Prevalence and predictors of undercorrected refractive errors in the Victorian population

Prevalence and Risk Factors of Refractive Errors and Effective Spectacle Coverage in Emiratis and Non-Emiratis Aged 40 Years or Older: the Dubai Eye Health Survey

PURPOSE

The aim was to investigate the prevalence and risk factors of refractive errors (REs) and the effective spectacle coverage in Emiratis and non-Emiratis in Dubai.

DESIGN

The Dubai Eye Health Survey was a population-based cross-sectional study of participants aged 40 years or older.

METHODS

Distance and near visual acuity (VA), and noncycloplegic automated refraction were tested according to a standardized protocol. Distance VA was tested using the Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart at 3 m and near VA was measured using the near vision logMAR chart at 40 cm under ambient lighting. Myopia was defined as spherical equivalent of refraction of less than -0.50 diopters (D), and hypermetropia as spherical equivalent of more than +0.50 D. Astigmatism was defined as cylinder power of 0.5 D or greater. Effective spectacle coverage for distance vision was computed as met need/(met need+unmet need+under-met need)×100%. Multivariable logistic regression models were used to examine associations between sociodemographic factors and RE.

RESULTS

The authors included 892 participants (446 Emiratis and 446 non-Emiratis) in the analysis. The prevalence of hypermetropia was 20.4% [95% confidence interval (CI): 16.8%-24.4%] in Emiratis and 20.6% (95% CI: 20.0%-24.7%) in non-Emiratis. The prevalence of myopia and high myopia was 27.4% (95% CI: 23.3%-31.7%) and 1.8% (95% CI: 0.8%-3.5%) in Emiratis, and 19.5% (95% CI: 15.9%-23.5%) and 0.9% (95% CI: 0.2%-2.3%) in non-Emiratis, respectively. High education (P=0.02) and not currently working (P=0.002) were risk factors of myopia in non-Emiratis only. The prevalence of astigmatism was 7.4% (95% CI: 5.1%-10.2%) in Emiratis and 1.6% (95% CI: 0.6%-3.2%) in non-Emiratis. This prevalence was higher in individuals aged over 60 years (P<0.001) and men (P=0.014) among Emiratis. The prevalence of anisometropia and uncorrected presbyopia was 11.4% (95% CI: 8.6%-14.8%) and 0.7% (95% CI: 0.1%-2.0%) in Emiratis, and 9.2% (95% CI: 6.7%-12.3%) and 0.4% (95% CI: 0.05%-1.6%) in non-Emiratis, respectively. The effective spectacle coverage was 62.3% (95% CI: 54.0%-70.6%) and 69% (95% CI: 60.5%-77.5%) in Emiratis and non-Emiratis, respectively.

CONCLUSIONS

A high proportion of Emiratis and non-Emiratis was affected by RE without optimal effective spectacle coverage, highlighting the imperativeness of intervention to alleviate the burden. The findings may help facilitate evidence-based policymaking concerning the delivery of eye care services and allocation of medical resources in Dubai.

When do contrast sensitivity deficits (or enhancements) depend on spatial frequency? Two ways to avoid spurious interactions

Studies across a broad range of disciplines-from psychiatry to cognitive science to behavioural neuroscience-have reported on whether the magnitude of contrast sensitivity alterations in one group or condition varies with spatial frequency. Significant interactions have often gone unexplained or have been used to argue for impairments in specific processing streams. Here, we show that interactions with spatial frequency may need to be re-evaluated if the inherent skew/heteroscedasticity was not taken into account or if visual acuity could plausibly differ across groups or conditions. By re-analysing a publicly available data set, we show that-when using raw contrast sensitivity data-schizophrenia patients exhibit an apparent contrast sensitivity impairment that lessens with spatial frequency, but that when using log-transformed data or when using generalized estimating equations, this interaction reversed. The reversed interaction, but not the overall contrast sensitivity deficit, disappeared when groups were matched on visual acuity. An analysis of the contrast threshold data yielded similar results. A caveat is that matching groups on acuity is probably only defensible if acuity differences arise from non-neural factors such as optical blur. Taken together, these analyses reconcile seemingly discrepant findings in the literature and demonstrate that reporting contrast sensitivity interactions with spatial frequency requires properly accounting for visual acuity and skew/heteroscedasticity.

