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Seang-Mei Saw

Publications and source records attributed to Seang-Mei Saw.

At least 19 recordsLinked to original sources
PubMed2006

An outbreak of Fusarium keratitis associated with contact lens wear in Singapore.

CONTEXT: Fungal keratitis is a potentially blinding condition that is rarely seen with contact lens wear. OBJECTIVE: To describe a nationwide outbreak of fungal keratitis caused by Fusarium species among contact lens wearers in Singapore. DESIGN, SETTING, AND PATIENTS: Nationwide, hospital-based case series. All cases of fungal keratitis among contact lens wearers in all ophthalmology departments in Singapore were reviewed along with the charts of all contact lens wearers with culture-proven fungal keratitis from March 2005 through May 2006. A standardized telephone interview was conducted to obtain additional clinical information. MAIN OUTCOME MEASURE: Diagnosis of Fusarium keratitis associated with contact lens wear. RESULTS: During the study period, 66 patients (68 affected eyes) were diagnosed with Fusarium keratitis associated with contact lens wear; the estimated annual national incidence is 2.35 cases per 10,000 contact lens wearers (95% confidence interval, 0.62-7.22). Patients ranged in age from 13 to 44 years (mean [SD], 27.1 [8.4] years), of which 32 (48.5%) were men. The vast majority (65 patients; 98.5%) wore soft, disposable contact lenses; 62 patients (93.9%) reported using 1 brand of contact lens cleaning solution (ReNu, Bausch & Lomb, Rochester, NY), including 42 patients (63.6%) who recalled using ReNu with MoistureLoc. Most patients (81.8%) reported poor contact lens hygiene practices, including overnight use of daily wear contact lenses (19.7%), and use of contact lenses past the replacement date (43.9%). The final best-corrected visual acuity ranged from 20/20 to 20/80. Five patients (5 eyes; 7.4%) required emergency therapeutic or tectonic corneal transplantation. CONCLUSIONS: A new and evolving epidemic of Fusarium keratitis associated with contact lens wear was found in Singapore. Physicians and eye care practitioners worldwide need to be aware of the likelihood of similar outbreaks emerging among contact lens wearers.

Adolescent↗
PubMed2006

An evidence-based analysis of surgical interventions for uncomplicated rhegmatogenous retinal detachment.

PURPOSE: To evaluate the various surgical interventions available for uncomplicated rhegmatogenous retinal detachment. METHODS: Reports of controlled clinical trials of surgical interventions (pneumatic retinopexy, scleral buckling and vitrectomy) for uncomplicated rhegmatogenous retinal detachment indexed in MEDLINE from 1968 to January 2006 were included. The primary outcomes evaluated included single-operation reattachment rates, multiple reoperation reattachment rates and improvements in visual acuity (VA). RESULTS: We found five controlled trials (two randomized) comparing the efficacy of pneumatic retinopexy versus scleral buckling. The single-operation reattachment rates were higher for scleral buckling, but the final reattachment rates were similar. We found nine controlled trials (four randomized) evaluating vitrectomy. There were no statistically significant differences between retinal reattachment rates or final visual acuities, except in one randomized and one non-randomized controlled trial in which the VAs were significantly better in the vitrectomy than the scleral buckling group. CONCLUSIONS: Pneumatic retinopexy is a possible alternative to scleral buckling in the treatment of uncomplicated rhegmatogenous retinal detachment. The rates of missed or new retinal breaks after pneumatic retinopexy, however, are higher than following scleral buckling. The clinical outcomes of vitrectomy for rhegmatogenous retinal detachment compare favourably.

Cryotherapy↗
PubMed2006

Longitudinal study of anisometropia in Singaporean school children.

