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Fulltext Stress and repetitive visual field assessment in glaucoma patients

Tan, Kok-Leong, Fhun, Lai-Chan, Ahmad Tajudin Liza Sharmini, Maizan Yaakub, Chong, Mei-Fong

Journal of Biomedical and Clinical Sciences, 2017;2(2):35-41.
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Glaucoma is a chronic disease that could affect the quality of life and is a potential stressor for patients. Visual field assessment is important in monitoring disease progression among glaucoma patients. Stress could influence the performance of patients in visual field test that may affect the reliability of the test. Our objective in this study was to determine the association between stress score using Depression, Anxiety and Stress Scale (DASS) questionnaire and reliability indices of Humphrey visual field analysis (HFA). A total of 155 primary and secondary glaucoma patients were recruited in the study. Face to face interview using stress component of DASS questionnaire was conducted after automated HFA test. Reliability indices; i.e. fixation loss, false positive, and false negative error, were used to determine the accuracy of HFA result. Only 12 patients (7.7%) were found to have elevated stress score. No significant correlation was found between DASS stress score and the reliability indices of HFA. There was 0.2 folds (95% confidence interval (CI) [-2.35, -0.06], p = 0.039) reduction of fixation loss for every number of HFA done. For every one year increase in age, there was 0.2 folds (95% CI [-0.38, -0.07], p = 0.006) reduction in false positive error in HFA.
Minimal stress may not affect the reliability of HFA assessment. Minimising stress among glaucoma patients is important not only for assessment of visual field but also for improvement of quality of life.
Treatment and decolorization of biologically treated Palm Oil Mill Effluent (POME) using banana peel as novel biosorbent

Mohammed RR, Chong MF

J Environ Manage, 2014 Jan;132:237-49.
PMID: 24321284 DOI: 10.1016/j.jenvman.2013.11.031

Palm Oil Mill Effluent (POME) treatment has always been a topic of research in Malaysia. This effluent that is extremely rich in organic content needs to be properly treated to minimize environmental hazards before it is released into watercourses. The main aim of this work is to evaluate the potential of applying natural, chemically and thermally modified banana peel as sorbent for the treatment of biologically treated POME. Characteristics of these sorbents were analyzed with BET surface area and SEM. Batch adsorption studies were carried out to remove color, total suspended solids (TSS), chemical oxygen demand (COD), tannin and lignin, and biological oxygen demand (BOD) onto natural banana peel (NBP), methylated banana peel (MBP), and banana peel activated carbon (BPAC) respectively. The variables of pH, adsorbent dosage, and contact time were investigated in this study. Maximum percentage removal of color, TSS, COD, BOD, and tannin and lignin (95.96%, 100%, 100%, 97.41%, and 76.74% respectively) on BPAC were obtained at optimized pH of 2, contact time of 30 h and adsorbent dosage of 30 g/100 ml. The isotherm data were well described by the Redlich-Peterson isotherm model with correlation coefficient of more than 0.99. Kinetic of adsorption was examined by Langergren pseudo first order, pseudo second order, and second order. The pseudo second order was identified to be the governing mechanism with high correlation coefficient of more than 0.99.
Start-up, steady state performance and kinetic evaluation of a thermophilic integrated anaerobic-aerobic bioreactor (IAAB)

Chan YJ, Chong MF, Law CL

Bioresour Technol, 2012 Dec;125:145-57.
PMID: 23026327 DOI: 10.1016/j.biortech.2012.08.118

Thermophilic treatment of palm oil mill effluent (POME) was studied in a novel integrated anaerobic-aerobic bioreactor (IAAB). The IAAB was subjected to a program of steady-state operation over a range of organic loading rate (OLR)s, up to 30 g COD/L day in order to evaluate its treatment capacity. The thermophilic IAAB achieved high chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of more than 99% for OLR up to 18.5 g COD/L day. High methane yield of 0.32 LCH(4) (STP)/g COD(removed) with compliance of the final treated effluent to the discharge limit were achieved. This is higher than that of the mesophilic system due to the higher maximum specific growth rate (μ(max)) of the thermophilic microorganisms. Besides, coupling the model of Grau second order model (anaerobic system) with the model of Monod (aerobic system) will completely define the IAAB system.
Biological treatment of anaerobically digested palm oil mill effluent (POME) using a Lab-Scale Sequencing Batch Reactor (SBR)

