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Displaying publications 41 - 56 of 56 in total

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Phospholipase A2 group v in benign familial fleck retina in a set of triplets

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.
Accutome PachPen handheld ultrasonic pachymeter: intraobserver repeatability and interobserver reproducibility by personnel of different training grades

Peyman M, Tai LY, Khaw KW, Ng CM, Win MM, Subrayan V

Int Ophthalmol, 2015 Oct;35(5):651-5.
PMID: 25189684 DOI: 10.1007/s10792-014-9989-6

To assess the intra-observer repeatability and inter-observer reproducibility of central corneal thickness (CCT) measurements of PachPen (Accutome, Inc., Pennsylvania, USA), a hand-held, portable ultrasonic pachymeter when used by an ophthalmic nurse compared to an ophthalmologist. Ophthalmology Clinic, University of Malaya Medical Center In this prospective study, CCT was measured in 184 eyes of 92 healthy subjects, first by a corneal surgeon experienced in ultrasound pachymetry (Observer 1) followed by an ophthalmic nurse new to the procedure (Observer 2). Nine measurements were obtained from each eye by each observer, independently. Measurements were compared between the observers. Coefficients of repeatability and reproducibility were calculated. The Bland-Altman plot was used to assess agreement between observers. Mean age of the study population was 54.3 ± 15.2 years old and consisted of 43.5% male. Mean CCT as measured by Observers 1 and 2 were 528.3 ± 32.9 and 530.7 ± 33.3 µm, respectively. Observer 1 showed higher repeatability of measurements compared to that of Observer 2 (coefficient of repeatability 3.46 vs. 5.55%). The measurements by both observers showed high correlation (0.96) and good agreement (mean difference -2.4 µm; 95% limits of agreement -21.4, 16.7 µm). Coefficient of reproducibility of measurements between observers was 5.08%. Accutome PachPen hand-held ultrasound pachymeters gives excellent intra-observer repeatability and inter-observer reproducibility by personnel of different training grades.
Refractive outcomes comparison between the Lenstar LS 900® optical biometry and immersion A-scan ultrasound

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.
Fulltext Spectral-domain optical coherence tomography evaluation of postoperative cystoid macular oedema following phacoemulsification with intraoperative complication

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.
ATRA-induced cerebral sinus thrombosis

Lee KR, Subrayan V, Win MM, Fadhilah Mohamad N, Patel D

J Thromb Thrombolysis, 2014 Jul;38(1):87-9.
PMID: 24046068 DOI: 10.1007/s11239-013-0988-7

All-trans retinoic acid (ATRA) and Idarubicin are part of the AIDA protocol employed for the treatment of Acute promyelocytic leaukaemia (APML) and has been associated with marked improvement in the prognosis. However, it is known to worsen the haematological picture during the course of induction of therapy. Herein, we present a case of an APML patient who developed a rare documented incidence of cerebral sinus thrombosis, first noticed as an ophthalmology referral. This 22 year old lady, a known APML patient was then started on chemotherapy based on AIDA protocol but 17 days into the initiation of therapy, she began to complain of blurred vision on the right eye. Anterior segments were normal but both fundi showed papilloedema with peripapillary haemorrhages. A contrast MRI that was then ordered showed multiple filling defects in numerous venous sinuses. She was started on anticoagulant treatment and the findings resolved. Though a rare case of its side-effects, ATRA usage in APML has a multitude of presentations since its primary pathology lies in the inherent pro-coagulant potential.
Assessment of polymerase chain reaction in the detection of pseudomonas aeruginosa in contact lens-induced severe infectious keratitis

Subrayan V, Peyman M, Lek Yap S, Mohamed Ali NA, Devi S

Eye Contact Lens, 2010 Jul;36(4):201-3.
PMID: 20531205 DOI: 10.1097/ICL.0b013e3181e3efa3

PURPOSE: The aim of this study is to evaluate the role of real-time polymerase chain reaction (PCR) and conventional bacterial culture methods in the detection of Pseudomonas aeruginosa in contact lens-induced severe, partially treated corneal ulcers referred to a tertiary center.
METHODS: The study duration was 6 months. All patients with contact lens-related corneal ulcer, requiring admission during the study period were recruited. Samples from corneal scrapings were simultaneously sent at the time of admission for PCR and culture testing. An in-house real-time PCR was developed to detect the P. aeruginosa lasA gene. The results of PCR and culture were compared using McNemar's chi2 test.
RESULTS: Ten patients were recruited. The mean age was 33 years (20-45 years). All the patients had contact lens-related keratitis (>4 mm) of which eight (80%) were found positive for P. aeruginosa by PCR or culture. There was no significant difference between PCR and culture in detecting P. aeruginosa (P<0.05).
CONCLUSIONS: PCR is, at least, as good as conventional cultures in detecting P. aeruginosa. It is a rapid assay as compared with culture, and early detection enables prompt treatment thus reducing the destructive effect of the organism on the cornea.
Fulltext Detection of Toxoplasma gondii DNA by PCR following microwave treatment of serum and whole blood

