MyMedR

Scanning laser edema index: a reliable tool to correlate with diabetic retinopathy and systemic risk factors?

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.

Fulltext Childhood blindness and severe visual impairment in Malaysia: a nationwide study

Patel DK, Tajunisah I, Gilbert C, Subrayan V

Eye (Lond), 2011 Apr;25(4):436-42.

PMID: 21350565 DOI: 10.1038/eye.2011.19

To determine the causes of childhood blindness and severe visual impairment (BL/SVI) in schools for the blind in Malaysia.

Colloid cyst of third ventricle mimicking normal tension glaucoma

Patel DK, Ali NA, Iqbal T, Subrayan V

Ann Ophthalmol (Skokie), 2008;40(3-4):177-9.

PMID: 19230359

Colloid cysts are rare intracranial tumors most commonly found in the third ventricle. We present a case of colloid cyst of the third ventricle that manifested as bilateral advance optic disc cupping, superior hemifield defects in the visual fields and normal intraocular pressure.

Combined optic neuropathy and central retinal artery occlusion in presumed ocular tuberculosis without detectable systemic infection

Ooi YL, Tai LY, Subrayan V, Tajunisah I

Ocul Immunol Inflamm, 2011 Oct;19(5):370-2.

PMID: 21834697 DOI: 10.3109/09273948.2011.594203

To report a rare case of combined optic neuropathy and central retinal artery occlusion in presumed ocular tuberculosis without systemic infection.

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.

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.

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 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.

Fulltext Retinal manifestations of patients with human immunodeficiency virus, a multiethnics study in Malaysia

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.

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 

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.

An unusual presentation of gestational thrombocytopenia

Lim CC, Patel DK, Bakhtiari A, Subrayan V

Platelets, 2013;24(6):498-9.

PMID: 22994680 DOI: 10.3109/09537104.2012.724484

Thrombocytopenia is classically defined as a platelet count of less than 150 000/µl. Counts from 100 000 to 150 000/µl are considered mildly depressed, 50 000 to 100 000/µl moderately depressed, and less than 50 000/µl severely depressed. Thrombocytopenia occurs in about 10% of pregnant women. Gestational thrombocytopenia (GT) is a diagnosis of exclusion and considered the most prevalent cause of thrombocytopenia in pregnancy. GT accounts for almost 75% of cases of thrombocytopenia in pregnancy. The cause of GT is unclear, although existing studies denote the possibility of accelerated platelet consumption and the increased plasma volume during pregnancy. The presence of antiplatelet antibodies is not specific to GT. The degree of thrombocytopenia in GT is usually mild to moderate, usually remaining greater than 70 000/µl. Patients are asymptomatic with no evidence of bleeding and rarely preconception history of thrombocytopenia. The platelet count returns to normal within 2-12 weeks post partum. We wish to report a unique case of GT presenting as blurred vision due to retinal hemorrhages.

Fulltext Extramedullary plasmacytoma of the eyelid: a case report and review of literature

Lim CC, Soong TK, Chuah KC, Subrayan V

Clin Exp Optom, 2013 May;96(3):349-51.

PMID: 22970978 DOI: 10.1111/j.1444-0938.2012.00797.x

Primary extramedullary plasmacytomas of the eyelid are rare with only five other cases reported in the literature. A 43-year-old Chinese man presented with painless swelling of the left lower eyelid that developed over the past two years. An incisional biopsy and histopathological analysis of the lesion revealed a primary extramedullary plasmacytoma of the eyelid. The tumour was completely excised. There has been no tumour recurrence over the last five years. This tumour should be among those considered when encountering an atypical adnexal lesion. A systemic examination, relevant clinical investigations, as well as life-long monitoring are essential for these patients due to the strong association of extramedullary plasmacytoma with multiple myeloma. When a lesion can be completely resected, surgery provides similar results to radiotherapy.

Retinal nerve fiber layer structure abnormalities in schizophrenia and its relationship to disease state: evidence from optical coherence tomography

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).

Fulltext Investigation of a PAX6 gene mutation in a Malaysian family with congenital aniridia

Lee PC, Lam HH, Ghani SA, Subrayan V, Chua KH

Genet. Mol. Res., 2014;13(2):3553-9.

