Search

Purpose To assess the influence of distance and near visual impairment on self-reported near visual functioning (VF) among adults in a multi-country study. Design Population-based cross-sectional study. Participants Participants aged ≥35 years were randomly selected with cluster sampling at seven sites: rural sites in Nepal (Kaski) and India (Madurai), a semi-rural site in China (Shunyi), semi-urban sites in South Africa (Durban) and Niger (Dosso), and urban sites in the United States (Los Angeles) and China (Guangzhou). Methods Binocular presenting distance and near visual acuity (VA) were measured with a LogMAR tumbling E chart at 4 meters and 40 cm, respectively. A 12-item near VF questionnaire interview was administered by trained local interviewers, with responses scored from 100 to 0 as visual “disability” increased. Multiple linear regression was used to investigate the association of age, gender, education and VA with overall eyesight, difficulty with activities and social functioning subscale scores. Main Outcome Measures VF subscale scores. Results The study sample consisted of 6,851 questionnaire respondents. The VF subscale scores decreased significantly with worse distance and near VA, and even mildly impaired VA could result in reduced VF at all sites. In multiple linear regression modeling, lower VF subscale scores were associated with older age in four sites, female gender in three sites, and greater education in two sites. The influence of near VA was greater than that of distance VA in three sites, and in one site distance VA was more influential than near VA. With study site included in the regression modeling, lower scores for the overall eyesight subscale (compared to the Shunyi reference site) were found in Guangzhou, Kaski and Durban; lower difficulty in activities scores were found in Kaski and Durban, but better scores in Guangzhou and Madurai; social functioning scores were lower in Kaski, Durban and Dosso. Conclusions Along the entire VA spectrum, lower levels of distance and near VA led to significant reductions in VF subscale scores, with wide variation both within and between study sites. The impact of near vision on VF should receive greater emphasis with further investigation in various socio-economic and cultural settings.

PurposeTo estimate the nationwide prevalence of visual impairment and associated refractive error in school children in Bhutan.MethodsThe sample of this prospective cross-sectional national survey comprised of randomly selected classes in levels IV-IX (age 10 to 15 years) from schools throughout Bhutan. The examination included measurement of visual acuity (VA), evaluation of ocular motility, refraction under cycloplegia, examination of the external eye, media and fundus. The principal cause of impairment was determined for eyes with uncorrected VA ≤6/12. The main outcome measures were distance VA and cycloplegic refractive error.ResultsWith a sampling frame of 1967 class-based clusters from 190 schools, 160 classes in 103 schools were randomly selected; 4985 (98.5%) of 5060 enumerated children were examined. The prevalence of uncorrected, presenting, and best-corrected visual impairment (VA≤6/12) in the better eye was 14.5%, 12.8%, and 0.34%, respectively. Refractive error was the principal cause (94.2%) of impaired vision and 88% of children who could achieve VA ≥6/9 with best correction were without necessary spectacles. The prevalence of myopia (≤ -0.5 D) was 6.64% and was associated with female gender (P = 0.004), urban schooling (P = 0.002), and greater parental education (PConclusionsReduced vision because of uncorrected refractive error is a public health problem among school-age children in Bhutan. Effective school eye health strategies are needed to eliminate this easily treatable cause of visual impairment.

PurposeTo assess the potential of ready-made (spherical) spectacles (RMS) in meeting the need for refractive correction in visually impaired children in China.MethodsEligible children aged 5–17 years were identified from the three study sites in China. Distance visual acuity was measured with a retroilluminated logarithm of the minimum angle of resolution chart with tumbling E optotypes. Cycloplegic autorefraction was performed on all children using a handheld autorefractor. If uncorrected visual acuity (UCVA) was ≤20/40 in either eye, best corrected visual acuity was measured with subjective refractive error.Results A total of 13 702 children were enumerated from the three studies, with 12 334 (90.0%) having both reliable visual acuity measurements and successful cycloplegia. Among the 12 334 study children, the prevalence of UCVA ≤20/40 in the better seeing eye was 16.4% (95% CI 15.0% to 17.8%), with 91.1% (1843) of these improving by ≥3 lines of visual acuity with refractive correction. Prevalence was 12.7% (95% CI 11.5% to 13.9%) for UCVA <20/50 with 97.4% (1521) improving by ≥3 lines, and 9.38% (95% CI 8.39% to 19.4%) for UCVA ≤20/63 with 98.4% (1138) improving by ≥3 lines. Depending on the severity of visual impairment, 62.8%–64.0% of children could be accommodated with RMS if not correcting for astigmatism of ≤0.75 dioptres and anisometropia of ≤0.50 spherical equivalent dioptres. Approximately 87% of children could be accommodated with RMS if astigmatism and anisometropia limits were increased to ≤1.25 and ≤1.50 dioptres, respectively.ConclusionsRMS could substantially alleviate visual morbidity in two-thirds or more of visually impaired schoolchildren in China. This cost-effective approach to refractive correction might also be useful in low/middle-income countries with poor access to optometric services.

To estimate the prevalence of vision impairment and blindness in 2014 among older adults in rural China with comparisons with the 2006 Nine-Province Survey.Population-based, cross-sectional study.Geographical cluster sampling was used in randomly selecting residents from a rural county or semi-rural district within 9 provinces: Beijing, Jiangsu, Guangdong, Heilongjiang, Jiangxi, Hebei, Ningxia, Chongqing, and Yunnan. Persons 50 years of age or older were enumerated through household visits and invited to examination sites for visual acuity testing and examination. Vision impairment and blindness in 2014 was compared with data from the 2006 survey.Among 51 310 examined persons, the prevalence of presenting vision impairment (20/63 to ≥20/400) in the better-seeing eye ranged from 6.05% to 15.3% across the 9 study sites, with presenting blindness (20/400) ranging from 0.66% to 5.35%. With best-corrected visual acuity, the prevalence of vision impairment ranged from 1.96% to 8.74%, and blindness from 0.47% to 5.01%. Vision impairment was associated with older age, female sex, and little or no education. The overall prevalence of presenting vision impairment and blindness decreased during the 2006-2014 interval by 6.31% and 29.0%, respectively; and by 16.1% and 38.0%, respectively, after standardization of 2006 prevalence rates to the 2014 population.Substantial progress has been made in the reduction of vision impairment in rural China. Nevertheless, vision impairment remains an important public health problem with substantial geographic disparities and with older age, female sex, and illiteracy as risk factors.

Purpose To investigate the progression of near vision loss and the cumulative incidence of near vision impairment (NVI) 6 years after initial examination of an urban Chinese cohort. Design Population-based, prospective cohort study. Participants People aged ≥35 years examined at baseline in the Yuexiu District of Guangzhou, China. Methods Participants examined at baseline were invited for 2-year and 6-year follow-up examinations in 2010 and 2014, respectively. Examinations included noncycloplegic autorefraction and binocular near visual acuity (NVA) with and without current near correction measured at 40 cm using a LogMAR ETDRS near vision tumbling E chart. Those with uncorrected binocular NVA (UCNVA) ≤20/40 underwent subjective refraction to obtain best-corrected binocular NVA (BCNVA). Main Outcome Measures Change in UCNVA between baseline and 2014 follow-up examinations and the 6-year cumulative incidence of vision impairment based on 3 definitions: NVA ≤20/40, ≤20/50, and ≤20/63. Results Among the 1817 baseline participants, 1595 (87.8%) were reexamined in 2010 and 1427 (78.5%) in 2014. Mean vision loss between baseline and the 2014 follow-up was 1.54 (±1.74) lines of UCNVA. Vision loss was associated with age 80 years or older, less education, and better baseline UCNVA. The 6-year cumulative incidence of uncorrected binocular NVI (UCNVI) across the 3 vision impairment definitions was 55.2% (95% confidence interval [CI], 46.1%–64.3%), 51.3% (95% CI, 44.0%–58.7%), and 42.4% (95% CI, 35.5%–49.3%), respectively. With best-corrected binocular NVI (BCNVI), incidence was 6.89% (95% CI, 4.28%–9.50%), 5.17% (95% CI, 2.89%–7.44%), and 2.62% (95% CI, 1.11%–4.12%), respectively. A higher incidence of UCNVI was associated with worse baseline UCNVA for all 3 impairment definitions. Similarly, incidence of BCNVI was associated with worse baseline BCNVA, but also with older age and education at the primary level or less. Gender was not significant for either UCNVI or BCNVI. Conclusions Approximately half of those aged 35 years or older develop UCNVI in 6 years, the overwhelming majority of whom can be corrected with spectacles. Cost-effective strategies to provide spectacles to this at-risk population remains an issue requiring further study.

