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PURPOSE To investigate the refractive outcome of combined cataract surgery and glaucoma drainage device (GDD) implantation compared with trabeculectomy and cataract surgery. SETTING Department of Ophthalmology, National University Health System, Singapore. DESIGN Retrospective cohort study. METHODS 206 eyes were enrolled for analysis: 50 had combined cataract surgery and trabeculectomy (trabeculectomy group), 50 had combined cataract surgery and GDD implantation (GDD group), and 106 had cataract surgery alone (control group). Refractive prediction error and absolute prediction error of each glaucoma surgery group were compared with the control group. Subgroup analysis was performed in the following axial length (AL) subgroups: short (

Micropulse transscleral cyclophotocoagulation (MPTCP) is only moderately effective in lowering intraocular pressure (IOP) and is useful as an adjunct procedure to other glaucoma surgeries. There was a small risk of loss of vision, prolonged hypotony, and phthisis bulbi.The aim of this study was to determine the efficacy and safety of a single MPTCP treatment for an Asian population with advanced glaucoma.This is a retrospective single-center study of 207 eyes (207 patients) with advanced glaucoma which underwent first-time MPTCP between January 1, 2008, and March 31, 2018. Success was defined as IOP of 6 to 21 mm Hg or ≥20% reduction in IOP without an increase in glaucoma medication from baseline, and without glaucoma reoperation. The IOP, best-corrected visual acuity, and number of glaucoma medications were also analyzed.The mean (SD) age was 64.9±16.9 years. The mean follow-up duration was 18.7±16.2 months. The rate of success at postoperative years 1 and 2 follow-up was 44.1% and 32.6%, respectively. The median survival time of MPTCP was 9.0 months and 85 (40.9%) eyes received reoperation. The mean IOP decreased from 31.5±12.0 mm Hg preoperatively to 22.1±10.3 and 23.8±11.8 mm Hg at postoperative years 1 and 2, respectively (P0.0001). The mean number of glaucoma medications was reduced from 3.3±1.0 preoperatively to 2.6±1.1 and 2.4±1.1 at postoperative years 1 and 2, respectively (P0.0001). Significant complications included prolonged hypotony [1 eye (0.5%)], phthisis bulbi [7 eyes (3.4%)], and best-corrected visual acuity reduction [29 eyes (13.9%)].Single first-time MPTCP for advanced glaucoma eyes was moderately effective in lowering IOP but50% failed by 1 year.

PURPOSE OF REVIEW: The use of slit lamp shields has been recommended by the American Academy of Ophthalmology as an infection control measure during the coronavirus disease 2019 pandemic. However, there is limited evidence regarding its efficacy to reduce viral transmission risks. We aim to provide an evidence-based approach to optimize the use of slit lamp shields during clinical examination. RECENT FINDINGS: Respiratory droplets from coughing and sneezing can travel up to 50 m/s and over a distance of 2 m, with a potential area of spread of 616 cm. Slit lamp shields confer added protection against large droplets but are limited against smaller particles. A larger shield curved toward the ophthalmologist and positioned closer to the patient increases protection against large droplets. A potential improvement to the design of such shields is the use of hydrophilic materials with antiviral properties which may help to minimize splashing of infectious droplets, reducing transmission risks. These include gold or silver nanoparticles and graphene oxide. SUMMARY: Slit lamp shields serve as a barrier for large droplets, but its protection against smaller droplets is undetermined. It should be large, positioned close to the patient, and used in tandem with routine basic disinfection practices.

Coronavirus disease 19 (COVID-19) was first reported in Wuhan, China, in December 2019, and has since become a global pandemic. Singapore was one of the first countries outside of China to be affected and reported its first case in January 2020. Strategies that were deployed successfully during the 2003 outbreak of severe acute respiratory syndrome have had to evolve to contain this novel coronavirus. Like the rest of the health care services in Singapore, the practice of ophthalmology has also had to adapt to this rapidly changing crisis. This article discusses the measures put in place by the 3 largest ophthalmology centers in Singapore's public sector in response to COVID-19, and the challenges of providing eye care in the face of stringent infection control directives, staff redeployments and “social distancing.” The recently imposed “circuit breaker,” effectively a partial lockdown of the country, has further limited our work to only the most essential of services. Our staff are also increasingly part of frontline efforts in the screening and care of patients with COVID-19. However, this crisis has also been an opportunity to push ahead with innovative practices and given momentum to the use of teleophthalmology and other digital technologies. Amidst this uncertainty, our centers are already planning for how ophthalmology in Singapore will be practiced in this next stage of the COVID-19 pandemic, and beyond.

PURPOSE To investigate the agreement of vertical cup-to-disc ratio (VCDR) measured from Heidelberg Retina Tomograph 3 (HRT-3), high-definition optical coherence tomography (HD-OCT), and clinical grading. METHODS A total of 933 consecutive subjects underwent optic nerve head imaging with HRT-3 and HD-OCT during a single visit. The vertical dimensions of the disc and cup were measured by slit-lamp examination using an eyepiece graticule. Bland-Altman plots evaluated the agreement in the VCDR obtained by the 2 instruments and clinical grading. RESULTS We found a significant trend for the difference in VCDR measured clinically and with HRT and HD-OCT (P

Purpose We hypothesize that patients with primary angle closure (PAC) have common significant facial characteristics that set them apart from an age-matched, sex-matched, and race-matched control population. The primary objective of this study was to test whether a 3-dimensional (3D) camera could pick up these differences in order to differentiate PAC patients from controls. Patients A total of 55 patients with PAC and 38 controls were included in the study. Materials and methods Cases and controls had their facial photographs taken using a 3-dimensional digital camera (3dMdFace System). The facial features in the captured photographs were analyzed using a computer software (Neural Network Toolbox). A regression formula was devised to show whether these facial parameters could be used to distinguish between patients and controls. Results Thirteen facial parameters were measured, and using a regression formula and neural network classification we were able to mathematically distinguish patients from controls using this method of screening. Conclusions PAC patients have distinct facial features that may be differentiated from those of normal individuals mathematically using 3D photography. There is potential for this 3D facial scanning technology in screening for PAC in the general population.

Background: With the use of ultrasound biomicroscopy, we aim to look at differences in anterior segment parameters of eyes with primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) in dark and light conditions.Methods: Ultrasound biomicroscopy was performed for 30 subjects with PACG and 30 subjects with POAG at initial presentation before any treatment. Measurements of angle opening distance (AOD-500 and AOD-750) and trabecular-iris space area (TISA-500 and TISA-750) 500 and 750 mm from the scleral spur in both dark and light conditions were made. Anterior chamber depth (ACD) and axial length (AL) were also measured.Results: The mean age of PACG patients was 67.6 ± 9.6 years and POAG patients 62.1 ± 13.9 years. The mean ACD (2.70 ± 0.53mm) in PACG patients was significantly different from that (3.32 ± 0.52mm) of POAG patients (p

Background. To evaluate the outcome and complications of transscleral suture-fixated posterior chamber intraocular lens (PCIOL) implantation combined with Ahmed glaucoma valve (AGV) surgery in Asian eyes. Design. This was a retrospective study that included 22 eyes from 22 participants. The surgeries were performed at Singapore’s National University Hospital. Participants underwent an Ahmed tube surgery, together with transscleral suture-fixated posterior chamber intraocular lens. Main Outcome Measures. Complete success was defined as 6 ≤ intraocular pressure (IOP) ≤ 21 mmHg without medications at the last follow-up visit, with no reoperation required and no progression to no perception of light (NPL). Results. At the last follow-up, there was a significant reduction in mean IOP (22.4 ± 6.5 mmHg versus 13.9 ± 3.9 mmHg; p<0.001) and mean number of intraocular pressure-lowering medications (2.45 ± 1.30 versus 0.05 ± 0.21; p<0.001). There was no significant change in visual acuity [1.43 ± 1.21 (LogMAR) versus 1.09 ± 1.31 (p=0.204)]. Sixteen eyes (72.7%) achieved complete success. The 3 commonest complications were bullous keratopathy, choroidal detachment, and displacement of intraocular lens. Conclusion and Relevance. This technique showed good success for intraocular pressure control and vision preservation. Postoperative complications were relatively common although most were self-limiting. Patients at increased risk of trabeculectomy failure may be suitable for this procedure.