Meganathan P, Singh S, Ling LY, Singh J, Subrayan V, Nissapatorn V

Southeast Asian J. Trop. Med. Public Health, 2010 Mar;41(2):265-73.
PMID: 20578507

Detection of Toxoplasma gondii in blood by means of the polymerase chain reaction (PCR) may facilitate early diagnosis of toxoplasmosis in different groups of patients. We evaluated this approach in 42 patients presenting with ocular or psychotic diseases by comparing the sensitivity and specificity of PCR after heat treatment using a microwave oven with a standard genomic DNA extraction method for paired serum and whole blood samples. The presence of serum IgM and IgG antibodies against T. gondii was detected using a standard commercial enzyme-linked immunosorbent assay and enzyme immunoassay for IgG avidity test. Of 42 whole blood samples, PCR after microwave treatment was positive in 8 samples with a sensitivity of 73% and specificity of 100% compared to 11 samples positive by the extraction method. Although none of 42 sera samples was PCR positive by the extraction method, 7 specimens were positive after microwave treatment. This is the first study to use a microwave heat treatment, which is simple, rapid and a promising alternative method, in detecting small amounts of T. gondii DNA in human blood. Furthermore, irradiation of blood samples with microwaves allows incorporation of PCR into a practical tool for routine clinical assessment of patients with Toxoplasma infection.
Intravitreal bevacizumab for radiation-induced cystoid macular oedema in patients with nasopharyngeal carcinoma: a clinical series

Subrayan V, Khaw KW, Peyman M, Koay AC, Tajunisah I

Ophthalmologica, 2013;229(4):208-11.
PMID: 23548379 DOI: 10.1159/000348630

To evaluate the outcome of intravitreal bevacizumab in the treatment of radiation-induced cystoid macular oedema among patients who underwent external beam radiotherapy for nasopharyngeal carcinoma.
Dosage-dependent reduction of macular pigment optical density in female breast cancer patients receiving tamoxifen adjuvant therapy

Lim IL, Loo AVP, Subrayan V, Khang TF, See MH, Alip A, et al.

Breast, 2018 Jun;39:117-122.
PMID: 29660599 DOI: 10.1016/j.breast.2018.04.003

It is now increasingly common for breast cancer patients to receive adjuvant tamoxifen therapy for a period of up to 10 years. As survival rate increases, managing tamoxifen ocular toxicities is important for patients' quality of life. Macular pigments in photoreceptor cells protect against free radical damage, which can cause macular degeneration. By reducing macular pigment concentration, tamoxifen may increase the risk of macular degeneration. Here, we compared macular pigment optical density (MPOD) and central macular thickness between breast cancer patients on tamoxifen adjuvant therapy (n = 70), and a control group (n = 72). Multiple regression analysis indicated that MPOD decreases with increasing tamoxifen dosage, up to a threshold of about 20 g, after which MPOD plateaus out. Mean MPOD in the treatment group (mean = 0.40) was significantly lower (p-value = 0.02) compared to the control group (mean = 0.47) for the left eye, and for the right eye (treatment mean = 0.39; control mean = 0.48; p-value = 0.009). No significant difference in mean central macular thickness was found between the treatment and the control group (p-values > 0.4). In the control group, MPOD and central macular thickness showed significant correlation (r∼0.30; p-values 
Identification of potential serum metabolic biomarkers for patient with keratoconus using untargeted metabolomics approach

Daphne Teh AL, Jayapalan JJ, Loke MF, Wan Abdul Kadir AJ, Subrayan V

Exp Eye Res, 2021 10;211:108734.
PMID: 34428458 DOI: 10.1016/j.exer.2021.108734

This study aimed to investigate the metabolite differences between patients with keratoconus and control subjects and identify potential serum biomarkers for keratoconus using a non-targeted metabolomics approach. Venous blood samples were obtained from patients with keratoconus (n = 20) as well as from age-, gender- and race-matched control subjects (n = 20). Metabolites extracted from serum were separated and analyzed by liquid chromatography/quadrupole time-of-flight mass spectrometer. Processing of raw data and analysis of the data files was performed using Agilent Mass Hunter Qualitative software. The identified metabolites were subjected to a principal component and hierarchical cluster analysis. Appropriate statistical tests were used to analyze the metabolomic profiling data. Together, the analysis revealed that the dehydroepiandrosterone sulfate from the steroidal hormone synthesis pathway was significantly upregulated in patients with keratoconus (p
Diabetes and pachymetry changes in pregnancy