BackgroundTo assess prevalence and causes of vision loss in Central and South Asia.MethodsA systematic review of medical literature assessed the prevalence of blindness (presenting visual acuityResultsIn Central and South Asia combined, age-standardised prevalences of blindness, MSVI and MVI in 2015 were for men and women aged 50+years, 3.72% (80% uncertainty interval (UI): 1.39–6.75) and 4.00% (80% UI: 1.41–7.39), 16.33% (80% UI: 8.55–25.47) and 17.65% (80% UI: 9.00–27.62), 11.70% (80% UI: 4.70–20.32) and 12.25% (80% UI:4.86–21.30), respectively, with a significant decrease in the study period for both gender. In South Asia in 2015, 11.76 million individuals (32.65% of the global blindness figure) were blind and 61.19 million individuals (28.3% of the global total) had MSVI. From 1990 to 2015, cataract (accounting for 36.58% of all cases with blindness in 2015) was the most common cause of blindness, followed by undercorrected refractive error (36.43%), glaucoma (5.81%), age-related macular degeneration (2.44%), corneal diseases (2.43%), diabetic retinopathy (0.16%) and trachoma (0.04%). For MSVI in South Asia 2015, most common causes were undercorrected refractive error (accounting for 66.39% of all cases with MSVI), followed by cataract (23.62%), age-related macular degeneration (1.31%) and glaucoma (1.09%).ConclusionsOne-third of the global blind resided in South Asia in 2015, although the age-standardised prevalence of blindness and MSVI decreased significantly between 1990 and 2015.

Purpose To study, for the first time, the effect of wearing ready-made glasses and glasses with power determined by self-refraction on children's quality of life. Methods This is a randomized, double-masked non-inferiority trial. Children in grades 7 and 8 (age 12–15 years) in nine Chinese secondary schools, with presenting visual acuity (VA) ≤6/12 improved with refraction to ≥6/7.5 bilaterally, refractive error ≤−1.0 D and

PURPOSE: To estimate surgical coverage of cataract-related vision impairment and blindness and visual acuity outcomes in operated eyes in rural China in 2014 with comparisons with the 2006 Nine-Province Survey. DESIGN: Population-based, cross-sectional study. METHODS: Geographical cluster sampling was used in randomly selecting residents from a rural county or semi-rural district within 9 provinces: Beijing, Jiangsu, Guangdong, Heilongjiang, Jiangxi, Hebei, Ningxia, Chongqing, and Yunnan. Persons 50 years of age or older were enumerated through household visits and invited to examination sites for visual acuity testing and ocular examination. Surgical coverage and visual acuity outcomes in 2014 were compared with data from the 2006 survey. RESULTS: Among 51 310 examined persons, surgical coverage among those presenting with cataract-related severe visual impairment or blindness (

To estimate the age-, gender-, and ethnicity-specific prevalence of amblyopia in children aged 5 to 15 years using data from the multi-country Refractive Error Study in Children (RESC).Population-based, cross-sectional study.Among 46 260 children aged 5 to 15 years who were enumerated from 8 sites in the RESC study, 39 551 had a detailed ocular examination and a reliable visual acuity (VA) measurement in 1 or both eyes. Information on ethnicity was available for 39 321 of these participants. This study focused on findings from the 39 321 children.The examination included VA measurements, evaluation of ocular alignment and refractive error under cycloplegia, and examination of the external eye, anterior segment, media, and fundus.The proportion of children aged 5 to 15 years with amblyopia in different ethnic cohorts. Amblyopia was defined as best-corrected visual acuity (BCVA) of ≤20/40 in either eye, with tropia, anisometropia (≥2 spherical equivalent diopters [D]), or hyperopia (≥+6 spherical equivalent D), after excluding children with fundus or anterior segment abnormalities.The overall prevalence of amblyopia was 0.74% (95% confidence interval, 0.64-0.83) with significant (P0.001) variation across ethnic groups: 1.43% in Hispanic, 0.93% in Chinese, 0.62% in Indian, 0.52% in Malay, 0.35% in Nepali, and 0.28% in African children. Amblyopia was not associated with age or gender. The most common cause of amblyopia was anisometropia.In this study, the prevalence of amblyopia varied with ethnicity and was highest in Hispanic children and lowest in African children. Most cases were unilateral and developed before the age of 5 years. The impact of changes of definitions on prevalence estimates is discussed.

Purpose To estimate the prevalence, potential determinants, and proportion of met need for near vision impairment (NVI) correctable with refraction approximately 2 years after initial examination of a multi-country cohort. Design Population-based, prospective cohort study. Participants People aged ≥35 years examined at baseline in semi-rural (Shunyi) and urban (Guangzhou) sites in China; rural sites in Nepal (Kaski), India (Madurai), and Niger (Dosso); a semi-urban site (Durban) in South Africa; and an urban site (Los Angeles) in the United States. Methods Near visual acuity (NVA) with and without current near correction was measured at 40 cm using a logarithm of the minimum angle of resolution near vision tumbling E chart. Participants with uncorrected binocular NVA ≤20/40 were tested with plus sphere lenses to obtain best-corrected binocular NVA. Main Outcome Measures Prevalence of total NVI (defined as uncorrected NVA ≤20/40) and NVI correctable and uncorrectable to >20/40, and current spectacle wearing among those with bilateral NVA ≤20/63 improving to >20/40 with near correction (met need). Results Among 13 671 baseline participants, 10 533 (77.2%) attended the follow-up examination. The prevalence of correctable NVI increased with age from 35 to 50–60 years and then decreased at all sites. Multiple logistic regression modeling suggested that correctable NVI was not associated with gender at any site, whereas more educated persons aged >54 years were associated with a higher prevalence of correctable NVI in Nepal and India. Although near vision spectacles were provided free at baseline, wear among those who could benefit was Conclusions Prevalence of correctable NVI is greatest among persons of working age, and rates of correction are low in many settings, suggesting that strategies targeting the workplace may be needed.

Objective To compare visual and refractive outcomes between self-refracting spectacles (Adaptive Eyecare, Ltd, Oxford, UK), noncycloplegic autorefraction, and cycloplegic subjective refraction. Design Cross-sectional study. Participants Chinese school-children aged 12 to 17 years. Methods Children with uncorrected visual acuity ≤6/12 in either eye underwent measurement of the logarithm of the minimum angle of resolution visual acuity, habitual correction, self-refraction without cycloplegia, autorefraction with and without cycloplegia, and subjective refraction with cycloplegia. Main Outcome Measures Proportion of children achieving corrected visual acuity ≥6/7.5 with each modality; difference in spherical equivalent refractive error between each of the modalities and cycloplegic subjective refractive error. Results Among 556 eligible children of consenting parents, 554 (99.6%) completed self-refraction (mean age, 13.8 years; 59.7% girls; 54.0% currently wearing glasses). The proportion of children with visual acuity ≥6/7.5 in the better eye with habitual correction, self-refraction, noncycloplegic autorefraction, and cycloplegic subjective refraction were 34.8%, 92.4%, 99.5% and 99.8%, respectively (self-refraction versus cycloplegic subjective refraction, P P P = 0.33). Spherical equivalent differed by ≥1.0 D in either direction from cycloplegic subjective refraction more frequently among right eyes for self-refraction (11.2%) than noncycloplegic autorefraction (6.0%; P = 0.002). Self-refraction power that differed by ≥1.0 D from cycloplegic subjective refractive error (11.2%) was significantly associated with presenting without spectacles ( P = 0.011) and with greater absolute power of both spherical ( P = 0.025) and cylindrical ( P = 0.022) refractive error. Conclusions Self-refraction seems to be less prone to accommodative inaccuracy than noncycloplegic autorefraction, another modality appropriate for use in areas where access to eye care providers is limited. Visual results seem to be comparable. Greater cylindrical power is associated with less accurate results; the adjustable glasses used in this study cannot correct astigmatism. Further studies of the practical applications of this modality are warranted. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.