PMID: 24737507 DOI: 10.4238/2014.March.24.15

Mutations in the PAX6 gene that cause aniridia have been identified in various ethnicities but not in the Malaysian population. Therefore, the objective of this study was to investigate the PAX6 mutation in a Malaysian family with congenital aniridia. In this study, a complete ophthalmic examination was performed on a Dusun ethnic family with aniridia. Genomic DNA was extracted from the peripheral blood of the subjects and screened for the PAX6 gene mutation using polymerase chain reaction amplification high-resolution melting curve analysis (PCR-HRM) followed by confirmation via direct DNA sequencing. A heterozygous G deletion (c.857delG) in exon 7 causing a frame shift in PAX6 was identified in all affected family members. Genotype-phenotype correlation analysis revealed congenital cataract and all affected family members showed a similar spectrum of aniridia with no phenotypic variability but with differences in severity that were age-dependent. In summary, by using a PCR-HRM approach, this study is the first to report a PAX6 mutation in a Malaysian family. This mutation is the cause of the aniridia spectra observed in this family and of congenital cataract.

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.

Role of Angiography in Systemic Lupus Erythematosus-Induced Choroiditis

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.

I think I have double vision? Or not? Internuclear Ophthalmoplegia following right lacunar infarct

Lee HN, Subrayan V

Med J Malaysia, 2021 Nov;76(6):950-952.

PMID: 34806694

Internuclear Ophthalmoplegia (INO) is an inability of the ipsilateral adduction with a contralateral horizontal abducting saccade on attempted gaze to the contra-lesion side. Injury to the medial longitudinal fasciculus (MLF) will obstruct the signalling pathway between the ipsilateral abducens nucleus and the contralateral medial rectus muscle. Infarction accounts for 38% of INO cases with mostly being unilateral (87%), followed by demyelination (34%), which mostly being bilateral (73%). Lacunar infarct is the most common ischemic stroke. INO can be easily missed due to its subtle presentation with no complaints from the patients. A full cranial nerves assessment, includes the extraocular muscles movement, is important. Ischemic and demyelinating INO typically recover. We present here of a case of INO following right lacunar infarct in a 72-year-old Malay woman. She had hypertensive crisis due to missed medications. Her blood pressure was well controlled throughout the hospital admission and finally she was discharged home with continuation of care at her primary facility.

Fulltext A rare occurrence of epithelial inclusion iris cyst after phacoemulsification

Kuganasan S, Voon Loo A, Subrayan V

Clin Exp Optom, 2015 Jan;98(1):97-8.

PMID: 25545950 DOI: 10.1111/cxo.12235

A comparative analysis of avoidable causes of childhood blindness in Malaysia with low income, middle income and high income countries

Koay CL, Patel DK, Tajunisah I, Subrayan V, Lansingh VC

Int Ophthalmol, 2015 Apr;35(2):201-7.

PMID: 24652461 DOI: 10.1007/s10792-014-9932-x

To determine the avoidable causes of childhood blindness in Malaysia and to compare this to other middle income countries, low income countries and high income countries. Data were obtained from a school of the blind study by Patel et al. and analysed for avoidable causes of childhood blindness. Six other studies with previously published data on childhood blindness in Bangladesh, Ethiopia, Nigeria, Indonesia, China and the United Kingdom were reviewed for avoidable causes. Comparisons of data and limitations of the studies are described. Prevalence of avoidable causes of childhood blindness in Malaysia is 50.5 % of all the cases of childhood blindness, whilst in the poor income countries such as Bangladesh, Ethiopia, Nigeria and Indonesia, the prevalence was in excess of 60 %. China had a low prevalence, but this is largely due to the fact that most schools were urban, and thus did not represent the situation of the country. High income countries had the lowest prevalence of avoidable childhood blindness. In middle income countries, such as Malaysia, cataract and retinopathy of prematurity are the main causes of avoidable childhood blindness. Low income countries continue to struggle with infections such as measles and nutritional deficiencies, such as vitamin A, both of which are the main contributors to childhood blindness. In high income countries, such as the United Kingdom, these problems are almost non-existent.

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