Anterior chamber depth (ACD) is a key anatomical risk factor for primary angle closure glaucoma (PACG). We conducted a genome-wide association study (GWAS) on ACD to discover novel genes for PACG on a total of 5,308 population-based individuals of Asian descent. Genome-wide significant association was observed at a sequence variant within ABCC5 (rs1401999; per-allele effect size = −0.045 mm, P = 8.17×10−9). This locus was associated with an increase in risk of PACG in a separate case-control study of 4,276 PACG cases and 18,801 controls (per-allele OR = 1.13 [95% CI: 1.06–1.22], P = 0.00046). The association was strengthened when a sub-group of controls with open angles were included in the analysis (per-allele OR = 1.30, P = 7.45×10−9; 3,458 cases vs. 3,831 controls). Our findings suggest that the increase in PACG risk could in part be mediated by genetic sequence variants influencing anterior chamber dimensions., Author Summary The anterior chamber is the space within the eye which is bound by the cornea, and the anterior surfaces of the iris and lens. Anterior chamber depth (ACD) is the distance measured along the eye's optical axis, from the cornea to the lens surface. ACD is an important risk factor for primary angle closure glaucoma (PACG), a major cause of irreversible blindness worldwide, and in particular, individuals of Asian ethnicity. In order to identify the genes that underlie PACG susceptibility, we conducted a two-staged study. We first conducted a large scale genetic study on a total of 5,308 population-based individuals of Asian descent to identify the genetic variants that influence ACD. This was followed by testing for associations between the identified genetic variant and PACG in another independent collection of 4,276 PACG cases and 18,801 controls. We found that a genetic variant within ABCC5 was associated with an increased risk of having PACG. Our findings suggest that the increase in PACG risk could in part be mediated by genetic sequence variants that influence the anterior chamber dimensions of the eye.

Background The aim of this study was to compare the efficacy and safety of micropulse and continuous wave diode transscleral cyclophotocoagulation in refractory glaucoma. Design Randomized, comparative, exploratory study in a tertiary hospital setting. Participants Patients with refractory, end-stage glaucoma. Methods Forty-eight patients were randomized to either treatment. The intraocular pressure, visual acuity, number of medicines and repeat treatment were monitored for 18 months. Complications that include visual acuity decline, prolonged anterior chamber inflammation, phthisis bulbi, scleral thinning and ocular pain were noted. Main Outcome Measure Intraocular pressure between 6 and 21 mmHg and at least a 30% reduction with or without anti-glaucoma medications after 18 months. Results A successful primary outcome was achieved in 75% of patients who underwent micropulse cyclophotocoagulation and 29% of patients who received continuous wave cyclophotocoagulation after 12 months (P

This study aims to systemically review the effect of laser iridotomy on the corneal endothelium. Searches were performed for studies that either compared corneal endothelial cell density/count, corneal thickness and morphology pre- and postiridotomy, or evaluated the postiridotomy development of corneal decompensation. There were 26 eligible studies. Our review shows that the effect of laser iridotomy on the corneal endothelium has been investigated with varying results. Although it has been demonstrated to be a relatively safe procedure, there is still the potential long-term risk of corneal decompensation, for which a corneal transplantation may be indicated eventually. The longest interval between laser iridotomy and corneal decompensation reported was 8 years. Mechanisms proposed for endothelial damage include direct focal injury, thermal damage, mechanical shock waves, iris pigment dispersion, transient rise in intraocular pressure, inflammation, turbulent aqueous flow, time-dependent shear stress on endothelium, chronic breakdown of blood-aqueous barrier and damage from bubbles that settled onto the endothelium. Inherent risk factors identified were iridotrabecular contact, current or prior acute angle closure, pigmented irides, small iris-to-endothelium distance, pre-existing endothelial disease and diabetes. Intervention-related risk factors include laser type, delivery and quantity. The significance of the risk factors and their direct association with the development of corneal decompensation remain to be determined. Understanding these risk factors may allow physicians to counsel their patients better. They may offer opportunities for preventive strategies, allowing us to ensure that a procedure performed to prevent disease progression and visual loss does not cause further morbidity.

Objective To describe anterior segment optical coherence tomography (ASOCT) parameters during acute primary angle closure (APAC) before therapeutic interventions and comparative analyses of biometric parameters of APAC eyes with fellow eyes. Design Prospective, comparative case series. Participants Thirty-one consecutive patients with APAC. Methods All patients underwent ASOCT imaging of both eyes during the attack, before therapeutic interventions were administered. Custom software was used to measure anterior chamber depth (ACD), anterior chamber area (ACA), anterior chamber volume (ACV), iris curvature (I-Curv), iris area (I-Area), lens vault (LV), and angle opening distance (AOD750), trabecular iris space area (TISA750), and iris thickness (IT750) at 750 μm from the scleral spur. Multivariate logistic regression modeling using forward selection was used to determine the most important biometric variables associated with APAC compared with the fellow eye during the attack. Main Outcome Measures Anterior segment biometric parameters associated with APAC. Results The mean age of the patients was 60.9±7.5 years, and 11 patients (35.5%) were male. The mean intraocular pressure was 3.8±9.2 mmHg in the APAC eye and 4.2±4.3 mmHg in the fellow eye before treatment ( P 0.001). After adjustment for pupil diameter, APAC eyes had smaller ACD, ACA, ACV, I-Curv (all P 0.001), AOD750 ( P = 0.037), TISA750 ( P = 0.043), I-Area ( P = 0.027), and IT750 ( P = 0.002) and larger LV ( P = 0.041) than fellow eyes. An optimal model consisting of 3 variables (pupil diameter, ACD, and I-Curv) explained 36.7% of the variance in APAC occurrence, with ACD accounting for 18.1% and I-Curv accounting for 14.1% of this variance. Conclusions Shallower ACD and smaller I-Curv were the 2 main anterior segment biometric parameters associated with APAC during the attack. These findings present new insights into the anterior segment biometric parameters of APAC and fellow eyes before therapeutic interventions. Anatomic changes in the anterior segment explained only about one third of the variance in APAC occurrence, and the role of nonanatomic factors require further investigation.

International audience; Primary angle closure glaucoma (PACG) is a major cause of blindness worldwide. We conducted a genome-wide association study (GWAS) followed by replication in a combined total of 10,503 PACG cases and 29,567 controls drawn from 24 countries across Asia, Australia, Europe, North America, and South America. We observed significant evidence of disease association at five new genetic loci upon meta-analysis of all patient collections. These loci are at EPDR1 rs3816415 (odds ratio (OR) = 1.24, P = 5.94 × 10(-15)), CHAT rs1258267 (OR = 1.22, P = 2.85 × 10(-16)), GLIS3 rs736893 (OR = 1.18, P = 1.43 × 10(-14)), FERMT2 rs7494379 (OR = 1.14, P = 3.43 × 10(-11)), and DPM2-FAM102A rs3739821 (OR = 1.15, P = 8.32 × 10(-12)). We also confirmed significant association at three previously described loci (P < 5 × 10(-8) for each sentinel SNP at PLEKHA7, COL11A1, and PCMTD1-ST18), providing new insights into the biology of PACG.