PURPOSE: The purpose of this study was to document the incidence rates of anisometropia, year-by-year prevalences, changes in the intereye difference in spherical equivalent (SE), and its association with myopia progression and axial length changes in a cohort of Singaporean school children. METHODS: This is a prospective cohort study of Singaporean school children (n = 1979) aged 7 to 9 years who were examined annually with cycloplegic refraction and ultrasonography over a 3-year period. RESULTS: In the 1908 children without anisometropia at commencement, the 3-year cumulative incidence rate of anisometropia (difference in SE at least 1.0 D) was 144 (7.55%; 95% CI: 6.42-8.85). The mean intereye difference in SE in all children at baseline was 0.29 +/- 0.46 D (SD: 0.46) and increased to 0.44 D (0.59) on the last examination. On the initial examination, 3.6% (95% CI: 2.8-4.4) or 71 children had anisometropia. Of the 59 of 71 children who completed all examinations, only 3 (5.1%) had an increase in the intereye difference in SE by at least 0.5 D, whereas 2 (3.4%) had a decrease of at least 0.5D. The mean intereye difference in SE was stable between visits. The change in intereye difference in SE correlated with the change in intereye axial length (r = 0.43). Compared with the isometropic children, each eye of the anisometropic children had a higher rate of progression of myopia. CONCLUSIONS: The 3-year incidence of anisometropia was 7.55% in these young Singaporean children. Although the frequency of anisometropia increased with time, the difference in SE between eyes tended to remain stable.

Anisometropia↗
PubMed2006

A cohort study of incident myopia in Singaporean children.

PURPOSE: To determine the risk factors of incident myopia in a school-based cohort study in Singaporean children. METHODS: A 3-year prospective cohort study was conducted in Singaporean school children aged 7 to 9 years in three schools at entry. Chinese children without myopia at baseline (n = 994) were included in the analysis. The main outcome was incident myopia, defined as spherical equivalent (SE) at least -0.75 D based on cycloplegic autorefraction. Other definitions of incident myopia, at least -0.5 D and at least -1.0 D, were also assessed. RESULTS: After controlling for school, age, gender, income, reading in books per week and intelligence quotient (IQ) test scores, we found the relative risk (RR) of incident myopia defined as -0.75 D to be 1.55 (95% confidence interval [CI] 1.18-2.04) for two versus no myopic parents. The multivariate RR of myopia for IQ in the third versus first tertile was 1.50 (95% CI, 1.19-1.89). However, the RR of incident myopia was 1.01 (95% CI, 0.97-1.05) for every unit increase in books read per week. Similar results were obtained with definitions of -0.5 and -1.0 D for incident myopia. CONCLUSIONS: These data provide new prospective evidence of essential links between parental myopia, IQ scores and subsequent myopia development. However, reading in books per week was not associated with incident myopia.

Child↗
PubMed2006

Myopia, axial length, and OCT characteristics of the macula in Singaporean children.

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.

Anthropometry↗
PubMed2005

Prevalence of essential tremor in Singapore: a study on three races in an Asian country.

To investigate the prevalence of Essential Tremor (ET) in Singapore and compare the rates between Singaporean Chinese, Malays, and Indians, a community-based survey among a disproportionate random sample of 15,000 individuals (9000 Chinese, 3000 Malays, 3000 Indians) aged 50 years and above was conducted. In phase 1, trained interviewers conducted a door-to-door survey using a screening questionnaire for Parkinson's disease. In phase 2, medical specialists examined participants who screened positive to evaluate for the presence of postural or kinetic tremor of the upper limbs, or head tremor. Participants with suspected ET had their diagnosis confirmed in phase 3 by a movement disorders specialist and fellow based on the latest core diagnostic criteria. Forty participants with classic ET were identified. The prevalence rate (PR) of ET was 2.37 per 1000 (95% CI: 1.65-3.32), age-adjusted to UICC world standard population. The PR was significantly higher in males (p=0.01) and increased significantly with age (p<0.001). Indians (PR=4.94 per 1000, 95% CI: 2.63-9.04) were 1.8 times more likely to have ET than Chinese (PR=2.77 per 1000, 95% CI: 1.78-4.17) (p=0.08). No Malays with ET were identified. The data suggest that the prevalence of ET increases with age, is higher in males and may be higher amongst Indians.

Age Distribution↗
PubMed2005

The age of menopause and the menopause transition in a multiracial population: a nation-wide Singapore study.