Vision Impairment and On-Road Driving

Good vision is important for safe driving. The impact of vision impairment associated with common eye diseases on driving performance, and the association between vision measures and driving performance, are discussed. Studies include those where participants drove a real vehicle on a closed road or on public roads. Closed-road studies include evaluation of both simulated and true vision impairment and day- and night-time driving. Collectively, the findings provide important insights into the impact of refractive conditions, cataracts, glaucoma, age-related macular degeneration, and hemianopic field loss on driving; however, study results show varying impacts on driving performance and are often limited by small sample sizes. Vision measures including motion sensitivity, contrast sensitivity, and useful field of view have stronger associations with driving performance than do visual acuity or visual fields, with studies suggesting that some drivers with field loss can compensate for their field defects through increased eye and head movements.

The prevalence of uncorrected refractive error in Japan: the Locomotive Syndrome and Health Outcome in Aizu Cohort Study

PURPOSE

Uncorrected refractive error (URE) is the leading cause of vision impairment and the second leading cause of blindness. It is a major public health challenge worldwide. However, the current status of URE in Japan is unclear.

STUDY DESIGN

Cross-sectional study.

METHODS

In 2012, a population-based cross-sectional study was conducted among community dwellers aged 40 years and older who received health check-ups in Minamiaizu and Tadami, Fukushima Prefecture, Japan. URE was considered when the presenting visual acuity in the better-seeing eye was < 0.5 and when visual acuity improved more than 1 line with refractive correction in the better-seeing eye. We estimated the age-specific prevalence of URE, and calculated the p-value for trend to examine the linear pattern of the association of the prevalence of URE and age.

RESULTS

This analysis included 2952 participants. The mean age (standard deviation [SD]) of the study population was 69.10(9.67) years and 57.79% were women. The overall prevalence of URE was 10.90% (95% CI, 9.77-12.05%). Prevalence by age category was 5.00% (95% CI, 2.03-10.03%), 6.09% (95% CI, 3.59-9.58%), 7.02% (95% CI, 5.49-8.81%), 11.96% (95% CI, 10.15-13.97%), and 22.39% (95% CI, 18.41-26.78%) for 40-49 years, 50-59 years, 60-69 years, 70-79 years, and 80 years or older, respectively (p-for trend, < 0.001).

CONCLUSIONS

The prevalence of URE was 10.9% and exceeded 20%, especially in individuals older than 80 years. Given the correlation between increasing incidence of URE and increase in age, public health intervention to promote awareness of URE is important, especially for the older population.

Prevalence of Uncorrected Refractive Error and Its Risk Factors; Tehran Geriatric Eye Study (TGES)

Purpose: To determine the age-sex-standardized prevalence of uncorrected refractive error and its determinantsMethods: This population-based cross-sectional study was conducted on 3310 people aged≥ 60 years in Tehran, Iran in 2019. Need for spectacles was defined as uncorrected visual acuity worse than 20/40 in better eye that could be corrected to more than 20/40 with suitable spectacles. Met need was defined as proportion of individuals with need for spectacles whose visual acuity was 20/40 or better with current spectacles. Unmet need was defined as proportion of individuals with need for spectacles who needed but did not have spectacles or their visual acuity was worse than 20/40 with current spectacles while suitable spectacles improved their visual acuity to 20/40 or better.Results: The age-sex-standardized prevalence of need for spectacles, met need, and unmet need was 16.67% (95% CI: 15.33-18.09), 7.81% (95% CI: 6.95-8.78), and 8.85% (95% CI: 7.77-10.07), respectively. Myopic subjects had the highest prevalence of need for spectacles (24.06%, 95% CI: 21.47-26.87). The odds ratio of met and unmet need in subjects≥ 80 years versus those aged 60-65 years was 0.36 (p-value: 0.009) and 2.34 (p-value: <0.001), respectively. The odds ratio of met and unmet need in subjects with a university education versus illiterate subjects was 1.72 (p-value: 0.045) and 0.42 (p-value: 0.007), respectively.Conclusion: The prevalence of uncorrected refractive error was lower in this study compared to previous studies. The met need rate was lower in subjects with older age and lower education levels.

Frequency and source of prescription eyewear insurance coverage in Ontario: a repeated population-based cross-sectional study using survey data

BACKGROUND

Insurance coverage may reduce cost barriers to obtain vision correction. Our aim was to determine the frequency and source of prescription eyewear insurance to understand how Canadians finance optical correction.

METHODS

We conducted a repeated population-based cross-sectional study using 2003, 2005 and 2013-2014 Canadian Community Health Survey data from respondents aged 12 years or older from Ontario, Canada. In this group, the cost of prescription eyewear is not covered by the government unless one is registered with a social assistance program or belongs to a specific population. We determined the frequency and source of insurance coverage for prescription eyewear in proportions. We used survey weights provided by Statistics Canada in all analyses to account for sample selection, a complex survey, and adjustments for seasonal effect, poststratification, nonresponse and calibration. We compared unadjusted proportions and adjusted prevalence ratios (PRs) of having insurance.