Background: To evaluate different mechanisms of primary angle closure and to quantify anterior chamber parameters in these mechanisms using anterior segment optical coherence tomography in an Asian population. Design: Hospital-based cross-sectional observational study. Participants: Forty-eight consecutive patients with primary angle closure glaucoma. Methods: Patients underwent complete ophthalmic examination and imaging of nasal-temporal angles with anterior segment optical coherence tomography. Images were categorized into four primary angle closure mechanisms: pupil block, plateau iris configuration, Thick peripheral iris roll and exaggerated lens vault. Parameters computed: anterior chamber depth central, anterior chamber depth at 1000 µm and 2000 µm anterior to scleral spur, lens vault, anterior chamber area, angle opening distance, trabecular iris space area and iris thickness. Main Outcome Measure: Anterior chamber parameters and primary angle closure mechanisms. Results: Mean values of anterior chamber depths: central (P

Keratoconus is an ectatic corneal disorder for which exciting therapeutic and diagnostic technologies are emerging. However, its pathogenesis is still heterogeneous and elusive. We researched overlooked Asian keratoconus data by literature review of databases (PubMed, MEDLINE, Ovid, Google Scholar, Cornea, and Cochrane) using key words "keratoconus, Asia, epidemiology, treatment, risk factors, genes" and names of Asian countries. Articles and their references were analyzed. Studies showed that keratoconus may be more prevalent, have earlier onset, and have greater disease progression in certain Asian and non-Asian ethnicities, particularly Indians, Pakistanis, Middle Easterners, and Polynesians, compared with white populations. Epidemiological risk factors include ethnicity, age (younger than 30 years), gender (male), positive family history, and eye rubbing. Genetic and disease risk factors include atopy, vernal keratoconjunctivitis, Down syndrome, pellucid marginal corneal degeneration, VSX1 (visual system homeobox 1) gene, and Leber congenital amaurosis. Differentiation of heterogeneous keratoconus subsets with detailed genotype-phenotype characterization may advance understanding. Comprehensive multiethnic population studies with valid large-scale data are needed. New effective treatments (deep anterior lamellar keratoplasty, intrastromal corneal ring segments, and corneal collagen cross-linking with riboflavin) are succeeding previous treatments.

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.

Purpose To evaluate the measurement of optic disc morphology using Heidelberg Retinal Tomography (HRT) with and without the aid of optic disc photos. Methods One hundred three children (aged 11 and 12 y, 52 boys) were selected randomly from the Singapore Cohort study of Risk Factors for Myopia. Optic nerve head topography and retinal nerve fiber layer thickness measurements were assessed using the HRT-II (Heidelberg, Germany) scanning laser ophthalmoscope. All contour lines were drawn by the same researcher on 2 occasions. The first drawing was made without optic disc photographs but using the 3-dimensional rotation assessment. The second drawing was made with the additional aid of digital monoscopic optic disc photographs. Results There was a high correlation between the measurements taken with and without optic disc photographs. For the global disc area, the difference between the mean readings was 0.67 mm2 and the intraclass correlation (ICC) was 0.81 [95% confidence interval (CI) 0.73-0.86]. The mean difference for the global cup-to-disc ratio was 0.03 [ICC 0.86 (95% CI 0.80-0.90)]. The ICCs were high across almost all of the readings except rim volume, in which the ICC was 0.57 (95% CI 0.43-0.69). Conclusions This study shows minimal differences in HRT measured optic disc parameters when optic disc photos are used to aid in the definition of the scleral ring. Omitting the use of disc photographs in measuring HRT outputs may translate into significant savings in time and logistics in simultaneously obtaining HRT and optic disc photographs in large population-based studies.

PURPOSE Compare the efficacy and safety profile of viscocanalostomy versus trabeculectomy in uncontrolled glaucoma. PATIENTS AND METHODS We looked through various search engines for randomized controlled trials directly comparing viscocanalostomy with trabeculectomy. Outcome measurements we examined were mean intraocular pressure difference at 6 months, 12 months, and 24 months, mean difference in postoperative number of antiglaucomatous medications and relative risk of adverse events. Subgroup analysis looked at studies that included 1 eye per patient, studies that included only white patients, studies with only primary open angle glaucoma, studies that did not allow the use of intraoperative mitomycin C in trabeculectomy treatment, studies that did not allow any postoperative use of antimetabolites, and studies with and without the use of postviscocanalostomy Nd:YAG goniopuncture. RESULTS Ten randomized controlled trials were selected and included in the meta-analysis with a total of 458 eyes of 397 patients with medically uncontrolled glaucoma. At 6 months, mean intraocular pressure difference was 2.25 mm Hg (95% confidence interval 1.38-3.12), at 12 months it was 3.64 mm Hg (2.74, 4.54), whereas at 24 months it was 3.42 mm Hg (1.80, 5.03). Trabeculectomy was found to have a significantly better pressure-lowering outcome (P

This paper aims to compare the efficacy, mean operative time and adverse effects of primary external dacryocystorhinostomy (DCR) versus primary endonasal DCR in treating acquired nasolacrimal duct obstruction. Searches were performed for studies comparing the two procedures. Two reviewers independently extracted data from 14 eligible studies. A random effects model was used to analyse the studies. Outcome measures were defined as patency of the nasolacrimal canal and mean operative time,and adverse effects as cutaneous scarring and bleeding.Both procedures were comparable in efficacy in terms of full success, partial success and anatomic patency. Subgroup analysis showed no significant difference between prospective and retrospective studies as well as between non-laser endonasal DCR versus external DCR and laser endonasal DCR versus external DCR. Endonasal DCR had a significantly shorter mean operative duration, be it laser endonasal DCR (mean difference: 37.65 min, 95% confidence intervals:3.54-71.75 min, P: 0.03) or non-laser endonasal DCR (mean difference: 19.22 min, 95% confidence intervals: 2.15-36.28 min, P: 0.03). The odds of post-operative bleeding was not significantly different between the two procedures, whereas post-operative cutaneous scarring was unique to external DCR and occurred in 50 out of 402 (12.44%) external DCRs recorded. Endonasal DCR has comparable success rates with external DCR and has a shorter operative time and no cutaneous scar. However, drawbacks include the steep learning curve and higher costs.

Objective To evaluate the performance of the Heidelberg Retina Tomograph II (HRT II, Heidelberg Engineering, Heidelberg, Germany) in diagnosing glaucoma in a population setting. Design Population-based cross-sectional study. Participants Of 3280 Malay persons aged 40 to 80 years who participated in the survey, 112 subjects (124 eyes) with glaucoma and a subset of 196 bilaterally normal subjects (392 eyes) were included for the evaluation of diagnostic ability of HRT II. Methods All glaucomatous and normal eyes underwent standardized ophthalmic assessment (including automated perimetry) and HRT II. Glaucoma was defined according to International Society for Geographical and Epidemiological Ophthalmology criteria. Area under the curve (AUC) receiver operating characteristic (ROC), sensitivity, and specificity were used to evaluate the diagnostic performance of HRT II algorithms. Marginal logistic regression models were used to evaluate the influence of optic disc size on the results of HRT II algorithms. Main Outcome Measures The HRT II algorithms: linear discriminant functions (LDFs) by Mikelberg et al (LDF1), Burk et al (LDF2), Bathija et al (LDF3), and Moorfields regression analysis (MRA). The MRA was subdivided into MRA1 with "borderline" outcomes as positive and MRA2 with "borderline" outcomes as negative. Results Subjects with cataract, visual impairment, astigmatism, and greater negative spherical equivalent, and of older age were more likely to yield lower quality images. For analyses by eye, AUCs were 0.789, 0.704, 0.755, 0.754, and 0.762 for MRA1, MRA2, LDF1, LDF2, and LDF3, respectively. At 85% specificity, sensitivities were 62.1%, 65.3%, and 66.9% for LDF1, LDF2, and LDF3, respectively. At 95% specificity, these figures decreased to 31.5%, 42.7%, and 45.2%, respectively. The sensitivity and specificity were 71.0% and 86.7% for MRA1 and 43.6% and 97.2% for MRA2, respectively. Similar estimates were found for analyses by person. Larger optic disc size was associated with increased sensitivity and false-positive rate for MRA1, LDF1, and LDF2. LDF1 and LDF3 were least affected by optic disc area, but the sensitivities were moderate and the false-positive rates were high across different optic disc areas. Conclusions The current HRT II algorithms are of limited value for population-based glaucoma screening in the Malay population and do not account adequately for optic disc size. Financial Disclosure(s) The authors have no proprietary or commercial interest in any materials discussed in this article.

