Displaying publications 1 - 20 of 56 in total

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  1. Ng JB, Poh RY, Lee KR, Subrayan V, Deva JP, Lau AY, et al.
    Clin. Lab., 2016 Sep 01;62(9):1731-1737.
    PMID: 28164597 DOI: 10.7754/Clin.Lab.2016.160144
    BACKGROUND: Keratoconus is an ocular degeneration characterized by the thinning of corneal stroma that may lead to varying degrees of myopia and visual impairment. Genetic factors have been reported in the pathology of keratoconus where Asians have a higher incidence, earlier onset, and undergo earlier corneal grafts compared to Caucasians. The visual system homeobox 1 (VSX1) gene forms part of a paired-like homeodomain transcription factor which is responsible for ocular development. The gene was marked as a candidate in genetic studies of keratoconus in various populations. Single nucleotide polymorphisms (SNPs) in the VSX1 gene have been reported to be associated with keratoconus. The detection of the SNPs involves DNA amplification of the VSX1 gene followed by genomic sequencing. Thus, the objective of this study aims to establish sensitive and accurate screening protocols for the molecular characterization of VSX1 polymorphisms.

    METHODS: Keratoconic (n = 74) and control subjects (n = 96) were recruited based on clinical diagnostic tests and selection criteria. DNA extracted from the blood samples was used to genotype VSX1 polymorphisms. In-house designed primers and optimization of PCR conditions were carried out to amplify exons 1 and 3 of the VSX1 gene. PCR conditions including percentage GC content, melting temperatures, and differences in melting temperatures of primers were evaluated to produce sensitive and specific DNA amplifications.

    RESULTS: Genotyping was successfully carried out in 4 exons of the VSX1 gene. Primer annealing temperatures were observed to be crucial in enhancing PCR sensitivity and specificity. Annealing temperatures were carefully evaluated to produce increased specificity, yet not allowing sensitivity to be compromised. In addition, exon 1 of the VSX1 gene was amplified using 2 different sets of primers to produce 2 smaller amplified products with absence of non-specific bands. DNA amplification of exons 1 and 3 consistently showed single band products which were successfully sequenced to yield reproducible data.

    CONCLUSIONS: The use of in-house designed primers and optimized PCR conditions allowed sensitive and specific DNA amplifications that produced distinct single bands. The in-house designed primers and DNA amplification protocols established in this study provide an addition to the current repertoire of primers for accurate molecular characterization of VSX1 gene polymorphisms in keratoconus research.

  2. Chang KM, Patel DK, Tajunisah I, Subrayan V
    Asia Pac J Public Health, 2015 Mar;27(2):217-24.
    PMID: 22887807 DOI: 10.1177/1010539512455047
    Retinopathy of prematurity (ROP) is one of the most important causes of childhood blindness worldwide. The trend of ROP in Malaysia was unclear because there was no national registry before 2002. The purpose of this study is to analyze ROP students of different ages in the schools for the blind in Malaysia in order to evaluate the trend of ROP from 1992 to 2001. Data were obtained from a previous survey of 24 blind schools. It was found that 78 students or 17.4% were blind/severely visual impaired as a result of ROP. There was a significant surge in the number of ROP students who were born in 1994 when the use of synthetic surfactants was first introduced in Malaysia; otherwise there was no increasing trend in the number of students with ROP. However, the percentage of ROP in total was increasing, which indicates that ROP is becoming a more important cause of childhood blindness in this country.
  3. See WYN, Ismail F, Sheikh Abdul Kadir SH, Subrayan V
    Curr Eye Res, 2021 Dec 29.
    PMID: 34963422 DOI: 10.1080/02713683.2021.2011326
    PURPOSE/ AIM: The main purpose of this work is to study the cellular viability effect of irradiated riboflavin in cultured human tenon fibroblasts.

