Displaying publications 1 - 20 of 38 in total

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  1. Chen LC, Low AL, Chien SF
    Appl Opt, 2004 Dec 10;43(35):6380-3.
    PMID: 15617273
    We propose the use of a truncated ball lens in a collimating system to transform a spherical wave from a highly divergent source into a plane wave. The proposed scheme, which incorporates a hyperbolic lens, is discussed, and the overall system is found to have a large acceptance angle and to be free of spherical aberration. Diffraction and polarization effects are neglected, as well as skew rays.
    Matched MeSH terms: Lens, Crystalline
  2. Sulieman A, Mayhoub F, Ibrahim HS, Omer H, Alkhorayef M, Abolaban FA, et al.
    Radiat Prot Dosimetry, 2021 Oct 12;195(3-4):314-318.
    PMID: 34265851 DOI: 10.1093/rpd/ncab107
    The objective of this study is to estimate the annual effective dose for cardiologists and nurses by measuring Hp(10) and Hp(0.07) during cardiac catheterization procedures. A total of 16 staffs members were working in interventional cardiology during 1 year at a tertiary hospital. The occupational dose was measured using calibrated thermo-luminescent dosemeters (TLD-100, LiF:Mg,Ti). The overall mean and range of the annual Hp(10) and Hp(0.07) (mSv) for cardiologists were 3.7 (0.13-14.5) and 3.2 (0.21-14.7), respectively. Cardiologists were frequently exposed to higher doses compared with nurses and technologists. The exposure showed wide variations, which depend on occupation and workload. Staff is adhered to radiation protection guidelines regarding shielding the trunk, thyroid shield, thus appropriately protected. Lens dose measurement is recommended to ensure that dose limit is not exceeded.
    Matched MeSH terms: Lens, Crystalline*
  3. Fogla R, Gujar P, Law M
    Indian J Ophthalmol, 2022 Feb;70(2):653-654.
    PMID: 35086256 DOI: 10.4103/ijo.IJO_1986_21
    The COVID-19 pandemic has brought a radical change in safety measures in outpatient clinics. The use of face masks by patients and healthcare workers has become a mandatory norm. Exhaled air with a face mask often follows an upward route. The warm exhaled air leads to fogging of 90/78D lens during fundus examination, hampering visualization. This can be prevented by the use of a simple yet innovative DIY adapter for a 90/78D lens, which can be made using simple household items such as PVC pipes or water hose pipes.
    Matched MeSH terms: Lens, Crystalline*
  4. Wai YZ, Chong YY, Lim LT, Chan JB, Chandrasekaran S
    BMC Res Notes, 2023 Jun 22;16(1):116.
    PMID: 37349840 DOI: 10.1186/s13104-023-06391-2
    BACKGROUND: To describe the preferred cataract surgery practices among Malaysian ophthalmologists and medical officers in comparison with the recommended practices.

    METHODS: An online questionnaire was sent out in April 2021, to Malaysian Ophthalmologists and medical officers who perform cataract surgeries. The questions were focused on the preferred cataract surgery practices of the participants. All data obtained were collected, tabulated and analysed.

    RESULTS: A total of 173 participants responded to the online questionnaire. 55% of the participants were within 31-40 years of age. 56.1% preferred peristaltic pump over venturi system. 91.3% of participants practised povidone iodine instillation to the conjunctival sac. With regards to the main wound incision, more than half of the surgeons (50.3%) preferred fixed superior incision and 72.3% of them preferred 2.75 mm microkeratome blade. Most of the participants (63%) were inclined towards C-Loop clear intraocular lens (IOL) with a single-handed push preloaded system. 78.6% of the surgeons routinely use carbachol in their cataract surgery.

    CONCLUSIONS: This survey provides some insight into the current practices among Malaysian ophthalmologists. Most of the practices are in line with international guidelines for preventing postoperative endophthalmitis. This article could help trainees and ophthalmologists benchmark and observe the common cataract surgery practices among their seniors and peers in Malaysia.