Background: Data regarding development of primary angle closure glaucoma (PACG) following acute primary angle closure (APAC) is conflicting. This study looks at outcomes after an APAC episode with a secondary aim to identify any risk factors that could predict progression to PACG. Methods: This is a retrospective review of the charts of consecutive patients who were diagnosed with APAC from December 2003 to June 2006. All were treated in a standard manner with initial intensive medical therapy or laser iridoplasty followed by early laser peripheral iridotomy within 24 h of presentation. Results: Forty-two eyes of 41 patients were analysed. The mean follow-up period was 27.3 ± 16.2 months. Nine eyes (21.4%) developed an increase in intraocular pressure (IOP) within a mean of 11.9 months (median 5 months) after resolution of APAC. Eight eyes went on to have trabeculectomy or glaucoma drainage device. At final follow up, the mean IOP of attack eye was 13.3 ± 2.92 mmHg. None of the eyes, including those that underwent surgery, required topical medication to control IOP. Thirty-eight eyes (90.5%) have BCVA of 6/6 to 6/12. The duration of symptoms before presentation (P = 0.00) and duration taken to abort the acute attack (P = 0.01) were found to be significantly associated with development of PACG. Conclusion: The results of this study suggest that outcomes following successful treatment of APAC may not be as poor as described previously. Early aggressive management of the acute episode may have a role to play in preventing development of PACG after APAC.

Although there are approximately 200 million people of Malay ethnicity living in Asia, the burden and risk factors of blinding eye diseases in this ethnic group are unknown. This study summarizes the rationale and study design of a population-based study of eye diseases among adult Malays in Singapore.A population-based cross-sectional study of Malays was designed in Singapore. The sampling frame consisted of all Malays aged 40-79 living in designated study areas in southwestern Singapore. From a list of 16,069 names provided by the Ministry of Home Affairs, age-stratified random sampling was used to select 5,600 names (1,400 people from each decade of 40-49, 50-59, 60-69, and 70-79 years). The target sample size for this study was 3,150 persons. Selected individuals were invited to a centralized clinic by letters, telephone calls, and home visits. Participants underwent standardized interview and assessment of blood pressure, anthropometry, presenting and best-corrected visual acuity, subjective refraction, ocular biometry, Goldmann tonometry, slit-lamp biomicroscopy, optic disc imaging, digital lens, and retinal photography. Blood and urine samples were collected for biochemical analyses and further stored for future studies. Selected participants also had gonioscopic examination, visual fields test, and assessment of ankle and brachial blood pressure to detect presence of peripheral vascular disease.This study provides population-based data on the prevalence of and risk factors for age-related eye diseases in people of Malay ethnicity in Singapore. Data from this study allow further understanding of the etiology and impact of eye diseases in this ethnic group.

Primary open-angle glaucoma is the most common optic neuropathy and an important cause of irreversible blindness worldwide. The optic nerve head or optic disc is divided in two parts: a central cup (without nerve fibers) surrounded by the neuroretinal rim (containing axons of the retinal ganglion cells). The International Glaucoma Genetics Consortium conducted a meta-analysis of genome-wide association studies consisting of 17,248 individuals of European ancestry and 6,841 individuals of Asian ancestry. The outcomes of the genome-wide association studies were disc area and cup area. These specific measurements describe optic nerve morphology in another way than the vertical cup-disc ratio, which is a clinically used measurement, and may shed light on new glaucoma mechanisms. We identified 10 new loci associated with disc area (CDC42BPA, F5, DIRC3, RARB, ABI3BP, DCAF4L2, ELP4, TMTC2, NR2F2, and HORMAD2) and another 10 new loci associated with cup area (DHRS3, TRIB2, EFEMP1, FLNB, FAM101, DDHD1, ASB7, KPNB1, BCAS3, and TRIOBP). The new genes participate in a number of pathways and future work is likely to identify more functions related to the pathogenesis of glaucoma. ? 2015

Purpose (i) To evaluate the medication adherence rate of glaucoma patients in Singapore. (ii) To evaluate patients' quality of life status. (iii) To explore the factors related to patients' nonadherence to medication. Patients and methods A cross-sectional, prospective study, using interviewer-administered survey questionnaires. A total of 314 patients were interviewed altogether, of which 175 (55.7%) were male and 139 (44.3%) were female. (i) Patients' medication adherence was assessed using the Reported Adherence to Medication scale. (ii) Patients' beliefs about glaucoma and treatment were evaluated using the Brief Illness Perception Questionnaire and the Beliefs about Medicine-Specific Questionnaire. (iii) Patients' quality of life was evaluated using Glaucoma Symptom Scale and The Glaucoma Quality of Life-15 questionnaire. Results Sixty-two (19.7%) patients reported themselves to be adherent to their medication. Male patients (P=0.044) and smokers (P=0.002) were more likely to be nonadherent to their medication regimen. Nonadherent patients were more likely to have (i) more concerns about their glaucoma medications (P=0.000); (ii) less belief in the effects of their medications (P=0.026); (iii) a lower quality of life (higher score of GQOL-15, P=0.014); (iv) less symptoms from their glaucoma (lower score of Glaucoma Symptom Scale, P=0.026); and (v) more effect on their lives from glaucoma (P=0.01). Conclusions The full-adherence rate is low among glaucoma patients. Having less belief in the need for and more concerns about their medication are the 2 factors associated with nonadherence. In the future, effective strategies should be explored to improve patients' beliefs. Nonadherence has an association with decreased quality of life. Strategies to improve adherence will need to deal with these areas.

Objective To examine the reliability of inexperienced observers in plotting optic disc contours on Heidelberg retinal tomography images before and after training. Design Observational study. Participants One hundred eyes that were randomly selected from the Singapore Indian Eye Study. Methods Both eyes of subjects were imaged with Heidelberg Retina Tomograph 3 (HRT-3; Heidelberg Engineering, Heidelberg, Germany). Optic disc contours were plotted on the same images by 2 new observers on 2 separate occasions, before and after 2-hour standardized training on the skills and tools available to accurately identify and delineate optic disc contours. These plottings were compared with an experienced, trained glaucoma expert (gold standard). Agreement and variability were analyzed by interclass correlation tests and Bland–Altman plots. Results A total of 182 images (18 excluded because of poor quality) from 89 Indian subjects were included. The mean age was 53.27 ± 7.25 years and 54.8% were male. There was moderate-to-high agreement between pretraining (both new observers) and experienced observer’s results (interclass correlation values range, 0.76–0.99). The interclass correlation improved for all the HRT-3 parameters after the 2 new observers were adequately trained. Comparing the interclass correlation values before and after training, the differences for mean retinal nerve fibre layer thickness for Observer 1 and all the HRT-3 parameters for Observer 2 were statistically significant. Conclusions This study shows that it is easy to train a new inexperienced observer to plot optic disc contours on HRT images, which translates into improved and acceptable interobserver variability and agreement.