    MATERIALS AND METHODS: The tenon tissue was harvested from a patient undergoing strabismus surgery. The human tenon fibroblast cell culture and isolation were performed according to the standard laboratory cell culturing protocol. The cells were divided into three groups: control, treatment with irradiated and non-irradiated riboflavin. There were five different concentrations (0.00156%, 0.003125%, 0.00625%, 0.0125%, 0.025%) in each group of riboflavin. The fibroblasts were treated with riboflavin and the cellular viability was assessed at 24-hour and 48-hour post treatment with MTT 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyl tetrazolium bromide colorimetric assay. The absorbance values were analysed using Magellan microplate reader data analysis. A triplicate of readings was taken. The data were presented as mean ± standard deviation of the triplicates. Statistical analysis was performed with Statistical Package for Social Sciences (SPSS) analysis version 23.

    RESULTS: Irradiated riboflavin caused a concentration-dependent cell death in human tenon fibroblast cell culture (p

  4. Khaw KW, Lam HH, Khang TF, Wan Ab Kadir AJ, Subrayan V
    BMC Ophthalmol, 2014;14:16.
    PMID: 24533465 DOI: 10.1186/1471-2415-14-16
    To report the rate of cystoid macular oedema (CMO) as detected by spectral-domain optical coherence tomography (SD-OCT) after intraoperative complication during phacoemulsification. The secondary objectives include comparing mean macular thickness and best-corrected visual acuity (BCVA) between those who developed postoperative CMO against those who did not.
  5. Tan TY, Shashinder S, Subrayan V, Krishnan G
    Auris Nasus Larynx, 2008 Jun;35(2):285-7.
    PMID: 18024042
    Silent sinus syndrome is a rare clinical condition in which patients present with spontaneous enophthalmos and hypoglobus secondary to collapse of orbital floor due to chronic subclinical maxillary sinusitis. It is postulated that obstruction of the osteomeatal complex lead to negative antrum pressure which causes the maxillary sinus atelectasis.
  6. Peyman M, Tajunisah I, Loo A, Chuah KC, Subrayan V
    J Diabetes Complications, 2012 May-Jun;26(3):210-3.
    PMID: 22520399 DOI: 10.1016/j.jdiacomp.2012.03.019
    To correlate Heidelberg Retina Tomograph (HRT) derived macular edema (DME) index with severity of diabetic retinopathy and systemic factors. A total of 300 diabetic patients were recruited for the study for each of them a value for the macular edema index was obtained using the HRT II. Patients' age, gender, duration and type of diabetes mellitus, latest HbA1c result and presence or absence of co-morbid factors (hypertension, ischemic heart disease, nephropathy) were recorded together with the stage of diabetic retinopathy. These were correlated with DME. Out of 300 patients, HRT defined macula edema was seen in 68 patients (22.6%). There is a wider and higher range (95% percentile) of macula edema index in the severe non proliferative diabetic retinopathy (NPDR) group. Independent samples t test showed significant difference between the severe NPDR group and no DR group (p<0.001), mild NPDR group (p<0.05) and moderate NPDR group (p<0.05). A higher macula edema index was also found to have a low degree of correlation with more advanced stages of retinopathy (r=0.310; p<0.001). Also nephropathy showed a strong and significant correlation with DME. Hypertension had moderately significant correlation with DME. This study found no correlation between ischemic heart disease and DME. HRT derived scanning laser edema index is a reliable objective tool to evaluate diabetic retinopathy and systemic risk factors.
  7. Lee KR, Peng LY, Iqbal TB, Subrayan V
    Ocul Immunol Inflamm, 2018;26(8):1146-1149.
    PMID: 28362518 DOI: 10.1080/09273948.2017.1298821
    PURPOSE: To report a case of systemic lupus erythematosus-induced choroidal vasculitis.

