplitude of accommodation and accommodation facility. Vergence functions measured the near point of convergence, vergence facility, and distance fusional vergence at break and recovery point. Ocular motor alignment was not statistically significant between both groups. Athletes had a statistically significant amplitude of accommodation for both the right eye (t=2.30, P=0.02) and the left eye (t=1.99, P=0.05). Conversely, non-athletes had better accommodation facility (t=-2.54, P=0.01) and near point of convergence (t=4.39, P<0.001) when compared to athletes. Vergence facility was found to be better among athletes (t=2.47, P=0.01). Nevertheless, non-athletes were significantly better for both distance negative and positive fusional vergence.

    CONCLUSION: Although the findings are still inconclusive as to whether athletes had superior visual skills as compared to non-athletes, it remains important to identify and elucidate the key visual skills needed by athletes in order for them to achieve higher performance in their sports.

  11. Zainudin H, Caszo BA, Knight VF, Gnanou JV
    Eurasian J Med, 2019 Jun;51(2):116-120.
    PMID: 31258349 DOI: 10.5152/eurasianjmed.2019.18106
    Objective: Regular moderate-intensity exercise has beneficial health effects, whereas regular strenuous exercise increases the production of oxidants that may lead to DNA, skeletal, and cardiac muscle damages. Triathletes experience strenuous muscular activity both during competition and training, being at risk of developing these tissue damages. The objective of the present study was to estimate DNA, skeletal, and cardiac muscle damages using blood biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), myoglobin, and cardiac troponin I (cTnI) among young triathletes.

    Materials and Methods: Age-matched seven male and seven female triathletes were recruited for the study. They were on a standardized training regimen and on average competed in at least one endurance event every month for the past 3-4 years. Serum biomarkers were measured using enzyme-linked immunosorbent assay at the start and at end of the racing season.

    Results: Both male and female triathletes showed a statistically significant increase in 8-OHdG. A similar pattern of increase was seen with serum myoglobin, which was not statistically significant in both male and female triathletes. cTnI levels did not show any change in both sexes.

    Conclusion: Our study shows that there could be an increased evidence of DNA damage among triathletes. However, similar effects were not observed with skeletal and cardiac muscle biomarkers.

  12. Omar R, Wan Abdul WMH, Knight VF
    BMC Public Health, 2019 Jun 13;19(Suppl 4):543.
    PMID: 31196018 DOI: 10.1186/s12889-019-6865-3
    BACKGROUND: School children are considered a high-risk group for visual impairment because uncorrected refractive errors and problems such as amblyopia can seriously affect their learning abilities and their physical and mental development. There are many studies reporting the prevalence of refractive errors among school children of different ethnic groups in Malaysia, however, studies concerning the prevalence of refractive errors among indigenous or Orang Asli children are very limited. Therefore, the objective of this study was to determine the prevalence and causes of visual impairment among Orang Asli children.

    METHODS: One hundred ten Orang Asli children aged 7 to 12 years old in Negeri Sembilan, Malaysia were selected. 51% of these children were boys while the remainders were girls. They underwent visual acuity test, cover test, Hirschberg's test, ocular external assessment and ophthalmoscopy. Children who failed the vision screening were then referred for further eye examination.

    RESULTS: Of these 110 Orang Asli children, 46 failed the vision screening and subsequently 45 of them were confirmed to have visual problems (40.9% of the total subjects). The main cause of visual impairment in this study was refractive error (34.5% of the total subjects) where the main refractive error found was hyperopia (28.2%) followed by amblyopia (2.7%), strabismus (1.8%) and ocular abnormalities (1.8%).

    CONCLUSION: Hence, vision screening and a comprehensive eye examination is very important and needs to be done on all Orang Asli children so that any visual problems can be detect at an early stage to avoid the development of learning difficulties among these already disadvantaged children.