Severe acute respiratory syndrome (SARS), a disease caused by a novel strain of coronavirus (SARS-CoV), first emerged 10 years ago and shortly evolved into a global epidemic. During the 2003 outbreak, there were 8096 people with reported probable SARS worldwide and a total of 774 associated mortalities.1 If not for immediate and concerted efforts worldwide to control the outbreak the numbers could have been even higher. In light of the current emergence of a SARS-like virus2 coinciding with the 10-year anniversary of the outbreak, and as the author of the original paper which found SARS-CoV in tears,3 it would seem timely to remind ophthalmologists and physicians to be on constant alert and adhere to infection control practices. SARS causes …

INTRODUCTION To describe the optic disc, visual field and ocular characteristics of a consecutive cohort of Asian patients with chronic primary angle-closure glaucoma (CPACG), and compare them with those having primary open-angle glaucoma (POAG). METHODS In a prospective comparative case series of new patients with POAG or CPACG in Singapore, all patients underwent visual acuity assessment, slit-lamp examination, tonometry, gonioscopy, refraction, Heidelberg Retina Tomograph (HRT) and Humphrey visual field (HVF) assessment. RESULTS 98 patients were enrolled (POAG n = 48; CPACG n = 50). CPACG patients were significantly older (66.5 ± 9.2 years vs. 64.1 ± 13.5 years; p = 0.027) and mostly female (p = 0.004). CPACG eyes had significantly higher intraocular pressure (26.9 ± 6.9 mmHg vs. 24.5 ± 3.3 mmHg; p = 0.03), shorter axial length (22.89 ± 0.97 mm vs. 24.26 ± 1.79 mm; p < 0.001) and shallower anterior chamber depth (2.60 ± 0.25 mm vs. 3.16 ± 0.48 mm; p < 0.001). HVF mean deviation or pattern standard deviation (PSD) did not differ significantly between POAG and CPACG eyes, but the latter had a lower PSD for a given mean deviation. HRT parameters between the two groups were not significantly different. CONCLUSION In this study, CPACG eyes had significantly higher presenting intraocular pressure than POAG eyes, but there were no significant differences in optic disc topography. A majority of the patients in both groups had moderate field defects at the time of presentation, followed by severe and then mild defects. The field loss in CPACG eyes was more diffuse than that in POAG eyes.

Aim To examine the association between branch retinal vein occlusion (BRVO) and quantitative optic disc topographic parameters. Methods The Singapore Indian Eye Study (SINDI) is a population-based study of 3400 Singapore Indians aged 40+ years. BRVO was defined and graded from retinal photographs. Optic disc parameters were quantified using the Heidelberg Retinal Tomograph III (HRT III). Associations were evaluated for individual eyes; the generalised estimating equation was used to account for correlation between fellow eyes. Results 6173 eyes (comprising 19 BRVO) had gradable retinal photographs and HRT images. After controlling for age, gender, and systemic (hypertension, diabetes, myocardial infarction) and ocular factors (intraocular pressure, glaucoma, central corneal thickness, axial length, previous laser photocoagulation), BRVO was associated with larger optic disc area (OR highest vs lowest tertile, 4.70; 95% CI 1.00 to 22.01; p=0.036), larger cup area (OR highest vs lowest tertile, 4.80; 95% CI 1.03 to 22.35; p=0.029) and larger cup–disc area ratio (OR highest vs lowest tertile, 4.44; 95% CI 0.95 to 20.66; p=0.037). After excluding glaucoma eyes, BRVO remained significantly associated with these parameters (p=0.027, p=0.018, p=0.024, respectively). Conclusions Quantitative optic disc parameters (optic cup and disc area) are associated with BRVO, even in non-glaucomatous eyes. Optic nerve head morphology may play a role in BRVO pathogenesis.

We determined the accuracy of the inferiorsuperiornasaltemporal (ISNT) neuroretinal rim area rule and its variants in adult Asian populations, and evaluated whether disc area impacts its performance characteristics.Participants in the Singapore Malay Eye Study (SiMES) and Singapore Indian Eye Study (SINDI) underwent standardized ocular examinations, including optic disc imaging with the Heidelberg retinal tomograph (HRT). Glaucoma was defined using the ISGEO criteria. HRT rim areas in the superior, inferior, nasal, and temporal quadrants were quantified. We determined sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values of violating the ISNT rule and 4 variants (IST, IS, IT, and combined IT and ST). The influence of disc area was analyzed with multivariate marginal logistic regression.There were 6112 participants (mean age: 57.6 ± 10.3 years). Glaucoma was present in 194 individuals (3.2%). Among 11,840 eyes, 232 (93.2%) of 249 glaucomatous eyes and 9768 (84.3%) of 11,591 nonglaucomatous eyes, violated the ISNT rule. The ISNT rule had highest sensitivity (93.5%), but lowest specificity (15.7%); IT had highest specificity (98.2%), but low sensitivity (7.4%). For all variants, PPVs were low (2.1%-8.4%) and NPVs were high (97.9-99.1%). Larger disc area was associated with reduced specificity for the ISNT rule (The ISNT rule based on HRT has high sensitivity, and the IT, ST, and combined IT and ST variants have high specificity. Disc area influences sensitivity, specificity, PPV, and NPV of the ISNT rule and its variants.The high sensitivity of the ISNT rule, and high specificities of its variants, may have potential utility when used in combination with other HRT algorithms for glaucoma assessment.

To investigate the agreement between scanning laser ophthalmoscopy (Heidelberg retinal tomograph 3; HRT-3) and high-definition optical coherence tomography (HD-OCT) for measurements of optic nerve head (ONH) parameters.As part of a population-based cross-sectional study, 913 consecutive Chinese subjects aged 40 years and older underwent HRT-3 and HD-OCT imaging of the ONH after pupillary dilation. Limits of agreement (LOA) derived from Bland-Altman analysis were calculated for ONH measurements.The mean age (± SD) of study participants was 54.2 ± 7.2 years and 52.0% were men. The two instruments showed no difference in mean optic disc area measurements (1.98 ± 0.37 for HD-OCT vs 1.98 ± 0.39 mm for HRT-3, p=0.95). HD-OCT showed smaller rim area (1.29 ± 0.24 vs 1.46 ± 0.27 mm, p0.001), but bigger cup-related parameters (p0.001 for all) than HRT-3. The highest correlations between the instruments were observed for cup volume (r(2)=0.74, p0.001) and disc area (r(2)=0.62, p0.001). The correlations for cup-to-disc ratio (CDR), vertical CDR and rim area were lower (r(2)=0.59, 0.48 and 0.24, respectively, p0.001 for all). The Bland-Altman plots demonstrated significant proportional bias for differences in all ONH parameters (p0.01 for all), with LOA greater for disc-related parameters (0.98-1.0) than cup-related parameters (0.26-0.50).There are substantial disagreements between HRT-3 and HD-OCT in ONH measurements. Although optic disc area measurements were similar, HD-OCT underestimates the rim area and overestimates cup parameters compared with HRT-3.

Background/aim This study aimed to provide an objective assessment of the effects on the aqueous outflow rate of various geometries of the scleral flap and sclerostomy created in trabeculectomy. Method Computer-based models and simulations of this surgical procedure were used to investigate the relative effects of various shapes and dimensions of scleral flap and sclerostomy on the aqueous outflow. Result In these computer simulations, increasing scleral flap size was found to be associated with an increase of 48.55% in aqueous egress. In addition, a square scleral flap increased the aqueous drainage by 36.26% compared with a triangular flap of equivalent flap area. Surprisingly, our simulation results showed that a smaller semicircular sclerostomy improved aqueous drainage by up to 33.00%, while a semicircular sclerostomy, compared with a circular sclerostomy, led to a further 6.16% increase in aqueous outflow. Decreasing flap thickness beyond half-thickness caused an additional increase in aqueous outflow. However, clinically the flap should not be thinner than half the thickness of the sclera as this may result in hypotony. Conclusion These simulations indicate that the optimal flow rate through operation site will be achieved in trabeculectomy using a square scleral flap with a large flap-to-sclerostomy ratio.