    METHODS: A 34-year-old woman with a long-standing history of systemic lupus erythematosus had a sudden painless loss of vision in the right eye over 12 hours. Ocular examination revealed a visual acuity of counting fingers of 1 foot on the right eye and 20/20 on the left. There was a relative afferent pupillary defect on the right side with a pink, distinct optic disk margin.

    RESULTS: Optical coherence tomography of the macula and fundus fluorescein angiogram for the eyes were normal. The MRI brain and orbit with the cerebral MRA did not show signs of optic neuritis or occipital vasculitic changes. However, the indocyanine green angiography revealed patches of ill-defined areas of choroidal hypofluorescence in the early- to mid-phase in the macula region.

    CONCLUSION: ICGA becomes the crucial tool in unmasking the presence of choroidal vasculitis.
  8. Lee WW, Tajunisah I, Sharmilla K, Peyman M, Subrayan V
    Invest Ophthalmol Vis Sci, 2013 Nov;54(12):7785-92.
    PMID: 24135757 DOI: 10.1167/iovs.13-12534
    We determined structural retinal nerve fiber layer (RNFL) changes in schizophrenia patients and established if the structural changes were related to the duration of the illness using spectral-domain optical coherence tomography (SD-OCT).
  9. Loo AV, Sujaya S, Peyman M, Florence S, Subrayan V
    Int J Ophthalmol, 2011;4(6):641-3.
    PMID: 22553736 DOI: 10.3980/j.issn.2222-3959.2011.06.13
    To investigate the fundus findings of patients infected with human immunodeficiency virus (HIV) in correlation to Highly Active Antiretroviral Therapy (HAART) and CD4 count.
  10. Koay CL, Quo MJ, Subrayan V
    Int Ophthalmol, 2017 Jun;37(3):655-671.
    PMID: 27558260 DOI: 10.1007/s10792-016-0306-4
    The purpose of this study was to investigate the reproducibility of choroidal thickness measurements in normal subjects on 3 spectral domain optical coherence tomography instruments, namely: Zeiss Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA), Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany), and Optovue RTVue (Optovue Inc., Fremont, CA). This cross-sectional non-interventional study was performed in a single institution. Images were obtained in 47 eyes of 47 healthy volunteers which age ranged between 23 and 72 without ocular pathology. All subjects were imaged on the fovea using Cirrus HD 1-line raster, Spectralis enhanced depth imaging, and RTVue retina-cross. The choroid was measured subfoveally and at intervals of 500 µm from the fovea nasally and temporally up to 2500 µm. Paired t test, modified Bland-Altman plot, and Pearson's correlation were used to compare the results. There is no significant difference between the systems for any measurement within 2500 µm either side of the fovea for most points. Inter-observer correlation was strong for RTVue, and moderate in both Cirrus and Spectralis.
  11. Naicker P, Sundralingam S, Peyman M, Juana A, Mohamad NF, Win MM, et al.
    Int Ophthalmol, 2015 Aug;35(4):459-66.
    PMID: 25024102 DOI: 10.1007/s10792-014-9970-4
    To determine the accuracy of intraocular lens (IOL) calculations in eyes undergoing phacoemulsification cataract surgery with IOL implantation using immersion A-scan ultrasound (US) and Lenstar LS 900(®) biometry. In this prospective study, 200 eyes of 200 patients were randomized to undergo either Lenstar LS 900(®) or immersion A-scan US biometry to determine the IOL dioptric power prior to phacoemulsification cataract surgery. Post-operative refractive outcomes of these two groups of patients were compared. The result showed no significant difference between the target spherical equivalent (SE) and the post-operative SE value by the Lenstar LS 900(®) (p value = 0.632) or immersion A-scan US biometry (p value = 0.438) devices. The magnitude of difference between the two biometric devices were not significantly different (p value = 0.868). There was no significant difference in the predicted post-operative refractive outcome between immersion A-scan US biometry and Lenstar LS 900(®). Based on the results, the immersion A-scan US technique is as accurate as Lenstar LS 900(®) in the hands of an experienced operator.
  12. Hassan M, Patel DK, Subrayan V
    Ann Ophthalmol (Skokie), 2009;41(3-4):203-5.
    PMID: 20214058
    We present a case of a newly acquired herpetic infection in the graft after penetrating keratoplasty.
  13. Lim CP, Loo AV, Khaw KW, Sthaneshwar P, Khang TF, Hassan M, et al.
    Br J Ophthalmol, 2012 May;96(5):704-7.
    PMID: 22353698 DOI: 10.1136/bjophthalmol-2011-301044
    To compare homocysteine (Hcy) concentration in the blood plasma, vitreous and aqueous of eyes with proliferative diabetic retinopathy (PDR) against control, and to investigate associations between Hcy concentration in blood plasma with that of aqueous and vitreous in these two groups.
  14. Bin NJ, Heng HM, Poh R, Noor SM, Subrayan V
    Retina, 2015 Jun;35(6):1266-72.
    PMID: 25549071 DOI: 10.1097/IAE.0000000000000446
    To evaluate the association of phospholipase A2, Group V (PLA2G5), with benign familial fleck retina in a consanguineous family with triplets.
  15. Soong TK, Koh A, Subrayan V, Loo AV
    Graefes Arch Clin Exp Ophthalmol, 2011 Dec;249(12):1755-60.
    PMID: 20607549 DOI: 10.1007/s00417-010-1444-4
    PURPOSE: To describe the epidemiology of ocular injuries presenting to the University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia.

