| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 From the Singapore National Eye Centre, Singapore; the 2 Department of Ophthalmology and the 3 Department of Community, Occupational and Family Medicine, National University of Singapore; the 4 Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison; the 5 Institute of Ophthalmology, University College London, United Kingdom; and the 6 Department of International Health, Johns Hopkins University School of Public Health, Baltimore, Maryland.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
METHODS. A disproportionate, stratified, clustered, random-sampling procedure was used to select names of 2000 Chinese people aged 40 to 79 years from the 1996 Singapore electoral register in the Tanjong Pagar district in Singapore. These people were invited to a centralized clinic for a comprehensive eye examination, including refraction. Refraction was also performed on nonrespondents in their homes. Myopia, high myopia, and hyperopia were defined as a spherical equivalent (SE) in the right eye of less than -0.5 D, less than -5.0 D, and more than +0.5 D, respectively. Astigmatism was defined as less than -0.5 D of cylinder. Anisometropia was defined as a difference in SE of more than 1.0 D between the two eyes. Only phakic eyes were analyzed.
RESULTS. From 1717 eligible people, 1232 (71.8%) were examined. Adjusted to the 1997 Singapore population, the overall prevalence of myopia, hyperopia, astigmatism, and anisometropia was 38.7% (95% confidence interval [CI]: 35.5, 42.1), 28.4% (95% CI: 25.3, 31.3), 37.8% (95% CI: 34.6, 41.1), and 15.9% (95% CI: 13.5, 18.4), respectively. The prevalence of high myopia was 9.1% (95% CI: 7.2, 11.2), with women having significantly higher rates than men. The age pattern of myopia was bimodal, with higher prevalence in the 40 to 49 and 70 to 81 age groups and lower prevalence between those age ranges. Prevalence was reversed in hyperopia, with a higher prevalence in subjects aged 50 to 69. There was a monotonic increase in prevalence with age for both astigmatism and anisometropia. Increasing educational levels, higher individual income, professional or office-related occupations, better housing, and greater severity of nuclear opacity were all significantly associated with higher rates of myopia, after adjustment for age and sex.
CONCLUSIONS. The results indicate that whereas myopia is 1.5 to 2.5 times more prevalent in adult Chinese residing in Singapore than in similarly aged European-derived populations in the United States and Australia, the sociodemographic associations are similar.
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
For other racial groups, population-based data are sparse. In the Baltimore Eye Survey, the prevalence of myopia in blacks (19.4%) was lower than in whites (28.1%).2 In the Barbados Eye Study the prevalence of myopia in black persons more than 40 years of age was 21.9%.7
In East Asia, although the prevalence of myopia is often presumed to be much higher, precise population-based data are not available.8 At present, the available information is based on studies conducted in selected subgroups of the population. In Taiwan, two studies covering school children aged 6 to 18 showed a prevalence of more than 80% by age 18 years.9 10 Another study in a Japanese student population showed an overall prevalence of approximately 50%,11 and a pilot study in Hong Kong in 355 adult Chinese aged 40 or more years showed a prevalence of approximately 40%.12 In Singapore, several studies in students and army recruits have indicated that the prevalence may be among the highest in the world.13 14 However, the prevalence of myopia in the adult population of Singapore or other East Asian countries is not known.
For other refractive errors such as hyperopia, astigmatism, and anisometropia, the prevalences have been estimated in the adult white and black populations,1 2 3 4 5 6 7 but information in adult East Asian populations is limited.
Although the cause of myopia is debatable,15 16 risk factors in the European-derived populations are well documented. Non–cataract-related myopia rates have been reported to be associated with higher education,1 2 3 4 5 17 certain occupations associated with near work4 7 and higher family income.1 Whether the same risk factors for myopia apply in East Asian countries is less clear.
The purpose of this study was to estimate the prevalence of different refractive errors in an adult Chinese population aged 40 years and more in Singapore. In particular, we were interested in evaluating risk factors associated with myopia in Chinese. Singapore is an urban city-state with a population of 3.2 million, 78% of whom are ethnic Chinese. Because a large number of Chinese residents in our study age group were first-generation immigrants from the southern provinces of Fujian and Guandong in China, some generalizability of our data to the Chinese population is possible.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Procedures
Before each examination, identity was verified from subjects’
national identity cards, after which written, informed consent was
obtained after an explanation of the study in Chinese, one of the
Chinese dialects, or English. Consent was signed in Chinese in 46% of
the participants, in English in 44%, and a cross in the remaining
10%.