OBJECTIVE: To describe the prevalence of menopausal symptoms, define the mean age of menopause, and determine contributory factors, which influence the experience of symptoms among Singaporean women of different racial groups. DESIGN: Cross-sectional nation-wide study of a random sample of 1000 women drawn from the entire population of Singaporean female (Chinese, Malay, and Indian) citizens between 45 and 60 years of age. Face-to-face interviews using structured questionnaires were conducted. RESULTS: The response rate was 69.9%. The mean age of natural menopause was 49.0 years. This was not significantly different between the three ethnic groups. Increasing parity delayed the age of menopause (P=0.007). Muscle and joint ache was the most commonly reported symptom (52.6%). Although the prevalence of significant hot flushes in the general study population was low (3.9%), it was the most commonly reported complaint by peri-menopausal women (14.6%). Prevalence of significant hot flushes decreased with time from menopause (P=0.007) and completely disappeared beyond the fifth year of menopause. Recent unhappy events were associated with an increased risk of symptoms (P<0.001). Women of Chinese origin experienced a lower risk of menopausal symptoms when compared with other ethnic groups (P<0.05). CONCLUSION: The mean age of menopause was 49.0 years among Singaporean women. Ethnicity and recent unhappy events were two major factors, which influenced the risk of experiencing menopausal symptoms. Among the three ethnic groups studied, Chinese women were the least likely to experience disturbing menopausal symptoms. The overall prevalence of menopausal symptoms was low when compared to studies on women in western societies.

Adult↗
PubMed2005

Utility assessment among cataract surgery patients.

PURPOSE: To evaluate the utility values (time trade-off, standard gamble for death, standard gamble for blindness) of patients scheduled for cataract surgery. SETTING: Tertiary eye hospital in Singapore. METHODS: Questions on time trade-off, standard gamble for death, standard gamble for blindness utilities, and visual function from an adapted version of the VF-14 were asked in a clinic interview of 217 Chinese patients. RESULTS: The mean utility time trade-off of cataract surgery patients was 0.77 (95% confidence interval [CI] 0.76, 0.78), mean standard gamble for death was 0.77 (95% CI 0.77, 0.78), and mean standard gamble for blindness was 0.76 (95% CI 0.75, 0.77). Adults with lower VF-14 scores had lower utilities, although there was no relationship between visual acuity and utilities. Utilities were also lower in patients who reported difficulty seeing in bright light. CONCLUSIONS: The utilities of cataract patients scheduled for surgery were comparable to those in patients with other chronic ocular diseases. Cataract surgery patients with lower utilities tended to have worse visual function and greater difficulty seeing in bright light.

Adult↗
PubMed2005

Utility values in Singapore Chinese adults with primary open-angle and primary angle-closure glaucoma.

PURPOSE: To evaluate utility values in Chinese glaucoma patients. PATIENT AND METHODS: Singapore Chinese residents (n = 213) with primary open-angle glaucoma or primary angle-closure glaucoma were recruited from a single tertiary ophthalmic center. Standard face-to-face interviews were conducted to ask about utility values (time trade-off and standard gamble for both death and blindness). Ocular information, including current visual acuity, intraocular pressure, visual field defect, and cup-disc ratio were also obtained. RESULTS: The mean time trade-off utility value was 0.88 (95% confidence interval 0.85, 0.91), and standard gamble for death and blindness were 0.94 (95% confidence interval 0.93, 0.96) and 0.95 (95% confidence interval 0.93, 0.97), respectively. Only 35.7% of patients were willing to trade time, and 34.3% willing to risk blindness in return for perfect vision. Both primary angle-closure glaucoma and primary open-angle glaucoma patients had similar utility values. After adjusting for age, gender, language spoken, educational level, and diagnosis, patients with better eye visual field PSD > 10 were 2.52 times (95% confidence interval 1.13, 5.61) more willing to trade time. In a multivariate model, the odds ratio of willingness to risk blindness for a complete hypothetical glaucoma cure was 9.88 (95% confidence interval 1.65, 59.23) for patients who had only visited an ophthalmologist 15 years or more ago, and 0.53 (95% confidence interval 0.27, 1.02) for patients who had previous trabeculectomy. CONCLUSION: Most Chinese glaucoma patients in Singapore are not willing to trade time or risk blindness. Patients with worse visual fields in the better-seeing eye are more willing to trade time; whereas patients who have not seen an ophthalmologist for at least 15 years or who had no history of a previous trabeculectomy are more willing to risk blindness.