Chan YJ, Chong MF, Law CL

J Environ Manage, 2010 Aug;91(8):1738-46.
PMID: 20430515 DOI: 10.1016/j.jenvman.2010.03.021

The production of highly polluting palm oil mill effluent (POME) has resulted in serious environmental hazards. While anaerobic digestion is widely accepted as an effective method for the treatment of POME, anaerobic treatment of POME alone has difficulty meeting discharge limits due to the high organic strength of POME. Hence, subsequent post-treatment following aerobic treatment is vital to meet the discharge limits. The objective of the present study is to investigate the aerobic treatment of anaerobically digested POME by using a sequencing batch reactor (SBR). The SBR performance was assessed by measuring Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and Total Suspended Solids (TSS) removal as well as Sludge Volume Index (SVI). The operating pH and dissolved oxygen concentrations were found to be 8.25-9.14 and 1.5-6.4 mg/L, respectively, throughout the experiment. The experimental results demonstrate that MLVSS, OLR and sludge loading rate (SLR) play a significant role in the organic removal efficiency of SBR systems and therefore, further investigation on these parameters was conducted to attain optimum SBR performance. Maximum COD (95-96%), BOD (97-98%) and TSS (98-99%) removal efficiencies were achieved at optimum OLR, SLR and MLVSS concentration ranges of 1.8-4.2 kg COD/m(3)day, 2.5-4.6 kg TSS/m(3)day and 22,000-25,000 mg/L, respectively. The effluent quality remained stable and complied with the discharge limit. At the same time, the sludge showed good settling properties with average SVI of 65. It is envisaged that the SBR process could complement the anaerobic treatment to produce final treated effluent which meets the discharge limit.
Fulltext The Diagnostic Challenges in Carotid Cavernous Fistula: A Case Series

Thiyagarajam K, Chong MF, Mohd Khialdin S

Cureus, 2021 Nov;13(11):e19696.
PMID: 34934568 DOI: 10.7759/cureus.19696

A carotid-cavernous fistula (CCF) is an arteriovenous fistula with an abnormal connection between the carotid artery and cavernous sinus that can be sight and life-threatening. The conjunctival injection is often the most prominent feature, and patients are commonly misdiagnosed for other ocular conditions leading to a delay in diagnosis and treatment. All three patients in this case series presented with persistent red eyes. They were all treated for conjunctivitis and only referred for further workup when other progressing ocular symptoms occurred. The diagnosis of CCF was confirmed with digital subtraction angiography and with successful endovascular embolization, their ocular symptoms resolved with preserved optic nerve function. A high index of suspicion in patients presenting with an atypical red eye is very crucial for timely diagnosis of CCF.
Performance and kinetic evaluation of an integrated anaerobic-aerobic bioreactor in the treatment of palm oil mill effluent

Chan YJ, Chong MF, Law CL

Environ Technol, 2017 Apr;38(8):1005-1021.
PMID: 27532518 DOI: 10.1080/09593330.2016.1217053

This work presents the evaluation of biokinetic coefficients for a novel integrated anaerobic-aerobic bioreactor (IAAB) at different organic loading rates (OLRs) (10.5-22.5 g COD/L per day) treating palm oil mill effluent. The overall efficiencies of the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were more than 99% for OLR up to 19.5 g COD/L day with biogas production containing 48-64% of methane. The effluent quality remained stable (BOD
Optimisation of extraction and sludge dewatering efficiencies of bio-flocculants extracted from Abelmoschus esculentus (okra)

Lee CS, Chong MF, Robinson J, Binner E

J Environ Manage, 2015 Jul 1;157:320-5.
PMID: 25929197 DOI: 10.1016/j.jenvman.2015.04.028