RESULTS

Insurance covered all or part of the costs of prescription eyewear for 62% of Ontarians in all 3 survey years. Of those insured, 84.1%-86.0% had employer-sponsored coverage, 9.0%-10.3% had government-sponsored coverage, and 5.7%-6.8% had private plans. Employer-sponsored coverage remained constant for those in households with postsecondary graduation but decreased significantly for those in households with less than secondary school graduation, from 67.0% (95% confidence interval [CI] 63.2%-70.8%) (n = 175 000) in 2005 to 54.6% (95% CI 50.1%-59.2%) (n = 123 500) in 2013-2014. Government-sponsored coverage increased significantly for those in households with less than secondary school graduation, from 29.2% (95% CI 25.5%-32.9%) (n = 76 400) in 2005 to 41.7% (95% CI 37.2%-46.1%) (n = 93 900) in 2013-2014. In 2013-2014, Ontarians in households with less than secondary school graduation were less likely than those with secondary school graduation to report employer-sponsored coverage (adjusted PR 0.79, 95% CI 0.75-0.84) but were more likely to have government-sponsored coverage (adjusted PR 1.27, 95% CI 1.06-1.53).

INTERPRETATION

Sixty-two percent of Ontarians had prescription eyewear insurance in 2003, 2005 and 2013-2014; the largest source of insurance was employers, primarily covering those with higher education levels, whereas government-sponsored insurance increased significantly among those with lower education levels. Further research is needed to elucidate barriers to obtaining prescription eyewear and the degree to which affordability impairs access to vision correction.

Prevalence and determinants of uncorrected refractive error among a socially vulnerable older adult population living in Armenia

OBJECTIVE

This study estimated the prevalence of uncorrected refractive error (URE) and its determinants in a socially vulnerable older population living in Armenia.

STUDY DESIGN

The study design used in the stidy is a cross-sectional study.

METHODS

A total of 485 people responded to a survey on sociodemographic characteristics, spectacle use, and ophthalmic services' use. All participants underwent a comprehensive ophthalmic examination including assessment of presenting and best-corrected visual acuity, measuring intraocular pressure and dilated eye fundus examination. Patients who had presenting visual acuity (<6/12) but improved ≥ one line with/without available spectacles after refraction in the better eye were considered to have URE. Descriptive statistics described the sample and estimated the prevalence of the URE in the population. Logistic regression models were used to evaluate its determinants.

RESULTS

The mean age of participants was 74.5 (7.27) years, ranging from 51 to 94 years. Women constituted the majority of participants (86%). The prevalence of URE in the better eye was 26%. In bivariate analysis, those who were older and who had less than 10 years of education had higher odds of URE than younger and more educated respondents. In multivariable analysis, only education remained associated with URE (OR = 3.71; 95% CI: 1.10-12.5). The rate of normal vision (≥6/12) improved from 58.9% to 81.5%, whereas the rate of visual impairment (<6/12) decreased from 41.1% to 18.5% after best correction in the better eye.

CONCLUSION

The prevalence of URE was high in this study population. The findings warrant the need for eye screening and provision of affordable spectacle correction to the target population in Armenia.

Prevalence and Associated Factors of Uncorrected Refractive Error in Older Adults in a Population-Based Study in France

Importance

Uncorrected refractive error (URE) is a common cause of visual impairment, but its prevalence in groups of older adults who could be pragmatic targets for improving optical correction remains unknown.

Objectives

To estimate the prevalence of URE in older adults, particularly in those with age-related eye disease and those who are unable to attend an outpatient clinic, and to identify the factors associated with URE.

Design, Setting, and Participants

This population-based cross-sectional analysis included 707 adults 78 years or older from the Alienor Study in Bordeaux, France. Data were collected from February 12, 2011, through December 21, 2012, and analyzed from November 1, 2017, through July 7, 2018.

Main Outcomes and Measures

Uncorrected refractive error was defined as the presenting distance visual acuity in the better-seeing eye improved by at least 5 letters on the Early Treatment Diabetic Retinopathy Study chart (≥1 line on the logMAR chart) using the best-achieved optical correction. Multivariate logistic regressions were used to determine the factors associated with URE.