Visual acuity was assessed in the following sequence as part of a standardized clinical examination. Habitual visual acuity was first determined with the initial distance spectacle correction (if any) using the logMAR chart (The Lighthouse, Long Island City, NY) under standard lighting conditions at 4 m.18 The visual acuity testing was performed as follows: Subjects began reading at the 6/12 equivalent line (0.3). If they were able to read more than three letters on that line, they proceeded to the next line below, until two mistakes were made on one line (i.e., only three letters correctly identified on that line). This line would then be recorded as the habitual visual acuity. If they were unable to read at least three letters, they would begin to read the line above and continued this process until at least three letters on one line had been read. If unable to read the chart at 4 m, the subject was moved to 2 m and then to 1 m from the chart. If subjects were unable to achieve minimum recordable logMAR acuity, the vision was recorded as perception or nonperception of light, as appropriate.
Refraction data on all subjects were recorded as follows. An initial objective refraction result was recorded by using an autorefractor (Retinomax K-plus; Nikon, Tokyo, Japan). Manual subjective refraction was then attempted to refine vision, using the results of the objective refraction as the starting point. The best corrected visual acuity was found, and both the derived refraction data and the visual acuity were recorded. Because of the age of our study population, no cycloplegia was used.
To maximize response rates, those who did not attend the clinic visit were offered an abbreviated examination in their homes. For this domiciliary examination, habitual visual acuity was assessed using a 3-m Snellen chart, with distance spectacle correction if needed. If the visual acuity was less than 6/12, the acuity was remeasured using a pinhole (best corrected visual acuity). Refraction was assessed using a handheld autorefractor (Retinomax K-plus; Nikon, Toyko, Japan). No manual subjective refraction was conducted on these subjects.
Definitions and Analysis
For this study, refraction data were based on subjective
refraction when participants had both subjective and objective
refraction and on objective refraction when only this information was
available. Preliminary analysis of data from participants with phakic
eyes who had both types of refraction in the right eye (n = 981)
indicated that the overall correlation between objective and subjective
refraction in spherical equivalents (SEs) was high (
= 0.98,
P < 0.001). Other reports will examine in detail the
variations in correlation between the two methods of refraction among
different age groups and refractive status. For our definitions of
emmetropia, myopia, hyperopia, and anisometropia, the refractive data
were converted to SE, which is derived by adding the spherical
component of the refraction to half the cylindrical component. The data
on the right and left eyes were initially analyzed separately. However,
because the correlation between the right and left eyes for SE was high
( = 0.83, P < 0.001), for the analysis of all
refractive errors other than anisometropia, we present data on only the
right eye. Emmetropia was defined as an SE of between -0.5 and 0.5 D.
Myopia was defined and analyzed on two levels separately: an SE of less
than -0.5 D and less than -1.0 D. High myopia was defined as SE of
less than -5.0 D. Hyperopia was defined an SE of more than +0.5D,
whereas anisometropia was defined as an SE difference between the right
and left eyes of more than 1.0 D. Astigmatism was analyzed in minus
cylinders and was defined as a less than -0.5 D of cylinder, without
reference to the axis. These definitions were chosen to enable direct
comparison between our data and those in other
studies.1
2
3
4
5
Lens nuclear opacity was graded by slit lamp examination using the modified Lens Opacity Classification System (LOCS) III score.19 Under this scoring system, nuclear opacity was graded in increasing severity from grade 1 to grade 6.
Because our study population was selected based on a disproportionate sampling technique (with more weights given to the older age groups), to provide a more accurate estimate of the actual prevalence of refractive errors in the population, age-adjusted rates were calculated based on the appropriate 1997 Singapore Chinese population (men, women, and both men and women).20 The associations between gender, age, and other socioeconomic variables, as well as lens nuclear opacity and the risk of myopia and high myopia were estimated by the odds ratio (OR) and its 95% confidence interval (CI). Multiple logistic regression was used to assess the mutually confounding effect of these variables on the risk of myopia and high myopia and to obtain adjusted estimates of the individual OR. Statistical analyses of the data were performed by a computer program (SPSS, Chicago, IL).