    Matched MeSH terms: Lens, Crystalline*
  5. Azhany Y, Norhayati A, Siti Raihan I, Liza Sharmini AT
    Malays Fam Physician, 2014;9(2):48-52.
    PMID: 25883765 MyJurnal
    To determine the clinical presentations, management and outcome of lens-induced glaucoma (LIG) in Hospital Universiti Sains Malaysia.
    Matched MeSH terms: Lens, Crystalline
  6. Thevi T, Reddy SC, Shantakumar C
    Malays Fam Physician, 2014;9(2):41-7.
    PMID: 25883764 MyJurnal
    The aim of the study was to compare the outcomes of phacoemulsification (Phaco) and extracapsular cataract extraction (ECCE) in a district hospital setting.
    Matched MeSH terms: Lens, Crystalline
  7. Ansarudin F, Abd Rahman T, Yamada Y, Rahman NHA, Kamardin K
    Sensors (Basel), 2020 Oct 16;20(20).
    PMID: 33081110 DOI: 10.3390/s20205849
    In the 5G mobile system, new features such as millimetre wave operation, small cell size and multi beam are requested at base stations. At millimetre wave, the base station antennas become very small in size, which is about 30 cm; thus, dielectric lens antennas that have excellent multi beam radiation pattern performance are suitable candidates. For base station application, the lens antennas with small thickness and small curvature are requested for light weight and ease of installation. In this paper, a new lens shaping method for thin and small lens curvature is proposed. In order to develop the thin lens antenna, comparisons of antenna structures with conventional aperture distribution lens and Abbe's sine lens are made. Moreover, multi beam radiation pattern of three types of lenses are compared. As a result, the thin and small curvature of the proposed lens and an excellent multi beam radiation pattern are ensured.
    Matched MeSH terms: Lens, Crystalline
  8. Bariah Mohd-Ali, Nazirin Arsad, Zainora Mohammed
    MyJurnal
    It is possible that different techniques used to measure axial length (AL) and anterior chamber depth (ACD) is the cause of discrepancy in refractive outcomes of cataract surgery. This study evaluated the agreement and repeatability of AL and ACD measurements using immersion and contact A-scan biometry techniques and compared the refractive outcomes from both techniques. Twenty four patients were evaluated for agreement and repeatability of AL and ACD measurements using the two different methods. The results were analyzed using Bland and Altman plots. Another 60 patients with age-related cataract were selected to compare the refractive outcomes between both methods. The IOL power was calculated using Sanders- Retzlaff- Kraff- Theoretical (SRK-T) equation. Refraction was determined between four to six weeks postoperatively and the results were analyzed using paired t-test. The results of this study showed good agreement between both techniques was noted with no significant difference detected between measurements (p > 0.05). Significant correlation was found in all parameters (AL: r = 0.99; p < 0.01, r = 0.99; p < 0.01) ACD: r = 0.91; p < 0.01, r = 0.97; p < 0.01). No significant difference in refractive outcomes of post cataract surgery was detected between the two techniques (p = 0.07). This study concludes that contact A-scan biometry and immersion techniques provide reliable results and should not be the cause of discrepancy in the refractive planned and outcome of cataract surgery.
    Matched MeSH terms: Lens, Crystalline
  9. Agarwal R, Iezhitsa IN, Agarwal P, Spasov AA
    Magnes Res, 2013 Jan-Feb;26(1):2-8.
    PMID: 23708888 DOI: 10.1684/mrh.2013.0336
    Senile cataract is the most common cause of bilateral blindness and results from the loss of transparency of the lens. Maintenance of the unique tissue architecture of the lens is vital for keeping the lens transparent. Membrane transport mechanisms utilizing several magnesium (Mg)-dependent ATPases, play an important role in maintaining lens homeostasis. Therefore, in Mg-deficiency states, ATPase dysfunctions lead to intracellular depletion of K(+) and accumulation of Na(+) and Ca(2+). High intracellular Ca(2+) causes activation of the enzyme calpain II, which leads to the denaturation of crystallin, the soluble lens protein required for maintaining the transparency of the lens. Mg deficiency also interferes with ATPase functions by causing cellular ATP depletion. Furthermore, Mg deficiency enhances lenticular oxidative stress by increased production of free radicals and depletion of antioxidant defenses. Therefore, Mg supplementation may be of therapeutic value in preventing the onset and progression of cataracts in conditions associated with Mg deficiency.
    Matched MeSH terms: Lens, Crystalline/pathology
  10. Agarwal R, Iezhitsa I, Agarwal P, Spasov A
    Exp Eye Res, 2012 Aug;101:82-9.
    PMID: 22668657 DOI: 10.1016/j.exer.2012.05.008
    Magnesium is one of the most important regulatory cation involved in several biological processes. It is important for maintaining the structural and functional integrity of vital ocular tissues such as lens. Presence of high magnesium content especially in the peripheral part of lens as compared to aqueous and vitreous humor has been observed. Magnesium plays significant role as a cofactor for more than 350 enzymes in the body especially those utilizing ATP. Membrane associated ATPase functions that are crucial in regulating the intracellular ionic environment, are magnesium-dependent. Moreover, the enzymes involved in ATP production and hydrolysis are also magnesium-dependent. Magnesium deficiency by interfering with ATPase functions causes increased intracellular calcium and sodium and decreases intracellular potassium concentration. Furthermore, magnesium deficiency is associated with increased oxidative stress secondary to increased expression of inducible nitric oxide synthase and increased production of nitric oxide. Thus the alterations in lenticular redox status and ionic imbalances form the basis of the association of magnesium deficiency with cataract. In this paper we review the mechanisms involved in magnesium homeostasis and the role of magnesium deficiency in the pathogenesis of cataract.