PURPOSE: To quantify changes in bleb morphology after laser suture lysis (LSL) using anterior segment optical coherence tomography (AS-OCT). PATIENTS AND METHODS: This was a prospective observational case series of patients who underwent trabeculectomy surgery with mitomycin-C and required subsequent LSL. Subjects were assessed before and immediately after LSL, and at 3 months after LSL. At each visit, a standardized cross-sectional AS-OCT image of the bleb was obtained, from which a masked observer measured bleb height (hB), cavity height (hC), wall cross sectional area (AW), cavity cross sectional area (AC), and bleb cross sectional area (AB) using custom software. RESULTS: Twenty-five subjects (25 eyes) were examined. LSL was performed at a mean of 21.5±16.3 days after trabeculectomy. Immediately after LSL, there was a significant increase in mean hB (P=0.026) and mean hC (P=0.45) from pre-LSL. At 3 months after LSL, there was a significant increase in mean hB (P=0.003), mean AC (P=0.047), and mean AB (P=0.006) as compared with before LSL. Increase in hB and hC immediately after LSL was predictive of outcome at month 3. CONCLUSIONS: AS-OCT was able to quantify changes in bleb morphology after LSL, some of which were predictive of eventual outcome.

PURPOSE To examine the relationship of central corneal thickness (CCT) with optic disc parameters measured by confocal scanning laser ophthalmoloscopy in a Malay population. METHODS This was a population-based cross-sectional study of Asian Malay adults aged 40-80 years living in Singapore. Participants had a standardized interview, examination, and imaging at a study clinic. CCT was measured with an ultrasound pachymeter. Confocal scanning laser imaging was performed on all participants to obtain optic disc parameters. Multivariate regression analyses controlling for age, sex, intraocular pressure, and other potentially confounding factors were conducted separately for disc area, rim area, cup-to-disc ratio, and mean cup depth. RESULTS Of the 3280 participants in the study, 2525 (77.0%) right eyes with reliable confocal scanning laser tomography images were included in this analysis, with 48 eyes defined to have primary open-angle glaucoma (POAG). In POAG subjects, CCT was positively correlated with rim area (regression coefficient of 0.372 mm(2) per 100 μm CCT increase; P = 0.035) and negatively correlated with cup-to-disc area ratio (-0.160 per 100 μm CCT increase; P = 0.024). There was no relationship between CCT and disc size (P = 0.088). In the 2468 subjects without glaucoma, there were no associations between CCT and confocal scanning laser tomography parameters. CONCLUSIONS In this population-based study, decreased CCT was associated with lower rim area and greater cup-to-disc area in subjects with POAG, but not in subjects without glaucoma.

To assess the determinants of image quality of Heidelberg Retina Tomography II (HRT II) and its association with optic disc parameters in a population-based setting.Population-based, cross-sectional study involving 3280 (78.7% response) Asian Malays aged 40 to 80 years.Three thousand fifty-six participants completed the HRT II test. Image quality was assessed using the mean pixel height standard deviation generated by the HRT II, with lower mean pixel height standard deviation indicating higher quality. Participants underwent an interviewer-administered questionnaire and a standardized ophthalmic examination, including visual acuity, applanation tonometry, gonioscopy, refraction, automated perimetry, and lens and fundus photography.The mean (standard deviation) and median of mean pixel height standard deviation in the study population were 34 (34) and 23 μm respectively. In multivariate regression models, older age and the presence of visual impairment, blindness, high myopia, and cataract were significantly associated with greater mean pixel height standard deviation (P.05 for all). People with a higher mean pixel height standard deviation were more likely to have smaller rim area and greater cup depth.People who are older or have high myopia, visual impairment, blindness, or cataract are more likely to have poor HRT II image quality. Poorer image quality is in turn associated with smaller optic rim area and greater cup depth. These data provide useful information when the HRT instrument is used for diagnosing glaucoma in the general population.

Purpose: To describe the prevalence and risk factors of ocular trauma in an urban Asian population. Methods: A population-based survey of 3280 (78.7% response rate) Malay people aged 40–80 years residing in Singapore was conducted in 2004–2006. Interviewer-administered questionnaire was used to ascertain a history of ocular trauma, defined as any eye injury requiring medical attention from a doctor. Results: Of the 3264 participants, 149 (5.0%, 95% confidence intervals [CI] 4.1–6.0%) reported a history of ocular trauma. Of those, 30.2% had trauma from a blunt object, 33.6% from a sharp object, and 22.1% from chemical burns. After adjusting for age and sex, men had a higher prevalence of ocular trauma than women (8.3% vs. 2.1%, age-adjusted odds ratio [OR] 4.7, CI 3.1–7.1), and younger persons had a higher risk of ocular trauma (per year increase in age, OR 0.98, CI 0.96–0.99). Consumption of alcohol was associated with higher likelihood of having ocular injury (OR 4.3, CI 2.2–8.4). Conclusions: One in 20 persons in this urban south-east Asian population had a history of ocular trauma. Younger persons, men and consumption of alcohol were risk factors for ocular trauma.

PURPOSE: To assess the near and distance visual acuity achieved with implantation of the ReSTOR SA60D3 and SN60D3 (Alcon Laboratories Inc) and Tecnis ZM900 (Abbott Medical Optics [AMO]) multifocal intraocular lens (IOL) after cataract surgery. METHODS: This is a retrospective study of 108 eyes of 54 patients who underwent uneventful bilateral phacoemulsification of cataract and IOL implantation at an ophthalmic center in Singapore by a single surgeon. Inclusion criteria were visually significant cataracts, corneal astigmatism RESULTS: No difference in mean postoperative uncorrected and best spectacle-corrected visual acuity for distance among the groups was noted. The ZM900 lens was significantly better than both ReSTOR lenses for uncorrected near vision with 96.7% achieving N5 compared to 75% of SA60D3 patients and 83.3% of SN60D3 patients ( P =.003). For distance corrected near vision, 100% of ZM900 patients achieved N5 compared to 83.3% for each the SA60D3 and SN60D3 IOLs ( P =.005). No significant difference between both ReSTOR lenses for near vision was noted. CONCLUSIONS: All three IOLs provide similar uncorrected and best corrected distance visual acuity. However, the ZM900 IOL provides better binocular distance corrected and uncorrected near acuity than the SA60D3 or SN60D3. The ZM900 IOL group was more myopic preoperatively compared to the other two groups, which may be a contributing factor. [ J Refract Surg. 2010;26:177–182.]

Objective To describe the prevalence and causes of low vision and blindness in a Malay population. Methods A population-based, cross-sectional study of 3280 participants of Malay ethnicity, aged 40 to 79 years, was conducted. Participants underwent standardized ophthalmic assessments to determine (1) presenting and best-corrected visual acuity according to US and modified World Health Organization definitions of blindness and low vision and (2) the primary causes of visual impairment. Results Of 4168 eligible individuals, 3280 participated in the study (78.7%). The population-weighted prevalence of bilateral blindness was 0.3% and of bilateral low vision, 4.4% (US definition of presenting visual acuity). After best-corrected visual acuity, the population-weighted prevalence of bilateral blindness was reduced to 0.1% and bilateral low vision to 1.0%. Cataract was the main cause of presenting unilateral (38.9%) and bilateral (65.2%) blindness, whereas undercorrected refractive error was the main cause of presenting unilateral (68.8%) and bilateral (52.2%) low vision. Diabetic retinopathy, age-related macular degeneration, and glaucoma were the other leading causes of blindness and low vision. Conclusions The age-standardized prevalences of bilateral blindness and low vision in a Malay population were lower when compared with other Asian studies. Undercorrected refractive error and cataract are the leading causes of visual impairment among the Malay adult population in Singapore.