This study was approved by the ethics committee of Singapore National Eye Center and performed in accordance with the tenets of the World Medical Association’s Declaration of Helsinki.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Of the 1232 subjects examined, 103 (8.4%) had had cataract extraction in their right eyes and were excluded. Sixteen (1.3%) had no refraction data for their right eyes, including four subjects with corneal opacities, dense cataracts, and other media opacities in which accurate refraction could not be performed.
Further analyses on myopia, hyperopia, and astigmatism were based on refraction data from the 1113 subjects with phakic eyes with refraction in the right eye. Table 1 shows the characteristics of subjects included in and excluded from the analysis. In general, subjects included in the analysis were younger; more likely to be professionals, office workers, and salespeople; lived in better housing; and had higher education levels and individual income. There was little difference between the two groups in gender and smoking status.
|
Figure 1 shows the distribution of the refraction in SEs in the study population. A total of 324 (29.1%) subjects were classified as emmetropic, 389 (35.0%) were classified as myopic (worse than -0.5 D), and 400 (35.9%) were hyperopic. Seventy-seven subjects (6.9%) had high myopia. This formed nearly 20% of the myopes in the study population. In addition, astigmatism was present in 489 subjects (43.9%).
|
2 test,
P = 0.04).
|
There were distinctive age and sex patterns for different refractive errors (Table 3) . For example, for myopia (Fig. 2) , the highest prevalence was in the 40 to 49 age group, and the second highest was in the 70 to 81 age group. Lower prevalence was seen between these two age groups. The highest prevalence in our population occurred in women aged 40 to 49 (51.7%, 95% CI: 43.7, 59.6) and the lowest in men aged 50 to 59 (25.2%, 95% CI: 17.3, 33.2). In contrast, the age pattern was reversed for hyperopia, with highest prevalence in the 60 to 69 age group (Fig. 2) . For both astigmatism and anisometropia, there was a monotonic increase in prevalence with age in both sexes (Fig. 3) .
|
|
|
|
|
Increasing education, better housing, and higher individual income were associated with higher odds of myopia and high myopia, after adjusting for age and sex. Professionals and office workers had higher odds of myopia compared with those in other occupations, after adjusting for age and sex. Finally, nuclear opacity was associated independently with myopia and high myopia, after adjusting for age, sex, and individual income (as an indicator for socioeconomic status). Similar results for the association with nuclear opacity were obtained when adjustment for socioeconomic status was made with other proxy variables, such as housing types and education, evidenced by the high correlation of these variables with one another.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
There are difficulties in direct comparison of rates of myopia with data in other studies, because of differing ages of participants, definitions of myopia, inclusion criteria, and research methodology. In the Beaver Dam study (age range: 43–84 years), an overall prevalence of myopia of 26.2% was found in persons with phakic eyes who had better than 20/40 visual acuity in at least one eye.3 In the Visual Impairment Project in Victoria, Australia, a prevalence of 17% was observed in the population (40–98 years), after exclusion of participants with aphakia or pseudophakia, corneal diseases, and media opacities associated with worse than 20/60 visual acuities.4 In the Blue Mountains Eye Study in Australia (age range: 49–97 years), the 15% myopia prevalence reported could not be directly compared with that in the current study, because their study population was a decade older.5 Similarly, the National Health and Nutrition Examination Survey (NHANES) in 1971 estimated that 25% of the population was myopic, but the subjects were much younger than ours (12–54 years).1 In addition, the investigators in that study defined myopia as any negative SE, based on refraction in participants whose visual acuity was worse than 20/40 and lensometry in those whose visual acuity was 20/40 or better. In the Baltimore Eye Survey (age range: 40–89 years), a prevalence of 22.7% was noted in white and black subjects aged 40 years and more.2 In that study as well as in ours, participants were older than 40 years, myopia was defined as SE of worse than -0.5 D, and all had noncycloplegic refraction, regardless of their visual acuity or whether they wore spectacles.