    Matched MeSH terms: Lens, Crystalline/metabolism
  11. Hamid SA, Rahman NHA, Yamada Y, Hung PV, Quoc DN
    Sensors (Basel), 2020 Oct 07;20(19).
    PMID: 33036419 DOI: 10.3390/s20195703
    Narrow beam width, higher gain and multibeam characteristics are demanded in 5G technology. Array antennas that are utilized in the existing mobile base stations have many drawbacks when operating at upper 5G frequency bands. For example, due to the high frequency operation, the antenna elements become smaller and thus, in order to provide higher gain, more antenna elements and arrays are required, which will cause the feeding network design to be more complex. The lens antenna is one of the potential candidates to replace the current structure in mobile base station. Therefore, a negative refractive index shaped lens is proposed to provide high gain and narrow beamwidth using energy conservation and Abbe's sine principle. The aim of this study is to investigate the multibeam characteristics of a negative refractive index shaped lens in mobile base station applications. In this paper, the feed positions for the multibeam are selected on the circle from the center of the lens and the accuracy of the feed position is validated through Electromagnetic (EM) simulation. Based on the analysis performed in this study, a negative refractive index shaped lens with a smaller radius and slender lens than the conventional lens is designed, with the additional capability of performing wide-angle beam scanning.
    Matched MeSH terms: Lens, Crystalline
  12. Bariah Mohd Ali, Goh, E.H.
    MyJurnal
    The objective of this study was to determine the efficiency of UV blocking monomers in contact lenses in providing eye protection from UV radiation. The spectral transmission of 8 contact lenses (7 soft contact lenses: Precision UV, Acuvue 2, Surevue, Omega, Encore UV, Durasoft 3 and Lunelle UV and 1 rigid gas permeable contact lens: Boston 7) was evaluated by using a dual beam spectrophotometer. Durasoft 3, a non UV absorbent contact lens was used as the control. The results showed that Precision UV contact lens absorbed UV light up to wavelength of 380 nm, whereas Acuvue 2 and Surevue absorbed up to 360 nm only. Omega, Encore UV and Lunelle UV lenses absorbed UV light up to 335 nm with spectral transmission of Lunelle UV being the highest among all soft contact lenses tested, which was 17%. Boston 7 could absorb UV light up to 385 nm, but the amount of UV light transmitted was higher than soft lenses, which was 30%. Durasoft 3 only blocked UV light at 200-245 nm. Precision UV lens had better UV blocker characteristics than the other contact lenses tested. UV blocking soft contact lenses could be an alternative for spectacles in protecting internal ocular structures from UV radiation.
    Matched MeSH terms: Lens, Crystalline
  13. Awal, M.A., Wan Ishaq, W.I., Bockari-Gevao, S.M.
    MyJurnal
    The present conventional (destructive) method used in determining LAI is laborious, difficult and time consuming. Thus, an image-based measurement using camera system with fish eye lens offers an alternative means for an accurate indirect measurement of LAI in oil palm. In this study, a methodology was developed to improve the leaf area index of the oil palm determination using hemispherical photography as an indirect method. A set of true LAI data, collected using the destructive method, were used as a reference to calibrate the LAI measurements obtained by the hemispherical photography. A good relationship (r = 0.85) was found between age of palm and hemispherical photographic LAI. However, the estimated LAI obtained by the hemispherical photographic method was underestimated as compared to the destructive method. Some means of calibration was necessary to determine the relationship between the actual LAI and the hemispherical photographic LAI. It was necessary to multiply the LAI value from 5 years to 16 years, by a clumping factor of 2.14 for 5 to 9 year old palms, 2.33 for 10 to 14-year old palms and 2.37 for above 15- year old palms to calculate the accurate LAI values. For palms which are less than 5 year old (i.e. 2 to 3 years in this study), the photography LAI value was equal to the calculated LAI value. This proposed that correction factors would solve this underestimation effect. In addition, two equations were also proposed to estimate the true LAI from the Photographic LAI for immature and mature oil palm plantation.
    Matched MeSH terms: Lens, Crystalline
  14. Choong YY, Lim KS
    Med J Malaysia, 2001 Mar;56(1):92-4.
    PMID: 11503304
    Phenothiazines have been associated with various ocular adverse effects, in particular cataract and corneal deposits. Several effects are vision threatening. Awareness of these effects, in particular by Psychiatrists and Ophthalmologist, is essential for prompt diagnosis and appropriate treatment. We report two patients presented to us with corneal deposits and lenticular opacities following long term use of Phenothiazines.
    Matched MeSH terms: Lens, Crystalline/drug effects; Lens, Crystalline/metabolism
  15. Syafruddin SE, Ling S, Low TY, Mohtar MA
    Biomolecules, 2021 Mar 31;11(4).
    PMID: 33807297 DOI: 10.3390/biom11040523
