Singapore National Eye Center

Singapore, Singapore

Singapore National Eye Center

Singapore, Singapore
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Tsai A.S.H.,Singapore National Eye Center | Loon S.C.,National University of Singapore
Clinical and Experimental Ophthalmology | Year: 2012

This paper aims to review the current methods available for the measurement of intraocular pressure after myopic laser in situ keratomileusis for the correction of myopia. Searches were performed for studies that assessed or compared various methods of intraocular pressure assessment. There were 20 eligible studies that explored the use of pneumotonometry, pressure phosphene tonometry, rebound tonometry, dynamic contour tonometry, statistical modeling, mathematical formulae, ocular response analyzer and even measuring intraocular pressure on the nasal cornea. Our review shows that an ideal method would be one that is independent of corneal factors. Dynamic contour tonometry and pressure phosphene tonometry held promise in research settings. More studies need to be done to validate the new methods of intraocular pressure assessment, especially in glaucoma patients. It is important to empower laser in situ keratomileusis patients with knowledge of these difficulties and potential implications for the future. © 2011 Royal Australian and New Zealand College of Ophthalmologists.

Neelam K.,Khoo Teck Puat Hospital | Neelam K.,Singapore Eye Research Institute | Cheung C.M.G.,Singapore National Eye Center | Ohno-Matsui K.,Tokyo Medical and Dental University | And 4 more authors.
Progress in Retinal and Eye Research | Year: 2012

Myopic choroidal neovascularization (CNV) is one of the leading causes of visual impairment worldwide. The clinical and socioeconomic impact of myopic CNV in Asian countries is particularly significant due to rising trend in the prevalence and severity of pathological myopia. The exact pathogenesis of myopic CNV remains unclear and there is paucity of information with respect to incidence and risk factors for myopic CNV from prospective studies. Furthermore, there are no recognized measures that may prevent or delay the development of CNV in eyes with pathological myopia. Advances have been made in the diagnosis and characterization of myopic CNV over the years. Until recently, treatment modalities for myopic CNV were limited to thermal laser photocoagulation and photodynamic therapy with verteporfin, both these modalities primarily aim at prevention of further visual loss. In the last 5 years, inhibitors of vascular endothelial growth factor (VEGF) have been used successfully and may improve vision to some extent. Nevertheless, the long-term safety and efficacy of anti-VEGF agents remains unknown. Furthermore, the risk of developing chorioretinal atrophy remains the key factor in determining the final visual outcome. This review article summarizes the current literature on myopic CNV, highlighting new evolving diagnostic and treatment modalities, prognostic factors influencing visual outcome, and areas of future research. © 2012 Elsevier Ltd.

Weinreb R.N.,University of California at San Diego | Aung T.,Singapore National Eye Center | Aung T.,National University of Singapore | Medeiros F.A.,University of California at San Diego
JAMA - Journal of the American Medical Association | Year: 2014

IMPORTANCE: Glaucoma is a worldwide leading cause of irreversible vision loss. Because it may be asymptomatic until a relatively late stage, diagnosis is frequently delayed. A general understanding of the disease pathophysiology, diagnosis, and treatment may assist primary care physicians in referring high-risk patients for comprehensive ophthalmologic examination and in more actively participating in the care of patients affected by this condition. OBJECTIVE: To describe current evidence regarding the pathophysiology and treatment of open-angle glaucoma and angle-closure glaucoma. EVIDENCE REVIEW: A literature search was conducted using MEDLINE, the Cochrane Library, and manuscript references for studies published in English between January 2000 and September 2013 on the topics open-angle glaucoma and angle-closure glaucoma. From the 4334 abstracts screened, 210 articles were selected that contained information on pathophysiology and treatment with relevance to primary care physicians. FINDINGS: The glaucomas are a group of progressive optic neuropathies characterized by degeneration of retinal ganglion cells and resulting changes in the optic nerve head. Loss of ganglion cells is related to the level of intraocular pressure, but other factors may also play a role. Reduction of intraocular pressure is the only provenmethod to treat the disease. Although treatment is usually initiated with ocular hypotensive drops, laser trabeculoplasty and surgerymay also be used to slow disease progression. CONCLUSIONS AND RELEVANCE: Primary care physicians can play an important role in the diagnosis of glaucoma by referring patients with positive family history or with suspicious optic nerve head findings for complete ophthalmologic examination. They can improve treatment outcomes by reinforcing the importance of medication adherence and persistence and by recognizing adverse reactions from glaucoma medications and surgeries. Copyright 2014 American Medical Association. All rights reserved.