Objective: To describe the distribution and determinants of the optic cup to disc ratio (CDR) in Malay adults in Singapore.Methods: This population-based, age-stratified study examined 3280 Malay people aged 40 to 80 years in Singapore. Participants underwent a standardized interview and an ocular examination. A slitlamp examination measured the vertical dimensions of the disc and cup, excluding areas of peripapillary atrophy and the Elschnig scleral ring.Results: Vertical CDR was recorded for 3228 right eyes and 3237 left eyes. The mean (SD) CDR was 0.40 (0.15) in both eyes. The CDR in the right eye increased with age (P < .001) and was greater in men vs women (age-adjusted CDR, 0.42 vs 0.39; P < .001). In multiple linear regression, significant determinants of greater CDR were increasing age, male sex, higher intraocular pressure (IOP), lower diastolic blood pressure, lower body mass index, and previous cataract surgery. Of these, higher IOP was the most important determinant of the CDR. After excluding 149 persons with glaucoma, male sex, higher IOP, lower diastolic blood pressure, lower body mass index, and diabetes mellitus were significant predictors of greater CDR.Conclusion: Greater vertical CDR was related to male sex, higher IOP, lower diastolic blood pressure, and lower body mass index.

Purpose To test the reliability of the Lens Opacities Classification System III (LOCS III) cataract grading between observers at different levels of ophthalmology experience. Setting Ophthalmology Department, National University Hospital, Singapore, Singapore. Methods In this comparative study, a non-ophthalmology trainee, a basic ophthalmology trainee, and an ophthalmology consultant graded cataracts in 28 patients preoperatively. The observers had a meeting to discuss their interpretations of the LOCS III manual to standardize the grading system and then graded 37 additional patients. Results There was a statistically significant increase in inter-observer agreement in all 3 LOCS III categories after standardization of the LOCS III system. The κ values after standardization fell in the moderate (0.41 to 0.60) to substantial (0.61 to 0.80) range. There was no statistically significant relationship between the observer's experience and the κ values. Conclusions There was an increase in inter-observer agreement in all categories after standardization between operators.

To assess the prevalence and types of glaucoma in an Asian Malay population.The Singapore Malay Eye Study is a population-based, cross-sectional survey that examined 3280 (78.7% response) persons aged 40 to 80 years. Participants underwent a standardized clinical examination including slit-lamp biomicroscopy, Goldmann applanation tonometry, and dilated optic disc assessment. Participants who were suspected to have glaucoma also underwent visual field examination (24-2 SITA standard, Humphrey Visual Field Analyzer II), gonioscopy, and repeat applanation tonometry. Glaucoma was defined according to International Society for Geographical and Epidemiologic Ophthalmology criteria.Of the 3280 participants, 150 (4.6%) had diagnosed glaucoma, giving an age- and sex-standardized prevalence of 3.4% (95% confidence interval [CI], 3.3%-3.5%). The age- and sex-standardized prevalence of primary open-angle glaucoma was 2.5% (95% CI, 2.4%-2.6%), primary angle-closure glaucoma 0.12% (95% CI, 0.10%-0.14%), and secondary glaucoma 0.61% (95% CI, 0.59%-0.63%). Of the 150 glaucoma cases, only 12 (8%) had a previous known history of glaucoma. Twenty-seven (18%) eyes had low vision (based on best corrected visual acuity logarithm of the minimal angle of resolution [logMAR]0.30 to1.00 in the eye with glaucoma for unilateral cases; and based on the better eye for bilateral cases) and 15 (10%) were blind (logMAR,/=1.00).The prevalence of glaucoma among Malay persons 40 years of age and older in Singapore is 3.4%, comparable to ethnic Chinese people in Singapore and other racial/ethnic groups in Asia. As in Chinese, Caucasians, and African people, primary open-angle glaucoma was the main form of glaucoma in this population. More than 90% of glaucoma cases were previously undetected.

This paper aims to compare the efficacy and tolerability of timolol versus brimonidine in the treatment of glaucoma. Comprehensive searches were performed using Medline, Embase and the Cochrane Controlled Trials Register for randomized controlled trials comparing timolol and brimonidine. Two reviewers independently assessed trials for eligibility and quality and extracted data. A random effects model was used to combine studies. Outcome was defined as the absolute mean intraocular pressure (IOP) reduction from baseline to end-point for efficacy, and relative risk (RR) for adverse events. Subgroup analysis and meta-regression were used to explore heterogeneity according to trial design and quality. Ten publications reporting on eight trials with 2387 participants were included in the meta-analysis. Two further trials were commented on qualitatively. IOP reduction was not significantly different between timolol and brimonidine. Weighted mean difference (WMD) of IOP reduction was 0.24 mmHg (favouring brimonidine) with a 95% confidence interval of -0.57 to 1.04 mmHg. There was significant heterogeneity between studies (chi(2) (13) = 73.75, P0.00001, I(2) = 91%). Subgroup analysis showed no significant WMD for studies where data were analysed from end-points/=6 months or6 months. Meta-regression analysis showed increased WMD IOP reduction in favour of brimonidine with increased trial quality (t(3) = -4.58, P = 0.01), but no significant association with trial duration (t(3) = 0.73, P = 0.51) or size (t(3) = -0.59, P = 0.57). The RR of ocular allergy was much lower with timolol than brimonidine (RR = 0.08, 95% confidence interval 0.01 to 0.47). Publication bias was not evident on a funnel plot, although the number of studies was small. The conclusion is that both drugs are equally effective in lowering IOP. Brimonidine is associated with a higher rate of allergy.

PURPOSE. The purpose of this study was to evaluate the associations between macular volume and thickness, as assessed by optic coherence tomography (OCT), with refraction and axial length (AL) in children.METHODS. A total of 104 Chinese school children (51 girls and 53 boys) 11 to 12 years of age were randomly selected from one school during the 2005 examination in the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). Cycloplegic autorefraction was performed to obtain refraction (defined as spherical equivalent [SE]) and ultrasound biometry performed to obtain the AL. Macular volume and thickness were then measured (StratusOCT3; Carl Zeiss Meditec, Dublin, CA).RESULTS. Children with moderate myopia (SE at least -3.0 D) tended to have smaller total macular volume and thinner quadrant-specific macular thickness (except in the inferior and superior inner quadrants), followed by children with low myopia (-0.5 -0.5 D). Total macular volume was positively associated with SE (beta = 1.58, 95% CI, 0.84 to 2.32, standardized beta = 0.14, P < 0.001) and negatively associated with AL (beta = -1.20, 95% CI, -1.62 to -0.79, standardized beta = 0.45, P < 0.001) in multiple linear regression models controlling for age and gender.CONCLUSIONS. In children, increasing axial myopia was associated with reduced macular volume and thickness. These findings suggest that early anatomic changes may be present in the retinas of children with axial myopia.

In the past decade, several large population based studies have provided new information on the prevalence of visual impairment and the major age related eye diseases in Asia. These include epidemiological studies from India, Taiwan, Mongolia, Singapore, and Japan. In particular, the epidemiology of refractive errors and glaucoma has been well characterised, providing insights not only into the public health implications of these conditions, but also into anatomical changes of the eye with ageing. In contrast, there are few well conducted population based studies on diabetic retinopathy and age related macular degeneration in Asia, two conditions that are likely to be important causes of blindness in the future.