Purpose To investigate the prevalence and visual acuity (VA) outcomes of cataract surgery in rural populations throughout China. Design Population-based, cross-sectional study. Participants Forty-five thousand seven hundred forty-seven adults 50 years of age and older. Methods Geographically defined cluster sampling was used in randomly selecting a cross-section of residents from a representative rural county within each of 9 provinces in mainland China. Participants underwent VA measurements, refraction, and a slit-lamp examination at local examination sites; those with previous cataract surgery were queried as to the year and type of surgical facility. Surgical procedure and evidence of surgery complications were noted during the examination. The principal cause of visual impairment was identified for eyes with VA of 20/40 or worse. Main Outcome Measures Cataract surgery procedure, presenting and best-corrected distance VA, and causes of visual impairment. Results Of 50 395 enumerated eligible persons, 45 747 (90.8%) were examined and tested for VA. The overall prevalence of cataract surgery was 2.09%. Surgical coverage among those with VA worse than 20/200 in both eyes because of cataract was 35.7%. Unoperated cataract was associated with older age, female gender, lack of education, and geographic area (province). Among the 1174 cataract-operated eyes, 31.1% had presenting VA of 20/32 or better, 15.4% had presenting VA of 20/40 to 20/63, 30.0% had presenting VA worse than 20/63 to 20/200, and 23.5% had presenting VA worse than 20/200. With best correction, the percentages were 57.6%, 6.2%, 18.5%, and 17.7%, respectively. Posterior capsule opacification, refractive error, and retinal disorders were the main causes in cataract-operated eyes with VA worse than 20/63. Conclusions Two thirds of those with bilateral visual impairment or blindness because of cataract remain in need of sight-restoring surgery. Posterior capsule opacification and refractive error, both readily amenable to treatment, were common in cataract-operated eyes. Sustained government efforts to provide access to affordable modern cataract surgery with a greater emphasis on postoperative follow-up and the quality of VA outcomes are needed. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The cataract surgical rate (CSR) in Gujarat, India is reported to be above 10,000 per million population. This study was conducted to investigate the prevalence and causes of vision impairment/blindness among older adults in a high CSR area.Geographically defined cluster sampling was used in randomly selecting personsor= 50 years of age in Navsari district. Subjects in 35 study clusters were enumerated and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity20/32.A total of 5158 eligible persons were enumerated and 4738 (91.9%) examined. Prevalence of presenting visual impairment20/63 to 20/200 in the better eye was 29.3% (95% confidence interval [CI]: 27.5-31.2) and 13.5% (95% CI: 12.0-14.9) with best correction. The prevalence of presenting bilateral blindness (20/200) was 6.9% (95% CI: 5.7-8.1), and 3.1% (95% CI: 2.5-3.7) with best correction. Presenting and best-corrected blindness were both associated with older age and illiteracy; gender and rural/urban residence were not significant. Cataract in one or both eyes was the main cause of bilateral blindness (82.6%), followed by retinal disorders (8.9%). Cataract (50.3%) and refractive error (35.4%) were the main causes in eyes with vision acuity20/63 to 20/200, and refractive error (86.6%) in eyes with acuity20/32 to 20/63.Visual impairment and blindness is a significant problem among the elderly in Gujarat. Despite a reportedly high CSR, cataract remains the predominant cause of blindness.

AbstrA ct Purpose: Investigate the prevalence and vision-related outcomes of cataract surgery in an area of high cataract surgical rate. Methods: Cluster sampling was used in randomly selecting individuals ≥ 50 years of age in 2007. Participants were queried regarding year and place of previous cataract surgery. Cataract surgical procedures and evidence of surgical complications were recorded. The principal cause was identified for eyes presenting with visual acuity (VA) ≤ 20/40. Results: A total of 4,738 persons were examined and 834 (17.6%) had cataract surgery. Intra- ocular lenses (IOLs) were used in 84.1% of the 1,299 cataract-operated eyes, with more than half of these having manual small incision surgery. Surgical coverage among the cataract blind (visual acuity [VA] < 20/200) was estimated as 72.2%. Coverage was associated with older age, literacy, and urban residence; gender was not significant. Among cataract-operated eyes, 18.7% presented with VA ≥ 20/32 and 18.0% were < 20/200. With best-corrected acuity, the corresponding percentages were 55.7% and 11.0%. Presenting and best-corrected VA ≥ 20/63 were associated with young age, literacy, and IOL surgery; urban residence and surgery in non-governmental organizations (NGO)/ private facilities were also significant for presenting VA; and recent surgery was significant for best-corrected VA. Refractive error was the main cause of vision impairment/blindness in cataractoperated eyes. Conclusions: Refractive error and posterior capsule opacification, easily treatable causes of visual impairment, are common among the operated. A greater emphasis on the quality of visual acuity outcomes along with sustained efforts to provide access to affordable surgery is needed.

Purpose: Assess visual impairment in school children of upper-middle socioeconomic status in Kathmandu for comparison with rural Jhapa District. Methods: Random selection of classes from secondary private schools in Kathmandu was used to identify the study sample. Children in 130 classes at 43 schools were enumerated using school records and examined between January‐May 2006. Examinations included visual acuity testing, ocular motility evaluation, cycloplegic refraction, and examination of the external eye, anterior segment, media, and fundus. The principal cause was determined for eyes with uncorrected visual acuity ≤20/40. Results :A total of 4,501 children in grades 5‐9 were enumerated; 4282 (95.1%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual impairment (≤20/40) in the better eye was 18.6%, 9.1%, and 0.86%, respectively. Refractive error was a cause in 93.3% of children with uncorrected visual impairment, amblyopia 1.8%, retinal disorders 1.3%, other causes 0.3%, and unexplained causes 4.4%. Among children correctable in at least one eye, 46.3% presented without the necessary spectacles. Visual impairment with myopia (-0.50 diopters) ranged from 10.9% in 10 year-olds to 27.3% in 15 year-olds, compared to 0.5%‐3.0% in rural Jhapa District. Myopic visual impairment was associated with grade level, female gender, parental education, parental spectacle usage, and Mongol ethnicity. Conclusions: Visual impairment with myopia among upper-middle socioeconomic school children in Kathmandu is higher than that in rural Nepal, and a public health problem because nearly half are without corrective spectacles. Effective strategies are needed to eliminate this easily treatable cause of visual impairment.

Purpose To evaluate the accuracy of noncycloplegic autorefraction in a representative sample of school-age children in China. Methods Refractive error was measured with an autorefractor, both before and after cycloplegia induced with cyclopentolate, in a population-based sample of 4973 children between the ages of 7 and 18 years. Spherical equivalent refractive error and astigmatism as represented by Jackson crossed-cylinders (J0 and J45) were the main outcome measures. Results Noncycloplegic measurements of equivalent spheres were consistently more negative or less positive than those after cycloplegia, with mean +/- SD differences of -1.23 +/- 0.97 D. The differences were particularly large for hyperopic eyes (mean difference of -2.98 +/- 1.65 D for hyperopia of at least +2.00 D) while becoming progressively smaller for emmetropic eyes, and smaller yet for myopic eyes (mean difference of -0.41 +/- 0.46 D for myopia of -2.00 D or more). Increasing age was associated with increased, but clinically insignificant, differences. Little difference was found between noncycloplegic and cycloplegic measurements of astigmatism: mean J0 and J45 differences were -0.08 +/- 0.13 D and -0.01 +/- 0.09 D, respectively. Conclusions Noncycloplegic autorefraction was found to be highly inaccurate in school-age children and, thus, not suitable for studies of refractive error or for prescription of glasses in this population.