  13. Norizan MN, Moklis MH, Ngah Demon SZ, Halim NA, Samsuri A, Mohamad IS, et al.
    RSC Adv, 2020 Nov 27;10(71):43704-43732.
    PMID: 35519676 DOI: 10.1039/d0ra09438b
    Carbon nanotubes (CNTs) have been recognised as a promising material in a wide range of applications, from safety to energy-related devices. However, poor solubility in aqueous and organic solvents has hindered the utilisation and applications of carbon nanotubes. As studies progressed, the methodology for CNTs dispersion was established. The current state of research in CNTs either single wall or multiwall/polymer nanocomposites has been reviewed in context with the various types of functionalisation presently employed. Functionalised CNTs have been playing an increasingly central role in the research, development, and application of carbon nanotube-based nanomaterials and systems. The extremely high surface-to-volume ratio, geometry, and hollow structure of nanomaterials are ideal for the adsorption of gas molecules. This offers great potential applications, such as in gas sensor devices working at room temperature. Particularly, the advent of CNTs has fuelled the invention of CNT-based gas sensors which are very sensitive to the surrounding environment. The presence of O2, NH3, NO2 gases and many other chemicals and molecules can either donate or accept electrons, resulting in an alteration of the overall conductivity. Such properties make CNTs ideal for nano-scale gas-sensing materials. Conductive-based devices have already been demonstrated as gas sensors. However, CNTs still have certain limitations for gas sensor application, such as a long recovery time, limited gas detection, and weakness to humidity and other gases. Therefore, the nanocomposites of interest consisting of polymer and CNTs have received a great deal of attention for gas-sensing application due to higher sensitivity over a wide range of gas concentrations at room temperature compared to only using CNTs and the polymer of interest separately.
  14. Faiz Norrrahim MN, Mohd Kasim NA, Knight VF, Mohamad Misenan MS, Janudin N, Ahmad Shah NA, et al.
    RSC Adv, 2021 Feb 10;11(13):7347-7368.
    PMID: 35423275 DOI: 10.1039/d0ra08005e
    Chemical contaminants such as heavy metals, dyes, and organic oils seriously affect the environment and threaten human health. About 2 million tons of waste is released every day into the water system. Heavy metals are the largest contributor which cover about 31% of the total composition of water contaminants. Every day, approximately 14 000 people die due to environmental exposure to selected chemicals. Removal of these contaminants down to safe levels is expensive, high energy and unsustainable by current approaches such as oxidation, biodegradation, photocatalysis, precipitation, reverse osmosis and adsorption. A combination of biosorption and nanotechnology offers a new way to remediate these chemical contaminants. Nanostructured materials are proven to have higher adsorption capacities than the same material in its larger-scale form. Nanocellulose is very promising as a high-performance bioadsorbent due to its interesting characteristics of high adsorption capacity, high mechanical strength, hydrophilic surface chemistry, renewability and biodegradability. It has been proven to have higher adsorption capacity and better binding affinity than other similar materials at the macroscale. The high specific surface area and abundance of hydroxyl groups within lead to the possible functionalization of this material for decontamination purposes. Several research papers have shown the effectiveness of nanocellulose in the remediation of chemical contaminants. This review aims to provide an overview of the most recent developments regarding nanocellulose as an adsorbent for chemical contamination remediation. Recent advancements regarding the modification of nanocellulose to enhance its adsorption efficiency towards heavy metals, dyes and organic oils were highlighted. Moreover, the desorption capability and environmental issue related to every developed nanocellulose-based adsorbent were also tackled.
  15. Osman MJ, Abdul Rashid JI, Khim OK, Zin Wan Yunus WM, Mohd Noor SA, Mohd Kasim NA, et al.
    RSC Adv, 2021 Jul 27;11(42):25933-25942.
    PMID: 35479481 DOI: 10.1039/d1ra04318h
    Acephate (Ac) is an organophosphate (OP) compound, which is able to inhibit the activity of acetylcholinesterase. Thus, the aim of this study was to optimize the detection of Ac using a thiolated acephate binding aptamer-citrate capped gold nanoparticle (TABA-Cit-AuNP) sensor that also incorporated an image processing technique. The effects of independent variables, such as the incubation period of TABA-Cit-AuNPs (3-24 h) for binding TABA to Cit-AuNPs, the concentration of phosphate buffer saline (PBS) (0.001-0.01 M), the concentration of thiolated acephate binding aptamer (TABA) (50-200 nM), and the concentration of magnesium sulphate (MgSO4) (1-300 mM) were investigated. A quadratic model was developed using a central composite design (CCD) from response surface methodology (RSM) to predict the sensing response to Ac. The optimum conditions such as the concentration of PBS (0.01 M), the concentration of TABA (200 nM), the incubation period of TABA-Cit-AuNPs (3 h), and the concentration of MgSO4 (1 mM) were used to produce a TABA-Cit-AuNPs sensor for the detection of Ac. Under optimal conditions, this sensor showed a detection ranging from 0.01 to 2.73 μM and a limit of detection (LOD) of 0.06 μM. Real sample analysis demonstrated this aptasensor as a good analytical method to detect Ac.
  16. Dzulkurnain NA, Mokhtar M, Rashid JIA, Knight VF, Wan Yunus WMZ, Ong KK, et al.
    Polymers (Basel), 2021 Aug 15;13(16).
    PMID: 34451266 DOI: 10.3390/polym13162728
    Conducting polymers have been widely used in electrochemical sensors as receptors of the sensing signal's analytes and transducers. Polypyrrole (PPy) conducting polymers are highlighted due to their good electrical conductive properties, ease in preparation, and flexibility of surface characteristics. The objective of this review paper is to discuss the theoretical background of the two main types of electrochemical detection: impedimetric and voltammetric analysis. It also reviews the application and results obtained from these two electrochemical detections when utilizing PPy as a based sensing material in electrochemical sensor. Finally, related aspects in electrochemical sensor construction using PPy will also be discussed. It is anticipated that this review will provide researchers, especially those without an electrochemical analysis background, with an easy-to-understand summary of the concepts and technologies used in electrochemical sensor research, particularly those interested in utilizing PPy as a based sensing material.
  17. Norrrahim MNF, Mohd Kasim NA, Knight VF, Ong KK, Mohd Noor SA, Abdul Halim N, et al.
    Polymers (Basel), 2021 Sep 24;13(19).
    PMID: 34641067 DOI: 10.3390/polym13193249
    The wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies have proven its use in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides this, the presence of an abundant OH groups in nanocellulose grants its unique surface modification, which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism are also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.
  18. Omar R, Anan NS, Azri IA, Majumder C, Knight VF
    BMJ Open, 2022 Jan 31;12(1):e048965.
    PMID: 35105614 DOI: 10.1136/bmjopen-2021-048965
    OBJECTIVE: The aim of this study is to determine the characteristics of eye injuries, medical costs and return-to-work status among industrial workers to provide better vision rehabilitative services.