Lim F.P.,Singapore National Eye Center | Lim F.P.,Singapore Eye Research Institute
Eye (London, England) | Year: 2014

PURPOSE: To evaluate imaging findings of patients with focal choroidal excavation (FCE) in the macula using swept-source optical coherence tomography (SS-OCT) and correlate it clinically.METHODS: Prospective observational case series. Eleven consecutive patients (12 eyes) with FCE were described. Data on demographics and clinical presentation were collected and imaging findings (including color photography, fundus autofluorescence imaging, fluorescein angiography, indocyanine green angiography, spectral-domain optical coherence tomography, and SS-OCT) were analyzed.RESULTS: The primary diagnosis was epiretinal membrane (two eyes), choroidal neovascularization (one eye), polypoidal choroidal vasculopathy (three eyes), central serous chorioretinopathy (one eye), and dry age-related macular degeneration (two eyes). Eleven out of 12 of the lesions were conforming. One presented with a non-conforming lesion that progressed to a conforming lesion. One eye had multiFCE and two had two overlapping choroidal excavations. Using the SS-OCT, we found the choroid to be thinned out at the area of FCE but sclera remained normal. The choroidal tissue beneath the FCE was abnormal, with high internal reflectivity and poor visualization of choroidal vessels. There was loss of contour of the outer choroidal boundary that appeared to be pulled inward by this abnormal choroidal tissue. A suprachoroidal space was noted beneath this choroidal tissue and the choroidal-scleral interface was smooth. Repeat SS-OCT 6 months after presentation showed the area of excavation to be stable in size.CONCLUSION: FCE can be associated with epiretinal membrane, central serous chorioretinopathy, and age-related macular degeneration. The choroid was thinned out in the area of FCE.

Wong I.Y.,University of Hong Kong | Wong R.L.,University of Hong Kong | Zhao P.,Singapore National Eye Center | Lai W.W.,University of Hong Kong
Retina | Year: 2013

PURPOSE:: To investigate the relationship of hypercholesterolemia and choroidal thickness in normal healthy volunteers. METHOD:: This was a cross-sectional observational study. Volunteers with no ocular abnormalities were examined using enhanced depth imaging optical coherence tomography. Choroidal and retinal thicknesses were measured at the fovea, and at 4 different locations 1 mm superior, inferior, temporal, and nasal to the fovea. Subjects were further divided into those with hypercholesterolemia (Group 1) and normal control subjects (Group 2) for subgroup analysis regarding the effect of hypercholesterolemia on choroidal thickness. Subjects with hypertension and diabetes were excluded. RESULTS:: A total of 322 eyes of 161 subjects were studied. Mean age was 59.9 years (range, 24-84 years). The mean subfoveal choroidal thickness was 261 ± 98.7 μm. Mean subfoveal choroidal thickness negatively correlated with age (r = -0.326; P = 0.001). The mean serum total cholesterol was 5.02 ± 0.98 mmol/L. In Group 1, it was 5.65 ± 1.15 mmol/L, while in Group 2, it was 4.72 ± 0.73 mmol/L. The difference was statistically significant (P = 0.003). Subjects in Group 1 tended to be older and have worse vision, although the difference did not reach statistical significance. The mean subfoveal choroidal thickness in Group 1 was 306 ± 111 μm, while that in Group 2 was 258 ± 97 μm. The difference was statistically significant (P = 0.041). The same difference was also found at the 1 mm nasal (P = 0.041) and 1 mm superior (P = 0.040). CONCLUSION:: The subfoveal choroidal thickness was found to be significantly higher in subjects with hypercholesterolemia. This has to be taken into account when analyzing choroidal thickness.