The production of natural biopolymers as flocculants for water treatment is highly desirable due to their inherent low toxicity and low environmental footprint. In this study, bio-flocculants were extracted from Hibiscus/Abelmoschus esculentus (okra) by using a water extraction method, and the extract yield and its performance in sludge dewatering were evaluated. Single factor experimental design was employed to obtain the optimum conditions for extraction temperature (25-90 °C), time (0.25-5 h), solvent loading (0.5-5 w/w) and agitation speed (0-225 rpm). Results showed that extraction yield was affected non-linearly by all experimental variables, whilst the sludge dewatering ability was only influenced by the temperature of the extraction process. The optimum extraction conditions were obtained at 70 °C, 2 h, solvent loading of 2.5 w/w and agitation at 200 rpm. Under the optimal conditions, the extract yield was 2.38%, which is comparable to the extraction of other polysaccharides (0.69-3.66%). The bio-flocculants displayed >98% removal of suspended solids and 68% water recovery during sludge dewatering, and were shown to be comparable with commercial polyacrylamide flocculants. This work shows that bio-flocculants could offer a feasible alternative to synthetic flocculants for water treatment and sludge dewatering applications, and can be extracted using only water as a solvent, minimising the environmental footprint of the extraction process.
Fulltext Hemicrania Continua With Scintillating Scotoma: A Rare Presentation

Hussein A, Han Shu T, Chong MF, Cheah CF

Cureus, 2020 Sep 27;12(9):e10680.
PMID: 33133846 DOI: 10.7759/cureus.10680

Headache can be a primary or secondary disorder. The characteristics of headache and its associated features, especially the presence of red flag signs, are important in distinguishing secondary from primary causes. Hemicrania continua is a type of primary headache disorder characterized by a continuous unilateral headache with episodes of exacerbations and association with cranial autonomic symptoms, which include several ocular symptoms. The absolute response to indomethacin remains the hallmark of this disease. We would like to report a rare case of hemicrania continua with scintillating scotoma during exacerbations apart from the typical autonomic features of conjunctival injection, ptosis, eyelid edema, and lacrimation.
Fulltext Antiphospholipid syndrome in lupus retinopathy

Ng HK, Chong MF, Azhany Y, Zunaina E

Clin Ophthalmol, 2014;8:2359-63.
PMID: 25473262 DOI: 10.2147/OPTH.S71712

Systemic lupus erythematosus (SLE) is a chronic, multisystem, autoimmune disease that can affect any part of the human body including the eyes. Common blinding ocular manifestations include central retinal artery occlusion (CRAO), central retinal vein occlusion (CRVO), severe vaso-occlusive retinopathy, and optic nerve involvement. Antiphospholipid syndrome (APS) in lupus is usually associated with large vessel occlusions and needs prompt treatment with anticoagulant. We are reporting two cases of APS in SLE patients that presented with CRVO (case 1) and vaso-occlusive lupus retinopathy (case 2). Both cases were positive for antiphospholipid antibody (APA) and were treated with immunosuppression, anticoagulant, and laser treatment. Thus, screening for APA is vital in SLE patients with lupus retinopathy, as prompt treatment with anticoagulants is important to prevent further vascular thrombosis, which worsens the visual prognosis.
Study site: Ophthalmology clinic, Hospital Raja Permaisuri Bainun, Ipoh, Perak, Malaysia
Fulltext The Noxious Intruder of the Eye: Endogenous Klebsiella Panophthalmitis