Adult↗
PubMed2005

Comparisons of the handheld autorefractor, table-mounted autorefractor, and subjective refraction in Singapore adults.

PURPOSE: The purpose of this article was to compare the Retinomax with the table-mounted autorefractor and subjective refraction in Singapore adults. METHODS: Adults (n = 100) attending a tertiary eye hospital clinic were examined by an optometrist. First, subjective refraction testing was performed using a trial lens set, followed by handheld autorefractor tests using the Nikon Retinomax and the table-mounted autorefractor (Topcon RM8000B). Spherical equivalent and vector components of astigmatism were analyzed: J0 (Cartesian astigmatism) and J45 (oblique astigmatism). RESULTS: The Retinomax autorefractor readings (mean = -4.69 D) were more minus compared with the table-mounted autorefractor (mean = -4.05 D) and subjective refraction (mean = -3.90 D). There were significant differences in J0 and J45 for comparisons between subjective refraction and Retinomax autorefraction, and table-mounted autorefraction and Retinomax autorefraction. CONCLUSION: The Retinomax autorefractor measures were more minus compared with the table-mounted autorefractor and subjective refraction. The Retinomax autorefractor is not recommended for research purposes, unless in remote inaccessible areas where a portable instrument is necessary and cycloplegia is not possible.

Adult↗
PubMed2005

Utility values and myopia in medical students in Singapore.

PURPOSE: Although technologies to correct myopia have progressed in recent years, it is not known how cost-effective such technologies are. In this paper, utility values of myopic medical students in Singapore were ascertained as a first step to deriving weights for quality adjustment in future cost-effectiveness studies of such technologies. METHODS: Students (n = 120) aged 18-22 years with myopia (spherical equivalent at least -0.5 D) from Singapore's sole medical school were recruited. Information on lifetime intention to undergo refractive surgery, contact lens use, proportion of waking time spent wearing corrective devices, and utility values using the time trade-off and standard gamble for death methods, were obtained. RESULTS: The mean utility values for time trade-off and standard gamble were 0.97 (95% confidence interval 0.96-0.98, median 1.00) and 0.99 (95% confidence interval 0.98-0.99, median 1.00), respectively. Utility values were significantly higher among those who reported a probability of less than 50% that they would undergo refractive surgery within their lifetime, compared with those who reported a probability of 50% or more (means 0.98 vs. 0.95, P < 0.001). CONCLUSION: Utility values in myopic medical students obtained in this study appear to be relatively high, compared with those obtained for other ophthalmic conditions.

Adolescent↗
PubMed2005

Myopia and associated pathological complications.

Besides the direct economic and social burden of myopia, associated ocular complications may lead to substantial visual loss. In several population and clinic-based cohorts, case-control and cross-sectional studies, higher risks of posterior subcapsular cataract, cortical and nuclear cataract in myopic patients were reported. Patients with high myopia (spherical equivalent at least -6.0 D) are more susceptible to ocular abnormalities. The prevalent risks of glaucoma were higher in myopic adults, and risks of chorioretinal abnormalities such as retinal detachment, chorioretinal atrophy and lacquer cracks increased with severity of myopia and greater axial length. Myopic adults were more likely to have tilted, rotated, and larger discs as well as other optic disc abnormalities. Often, these studies support possible associations between myopia and specific ocular complications, but we cannot infer causality because of limitations in study methodology. The detection and treatment of possible pathological ocular complications is essential in the management of high myopia. The ocular risks associated with myopia should not be underestimated and there is a public health need to prevent the onset or progression of myopia.

Adolescent↗
PubMed2005

Incidence and progression of myopia in Singaporean school children.