The racial and ethnic variation of myopia has been reported in population-based studies in European-derived societies. For other populations, limited data are available. Racial variation was shown in the United States, where the NHANES report indicated that the prevalence of myopia was significantly lower among blacks than whites.1 Using the same definition of myopia as in the Beaver Dam study and after adjustments for age, gender, and education, the Baltimore Eye Survey reported a 28.1% prevalence in whites (similar to the Beaver Dam prevalence of 26.2%) but only 19.4% in blacks.2 The prevalence of myopia in the black population in Barbados (age range: 40–84 years) was recently shown to be 21.9%.7 In contrast, the prevalence of myopia has been reported to be lower than 5% in Australian Aborigines21 and in the populations in the Solomon Islands22 and Malawi.23
In East Asia, the apparent high prevalence of myopia was first observed in the 1930s in China.24 Since then, several studies have confirmed that the prevalence may be above 50% in selected high-risk populations.9 10 11 13 14 Wensor et al.4 noted that residents in Australia who had been born in Southeast Asia had a higher prevalence of myopia than those born elsewhere, even after controlling for education. Our study adds support to the suggestion that the prevalence of myopia in East Asians is higher. There are no data that adequately explain the high prevalence of myopia in East Asians. Both environmental and genetic factors appear to play important roles.8 15 16 Possible environmental reasons suggested include an apparent increase in formal education and more time spent on near work tasks by East Asians.8 Genetic variations between East Asians and European-derived populations have also been suggested but not substantiated.8 15 16
One particular concern is that almost 7% of our population could be classified as having high myopia (worse than -5.0 D). Adjusted to the adult Chinese population aged 40 to 79 years in Singapore, the prevalence of high myopia was nearly 10%. This figure is higher than data in reports from European-derived populations. In the Visual Impairment Project, high myopia of similar definition was found in less than 2% of their subjects with myopia.4 The prevalence of high myopes in the Baltimore Eye Survey, in which a slightly different definition was used for high myopia (worse than -6.0 D), was approximately 1.4%.2 There are two important ophthalmic implications in the rate of high myopia. First, high myopia has a higher risk of cataract, glaucoma, myopic macular degeneration, and retinal detachment.15 Second, the results of refractive surgery are less predictable in subjects with high myopia.25
Other demographic patterns have been noted in European-derived populations with refractive errors. Age has been highly correlated with the prevalence of different refractive errors. For both astigmatism and anisometropia, there was an age-dependent increase in prevalence in our study that was similar to that reported in white populations.2 5 For myopia, both population and non–population-based studies have shown that the prevalence generally follows a bimodal pattern in adults, initially declining with age and then increasing in the upper age groups.2 3 4 Because the age pattern of myopia was described half a century ago,26 the exact rationale for this observation is still controversial. One theory involves changes in the refractive index gradient of the lens with age.27 In the Beaver Dam Study, increasing level of nuclear opacity was an important determinant of the age-related increase in myopia after 70 years.28 An alternative explanation to age-related variations is that a real increase in the prevalence of myopia has occurred between the younger population compared with older people.29 It seems likely that both mechanisms are operating in our population as well.
The association of gender with refractive errors has not been well established. In the NHANES report, the prevalence of myopia was significantly lower in men than women.1 In the Beaver Dam study, a small gender difference was seen in the rates of myopia3 but in the Baltimore Eye Survey, no gender difference was found.2 Similarly, our study does not indicate significant gender differences. Although women were more likely to have high myopia (Table 5) , the overall rates of myopia and other refractive errors were similar in both genders across the entire age range (Table 3) .
Educational status, occupation, and income have been among the most frequently noted socioeconomic associations of myopia and hyperopia. These associations may be an indicator of near work and support the use–abuse theory for myopia.15 16 In the NHANES study, the prevalence of myopia increased with family income and educational level.1 Both the Baltimore and Beaver Dam studies showed a monotonic relationship between education and myopia.2 3 Our study found a direct relationship between increasing education and myopia and an inverse relationship with hyperopia. The Visual Impairment Project in Melbourne found that professionals and clerks had higher risks of myopia.4 One possible explanation was the association of these occupations with greater amounts of near work. We found similar higher odds of myopia in people who were professionals and office workers. Income and better housing are indicators of socioeconomic status and have been reported to be related to myopia in white populations,1 as was similarly seen in ours. As expected, we observed no distinctive trends of sociodemographic factors with either astigmatism or anisometropia.