PURPOSE: To assess the progression of refractive error and the incidence of myopia in school-age children in the Shunyi District of Beijing, China. DESIGN: A longitudinal cohort study. METHODS: A population-based sample of 4,662 children initially examined in 1998 at ages 5 to 13 years was reexamined between September and November, 2000. Refractive error was measured under cycloplegia with autorefraction. Age, sex, and baseline refractive error were evaluated as risk factors for progression. RESULTS: In 28.5 months, the average change in refractive error was −0.42 diopters (standard deviation, 0.68) in right eyes. Myopic shift of refractive error was associated with female sex, older age, and higher myopic or hyperopic refractive error at baseline. The average change in astigmatic error was essentially zero, with significant change in both directions more likely among those with higher baseline astigmatism. Findings were similar for left eyes. The cumulative incidence of myopia, defined as a spherical equivalent refractive error of −0.50 diopters or more in either eye, among initial emmetropes and hyperopes was 14.1% (95% confidence interval [CI], 11.8%–16.5%) for male and 23.5% (95% CI, 20.8%–26.1%) for female subjects. Myopia incidence increased sixfold to sevenfold between baseline age 5 and 12, before decreasing at age 13, for both male and female subjects. CONCLUSIONS: In the design of cost-effective programs for the periodic screening and treatment of uncorrected refractive error, children initially found to require refractive correction should be targeted for relatively frequent rescreening, as should girls and older children. Further study is required to better understand environmental and genetic risk factors for myopia development and progression.

To assess the prevalence of vision impairment, blindness, and cataract surgery and to evaluate visual acuity outcomes after cataract surgery in a south Indian population.Cluster sampling was used to randomly select a cross sectional sample of peopleor =50 years of age living in the Tirunelveli district of south India. Eligible subjects in 28 clusters were enumerated through a door to door household survey. Visual acuity measurements and ocular examinations were performed at a selected site within each of the clusters in early 2000. The principal cause of visual impairment was identified for eyes with presenting visual acuity6/18. Independent replicate testing for quality assurance monitoring was performed in subjects with reduced vision and in a sample of those with normal vision for six of the study clusters.A total of 5795 people in 3986 households were enumerated and 5411 (93.37%) were examined. The prevalence of presenting and best corrected visual acuityor =6/18 in both eyes was 59.4% and 75.7%, respectively. Presenting vision6/60 in both eyes (the definition of blindness in India) was found in 11.0%, and in 4.6% with best correction. Presenting blindness was associated with older age, female sex, and illiteracy. Cataract was the principal cause of blindness in at least one eye in 70.6% of blind people. The prevalence of cataract surgery was 11.8%-with an estimated 56.5% of the cataract blind already operated on. Surgical coverage was inversely associated with illiteracy and with female sex in rural areas. Within the cataract operated sample, 31.7% had presenting visual acuityor =6/18 in both eyes and 11.8% were6/60; 40% were bilaterally operated on, with 63% pseudophakic. Presenting vision was6/60 in 40.7% of aphakic eyes and in 5.1% of pseudophakic eyes; with best correction the percentages were 17.6% and 3.7%, respectively. Refractive error, including uncorrected aphakia, was the main cause of visual impairment in cataract operated eyes. Vision6/18 was associated with cataract surgery in government, as opposed to that in non-governmental/private facilities. Age, sex, literacy, and area of residence were not predictors of visual outcomes.Treatable blindness, particularly that associated with cataract and refractive error, remains a significant problem among older adults in south Indian populations, especially in females, the illiterate, and those living in rural areas. Further study is needed to better understand why a significant proportion of the cataract blind are not taking advantage of free of charge eye care services offered by the Aravind Eye Hospital and others in the district. While continuing to increase cataract surgical volume to reduce blindness, emphasis must also be placed on improving postoperative visual acuity outcomes.

Background: The prevalence of vision impairment, unilateral/bilateral blindness, and cataract surgery were estimated in a population based survey among the elderly in a suburban area of Hong Kong. Methods: 15 public, private, and home ownership scheme housing estates in the Shatin area of Hong Kong were subjected to cluster sampling to randomly select a cross section of people 60 years of age or older. Visual acuity measurements and ocular examinations were conducted at a community site within each estate. The principal cause of reduced vision was identified for eyes with presenting visual acuity worse than 6/18. Results: A total of 3441 subjects from an enumerated population of 4487 (76.7%) completed an eye examination. The prevalence of presenting visual acuity less than 6/18 in at least one eye was 41.3%; and 73.1% in those 80 years of age or older. Unilateral blindness (acuity

Background: Visual acuity, visual functioning, and vision related quality of life outcomes after cataract surgery were assessed in a population based study in a suburban area of Hong Kong. Methods: A cluster sampling design was used to select apartment buildings within housing estates for enumeration. All enumerated residents 60 years of age or over were invited for an eye examination and visual acuity measurement at a site within each estate. Visual functioning (VF) and vision related quality of life (QOL) questionnaires were administered to interview subjects who had undergone cataract surgery and to unoperated people with presenting visual acuity less than 6/60 in either eye, and a sample of those with normal visual acuity. Results: 36.6% of the 310 cataract operated individuals had presenting visual acuity 6/18 or better in both eyes, and 40.0% when measured by pinhole. 4.5% were blind, with presenting visual acuity less than 6/60 in both eyes. Of operated eyes, 59.6% presented with visual acuity 6/18 or better. 11.2% of the operated eyes were blind with vision less than 6/60. Visual acuity outcomes 6/18 or better were marginally associated with surgery in private versus public hospitals. Lens status (pseudophakic versus aphakic) and surgical period (within the most recent 3 years versus before) were not significantly related to vision outcomes. Mean VF and QOL scores decreased consistently with decreasing vision status. Spearman correlation with vision status was 0.420 for VF scores and 0.313 for QOL scores. Among VF/QOL subscales, correlation was strongest for visual perception (r = 0.447) among VF subscales and weakest for self care (r = 0.171) among QOL subscales. Regression adjusted VF and QOL total scores for cataract operated individuals were slightly lower than for those of visually comparable unoperated individuals (p

To assess the clinical outcomes of cataract surgery in rural southern India.Cluster sampling was used in randomly selecting a cross-sectional sample of persons 50 years of age or older for visual acuity measurement, refraction, and ocular examination in 1999. Subjects were queried as to the date and place of surgery for each cataract-operated eye. Surgical complications were noted and the principal cause of reduced vision was identified for eyes with presenting visual acuity worse than 6/18.Within the cataract-operated sample of 682 persons, 13.8% had presenting visual acuity worse than 6/60 in both eyes, 25.2% better than or equal to 6/18 in both eyes, and 37.8% were bilaterally operated on. For aphakic eyes, 50.5% presented with visual acuity better than or equal to 6/18; 82.6% with best-correction. For pseudophakic eyes, the corresponding percentages were 78.0% and 94.5%. Over one-third of all eyes were pseudophakic, and nearly three-fourths had been operated on in non-governmental facilities. Uncorrected aphakia and other refractive error were the main causes of vision impairment. In multiple logistic regression modeling, poor presenting visual acuity in aphakic eyes was associated with illiteracy, rural residence, and surgery in government facilities; gender and time period of surgery were not predictors of vision outcomes. None of these variables were associated with best-corrected outcomes in aphakic eyes, nor with presenting and best-corrected outcomes in pseudophakic eyes.Visual acuity outcomes in pseudophakic eyes were good. More attention must be given to needless vision impairment among the cataract-operated because of inadequate aphakic correction, especially among those operated on in government facilities, the illiterate, and those living in rural villages.

To determine uptake, barriers and outcomes in the follow-up of patients referred for free-of-charge, expedited cataract surgery in the Sao Paulo Eye Study (SPES).SPES was a population-based study of urban, low-middle income residents aged ≥50 years. Presenting visual acuity (PVA), best-corrected visual acuity, refraction, and slit-lamp examination were performed in 3677 participants. For subjects with cataract as a principal cause of best-corrected visual acuity ≤20/40, surgery was offered free of charge. Two years after the baseline study, surgery uptake, barriers to surgery, and visual outcomes were analyzed.Among 210 (5.71%) participants who had a cataract surgery indication at baseline, 164 (78.1%) were successfully contacted and 55 (33.5%) reported being operated on for cataract, with 51 agreeing to be re-examined. In a multiple logistic regression model, age, sex, schooling, previous cataract surgery, and PVA at baseline were not significantly associated with surgery uptake. Co-existing health conditions (20.4%), fear of surgery (12.2%) and fear of losing eyesight (11.6%) were the most frequent barriers to cataract surgery adherence. Among the 69 eyes operated on in the interval between baseline and follow-up, PVA ≥20/63 was observed in 50 (72.6%, 95% confidence interval, CI, 62.2-82.3%), PVA20/63-20/200 in 11 (15.8%, 95% CI 8.9-22.9%) and PVA20/200 in 8 (11.6%, 95% CI 5.3-17.9%).Quality of surgery is an increasing determinant of uptake rates. Although free-of-charge and expedited cataract surgery was offered, surgical outcomes might have influenced the low uptake. Aside from cataract surgery campaigns, improvement of surgeon skills, accurate biometry, treatment of ocular comorbidities, postoperative follow-up and eye-care education are needed.