Chai HX, Samsudin A, Jayaraman K, Chong MF

Cureus, 2021 Oct;13(10):e18725.
PMID: 34790480 DOI: 10.7759/cureus.18725

Endogenous Klebsiella pneumoniae panophthalmitis commonly affects those with compromised immunity. The occurrence of this infection in healthy individuals is rare. We describe the case of a healthy adult who presented with endogenous Klebsiella pneumoniae panophthalmitis from an asymptomatic liver abscess. A 64-year-old, previously healthy gentleman presented with rapidly progressive left eye periorbital swelling and blurring of vision. He had a low-grade fever three days prior to the development of ocular symptoms, but otherwise no other systemic complaints. Visual acuity was light perception in the left eye, and ocular motility was restricted in all directions of gaze. Ocular examination revealed proptosis, severe conjunctival chemosis, hazy cornea, and fibrin deposition in the anterior chamber. The posterior segment could not be visualized. Ultrasound of the hepatobiliary system revealed an abscess in the right lobe of his liver. His blood cultures grew Klebsiella pneumoniae. Despite being treated with high-dose intravenous antibiotics, his eye condition deteriorated. Evisceration was performed when he developed scleral melting and globe perforation. We highlight the importance of a high index of suspicion of endogenous Klebsiella panophthalmitis as it can be easily missed in healthy adults. Early diagnosis and prompt management are needed to prevent morbidity and mortality from this devastating infection.
Diagnosis of Ankylosing Spondylitis: Do not let the spine bites the eye

Chew CC, Chin JJ, Wan Hitam WH, Chong MF, Ahmad Tajudin LS

Malays Fam Physician, 2021 Jul 22;16(2):73-77.
PMID: 34386168 DOI: 10.51866/cr1121

Background: A diagnosis of ankylosing spondylitis (AS) is challenging and often delayed despite patients being symptomatic. Low back pain is the most common initial symptom, appearing in the second and third decades of life. Acute anterior uveitis (AAU) occurs much later in the course of the disease, often when the destruction of the spine is already debilitating.
Objective: Here, we report three cases of AS that were diagnosed after the patients developed AAU. Methods: A case series illustrated AAU leading to the diagnosis of AS years after the initial episode of low back pain. A comparison of the clinical presentation, diagnosis, and outcomes was also illustrated.
Result: We report three cases of acute anterior uveitis (AAU)-associated AS diagnosed only after many visits to the primary health care provider with the complaint of chronic low back pain. All three patients had irreversible radiological changes upon diagnosis of AS. The AAU resolved with topical steroids, and one patient developed cataract.
Conclusion: A high index of suspicion of AS in a young adult with chronic back pain before the development of AAU may prevent further functional loss and provide a better prognosis. Diagnosis of AS following AAU is not only associated with dependency but also may rob the vision of a young adult.
Removal of boron from ceramic industry wastewater by adsorption-flocculation mechanism using palm oil mill boiler (POMB) bottom ash and polymer

Chong MF, Lee KP, Chieng HJ, Syazwani Binti Ramli II

Water Res, 2009 Jul;43(13):3326-34.
PMID: 19487007 DOI: 10.1016/j.watres.2009.04.044

Boron is extensively used in the ceramic industry for enhancing mechanical strength of the tiles. The discharge of boron containing wastewater to the environment causes severe pollution problems. Boron is also dangerous for human consumption and causes organisms' reproductive impediments if the safe intake level is exceeded. Current methods to remove boron include ion-exchange, membrane filtration, precipitation-coagulation, biological and chemical treatment. These methods are costly to remove boron from the wastewater and hence infeasible for industrial wastewater treatment. In the present research, adsorption-flocculation mechanism is proposed for boron removal from ceramic wastewater by using Palm Oil Mill Boiler (POMB) bottom ash and long chain polymer or flocculant. Ceramic wastewater is turbid and milky in color which contains 15 mg/L of boron and 2000 mg/L of suspended solids. The optimum operating conditions for boron adsorption on POMB bottom ash and flocculation using polymer were investigated in the present research. Adsorption isotherm of boron on bottom ash was also investigated to evaluate the adsorption capacity. Adsorption isotherm modeling was conducted based on Langmuir and Freundlich isotherms. The results show that coarse POMB bottom ash with particle size larger than 2 mm is a suitable adsorbent where boron is removed up to 80% under the optimum conditions (pH=8.0, dosage=40 g bottom ash/300 ml wastewater, residence time=1h). The results also show that KP 1200 B cationic polymer is effective in flocculating the suspended solids while AP 120 C anionic polymer is effective in flocculating the bottom ash. The combined cationic and anionic polymers are able to clarify the ceramic wastewater under the optimum conditions (dosage of KP 1200 B cationic polymer=100 mg/L, dosage of AP 120 C anionic polymer=50 mg/L, mixing speed=200 rpm). Under the optimum operating conditions, the boron and suspended solids concentration of the treated wastewater were reduced to 3 mg/L and 5 mg/L respectively, satisfying the discharge requirement by Malaysia Department of Environment (DOE). The modeling study shows that the adsorption isotherm of boron onto POMB bottom ash conformed to the Freundlich Isotherm. The proposed method is suitable for boron removal in ceramic wastewater especially in regions where POMB bottom ash is abundant.
The Epidemiological Profile of Open Globe Injuries and Prognostic Factors in a Tertiary Care Centre