Santiagu F, Bakhtiari A, Iqbal T, Khaliddin N, Lansingh VC, Subrayan V

Int Ophthalmol, 2018 Oct;38(5):2069-2076.
PMID: 28879527 DOI: 10.1007/s10792-017-0701-5

BACKGROUND: Purpose of this study is to evaluate changes in the central corneal thickness (CCT) in patients during the third trimester and postpartum phases of normal pregnancy, pregestational diabetes mellitus (DM), and gestational diabetes mellitus (GDM).
METHODS: This was a prospective study. Patients that fulfilled the inclusion criteria were recruited from the obstetric clinic. They were grouped into normal pregnancy, pregestational DM, and GDM. Ophthalmic assessment and haematological investigations were done during the third trimester (after 28 weeks of gestation) and in the postpartum phase (6 weeks postpartum).
RESULTS: A total of 192 pregnant patients were recruited for this study. Out of the 192 patients, only 143 of them came back for their follow-up 6 weeks postpartum. A total of 70 (36.5%) normal pregnancy patients, 51 (26.6%) DM patients, and 71 (36.9%) GDM patients were included in this prospective study. Our study showed that the CCT decreased postpartum in all three groups. Patients in all three groups did not have significantly different CCT during the third trimester of pregnancy and postpartum phase. However, patients who had thicker CCT irrespective of the grouping during the third trimester also had a thicker CCT post-delivery (p value <0.001). However, these changes did not appear to affect refractive error and visual acuity.
CONCLUSIONS: Diabetes mellitus during pregnancy did not appear to influence the CCT.
Study site: Obstetrics clinic, University Malaya Medical Center (UMMC), Kuala Lumpur, Malaysia
Cladosporium cladosporioides keratomycosis: a case report

Chew FLM, Subrayan V, Chong PP, Goh MC, Ng KP

Jpn. J. Ophthalmol., 2009 Nov;53(6):657-659.
PMID: 20020251 DOI: 10.1007/s10384-009-0722-3
Effects of ranibizumab on TGF-β1 and TGF-β2 production by human Tenon's fibroblasts: An in vitro study

Noh SM, Abdul Kadir SH, Crowston JG, Subrayan V, Vasudevan S

Mol Vis, 2015;21:1191-200.
PMID: 26539031

Inhibiting exaggerated wound healing responses, which are primarily mediated by human Tenon's fibroblast (HTF) migration and proliferation, has become the major determining factor for a successful trabeculectomy. Antivascular endothelial growth factor (anti-VEGF) has showed promising results as a potential antifibrotic candidate for use concurrently in trabeculectomy. Preliminary cohort studies have revealed improved bleb morphology following trabeculectomy augmented with ranibizumab. However, the effects on HTFs remain unclear. This study was conducted to understand the effects of ranibizumab on transforming growth factor (TGF)-β1 and transforming growth factor (TGF)-β2 expression by HTFs.
Plasma, aqueous and vitreous homocysteine levels in proliferative diabetic retinopathy

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.
Visual System Homeobox 1 (VSX1) Gene Analysis in Keratoconus: Design of Specific Primers and DNA Amplification Protocols for Accurate Molecular Characterization

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.
Fulltext Association of copy number variations in complement factor H-Related genes among age-related macular degenerative subjects

Bakri NM, Ramachandran V, Kee HF, Subrayan V, Isa H, Ngah NF, et al.

Kaohsiung J. Med. Sci., 2017 Dec;33(12):602-608.
PMID: 29132549 DOI: 10.1016/j.kjms.2017.08.003

Age-related macular degeneration (AMD) is the most widely recognised cause of irreversible vision loss and previous studies have suggested that the advancement of wet AMD is influenced by both modifiable and non-modifiable elements. Single nucleotide polymorphism (SNPs) and copy number of variations (CNVs) have been associated with AMD in various populations, however the results are conflicting. Our aim is to determine the CNVs of Complement Factor H-Related genes among Malaysian subjects with wet AMD. 130 patients with wet AMD and 120 healthy controls were included in this research. DNA was extracted from all subjects and CNVs of CFH, CFHR1 and CFHR3 genes; determined using quantitative real-time PCR and were compared between the two groups. A consistent association was observed between CFH gene and wet AMD susceptibility (P

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