Purpose To assess the outcomes of cataract surgery in rural northwest India. Design Population-based, cross-sectional study. Participants A total of 549 cataract-operated persons (723 operated eyes). Methods Cluster sampling was used in randomly selecting a cross-sectional sample of persons 50 years of age or older for visual acuity measurement, refraction, and slit-lamp and direct ophthalmoscope examination early in 1999. Those operated on for cataract were queried as to the date and place of surgery. The principal cause of reduced vision was identified for all examined eyes with presenting visual acuity worse than 6/18. Main outcome measures Presenting and best-corrected visual acuity and cause of vision loss. Results Presenting visual acuity was less than 6/60 in the better eye in 33.7% of cataract-operated persons and greater than or equal to 6/18 in both eyes in 8.2%; 31.7% were bilaterally operated on. Of cataract-operated eyes, 44.1% initially had visual acuity less than 6/60 and 31.5% greater than or equal to 6/18; with best correction, the corresponding percentages were 14.0% and 61.5%. Intracapsular cataract extraction was used in 92% of cases, and 66% had been operated on in surgery camps. Surgical complications were common and a major cause of vision impairment. In multiple logistic regression modeling, female gender and residence in a rural area were associated negatively with both presenting and best-corrected visual acuity outcomes, and surgery conducted before 1990 was associated negatively with best-corrected visual acuity. Place of surgery and subject schooling were not associated with vision outcomes. Conclusions Cataract surgery subjects in rural areas of India that are without adequately equipped facilities and skilled surgeons, and lack of availability of intraocular lenses, are not realizing the full sight-restoring potential of modern-day surgery. Emphasis on the quality of cataract surgery outcomes must be increased to keep pace with that being given to increasing surgical volume.

PURPOSE: To assess the prevalence of refractive errors and vision impairment in school-age children in a suburban area (La Florida) of Santiago, Chile. METHODS: Random selection of geographically defined clusters was used to identify a representative sample of children 5 to 15 years of age. Children in the 26 selected clusters were enumerated through a door-to-door survey and invited to report to a community health clinic for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and examination of the external eye, anterior segment, media, and fundus were done from April through August 1998. Independent replicate examinations of all children with reduced vision and a sample of those with normal vision were done for quality assurance monitoring in six clusters. RESULTS: A total of 6,998 children from 3,830 households were enumerated, and 5,303 children (75.8%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.50 (20/40) or worse in at least one eye was 15.8%, 14.7%, and 7.4%, respectively; 3.3% had best visual acuity 0.50 or worse in both eyes. Refractive error was the cause in 56.3% of the 1,285 eyes with reduced vision, amblyopia in 6.5%, other causes in 4.3%, with unexplained causes in the remaining 32.9%. Myopia −0.50 diopter or less in either eye was present in 3.4% of 5-year-old children, increasing to 19.4% in males and 14.7% in females by age 15. Over this same age range, hyperopia 2.00 diopters or greater decreased from 22.7% to 7.1% in males and from 26.3% to 8.9% in females. Females had a significantly higher risk of hyperopia than males. CONCLUSIONS: Refractive error, associated primarily with myopia, is a major cause of reduced vision in school-age children in La Florida. More than 7% of children could benefit from the provision of proper spectacles. Efforts are needed to make existing programs that provide free spectacles for school children more effective. Further studies are needed to determine whether the upward trend in myopia continues far beyond 15 years of age.

PURPOSE: To assess the prevalence of refractive error and vision impairment in school age children in the terai area of the Mechi zone in Eastern Nepal. METHODS: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Children in the 25 selected clusters were enumerated through a door-to-door household survey and invited to village sites for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and anterior segment, media, and fundus examinations were done from May 1998 through July 1998. Independent replicate examinations for quality assurance monitoring took place in all children with reduced vision and in a sample of those with normal vision in seven villages. RESULTS: A total of 5,526 children from 3,724 households were enumerated, and 5,067 children (91.7%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.5 (20/40) or worse in at least one eye was 2.9%, 2.8%, and 1.4%, respectively; 0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause in 56% of the 200 eyes with reduced uncorrected vision, amblyopia in 9%, other causes in 19%, with unexplained causes in the remaining 16%. Myopia −0.5 diopter or less in either eye or hyperopia 2 diopters or greater was observed in less than 3% of children. Hyperopia risk was associated with female gender and myopia risk with older age. CONCLUSIONS: The prevalence of reduced vision is very low in school-age children in Nepal, most of it because of correctable refractive error. Further studies are needed to determine whether the prevalence of myopia will be higher for more recent birth cohorts.

PURPOSE: To assess the prevalence of refractive errors and vision impairment in school-age children in Shunyi District, northeast of Beijing, the Peoples Republic of China. METHODS: Random selection of village-based clusters was used to identify a sample of children 5 to 15 years of age. Resident registration books were used to enumerate eligible children in the selected villages and identify their current school. Ophthalmic examinations were conducted in 132 schools on children from 29 clusters during May 1988 to July 1998, including visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and examination of the external eye, anterior segment, media, and fundus. Independent replicate measurements of all children with reduced vision and a sample of those with normal vision were done for quality assurance monitoring in three schools. RESULTS: A total of 6,134 children from 4,338 households were enumerated, and 5,884 children (95.9%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.5 (20/40) or worse in at least one eye was 12.8%, 10.9%, and 1.8%, respectively; 0.4% had best visual acuity 0.5 or worse in both eyes. Refractive error was the cause in 89.5% of the 1,236 eyes with reduced vision, amblyopia in 5%, other causes in 1.5%, with unexplained causes in the remaining 4%. Myopia −0.5 diopter or less in either eye was essentially absent in 5-year-old children, but increased to 36.7% in males and 55.0% in females by age 15. Over this same age range, hyperopia 2 diopters or greater decreased from 8.8% in males and 19.6% in females to less than 2% in both. Females had a significantly higher risk of both myopia and hyperopia. CONCLUSIONS: Reduced vision because of myopia is an important public health problem in school-age children in Shunyi District. More than 9% of children could benefit from prescription glasses. Further studies are needed to determine whether the upward trend in the prevalence of myopia continues far beyond age 15 and whether the development of myopia is changing for more recent birth cohorts.

PURPOSE. To quantify and compare the reduction in quality of life due to visual impairment and angina using patient preferences (utilities). METHODS. Using a standard time tradeoff method, we obtained utilities for current vision, monocular and binocular blindness, current angina, and moderate angina in 60 patients with both vision problems and angina pectoris who sought care at the National Eye Institute (NEI), National Naval Medical Center, or Barnes-Jewish Hospital. Patients were characterized clinically based on visual acuity and the Duke Activity Status Index (DASI). Patients also completed a seven-item version of the NEI Visual Functioning Questionnaire and the SF-36 Health Survey Questionnaire. RESULTS. Patients had a median visual acuity of 20/100 in the worst eye, 20/40 in the better eye, and a median DASI of 24.2 (0 = severe functional limitations due to anginal symptoms, 58.2 = no limitations). There was substantial variation in utilities among patients. The average utility for current vision (...