Ng HR, Chee SF, Chai KS, Chong MF, Mustapha M

Cureus, 2021 Jun;13(6):e15846.
PMID: 34327079 DOI: 10.7759/cureus.15846

Purpose To describe the epidemiology of open globe injuries and its prognostic factors from the perspectives of a tertiary care centre in northern Malaysia. Methods A retrospective study of open globe injuries in a period of three years between June 2017 and May 2020. Patients presenting with open globe injuries were identified and recruited from hospital census. Case records were retrieved and analysed after recruitment. Results A total of 114 patients with 118 open globe injuries were included in the study. Four patients had bilateral eye involvement. Men were found to have seven and a half times higher rate of ocular injuries than women. The predominant age group of ocular trauma presentation was in younger adults between the age of 21 and 30 years old. Work-related injuries account for almost half of the globe injuries (48.7%) followed by motor vehicle accident-related, domestic accident-related, and others. The significant factors related to the visual outcome are presenting visual acuity (VA), presence of relative afferent pupillary defect (RAPD) and vitreous loss. Conclusion The factors related to visual outcomes in this study may aid the clinician in determining the visual prognosis of ocular injuries. Young working males were the most susceptible group to sustain penetrating ocular injuries due to their job nature. Health education and safety at workplace are essential to reduce the occurrence of ocular injuries.
Fulltext Posterior Vitreous Detachment Precipitated by Yoga

Chong SY, Fhun LC, Tai E, Chong MF, Sonny Teo KS

Cureus, 2018 Jan 24;10(1):e2109.
PMID: 29581921 DOI: 10.7759/cureus.2109

Yoga has recently been touted as a means to improve physical and mental well-being. However, no form of exercise is without its risks. A 32-year-old Chinese female with moderate myopia complained of right eye sudden onset of floaters and mild blurring of vision after the head-down posture. The visual acuity was 6/12 in the right eye and 6/9 in the left eye. A right eye fundus examination showed posterior vitreous detachment, with a small blood clot located at the inferior margin of the optic disc. The patient was diagnosed with right eye vitreous hemorrhage secondary to acute posterior vitreous detachment and was managed conservatively. Acute changes in posture, especially between an upright and a head-down position, may cause acute posterior vitreous detachment. As yoga practitioners may be required to assume this head-down position, myopic patients should be warned of the possible ocular complications of this exercise.
Non-arteritic anterior ischaemic optic neuropathy secondary to menorrhagia in a young healthy woman

Koh KL, Sonny Teo KS, Chong MF, Wan Hitam WH

BMJ Case Rep, 2018 Jun 27;2018.
PMID: 29950366 DOI: 10.1136/bcr-2018-225113

Non-arteritic anterior ischaemic optic neuropathy (NAION) may develop due to severe anaemia and hypotension which is seen in acute blood loss. The devastating visual loss is often irreversible. We report a case of NAION in a 20-year-old healthy woman, who presented on the third day of a heavy menstrual cycle with hypovolaemic shock. On day 2 of admission, she had sudden right eye blurring of vision at the superior field on awakening from sleep. Funduscopy revealed a pale and swollen right optic disc. There was a dense right superior altitudinal visual field defect. Her haemoglobin level was low (3.6 g/dL), but she refused blood transfusion due to her religious belief (Jehovah's Witness) and opted for conservative management. She later developed right optic atrophy with persistent visual field defect despite an improved haemoglobin level of 10.5 g/dL.
Evaluation of Retinal Nerve Fiber Layer and Macular Thickness Pre- and Post-Chemotherapy With Carboplatin and Paclitaxel in Patients With Endometrial and Ovarian Cancer