    Cells encounter a myriad of endogenous and exogenous stresses that could perturb cellular physiological processes. Therefore, cells are equipped with several adaptive and stress-response machinery to overcome and survive these insults. One such machinery is the heat shock response (HSR) program that is governed by the heat shock factors (HSFs) family in response towards elevated temperature, free radicals, oxidants, and heavy metals. HSF4 is a member of this HSFs family that could exist in two predominant isoforms, either the transcriptional repressor HSFa or transcriptional activator HSF4b. HSF4 is constitutively active due to the lack of oligomerization negative regulator domain. HSF4 has been demonstrated to play roles in several physiological processes and not only limited to regulating the classical heat shock- or stress-responsive transcriptional programs. In this review, we will revisit and delineate the recent updates on HSF4 molecular properties. We also comprehensively discuss the roles of HSF4 in health and diseases, particularly in lens cell development, cataract formation, and cancer pathogenesis. Finally, we will posit the potential direction of HSF4 future research that could enhance our knowledge on HSF4 molecular networks as well as physiological and pathophysiological functions.
    Matched MeSH terms: Lens, Crystalline/cytology; Lens, Crystalline/metabolism
  16. Shanisha Rubiny A/P Vardi Veloo, Subhadeep Das
    MyJurnal
    Diabetes mellitus is a condition of increase glucose concentration in blood plasma. Complication of diabetes mellitus are progressive and leads to several changes on ocular surface. Lack of data focusing on changes in ocular surface among early detect diabetes. Therefore, the aim of the study is to focus on the prevalence of changes in Meibomian glands, tear films and crystalline lens among early detect diabetes type 2. A descriptive cross sectional study was conducted to assess the grading of Meibomian glands, number of expressible glands, Tear-break up time (TBUT), schirmer’s test I , and crystalline lens in 100 eyes of 50 patients who has type 2 diabetes less than 5 years. Demographic information , medical and ocular history was recorded. Data was entered on SPSS version 25- descriptive analysis. The mean ± standard deviation for age was 51.08 ± 8.708 and the years of diabetes was 3.14 ± 1.498. The results stated, more people has MGD grade 1 with percentage of 39% . Besides, TBUT test has mean ± SD of 4.74 ± 1.404 and tear production with mean of 15.1± 8.650. There were 54% more patients has no changes on crystalline lens. Approximately, high prevalence in changes of Meibomian gland, and tear film while low prevalence on changes of crystalline lens among shorter duration diabetic patients.
    Matched MeSH terms: Lens, Crystalline
  17. Rizal, A.M., Muhammad, M., Aljunid, S.M., Normalina, M., Faridah Hanom, A., Chuah, K.L., et al.
    MyJurnal
    Background: A randomised single blinded clinical trial comparing the effectiveness of two methods of cataract surgery with intraocular lens implantation: extracapsular cataract extraction (ECCE) and phacoemulsification (PEA) was carried out at Hospital Universiti Kebangsaan Malaysia (HUKM) between March 2000 and August 2001. Methods: The effectiveness of cataract surgery was assessed from the quality of life specifically for vision via Visual Function 14 (VF-14) preoperatively, one week, two months and six months after surgery. Results: The result showed that there was a significant increased in VF-14 scores after a week, two months and six months postoperation compared to the score before surgery for both techniques. However there was no significant difference in VF-14 scores when compared between ECCE and PEA. Conclusions: This study indicated that both techniques give equal benefit to cataract patients. Since effectiveness of cataract surgery with intraocular lens implantation is unrelated to operative procedures, less costly technique should be promoted.
    Matched MeSH terms: Lens, Crystalline
  18. Vijayasingham L, Jogulu U, Allotey P
    Soc Sci Med, 2020 01;245:112699.
    PMID: 31785425 DOI: 10.1016/j.socscimed.2019.112699
    Reports of work change and transitions are common amongst individuals with chronic illnesses such as multiple sclerosis (MS). However, there is little research on the lived experience of these work transitions. The scarcity of this research is particularly evident within low-and-middle-income countries, where protection laws and resources such as anti-discrimination laws and reasonable work modifications may not exist or be well enforced. In this paper, we explore how and why individuals with MS seek and achieve work transitions in the structural context of Malaysia. We interviewed ten working individuals with MS (July-december 2015) using a joint hermeneutic phenomenology and constructivist grounded theory approach. Using a broad conceptual lens of 'sustainable careers', we examine their careers as a series of experiences, decisions, and events, paying attention to the influences of context, time, their personal levels of agency and sense of meaning. Participants described work transitions as early as within the first year of diagnosis, that were prompted by voluntary, involuntary and semi-voluntary reasons. Key aspects of the process of seeking new roles included an exploration of alternative roles and paths, and then acquiring, trialing/adapting and remaining engaged in their new roles. Participants identified the perception and experience of 'being unemployable', based on how their diagnosis and short-term symptoms were responded to by employers. Nevertheless, participants used various strategies and career resources to obtain and maintain meaningful work roles. However, success in obtaining or maintaining new roles were not equally achieved. This research draws attention to the cumulative economic disadvantage of a chronic illness diagnosis, even at milder and episodic stages. Furthermore, it reiterates the need for cohesive structural protection in low-and-middle-income countries to facilitate a more equal ability to remain economically resilient and capable of engaging in meaningful long-term careers when living with a chronic illness.
    Matched MeSH terms: Lens, Crystalline
  19. Safari MJ, Wong JH, Kadir KA, Thorpe NK, Cutajar DL, Petasecca M, et al.
    Eur Radiol, 2016 Jan;26(1):79-86.
    PMID: 26002131 DOI: 10.1007/s00330-015-3818-9
    OBJECTIVES: To develop a real-time dose-monitoring system to measure the patient's eye lens dose during neuro-interventional procedures.