PURPOSE: To determine the incidence and progression rates of myopia in young Singaporean children. METHODS: A prospective cohort study, the Singapore Cohort Study of the Risk Factors for Myopia (SCORM), was conducted in two schools in Singapore (1999-2002). Children aged 7 to 9 years (n=981) were followed up over a 3-year period. Cycloplegic autorefraction and biometry parameter measures were performed annually, according to the same protocol. RESULTS: The 3-year cumulative incidence rates were 47.7% (95% confidence interval [CI]: 42.2-53.3), 38.4% (95% CI: 31.4-45.4), and 32.4% (95% CI: 21.8-43.1) for 7-, 8-, and 9-year-old children, respectively. The 3-year cumulative incidence rates were higher in Chinese (49.5% vs. 27.2%) and in 7-year-old compared with 9-year-old children at baseline (47.7% vs. 32.4%), though the latter relationship was of borderline significance after adjustment for race, gender, amount of reading (books/week), and parental myopia (P=0.057). Premyopic children with greater axial lengths, vitreous chamber depths, and thinner lenses were more prone to the development of myopia, after controlling for age, gender, race, reading, and parental myopia. The 3-year mean cumulative myopia progression rates were -2.40 D (95% CI: -2.57 to -2.22) in 7-year-old myopic children, -1.97 (95% CI: -2.16 to -1.78) in 8-year-olds, and -1.71 (95% CI: -1.98 to -1.44) in 9-year-olds. CONCLUSIONS: Both the incidence and progression rates of myopia are high in Singaporean children.

Age Distribution↗
PubMed2004

Anisometropia in Singapore school children.

PURPOSE: To report the prevalence rates of anisometropia in a school population and determine the relative contribution of refractive power and axial length to the measured anisometropia. DESIGN: Population-based cross-sectional study. METHODS: Autorefraction, keratometry, and ultrasonography studies were made. SETTING: Three schools, located on the eastern, northern, and western part of Singapore. STUDY POPULATION: In all, 1,979 children aged 7 to 9 years were recruited for this study. The study sample included Chinese (n = 1,481), Malay (n = 324), and Asian Indian (n = 174) children; 720 subjects have myopia (spherical equivalent <= -0.5 diopters) in at least one eye. MAIN OUTCOME MEASURE: Anisometropia. RESULTS: The prevalence rates of anisometropia, in terms of spherical equivalent (SE) difference of at least 1.5 diopters and 2.0 diopters were 1.57% (95% confidence interval [CI]: 1.1, 2.2) and 1.01% (95% CI: 0.6, 1.6), respectively. The prevalence rate of anisometropia (at least 2.0 diopters) among the children with at least one myopic eye was 2.4% (95% CI: 1.4, 3.8), whereas in those without any myopic eyes, the prevalence rate was only 0.2% (95% CI: 0.06, 0.8). The spherical equivalent difference between the right and left eyes was positively correlated with the difference in axial lengths (P <.001). The difference in corneal refractive power is not statistically different between the anisometropic and the nonanisometropic children. CONCLUSIONS: The anisometropia prevalence rate in a childhood population with a relatively high prevalence of myopia was reported. The origin of the anisometropia is axial, and these results suggest that the differential rate of elongation between the two eyes of nonmyopic subjects results in anisometropia.

Anisometropia↗
PubMed2004

Optic disk and retinal characteristics in myopic children.

PURPOSE: To examine the baseline retina and optic disk characteristics in children. DESIGN: Cross-sectional study. METHODS: Subjects included 679 subjects with myopia and 100 with emmetropia, aged 8 to 13 years. Digital retina imaging and cycloplegic autorefraction were conducted to look for signs of retinal degeneration. Other outcome measures were vertical and horizontal cup-to-disk (CD) ratios, CD area ratio, parapapillary atrophy (PPA)-to-disk area ratio, and disk rotational angle. RESULTS: The prevalence of lattice degeneration was 0.15% (95% confidence interval: 0.008-1.00). No other retinal abnormalities were detected. Increased PPA-to-disk area ratio was associated with increased axial length, increased myopia severity, and increasing age. Cup-to-disk ratios were smaller in subjects with myopia compared with those with emmetropia, but this did not correlate with severity of myopia. In subjects with severe myopia, the upper pole of the disk was rotated away from the fovea but to lesser extent than in those with emmetropia or milder myopia. CONCLUSIONS: Apart from PPA, degenerative features were not commonly found in this study.