Chin JJ, Wan Hitam WH, Chong MF, Lee SJ, Yew JM, Ngoo QZ

Cureus, 2023 Aug;15(8):e43943.
PMID: 37746413 DOI: 10.7759/cureus.43943

Background Carboplatin and paclitaxel are two standard chemotherapeutic agents known to cause neurotoxicity. In this study, we aim to evaluate the toxicity of these agents by measuring the peripapillary retinal nerve fiber layer (RNFL) and macular thickness in patients with endometrial and ovarian cancers who are receiving them. Methods A one-year prospective cohort study involving 28 patients who were treated intravenously with carboplatin (200-400 mg/m2) and paclitaxel (175 mg/m2) three-weekly for six cycles was conducted. RNFL and macula thickness were measured using optical coherence tomography (OCT) before the commencement of chemotherapy, after the third cycle, and one month after the sixth cycle. The main outcome measurements were the average RNFL thickness and central subfield thickness of the macula. Results The mean age of the 28 participants was 54.68 years old (standard deviation [SD] 9.03). Eleven had endometrial cancer, while 17 had ovarian cancer. The mean of the average RNFL thickness during baseline pre-chemotherapy was 96.43 µm (SD 11.39). One month after cessation of treatment, the mean RNFL thickness increased to 101.57 µm (SD 13.54). Statistical analysis showed a significant increment in the mean RNFL thickness (p ≤ 0.001), from baseline to after three cycles, and baseline to one month after six cycles of chemotherapy, except the nasal quadrant. The increment of all macular quadrants was statistically significant (p < 0.05) except for central subfield thickness. Conclusion Systemic administration of carboplatin and paclitaxel affected both the peripapillary RNFL and macula thickness. This represents early evidence of subacute subclinical retinal toxicity. OCT can be used as a screening tool to assess peri-chemotherapeutic retinal alterations.
Enzymatic pretreatment to enhance anaerobic bioconversion of high strength wastewater to biogas: A review

Liew YX, Chan YJ, Manickam S, Chong MF, Chong S, Tiong TJ, et al.

Sci Total Environ, 2020 Apr 15;713:136373.
PMID: 31954239 DOI: 10.1016/j.scitotenv.2019.136373

Oil and grease, carbohydrate, protein, and lignin are the main constituents of high strength wastewaters such as dairy wastewater, cheese whey wastewater, distillery wastewater, pulp and paper mill wastewater, and slaughterhouse wastewaters. These constituents have contributed to various operational problems faced by the high-rate anaerobic bioreactor (HRAB). During the hydrolysis stage of anaerobic digestion (AD), these constituents can be hydrolyzed. Since hydrolysis is known to be the rate-limiting step of AD, the overall AD can be enhanced by improving the hydrolysis stage. This can be done by introducing pretreatment that targets the degradation of these constituents. This review mainly focuses on the biological pretreatment on various high-strength wastewaters by using different types of enzymes namely lipase, amylase, protease, and ligninolytic enzymes which are responsible for catalyzing the degradation of oil and grease, carbohydrate, protein, and lignin respectively. This review provides a summary of enzymatic systems involved in enhancing the hydrolysis stage and consequently improve biogas production. The results show that the use of enzymes improves the biogas production in the range of 7 to 76%. Though these improvements are highly dependent on the operating conditions of pretreatment and the types of substrates. Therefore, the critical parameters that would affect the effectiveness of pretreatment are also discussed. This review paper will serve as a useful piece of information to those industries that face difficulties in treating their high-strength wastewaters for the appropriate process, equipment selection, and design of an anaerobic enzymatic system. However, more intensive studies on the optimum operating conditions of pretreatment in a larger-scale and synergistic effects between enzymes are necessary to make the enzymatic pretreatment economically feasible.

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