Lim Z.,Singapore National Eye Center
Journal of AAPOS : the official publication of the American Association for Pediatric Ophthalmology and Strabismus / American Association for Pediatric Ophthalmology and Strabismus | Year: 2012

To review the management and outcomes of pediatric patients with cataract who were managed by one of two surgeons at a single institution. An observational series of consecutive cases identified from the hospital's outpatient billing records and surgical data program were used. Visual acuity was measured with the Snellen or Allen charts. Glaucoma was defined as IOP >20 mm Hg with clinical signs of glaucoma or visual field loss. Procedures for aphakic/pseudophakic glaucoma were excluded from analysis of additional surgeries performed subsequent to cataract extraction. The search identified 778 patients (1,122 eyes) diagnosed with cataract over 10 years. Of these, 74% of eyes were treated surgically. Those patients with total, nuclear, and lamellar cataracts were significantly more likely than the overall population to undergo surgery. Additional surgeries were required in 12% of surgically treated eyes, with pseudophakic eyes representing more than one-half. Aphakic and pseudophakic glaucoma prevalence were 12% and 1%, respectively. Cataract morphology was not found to be a predisposing factor in the development of glaucoma. Visual outcomes were significantly better for posterior subcapsular (P = 0.0001), nuclear (P = 0.025), lamellar (P = 0.03), and traumatic cataracts (P = 0.005) than for other morphological types at all ages. Visual acuity was 20/30 or better in 63% of children with unilateral pseudophakia, 45% of children with unilateral aphakia, and approximately 75% of children with bilateral aphakia and pseudophakia. Patients with total, nuclear, and lamellar cataracts were more likely to undergo surgery. Approximately 10% of patients required additional surgeries. No cataract morphology predisposed patients to developing glaucoma. Good visual outcomes were attained in bilaterally pseudophakic/aphakic and unilaterally pseudophakic children. Copyright © 2012 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved.

Teo L.,Singapore National Eye Center
Orbit (Amsterdam, Netherlands) | Year: 2013

To describe the histopathological distribution of biopsied lacrimal gland lesions in a tertiary referral centre in Singapore. This was a retrospective chart review. Clinical records of patients who underwent lacrimal gland biopsy at a tertiary referral centre in Singapore between 2000 to 2010, were reviewed. Data collated included patient demographics, clinical presentation, association with systemic disease and histopathological diagnosis. Sixty-nine patients were studied. Median age of presentation was 50 years. Forty patients (58%) were female and the majority (84%, n = 29) were Chinese. The mean follow-up duration was 35.0 ± 34.5 months. 30.4% (n = 21) of the patients had bilateral disease. Chronic dacryoadenitis (46%, n = 32) was the most common histopathological diagnosis, followed by lymphoproliferative disorders (38%, n = 26) and pleomorphic adenoma (10%, n = 7). The diagnoses in four other patients included adenoid cystic carcinoma, lacrimal gland hypertrophy, lacrimal duct cyst and orbital vascular malformation. Chronic dacryoadenitis and lymphoproliferative disorders are the two commonest causes of lacrimal gland lesions in our series. Although many cases remain non-specific, about 60% have a specific inflammation that may be associated with a systemic disease. As one third of our patients with lymphoproliferative disease of the lacrimal gland had an associated systemic lymphoma, patients with such lesions should be referred for investigation of possible systemic lymphoma. The results of our study can aid in providing a more targeted approach to patient management.