PURPOSE: To estimate the prevalence of blindness and cataract surgery among older adults in rural China. METHODS: Cluster sampling was used in randomly selecting men and women aged 50 years or older for visual acuity testing and an eye examination in 28 villages in Shunyi County. The survey, which was carried out in the fall of 1996, was preceded by a pilot study in which operational methods were refined and quality assurance evaluations carried out. RESULTS: Of 5,555 enumerated subjects ≥50 years of age, 91.5% (5,084/5,555) were examined and 90.9% (5,052/5,555) were tested for visual acuity. In this population, 2.8% (139/5,052) were blind, defined as presenting visual acuity less than 6/60 in both eyes. Blindness was associated with older age and female sex. Cataract was the principal cause of blindness in at least one eye in 48.2% (67/139) of blind people. The ratio of those blind from cataract who were operated on to the those who could have been operated on, cataract surgical coverage, was estimated to be 47.8% (54/113). Cataract surgery was associated with younger age but not sex or education. CONCLUSIONS: Blindness, particularly blindness related to cataract, continues to be a significant problem among the elderly, especially women, in this population-based sample of rural Chinese. Despite an active eye-care program in Shunyi County, only half of those who might benefit from cataract surgery are receiving it.

PURPOSE: To measure visual acuity and vision-related quality of life in individuals in rural China operated on for cataract. METHODS: Five thousand fifty-two persons age 50 years and older, 90.9% (5,052/5,555) of a randomly selected population in Shunyi County, were examined in the fall of 1996. Visual functioning and quality of life questionnaires were administered to those with presenting visual acuity less than 6/60 in either eye and to those who were aphakic or pseudophakic. RESULTS: Of the 87 individuals operated on for cataract, 12% (10/87) had presenting visual acuity of 6/18 or more in both eyes, and 24.1% (21/87) had less than 6/60. Twenty-five percent (29/116) of the 116 eyes operated on for cataract had presenting visual acuity of 6/18 or more, and 44.8% (52/116) had less than 6/60. Aphakic cases without glasses and uncorrectable aphakia attributable to surgical complications were common. In a multivariate regression model, including time period of surgery, hospital type, and surgical procedure, only pseudophakia was associated with better outcomes ( P = .05). On a scale from 0 (maximum problems) to 100 (no problems), the mean visual functioning score (±SD) for the operated-on population was 61.9 ± 30.0, and 71.0 ± 31.8 for the quality of life questionnaire. These scores were comparable to those of the unoperated-on population with moderate bilateral blindness ( CONCLUSIONS: Both clinical and patient-reported cataract surgery outcomes are below what should be achievable. Improvement in outcomes must be given greater emphasis if the potential of cataract surgery in restoring sight is to be realized.

BACKGROUND—Visual acuity and vision related quality of life outcomes in cataract surgery were evaluated in a population based survey in two geographic zones in Nepal. METHODS—Case finding was based on random sampling using a stratified cluster design with door to door enumeration of people aged ⩾45 years followed by eye examinations at village sites. All aphakics/pseudophakics, those with visual acuity less than 6/60 in either eye, and a sample of those with normal visual acuity were administered visual functioning (VF) and quality of life (QOL) questionnaires. RESULTS—15% of the 159 cataract operated cases had presenting visual acuity ⩾6/18 in both eyes, 38% with best corrected visual acuity. 21% were still blind with presenting visual acuity

Purpose: To compare the effects of extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/PC-IOL) vs intracapsular cataract extraction with aphakic glasses (ICCEAG) on everyday visual functioning and quality of life. Methods: In a nonmasked randomized controlled clinical trial, 3,400 bilateral vision-impaired patients, aged 40 to 75 years, with operable cataract were randomly assigned to receive one of the two treatment options. One half in each group were randomly selected for interviewer administration of visual functioning and quality of life questionnaires before surgery and at 6 and 12 months after surgery. Results: Both ICCE-AG and ECCE/PC-IOL produced dramatic improvements in visual functioning and quality of life scores. Patients receiving ECCE/PC-IOL reported larger beneficial changes than did those receiving ICCE-AG, compatible with additional beneficial effects of a moderate magnitude for visual functioning and of a smaller beneficial magnitude for quality of life. All between-group differences were highly statistically significant ( P Conclusions: In this developing-country setting, ICCE-AG and ECCE/PC-IOL were associated with substantial benefits in improved everyday vision function and vision-related quality of life. Patients who received ECCE/PC-IOL reported greater benefits and fewer problems with vision than did patients who received ICCE-AG.

Purpose: To evaluate the safety and efficacy of extracapsular cataract extraction with posterior chamber intraocular lens (ECCE/PC-IOL) compared with intracapsular cataract extraction with aphakic glasses (ICCE-AG). Methods: In a nonmasked randomized controlled clinical trial, 3,400 bilaterally visionimpaired patients aged 40 to 75 years with operable cataract were randomly assigned to receive either ICCE-AG or ECCE/PC-IOL at the Aravind Eye Hospital in India. The surgery was performed by one of four study surgeons. Patients were hospitalized for 5 postoperative days, with followup visits at 2, 6, and 12 months after discharge. Postsurgery evaluations were conducted by two independent study ophthalmologists. Results: At any single postoperative follow-up time point, there were no statistically significant differences of clinical relevance between treatment groups for any complication of a serious nature except cystoid macular edema, which was more common with ICCE (4.2% vs 1.6%). In general, whether of a trivial, intermediate, or serious nature, complication rates were low at each evaluation time point. Cumulatively, the incidence of serious complications of all types throughout the 1-year study period was 14.5% for patients in the ICCE-AG group and 7.7% in the ECCE group ( P ). Best-corrected visual acuity of 20/40 or better at 12 months was attained by 90.7% of ICCE-AG patients and 96.3% of ECCE/PC-IOL patients ( P ). Conclusions: Although both operative procedures are safe and effective for cataract patients with bilateral impairment, ECCE/PC-IOL is superior to ICCE-AG in terms of both visual acuity restoration and safety.

Purpose: To determine the use of eye care services by type of provider (ophthalmologist, optometrist, and non-ophthalmologist physician) in the Medicare population. Methods: As a basis for characterizing eye conditions and ophthalmic services among a population 65 years of age and older, 1991 claims from a representative 5% sample of Medicare beneficiaries were analyzed using a previously described classification scheme. Analysis was specifically conducted by type of provider as well as by the service provided. Results: Almost one half of the approximately 30 million Medicare beneficiaries 65 years of age or older received eye care services in 1991, resulting in more than 35,000,000 visits (claims). Ophthalmologists provided services to 71 % of this eye care population, and optometrists to 22%; 36% of this population received ophthalmic-related services from other providers, and 14% from only other providers (commonly for eye lid dermatitis and tumors). Cataract was the most common condition, accounting for 41 of visits to ophthalmologists (and 1.2 million cases of surgery), glaucoma accounted for 19% of visits, and retinal diseases for 14%. The visit percentages for optometrists are 58%, 8%, and 11 %, respectively. Ophthalmic examination and evaluation accounted for 63% of the 28,000,000 paid ophthalmologists' procedures, and 58% of the 5,500,000 optometrists' procedures. Conclusion: Optometrists and physicians other than ophthalmologists were the sole providers of ophthalmic-related services to a large percentage of beneficiaries who received eye care in 1991. Within the universe of service provided by ophthalmologists, the majority of all care consisted of evaluation and management services as opposed to surgical procedure-based care.

Pharmacokinetic models have been developed to assist in extrapolating results from rodent bioassays. However, in numerous circumstances, it is necessary to combine such models with cellular response models to fully define interspecies and dose extrapolations. Interactions between pharmacokinetic target tissue end points (DNA adduct formation) and cellular proliferation in liver and urinary bladder carcinogenesis is illustrated with the results from the ED01 study involving 2-acetylaminofluorene administered to female mice. The interaction of genotoxic and cell proliferative effects are also illustrated in a co-carcinogenesis study with low doses of N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide and high doses of sodium saccharin. The application of such interactions to humans is illustrated for the case of cigarette smoke-induced bladder cancer.