    DESIGN: Prospective analysis of all ocular trauma injuries presenting to the Department of Ophthalmology in UMMC from 1 January 2008 to 31 December 2008.

    PARTICIPANTS: A total of 603 eyes of 546 patients were recruited for the study.

    METHODS: All patients presenting to the department with ocular trauma injuries were assessed by an ophthalmologist. Data on the type and source of injury, demographic profile of the patients, and clinical presentation were documented using a uniform and validated datasheet.

    RESULTS: Among eye injury cases, 481 patients (88.1%) were male, with a male-to-female ratio of 7.4:1. Of the patients, 412 (75.5%) were Malaysian while the remaining 134 (24.5%) were of non-Malaysian nationality. The average age was 31.5 years (range 1-81 years). A total of 238 injured eyes (43.6%) were work-related. The common sources of eye trauma include the use of high-powered tools (30.8%), motor vehicle accident (23.1%), and domestic accidents (17.7%). Only six patients (2.5%) reported to having used eye protective device (EPD) at time of their work-related injuries.

    CONCLUSIONS: A major cause of preventable ocular injuries in Malaysia was work-related trauma. Ocular injuries can be reduced by the use of eye protection devices and the implementation of appropriate preventive strategies to address each risk factor. Effective training is an integral part of occupational safety and health, which should be made mandatory at the workplace. In addition, there should be a continual assessment of safety and health issues at the workplace. A long-term database of all ocular injuries in Malaysia is recommended, to aid research on a larger scale and the development of new preventive strategies for ocular injuries.

  16. Ismail F, Peyman M, Waran V, Vasudevan S, Subrayan V
    Optom Vis Sci, 2015 Apr;92(4 Suppl 1):S33-5.
    PMID: 25730333 DOI: 10.1097/OPX.0000000000000528
    To report a rare case of nasal chondroma presenting as hypertelorism.
  17. Vairavan N, Tajunisah I, Subrayan V, Waran V
    Orbit, 2009;28(6):442-3.
    PMID: 19929682 DOI: 10.3109/01676830903103365
    Surgical approaches are becoming increasingly minimally invasive, without compromising either safety or ease. Penetrating ocular foreign bodies has traditionally been approached either by intraocular or supraorbital access. We successfully attempted a minimally invasive approach to remove a retrobulbar foreign body under computer-assisted image guidance in a 19-year-old man involved in an industrial mishap.
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