    SETTING: Nationwide data from the Social Security Organisation (SOCSO) of Malaysia.

    PARTICIPANTS: A stratified random sample of workers registered with the SOCSO of Malaysia with documentation of eye injury.

    PRIMARY AND SECONDARY OUTCOME MEASURES: Characteristics of eye injuries and medical costs related to eye injury (primary) and return-to-work status (secondary).

    RESULTS: A total of 884 from 8861 case files workplace accidents involving eye injury registered with Social Security Services (SOCSO) were identified. The mean age was 35±10 years and the highest incidence of work-related eye injury occurred in the age group 30-39 years and among Malay ethnics. Males are affected more than females' workers. The highest cause of eye injury was the impact from a moving object excluding falling objects (89.2%) and anterior segment injuries occurred more than posterior segment injuries. The total direct and Indirect medical cost was RM1 108 098.00 (US$316 599.40) and RM4 150 140.00 (US$1 185 754.20) for 884 cases.

    CONCLUSION: The majority of workers suffered from the low level of eye injury. A significant relationship was found between the severity of eye injury and employee work status. The indirect cost of medical and vision rehabilitation was higher than the direct cost. Awareness and vision rehabilitation programmes at the workplace need to be addressed for better prevention and rehabilitative service.

  19. Nasir MHM, Taha MM, Razali N, Ilyas RA, Knight VF, Norrrahim MNF
    Materials (Basel), 2022 Nov 15;15(22).
    PMID: 36431566 DOI: 10.3390/ma15228082
    The thermal and rheological properties of bio-composite filament materials are crucial characteristics in the development of a bio-composite Fused Deposition Modeling (FDM) filament since the printing mechanism of FDM strongly depends on the heating and extrusion process. The effect of chemical treatment on the thermal and rheological properties was investigated to develop composite filaments for FDM using natural fibres such as sugar palm fibre (SPF). SPF underwent alkaline and silane treatment processes before being reinforced with PLA for improving adhesion and removing impurities. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetric (DSC), and Melt Flow Index (MFI) analyses were conducted to identify the differences in thermal properties. Meanwhile, a rheological test was conducted to investigate the shear stress and its viscosity. The TGA test shows that the SPF/PLA composite treated with NaOH and silane showed good thermal stability at 789.5 °C with 0.4% final residue. The DSC results indicate that the melting temperature of all samples is slightly the same at 155 °C (in the range of 1 °C), showing that the treatment does not interfere with the melting temperature of the SPF/PLA composite. Thus, the untreated SPF/PLA composite showed the highest degradation temperature, which was 383.2 °C. The SPF/PLA composite treated with NaOH and silane demonstrated the highest melt flow index of 17.6 g/min. In conclusion, these findings offer a reference point for determining the filament extrusion and printability of SPF/PLA composite filaments.
  20. Taharuddin NH, Jumaidin R, Ilyas RA, Kamaruddin ZH, Mansor MR, Md Yusof FA, et al.
    Materials (Basel), 2022 Dec 15;15(24).
    PMID: 36556760 DOI: 10.3390/ma15248954
    Thermoplastic starch is a material that has the potential to be environmentally friendly and biodegradable. However, it has certain drawbacks concerning its mechanical performance and is sensitive to the presence of moisture. The current study assessed agar-containing thermoplastic sago starch (TPSS) properties at various loadings. Variable proportions of agar (5%, 10%, and 15% wt%) were used to produce TPSS by the hot-pressing method. Then, the samples were subjected to characterisation using scanning electron microscopy (SEM), mechanical analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and moisture absorption tests. The results demonstrated that adding agar to starch-based thermoplastic blends significantly improved their tensile, flexural, and impact properties. The samples' morphology showed that the fracture had become more erratic and uneven after adding agar. FT-IR revealed that intermolecular hydrogen bonds formed between TPSS and agar. Moreover, with an increase in agar content, TPSS's thermal stability was also increased. However, the moisture absorption values among the samples increased slightly as the amount of agar increased. Overall, the proposed TPSS/agar blend has the potential to be employed as biodegradable material due to its improved mechanical characteristics.
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