Introduction: Presbyopia is an important cause of avoidable visual disability. Objective: To estimate the prevalence of near vision impairment and spectacle coverage among middle and older-aged adults in rural Nepal. Materials and methods: The surveys was carried out among the people of age 35 and over in randomly-selected cluster samples in rural settings of Kaski district of western Nepal, Near visual acuity, with and without presenting near correction, was measured at 40 cm using a LogMAR near vision tumbling E chart under ambient indoor lighting. Subjects with uncorrected binocular distance vision of 20/40 or worse were refracted and those with near vision of 20/40 or worse tested with plus sphere to obtain the best-corrected binocular near visual acuity. Results: A total of 2,360 persons aged 35 years and over were enumerated and 2,156 (91.3 %) were examined. The age- and gender-standardized prevalence of uncorrected near visual impairment (vision of 20/40 or worse) in study population was found to be 66.1 %. Near vision could not be corrected (>20/40) even after distance and near vision correction in 6.4 % . Using the multiple logistic regression models, uncorrected visual impairment was associated with an older age (odds ratio [OR] = 1.13, P < 0.001) and a lower educational level (OR = 1.11, P = 0.01) was less associated with female gender (OR = 0.72, P = 0.038). Over 90 % of people with near visual impairment did not have spectacles. Conclusion: The prevalence of presbyopia appears to be higher with an earlier onset and over 90 % of people in need of near correction do not have spectacles in this setting. DOI: http://dx.doi.org/10.3126/nepjoph.v4i1.5845 NEPJOPH 2012; 4(1): 17-22

Objective To compare outcomes between adjustable spectacles and conventional methods for refraction in young people. Design Cross sectional study. Setting Rural southern China. Participants 648 young people aged 12-18 (mean 14.9 (SD 0.98)), with uncorrected visual acuity ≤6/12 in either eye. Interventions All participants underwent self refraction without cycloplegia (paralysis of near focusing ability with topical eye drops), automated refraction without cycloplegia, and subjective refraction by an ophthalmologist with cycloplegia. Main outcome measures Uncorrected and corrected vision, improvement of vision (lines on a chart), and refractive error. Results Among the participants, 59% (384) were girls, 44% (288) wore spectacles, and 61% (393/648) had 2.00 dioptres or more of myopia in the right eye. All completed self refraction. The proportion with visual acuity ≥6/7.5 in the better eye was 5.2% (95% confidence interval 3.6% to 6.9%) for uncorrected vision, 30.2% (25.7% to 34.8%) for currently worn spectacles, 96.9% (95.5% to 98.3%) for self refraction, 98.4% (97.4% to 99.5%) for automated refraction, and 99.1% (98.3% to 99.9%) for subjective refraction (P=0.033 for self refraction v automated refraction, P=0.001 for self refraction v subjective refraction). Improvements over uncorrected vision in the better eye with self refraction and subjective refraction were within one line on the eye chart in 98% of participants. In logistic regression models, failure to achieve maximum recorded visual acuity of 6/7.5 in right eyes with self refraction was associated with greater absolute value of myopia/hyperopia (P

A mathematical model simulating lymphomagenesis based on the two-hit theory of carcinogenesis is presented by contrasting the biologic variables responsible for a high risk of developing Burkitt lymphoma (BL) in three immunosuppressed groups with that of nonendemic BL. In this model, the pro-B lymphocyte is considered to be the target for BL-specific translocations such as t(8;14). With repeated mitosis, the target cell pool expands in the high-risk individual, and, thereby, the opportunities for a spontaneous translocation to arise are increased. The chromosomal translocation endows the target cell with survival advantages, and, hence, lymphoma develops. Modeling results demonstrate that this increased cell proliferation is sufficient in accounting entirely for the increase in tumor prevalence. Preventing enhanced cellular proliferation by obviating immune deficiency and treating patients with agents that restore immunity or have antiviral and antiproliferative properties prior to conversion from polyclonal B-cell proliferation to monoclonal malignancy could obviate the development of BL.

To determine the natural end-point for refractive development during childhood.Cycloplegic (1% cyclopentolate) autorefraction was performed on 38, 811 children aged 5 and 15 in population-based samples at eight sites in the Refractive Error Study in Children (RESC). Refractions (right eye) were categorized as myopic (≤-0.5 D), emmetropic (-0.5 to ≤+0.5 D), mildly hyperopic (+0.5 to ≤+2.0 D and hyperopic (+2.0 D).At five sites (Jhapa - rural Nepal, New Delhi - urban India, Mahabubnagar - rural India, Durban - semi-urban South Africa and La Florida - urban Chile), there was20% myopia by age 15. Mild hyperopia was the most prevalent category at all ages, except for Mahabubnagar where emmetropia became the marginally most prevalent category at ages 14 and 15. At the other sites (Gombak - semi-urban Malaysia, Shunyi - semi-rural China and Guangzhou - urban China), there was substantial (35%) myopia by age 15. At these sites, mild hyperopia was the most prevalent category during early childhood, and myopia became the predominant category later. In Gombak district and Guangzhou, emmetropia was a minor category at all ages, with myopia increasing as mild hyperopia decreased. In Shunyi district, emmetropia was the most prevalent category over the ages 11-14.Emmetropia was not the predominant outcome for refractive development in children. Instead, populations were predominantly mildly hyperopic or substantial amounts of myopia appeared in them. This suggests that mild hyperopia is the natural state of refractive development in children and that emmetropia during childhood carries the risk of subsequent progression to myopia.

Purpose To investigate the population-based prevalence of keratoconus in US individuals aged 65 years and older. Design Multiyear retrospective cross-sectional claims analysis. Methods Fee-for-service claims from a 5% national sample of Medicare beneficiaries aged 65 years and older were reviewed. Claims records were queried on an annual basis for the years 1999 through 2003 for ICD-9 codes specific to keratoconus. The number of beneficiaries with keratoconus-related claims was counted for each calendar year. Results The number of beneficiaries receiving care for keratoconus rose steadily from 15.7/100,000 beneficiaries in 1999 to 18.5/100,000 in 2003, averaging 17.5/100,000 across the 5 years of the study. Keratoconus rates declined with increasing age but did not differ by gender. Keratoconus care was more prevalent in whites than in other races. Conclusions Keratoconus is an uncommon disease in the Medicare population. Longitudinal analysis of Medicare claims data may provide a useful tool for monitoring uncommon diseases, such as keratoconus, in the elderly.

The cost and effectiveness of eight approaches to reducing barriers to cataract surgery were evaluated in a rural area of South India during 1987-1989. The approaches were based on four intervention alternatives--aphakic motivator (AM), basic eye health worker (BW), screening van (SV), and mass media (MM). Each intervention was offered at two levels of economic incentive: partial, which provides free surgery and hospital stay, and full, which also provides transport from the recipient's village to the hospital and free food during the hospital stay. Evaluations took place in a probability selection of 90 villages, including ten control villages not subjected to either of the interventions. Only costs unique to patients from the intervention villages were considered: Health education and screening costs were included, surgery costs were not. Percentage reductions in the cataract blind backlog and increases in surgical coverage were used as effectiveness measures. Analyses suggest that the SV and AM interventions, both with full economic incentive, offer the greatest advantage. The AM intervention is the more effective of the two, but also the more costly.

Purpose Assess prevalence and causes of vision impairment among low-middle income school children in Sao Paulo. Methods Cluster sampling was used to obtain a random sample of children ages 11 to 14 years from public schools (grades 5-8) in three districts from June to November 2005. The examination included visual acuity testing, ocular motility, and examination of the external eye, anterior segment, and media. Cycloplegic refraction and fundus examination were performed in children with uncorrected visual acuity 20/40 or worse in either eye. A principal cause of visual impairment was determined for eyes with uncorrected visual acuity of 20/40 or worse. Results A total of 2825 children were enumerated and 2441 (86.4%) were examined. The prevalence of uncorrected, presenting, and best-corrected visual acuity 20/40 or worse in the better eye was 4.82%, 2.67%, and 0.41%, respectively. Spectacles were used by 144 (5.9%) children. Refractive error was a cause in 76.8% of children with visual impairment in one or both eyes; amblyopia, 11.4%; retinal disorders, 5.9%; other causes, 2.7%; and unexplained causes, 7.7%. Myopic visual impairment (spherical equivalent -0.50 D in one or both eyes) was not associated with age or grade level, but female sex was marginally significant (P = 0.070). Hyperopic visual impairment (+2.00 D or more) was not associated with age, grade level, or sex. Conclusions The prevalence of reduced vision in low-middle income urban Sao Paulo school children was low, most of it because of uncorrected refractive error. Cost-effective strategies are needed to address this easily treated cause of vision impairment.