Background: Ischaemic changes in the iris occur frequently after an episode of acute primary angle closure (APAC). The aim of this study was to investigate the significance of such changes with regards to visual outcome. Methods: Acute primary angle closure cases were treated with medical therapy followed by laser peripheral iridotomy after resolution of the acute episode. Subjects were examined at 1, 4, 8, 12 and 16 weeks post laser peripheral iridotomy. Eyes were examined for signs of iris ischaemic changes (IIC), defined as the presence of iris whorling or stromal atrophy. Iris photographs were also taken at weeks 1, 8 and 16. Subjects requiring glaucoma medication or filtering surgery during the follow-up period were excluded. The visual acuity and visual field (using automated white-on-white threshold perimetry) at week 16 were used in the assessment of visual outcome. Results: Sixty-one subjects with APAC completed the study. The majority of subjects were female (82%) and Chinese (92%), and the mean age was 59 ± 8.8 years. More than half the subjects (52.5%) were found to have developed IIC during the study, 65% of whom already had signs of IIC by the first week. Only 13 subjects (41%) with IIC and 6 subjects (21%) without IIC had an abnormal visual field defect at week 16 (P = 0.09). There was also no difference in visual acuity at week 16, the majority of subjects in both groups having visual acuity of 6/12 or better. Conclusions: The development of iris ischaemic changes after a single episode of APAC may not be associated with an adverse visual outcome.

We determined the impact of glaucoma severity and laterality on vision-specific functioning (VF) in an Asian population.The Singapore Malay Eye Study (SiMES) was a population-based cross-sectional study of 3280 Malays aged 40 to 80 years. VF was assessed using the VF-11 questionnaire. Associations between VF-11 score and glaucoma clinical indices (glaucoma severity in better and worse eyes, and laterality) were determined by multivariate regression modeling. Glaucoma severity was defined as mild, moderate, advanced, and severe based on the Hodapp-Anderson-Parish system. Rasch analysis was used to validate the VF-11 and determine its psychometric properties.Of 926 persons analyzed, 123 had glaucoma (13.3% glaucoma prevalence in analyzed sample). The mean ± SD VF score was 3.64 ± 1.05 log of odds units (Logits). In multivariate models adjusting for sociodemographic, ocular, and systemic variables, poorer VF was associated with increasingly worse eye visual field loss (β = 0.016, 95% confidence interval [CI] 0.004-0.029, P0.001), but not that of the better eye (P0.05). Compared to controls, VF was reduced in individuals with worse eye advanced and severe glaucoma (β = -0.65, 95% CI -1.03 to -0.28, P0.05), but not mild or moderate glaucoma (P0.05). Compared to controls, VF was reduced in unilateral (β = -0.29, 95% CI -0.54 to -0.04, P0.05), but not bilateral glaucoma (P0.05). These associations remained significant after adjusting for presenting and best-corrected visual acuity.Among Singaporean Malays, unilateral, and advanced and severe glaucoma in the worse eye significantly impacts on VF. Identifying early-stage glaucoma, preventing progression, and visual rehabilitation in advanced glaucoma are important aspects of glaucoma management.

Purpose To examine the correlation and agreement of stereometric parameters between Heidelberg Retinal Tomograph version 2 (HRT-2) and HRT-3 in a normal Asian population. Methods This was a population-based study using data from the Singapore Malay Eye Study. Participants underwent a standardized and complete ophthalmic examination. A confocal laser ophthalmoscope using HRT-2 was used to take retinal images by 2 trained operators. Disc contours were drawn by a single experienced ophthalmologist. Without modifying the contours, the exact images were then exported and analyzed with HRT-3 software. Paired t tests were used to compare mean differences, whereas interclass correlations and Bland-Altman plots were used to assess agreement and trend of Moorfields regression analysis parameters between HRT-2 and HRT-3. Results A total of 2960 Malay participants [mean age, 58.3 y (SD 10.9); 50.5% female] were included. Average disc size was 2.15 μm. Interclass correlations and Bland-Altman plots showed good agreement between HRT-2 and HRT-3. However, global disc area, rim area, cup area, cup-disc area ratio, rim-disc area ratio, and rim volume were significantly different between HRT-2 and HRT-3, with all area and rim volume measurements using HRT-2 were approximately 4% larger compared with HRT-3. Analysis of HRT-2 and HRT-3 parameters from different sectors of the scans showed an inconsistent change in measurement values. Cup shape measurement was significantly different in the temporal region compared with the nasal region of the optic nerve head. Conclusions There was good correlation between the 2 HRT versions and conversion equations were possible to calibrate HRT-3 parameters from HRT-2 measurements in Asian eyes. However, HRT-2 and HRT-3 showed significant differences in stereometric parameters. Further studies are needed to determine the impact of such differences and in comparative accuracy of HRT-2 versus HRT-3 for diagnosis and monitoring of glaucoma.

Purpose To examine the relationship of diabetes and hyperglycemia with central corneal thickness (CCT) in Malay adults in Singapore. Design Population-based cross-sectional study. Participants Three thousand two hundred eighty Malay adults ages 40–80 years living in Singapore. Methods The study population was selected using an age-stratified random sampling procedure of Malay 40- to 80-year-olds living in the southwestern part of Singapore. Participants had a standardized interview, examination, and ocular imaging at a centralized study clinic. Central corneal thickness was measured with an ultrasound pachymeter, and nonfasting serum glucose and glycosylated hemoglobin (Hb A 1C ) was obtained from all participants. Diabetes was defined as having nonfasting glucose levels of ≥200 mg/dl (11.1 mmol/l), a self-report of diabetic medication use, or physician diagnosis of diabetes. Main Outcome Measures Central corneal thickness. Results Of the 3280 (78.7% response) participants, data on CCT were available on 3239 right eyes. Central corneal thickness was normally distributed, with a mean of 541.2 μm. There were 748 persons with diabetes (23.0%). After controlling for age and gender, central corneas were significantly thicker in persons with diabetes than in those without diabetes (547.2 μm vs. 539.3 μm, P P = 0.023) and higher Hb A 1C (537.8, 541.0, 541.4, and 545.5, comparing increasing Hb A 1C quartiles; P Conclusions This population-based study among Malays showed that diabetes and hyperglycemia are associated with thicker central corneas, independent of age and IOP levels. These findings may have implications for understanding the relationship between diabetes and glaucoma.

PURPOSE. To evaluate the relationships in Singapore school children between optic nerve head parameters and retinal nerve fiber layer thickness images by using the Heidelberg Retinal Tomograph ( HRT; Heidelberg Engineering, Heidelberg, Germany) and determining optic disc tilt and refractive error.METHODS. This was a cross-sectional study involving 316 children 11 and 12 years of age ( 163 girls and 153 boys) selected randomly from one of the three schools in the Singapore Cohort study of Myopia. A total of 13 optic disc parameters were obtained from HRT images acquired before cycloplegia. Refractive errors were measured by cycloplegic autorefraction. The presence of optic disc tilt or otherwise was determined by two independent assessors using stereoscopic viewing of retinal photographs.RESULTS. Of the 316 children, 142 had tilted discs. The tilting of optic discs was associated with a smaller disc, rim or cup area measurements, cup-to-disc area ratios, cup volumes or cup depths, but with a larger measured rim volume, rim-to-disc area ratios, height variation of the contour, retinal nerve fiber layer thicknesses or volumes, and a more negative cup shape measure ( all P < 0.001). Decreased maximum cup depths were significantly associated with longer axial lengths ( P < 0.001), but were not associated with spherical equivalent ( P < 0.693). These associations remained only in children without tilted discs, but were no longer significant in those with tilted discs. Other HRT parameters were not associated with axial lengths or myopic status.CONCLUSIONS. Optic nerve head parameters and retinal nerve fiber layer thickness measured by the current HRT algorithms are strongly influenced by the tilting of the optic nerve head, but not by refractive errors or axial length.