    METHODS: Radiation dose received at left outer canthus (LOC) and left eyelid (LE) were measured using Metal-Oxide-Semiconductor Field-Effect Transistor dosimeters on 35 patients who underwent diagnostic or cerebral embolization procedures.

    RESULTS: The radiation dose received at the LOC region was significantly higher than the dose received by the LE. The maximum eye lens dose of 1492 mGy was measured at LOC region for an AVM case, followed by 907 mGy for an aneurysm case and 665 mGy for a diagnostic angiography procedure. Strong correlations (shown as R(2)) were observed between kerma-area-product and measured eye doses (LOC: 0.78, LE: 0.68). Lateral and frontal air-kerma showed strong correlations with measured dose at LOC (AKL: 0.93, AKF: 0.78) and a weak correlation with measured dose at LE. A moderate correlation was observed between fluoroscopic time and dose measured at LE and LOC regions.

    CONCLUSIONS: The MOSkin dose-monitoring system represents a new tool enabling real-time monitoring of eye lens dose during neuro-interventional procedures. This system can provide interventionalists with information needed to adjust the clinical procedure to control the patient's dose.

    KEY POINTS: Real-time patient dose monitoring helps interventionalists to monitor doses. Strong correlation was observed between kerma-area-product and measured eye doses. Radiation dose at left outer canthus was higher than at left eyelid.

    Matched MeSH terms: Lens, Crystalline/radiation effects*
  20. Lockie P
    Aust N Z J Ophthalmol, 1987 Aug;15(3):207-9.
    PMID: 3675913
    Ciliary-block glaucoma occurred in one eye of a 65-year-old-male, following a combined trabeculectomy and extracapsular lens extraction for long-standing angle-closure glaucoma. After pupillary block was excluded as a cause, a posterior capsulotomy resolved the condition. This procedure was repeated successfully when a flat anterior chamber recurred on spontaneous closure of the initial capsulotomy. The ciliary block appeared to be caused by the residual zonule and lens capsule.
    Matched MeSH terms: Lens, Crystalline/surgery*
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