To describe the prevalence of refractive error in the United States.The 1999-2004 National Health and Nutrition Examination Survey (NHANES) used an autorefractor to obtain refractive error data on a nationally representative sample of the US noninstitutionalized, civilian population 12 years and older. Using data from the eye with a greater absolute spherical equivalent (SphEq) value, we defined clinically important refractive error as follows: hyperopia, SphEq value of 3.0 diopters (D) or greater; myopia, SphEq value of -1.0 D or less; and astigmatism, cylinder of 1.0 D or greater in either eye.Of 14,213 participants 20 years or older who completed the NHANES, refractive error data were obtained for 12,010 (84.5%). The age-standardized prevalences of hyperopia, myopia, and astigmatism were 3.6% (95% confidence interval [CI], 3.2%-4.0%), 33.1% (95% CI, 31.5%-34.7%), and 36.2% (95% CI, 34.9%-37.5%), respectively. Myopia was more prevalent in women (39.9%) than in men (32.6%) (P.001) among 20- to 39-year-old participants. Persons 60 years or older were less likely to have myopia and more likely to have hyperopia and/or astigmatism than younger persons. Myopia was more common in non-Hispanic whites (35.2%) than in non-Hispanic blacks (28.6%) or Mexican Americans (25.1%) (P.001 for both).Estimates based on the 1999-2004 NHANES vision examination data indicate that clinically important refractive error affects half of the US population 20 years or older.

Investigate prevalence and causes of vision impairment/blindness in older adults in a low-middle income area of Sao Paulo, Brazil.Cluster sampling, based on geographically defined census sectors, was used in randomly selecting cross-sectionally persons 50 years of age or older. Subjects were enumerated through a door-to-door survey and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity less than 20/32.A total of 4,224 eligible persons in 2,870 households were enumerated, and 3,678 (87.1%) examined. The prevalence of presenting visual acuityor = 20/32 in both eyes was 61.6% (95% confidence interval [CI]: 59.4%-63.9%), and 80.4% (95% CI: 78.8%-82.1%) with best correction. The prevalence of visual impairment (20/63 toor =20/200) in the better eye was 4.74% (95% CI: 3.97%-5.53%), and 2.00% (95% CI: 1.52%-2.49%) with best correction. The prevalence of presenting bilateral blindness (20/200) was 1.51% (95% CI: 1.20%-1.82%), and 1.07% (95% CI: 0.79%-1.35%) with best correction. Presenting blindness was associated with older age and lack of schooling. Retinal disorders (35.3%) and cataract (28.3%) were the most common causes of blind eyes. Cataract (33.2%), refractive error (32.3%), and retinal disorders (20.3%) were the main causes of vision impairment20/63 toor = 20/200, with refractive error (76.8%) and cataract (12.2%) as main causes for eyes with acuity20/32 toor = 20/63.Vision impairment is a significant problem in older Brazilians reinforcing the need to implement prevention of blindness programs for elderly people with emphasis on those without schooling.

The conceptual role of the physician in delivery of health care services/patient care is likely to undergo significant change in the coming years as the nature of our society and economy changes. The continued aging of the baby boomers, projected shifts in ethnic and racial makeup of the working-age population, exponential health care costs increases, along with changes in financing of health care, intervening health care regulatory bodies, and improved access to health information, will collectively continue to drive health care consumerism. Evolving markets in health care create new opportunities and challenges in providing higher quality, lower-cost care that better meets patient needs and expectations. Although much attention has been given to the process of “disruptive innovation” as a key ingredient in the transitioning of the health care to furnish an affordable higher quality product, little discussion has centered on the assumptions and expectations underlying the role of the physician in delivering these services. To appreciate better what these roles might be in a comparatively open-market model of healthcare, we must more thoroughly understand the “product” or “service” that physicians are offering for “purchase” by prospective patients who assume the role of ultimate “consumers.” The drivers of this need are at least twofold. First, the expansion of competitive markets into more health care specialties (especially those with more lucrative payment for providers) means that providers must now consider the way in which their patients evaluate the service received. Second, a greater appreciation of the need for patients to use medications and follow-up care for chronic diseases (“adherence”) will increase the pressure to motivate all involved to do better, especially if providers might one day be held accountable for such behavior patterns. Currently, in health care, patients equate customer service with overall perceived quality of their health care experience. Although quality of health care services has gained tremendous interest in recent years, it has generally been evaluated by 2 separate and independent groups of stakeholders. First, governmental and nonprofit agencies (e.g., Centers for Medicare and Medicaid Services, Institute of Medicine, Agency for Healthcare Research and Quality, and Joint Commission on Accreditation of Healthcare) have focused on safety and compliance with standardized practice guidelines as quality indicators of healthcare services. Second, payors have concentrated on patient satisfaction and expectations as a measure or means of promoting quality of health care services. Thus, patient perceptions and satisfaction with valued components of health care are quality indicators from the payor and ultimately the

PURPOSE: Data on the prevalence and causes of functional low vision (FLV) in adults and children are lacking but are important for planning low-vision services. This study was conducted to determine the prevalence and causes of FLV among children recruited in eight population-based prevalence surveys of visual impairment and refractive error from six countries (India [2 locations]; China [2 locations]; Malaysia, Chile, Nepal, and South Africa). METHODS: Using the same protocol, 4082 to 6527 children aged 5 (or 7) to 15 years were examined at each site. Uncorrected and presenting visual acuities were successfully measured with retroilluminated logMAR tumbling-E charts in 3997 to 5949 children; cycloplegic autorefraction was performed and best corrected acuities assessed. All children were examined by an ophthalmologist and a cause of visual loss assigned to eyes with uncorrected acuity < or =6/12. The prevalence of FLV was determined overall and by site; associations with gender, age, parental education and urban/rural location were assessed with logistic regression. RESULTS: The prevalence of FLV ranged from 0.65 to 2.75 in 1000 children, with wide confidence intervals. The overall prevalence was 1.52 in 1000 children (95% CI 1.16-1.95). FLV was significantly associated with age (odds ratio [OR] 1.13 for each year, P = 0.01), and parental education was protective (OR 0.75 for each of five levels of education, P = 0.017). Retinal lesions and amblyopia were the commonest causes. CONCLUSIONS: More studies are needed to determine the prevalence and causes of FLV in children so that services can be planned that promote independence, improve quality of life, and increase access to education.

The screening of asymptomatic high-risk populations has been evaluated using a biologically based model of bladder cancer. The model is built upon a mathematical representation of the induction of precursor bladder lesions with possible progression through clinical disease states. Screening strategies are based on regimens that include voided urine cytology. Diagnostic and therapeutic components of the model provide the basis for end results evaluation. Cytology screening is projected to increase average life expectancy by 1 to 3 years among those diagnosed while reducing deaths from bladder cancer by more than 50%. The additional contribution to be realized with a screening test of perfect sensitivity would be primarily in the increased identification of dysplasia and low-grade superficial papillary neoplasms, lesions that are much less life-threatening than the high-grade lesions already detectable by cytology. The theoretical potential of screening is not realizable because of diagnostic inaccuracies and treatment failures.

The development of tumors in relationship to 2-acetylaminofluorene (AAF) dose and time on study has been evaluated in an experiment conducted by the National Center for Toxicological Research (NCTR) using more than 24,000 female BALB/c mice. By using a biologically based model of two-event carcinogenesis accounting explicitly for both genotoxic and nongenotoxic proliferative effects at the cellular level, we provide a unifying explanation for the apparently disparate dose-response results observed in the urinary bladder and liver. Experimental observations of dose-related DNA adduct levels in both tissues and hyperplasia in the bladder were utilized in estimation of model parameters. Analyses demonstrate that tumor prevalence in the liver can be explained entirely by the influence of AAF on the first of two genetic events and in the bladder by the synergy between AAF genotoxicity affecting both genetic events and cellular proliferation at higher doses. These results are consistent across the entire ED01 data set.