Lens opacity appears to be an important ocular determinant of refractive error. There was a dose–response pattern between level of lens opacity and rate of astigmatism. For myopia, persons with the highest levels of nuclear opacity in our study (LOCS III grade 5 or 6) had an OR of 16 compared with the lowest levels (LOCS III grade 1 or 2). This was apparent also in the Visual Impairment Project in Australia.4
In conclusion, our study provides further epidemiologic data on the prevalence of refractive errors in an adult Chinese population in Asia. First, we showed that the prevalence of myopia was one and a half to two and a half times higher than in similarly aged European derived populations in the United States and Australia. Second, up to 10% of our population had high myopia, with potentially serious ophthalmic implications. Third, although the rate of myopia was different from that in whites and blacks, the sociodemographic and ocular risk factors were similar, indicating a common pathophysiological basis for myopia.
|
Acknowledgements |
|---|
|
Footnotes |
|---|
Submitted for publication October 6, 1999; revised December 22, 1999; accepted January 7, 2000.
Commercial relationships policy: N.
Corresponding author: Steve K. L. Seah, Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore 168751, Singapore. snecss{at}pacific.net.sg
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  J. M. Ip, K. A. Rose, I. G. Morgan, G. Burlutsky, and P. Mitchell Myopia and the Urban Environment: Findings in a Sample of 12-Year-Old Australian School Children Invest. Ophthalmol. Vis. Sci., September 1, 2008; 49(9): 3858 - 3863. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Y. Wong, E. W. Chong, W.-L. Wong, M. Rosman, T. Aung, J.-L. Loo, S. Shen, S.-C. Loon, D. T. H. Tan, E. S. Tai, et al. Prevalence and Causes of Low Vision and Blindness in an Urban Malay Population: The Singapore Malay Eye Study Arch Ophthalmol, August 1, 2008; 126(8): 1091 - 1099. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Vitale, L. Ellwein, M. F. Cotch, F. L. Ferris III, and R. Sperduto Prevalence of Refractive Error in the United States, 1999-2004 Arch Ophthalmol, August 1, 2008; 126(8): 1111 - 1119. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Dirani, S. N. Shekar, and P. N. Baird The Role of Educational Attainment in Refraction: The Genes in Myopia (GEM) Twin Study Invest. Ophthalmol. Vis. Sci., February 1, 2008; 49(2): 534 - 538. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J L Y Yip, T Aung, T-Y Wong, D Machin, P T Khaw, K-T Khaw, S Seah, and P J Foster Socioeconomic status, systolic blood pressure and intraocular pressure: the Tanjong Pagar Study Br. J. Ophthalmol., January 1, 2007; 91(1): 56 - 61. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. K.-S. Leung, S. Mohamed, K. S. Leung, C. Y.-L. Cheung, S. L.-w. Chan, D. K.-y. Cheng, A. K.-c. Lee, G. Y.-o. Leung, S. K. Rao, and D. S. C. Lam Retinal Nerve Fiber Layer Measurements in Myopia: An Optical Coherence Tomography Study Invest. Ophthalmol. Vis. Sci., December 1, 2006; 47(12): 5171 - 5176. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.-D. Luo, G. Gazzard, A. Fong, T. Aung, S. T. Hoh, S.-C. Loon, P. Healey, D. T. H. Tan, T.-Y. Wong, and S.-M. Saw Myopia, Axial Length, and OCT Characteristics of the Macula in Singaporean Children. Invest. Ophthalmol. Vis. Sci., July 1, 2006; 47(7): 2773 - 2781. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Han, M. K. H. Yap, J. Wang, and S. P. Yip Family-Based Association Analysis of Hepatocyte Growth Factor (HGF) Gene Polymorphisms in High Myopia. Invest. Ophthalmol. Vis. Sci., June 1, 2006; 47(6): 2291 - 2299. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. K. Nirmalan, S. Krishnaiah, B. R. Shamanna, G. N. Rao, and R. Thomas A population-based assessment of presbyopia in the state of andhra pradesh, South India: the andhra pradesh eye disease study. Invest. Ophthalmol. Vis. Sci., June 1, 2006; 47(6): 2324 - 2328. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Tarczy-Hornoch, M. Ying-Lai, R. Varma, and the Los Angeles Latino Eye Study Group Myopic Refractive Error in Adult Latinos: The Los Angeles Latino Eye Study Invest. Ophthalmol. Vis. Sci., May 1, 2006; 47(5): 1845 - 1852. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T Y Wong, S-C Loon, and S-M Saw The epidemiology of age related eye diseases in Asia. Br. J. Ophthalmol., April 1, 2006; 90(4): 506 - 511. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S.-Y. Wu, Y. J. Yoo, B. Nemesure, A. Hennis, M. C. Leske, and the Barbados Eye Studies Group Nine-Year Refractive Changes in the Barbados Eye Studies Invest. Ophthalmol. Vis. Sci., November 1, 2005; 46(11): 4032 - 4039. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W-M Chan, M Ohji, T Y Y Lai, D T L Liu, Y Tano, and D S C Lam Choroidal neovascularisation in pathological myopia: an update in management Br. J. Ophthalmol., November 1, 2005; 89(11): 1522 - 1528. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. C. C. Lim, S.-T. Hoh, P. J. Foster, T.-H. Lim, S.-J. Chew, S. K. L. Seah, and T. Aung Use of Optical Coherence Tomography to Assess Variations in Macular Retinal Thickness in Myopia Invest. Ophthalmol. Vis. Sci., March 1, 2005; 46(3): 974 - 978. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Raju, S. Ve Ramesh, H. Arvind, R. George, M. Baskaran, P. G. Paul, G. Kumaramanickavel, C. McCarty, and L. Vijaya Prevalence of Refractive Errors in a Rural South Indian Population Invest. Ophthalmol. Vis. Sci., December 1, 2004; 45(12): 4268 - 4272. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D S C Lam, W-M Chan, D T L Liu, D S P Fan, W W Lai, and K K L Chong Photodynamic therapy with verteporfin for subfoveal choroidal neovascularisation of pathologic myopia in Chinese eyes: a prospective series of 1 and 2 year follow up Br. J. Ophthalmol., October 1, 2004; 88(10): 1315 - 1319. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
The Eye Diseases Prevalence Research Group The Prevalence of Refractive Errors Among Adults in the United States, Western Europe, and Australia Arch Ophthalmol, April 1, 2004; 122(4): 495 - 505. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Wickremasinghe, P. J. Foster, D. Uranchimeg, P. S. Lee, J. G. Devereux, P. H. Alsbirk, D. Machin, G. J. Johnson, and J. Baasanhu Ocular Biometry and Refraction in Mongolian Adults Invest. Ophthalmol. Vis. Sci., March 1, 2004; 45(3): 776 - 783. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. R. A. Bourne, B. P. Dineen, D. M. N. Huq, S. M. Ali, and G. J. Johnson Correction of Refractive Error in the Adult Population of Bangladesh: Meeting the Unmet Need Invest. Ophthalmol. Vis. Sci., February 1, 2004; 45(2): 410 - 417. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-Y. Cheng, W.-M. Hsu, J.-H. Liu, S.-Y. Tsai, and P. Chou Refractive Errors in an Elderly Chinese Population in Taiwan: The Shihpai Eye Study Invest. Ophthalmol. Vis. Sci., November 1, 2003; 44(11): 4630 - 4638. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. J. Foster, D. Machin, T.-Y. Wong, T.-P. Ng, J. F. Kirwan, G. J. Johnson, P. T. Khaw, and S. K. L. Seah Determinants of Intraocular Pressure and Its Association with Glaucomatous Optic Neuropathy in Chinese Singaporeans: The Tanjong Pagar Study Invest. Ophthalmol. Vis. Sci., September 1, 2003; 44(9): 3885 - 3891. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P J Foster, T Y Wong, D Machin, G J Johnson, and S K L Seah Risk factors for nuclear, cortical and posterior subcapsular cataracts in the Chinese population of Singapore: the Tanjong Pagar Survey Br. J. Ophthalmol., September 1, 2003; 87(9): 1112 - 1120. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. S. Wolffsohn, B. Gilmartin, R. W.-h. Li, M. H. Edwards, S. W.-s. Chat, J. K.-f. Lew, and B. S.-y. Yu Nearwork-Induced Transient Myopia in Preadolescent Hong Kong Chinese Invest. Ophthalmol. Vis. Sci., May 1, 2003; 44(5): 2284 - 2289. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Y. Wong, P. J. Foster, G. J. Johnson, and S. K. L. Seah Refractive Errors, Axial Ocular Dimensions, and Age-Related Cataracts: The Tanjong Pagar Survey Invest. Ophthalmol. Vis. Sci., April 1, 2003; 44(4): 1479 - 1485. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T Y Wong and D T Tan The SERI-ARVO Meeting and future challenges of ophthalmic research in Asia Br. J. Ophthalmol., April 1, 2003; 87(4): 379 - 380. [Full Text] [PDF]
|
|
|
|