Adolescent↗
PubMed2004

Visual experience during phacoemulsification under topical versus retrobulbar anesthesia: results of a prospective, randomized, controlled trial.

PURPOSE: To compare the subjective visual experience of cataract patients during phacoemulsification and intraocular lens implantation under topical anesthesia (TA) vs retrobulbar anesthesia (RA). DESIGN: Prospective, randomized, controlled trial. METHODS: Three hundred six cataract patients eligible for phacoemulsification and intraocular lens implantation were randomized to receive either TA or RA during surgery by one of three surgeons. The surgeons were familiar with both anesthetic techniques and operated on the patients using the technique to which the patients were randomized. A masked interviewer conducted in-person interviews with the patients using a standardized questionnaire about their intraoperative visual experience and their reaction to their visual experience between 30 minutes and 4 hours after the surgery. RESULTS: Two patients (one in each group) had intraoperative posterior capsule rupture and were excluded from analysis. There was no statistically significant difference between TA (n = 154) and RA (n = 150) groups, except that more males compared with females had TA (P = .03). More patients who had TA reported perception of light (P < .001) and colors (P < .001) and a change (either increase or decrease) in light brightness during the course of the surgery (P < .001). There was no statistically significant difference in the proportions of patients who saw movements, flashes, instruments, or the surgeon or medical staff during the operation and who found their visual sensations frightening in the two groups. However, 10.4% in the TA group and 9.3% in the RA group found their visual experience frightening. CONCLUSIONS: More patients undergoing cataract surgery under TA compared with RA reported perception of light, colors, and a change in light brightness. A significant proportion of patients in both groups found the visual experience frightening.

Administration, Topical↗
PubMed2004

Causes of blindness, low vision, and questionnaire-assessed poor visual function in Singaporean Chinese adults: The Tanjong Pagar Survey.

OBJECTIVE: To determine the prevalence rates and causes of low vision, blindness, and patient-assessed deficient visual function among Singaporean Chinese adults. DESIGN: Population-based cross-sectional survey. PARTICIPANTS: Singaporean Chinese adults 40 to 79 years old (n = 1152). METHODS: From an initial sampling frame of 40- to 79-year-old Chinese in the Tanjong Pagar district in Singapore, 2000 subjects were selected using a disproportionate, stratified, clustered, random-sampling method. Of 1717 eligible subjects, 1232 were examined (participation rate = 71.8%), and 80 adults who did not have visual acuity (VA) data were excluded from the analysis. MAIN OUTCOME MEASURES: Bilateral low vision was defined as best-corrected VA (BCVA) worse than 6/18 and 3/60 or better, and bilateral blindness as BCVA worse than 3/60 in the better eye or constriction of the visual field to within 10 degrees of fixation, in accordance with the World Health Organization criteria. Patient-assessed visual function was measured using a modified VF-14 questionnaire. RESULTS: The age- and gender-adjusted prevalence rates were 1.1% (95% confidence interval [CI], 0.6-1.8) for bilateral low vision and 0.5% (95% CI, 0.2-1.1) for bilateral blindness, and the mean visual function score was 98.6. The rates of bilateral low vision and blindness increased with age, whereas visual function scores decreased with age, even after adjusting for gender and education. Cataract accounted for 58.8% of bilateral low vision, 20.0% of bilateral blindness, and 52.0% of poor visual function (score<90). Glaucoma contributed to 60.0% of bilateral blindness. CONCLUSION: The age- and gender-adjusted rates of low vision and blindness were 1.1% and 0.5%, respectively. Glaucoma is a leading cause of blindness in Singaporean Chinese adults, in addition to well-recognized causes in the rest of Asia such as cataract.

Adult↗