Age-related cataract is the opacification of the lens, which occurs as a result of denaturation of lens proteins. Age-related cataract remains the leading cause of blindness globally, except in the most developed countries. A key question is what is the best way of removing the lens, especially in lower income settings. To compare two different techniques of lens removal in cataract surgery: manual small incision surgery (MSICS) and extracapsular cataract extraction (ECCE). We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 1), MEDLINE (January 1950 to February 2012), EMBASE (January 1980 to February 2012), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to February 2012), Web of Science Conference Proceedings Citation Index- Science (CPCI-S), the metaRegister of Controlled Trials (mRCT) (, ( and the WHO International Clinical Trials Registry Platform (ICTRP) ( There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 14 February 2012. We included randomised controlled trials (RCTs) only. Participants in the trials were people with age-related cataract. We included trials where MSICS with a posterior chamber intraocular lens (IOL) implant was compared to ECCE with a posterior chamber IOL implant. Data were collected independently by two authors. We aimed to collect data on presenting visual acuity 6/12 or better and best-corrected visual acuity of less than 6/60 at three months and one year after surgery. Other outcomes included intraoperative complications, long-term complications (one year or more after surgery), quality of life, and cost-effectiveness. There were not enough data available from the included trials to perform a meta-analysis. Three trials randomly allocating people with age-related cataract to MSICS or ECCE were included in this review (n = 953 participants). Two trials were conducted in India and one in Nepal. Trial methods, such as random allocation and allocation concealment, were not clearly described; in only one trial was an effort made to mask outcome assessors. The three studies reported follow-up six to eight weeks after surgery. In two studies, more participants in the MSICS groups achieved unaided visual acuity of 6/12 or 6/18 or better compared to the ECCE group, but overall not more than 50% of people achieved good functional vision in the two studies. 10/806 (1.2%) of people enrolled in two trials had a poor outcome after surgery (best-corrected vision less than 6/60) with no evidence of difference in risk between the two techniques (risk ratio (RR) 1.58, 95% confidence interval (CI) 0.45 to 5.55). Surgically induced astigmatism was more common with the ECCE procedure than MSICS in the two trials that reported this outcome. In one study there were more intra- and postoperative complications in the MSICS group. One study reported that the costs of the two procedures were similar. There are no other studies from other countries other than India and Nepal and there are insufficient data on cost-effectiveness of each procedure. Better evidence is needed before any change may be implemented. Future studies need to have longer-term follow-up and be conducted to minimize biases revealed in this review with a larger sample size to allow examination of adverse events.

Khor W.B.,Duke University | Khor W.B.,Singapore National Eye Center | Afshari N.A.,University of California at San Diego
Current Opinion in Ophthalmology | Year: 2013

PURPOSE OF REVIEW: There is a growing number of patients who wish to remain spectacle independent after cataract surgery, and this number includes some of the millions of people worldwide who have undergone laser in situ keratomileusis (LASIK). This article reviews the evidence of the use of presbyopia-correcting intraocular lenses (IOLs) in patients who have previously undergone LASIK. RECENT FINDINGS: Small studies have demonstrated that the use of hybrid refractive-diffractive multifocal IOLs in eyes with previous myopic or hyperopic LASIK can result in good refractive results. However, refractive surprise can be common and may require further intervention, such as laser surgery enhancement, to achieve satisfactory results. The use of these IOLs can also result in lost lines of vision, and visual quality may be poorer under mesopic or glare conditions. No reports were found regarding the use of accommodating IOLs in such patients. SUMMARY: There is a surprising paucity of literature on this topic, given the millions that have undergone LASIK. Further and timelier research is needed to assess the use of newer multifocal and accommodating IOLs in post-LASIK eyes, the effect of IOL asphericity on visual quality, and patients' experience, satisfaction and level of spectacle independence after surgery. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Chua D.,Singapore National Eye Center | Cullen J.F.,Singapore National Eye Center
Singapore Medical Journal | Year: 2014

We report five cases of non-arteritic anterior ischaemic optic neuropathy (NA-AION) where spontaneous resolution of the optic disc swelling occurred, and all relevant visual modalities were normal at presentation and remained so until resolution of the process after a median time of 9.6 weeks. This condition, which can be termed ‘incipient NA-AION’ or ‘threatened NA-AION’, should be recognised so that unnecessary investigations for other and more serious causes of optic disc swelling can be prevented. © 2014, Singapore Medical Association. All Rights Reserved.

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