Results

The study population of 707 adults 78 years or older (64.8% women; mean [SD] age, 84.3 [4.4] years) had a prevalence of URE of 38.8% (95% CI, 35.2%-42.5%). Prevalence was high for participants with eye disease (range, 35.0% [95% CI, 28.4%-42.0%] to 44.1% [95% CI, 27.2%-62.1%], depending on the disease) and those without eye disease (30.1%; 95% CI, 24.0%-36.7%). Prevalence was higher in participants who were examined at home (because they could not come to the clinic) than in those examined at the clinic (49.4% [95% CI, 42.8%-55.9%] vs 33.5% [95% CI, 29.2%-37.9%]; P < .001). Having an eye examination performed at home (odds ratio [OR], 1.64; 95% CI, 1.13-2.37), living alone (OR, 0.65; 95% CI, 0.47-0.90), and having the perceptions that the ophthalmologist consultation fees are too expensive (OR, 1.94; 95% CI, 1.12-3.36) and that declining visual acuity is normal with aging (OR, 1.47; 95% CI, 1.04-2.08) were all associated with URE.

Conclusions and Relevance

These study results show that the prevalence of URE was high in this population and suggest that preventive strategies aimed at enhancing optical correction could be directed to all older adults and to specific groups by implementing at-home eye examinations for those who have difficulties attending an outpatient clinic and by focusing on those with eye disease who probably already have a regular ophthalmologic follow-up. More studies are needed to evaluate prevalence of URE in different populations and countries with various eye care systems.

Prevalence, associations and characteristics of severe uncorrected refractive error in the Australian National Eye Health Survey

IMPORTANCE

In Australia, nationally representative data of the burden and associations of severe uncorrected refractive error are scarce.

BACKGROUND

To report the prevalence and characteristics of severe uncorrected refractive error in Indigenous and non-Indigenous Australians.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

A total of 3098 non-Indigenous Australians aged 50 to 98 and 1738 Indigenous Australians aged 40 to 92 living in 30 randomly selected Australian sites were examined.

METHODS

Severe uncorrected refractive error was defined as an improvement of ≥2 lines on the logMAR chart in one or both eyes in participants with a presenting visual acuity <6/12.

MAIN OUTCOME MEASURE

Severe uncorrected refractive error RESULTS: Prevalence of severe uncorrected refractive error was 11.0% (95% confidence interval 9.3-13.0) in non-Indigenous and 14.5% (12.5-16.7) in Indigenous Australians. Eighty-two percent of non-Indigenous and 77% of Indigenous participants had a spherical equivalent refraction between -2.00D and +2.00D. Indigenous Australians who were older (odds ratio [OR] for 70-79 years vs 40-49 years = 3.59), resided in outer regional areas (OR = 1.78) and did not have an eye examination in the previous 2-years (OR = 1.50) were associated with higher odds of severe uncorrected refractive error. Geographical remoteness (OR = .68 for inner regional), male gender (OR = 1.30), older age (OR for 70-79 years vs 50-59 years = 1.51) and failure to have an eye examination in the previous 2-years (OR = 2.06) were associated with severe uncorrected refractive error among non-Indigenous participants.

CONCLUSIONS AND RELEVANCE

Increased public awareness of the importance of regular optometric examinations may be required in groups at high risk of severe uncorrected refractive error.

Effects of Light Scatter and Blur on Low-Contrast Vision and Disk Halo Size

PURPOSE

To investigate the individual effects of forward light scatter (FLS) and refractive blur on low-contrast vision and the size of the disk halo produced in response to an external glare source.

METHODS

Monocular disk halo radius, high- and low-contrast distance visual acuity (HCVA, LCVA), and contrast sensitivity (CS) were determined in 25 eyes of 25 healthy subjects under normal, FLS, and blur conditions. FLS was induced using the filter Black ProMist 2 to simulate an early cataract. Blur was induced using a +1.00 diopter lens to simulate an uncorrected refractive error.

RESULTS

Similar significant mean increases in halo radius were observed for the FLS (0.32 ± 0.10 log arc min; P < .0001) and refractive blur (0.40 ± 0.18 log arc min; P < .0001). Under induced blur, 3 lines of HCVA (0.32 ± 0.15 logMAR; P < .0001) and 4 lines of LCVA (0.39 ± 0.16 logMAR; P < .0001) were lost. FLS had a minimal (but significant) effect on HCVA, but worsened mean LCVA by more than 1 line (0.13 ± 0.10 logMAR; P < .0001). Similar significant mean CS reductions of 0.17 ± 0.12 (P < .0001) and 0.14 ± 0.12 log units (P < .0001) were produced in response to FLS and refractive blur, respectively (approximately 1 triplet).

CONCLUSIONS

Forward light scatter and refractive blur contributed to an increased size of the disk halo produced by a glare source in similar proportion. Although defocus blur has a substantial effect on LCVA, a loss of more than 1 line of LCVA after best refractive correction would be indicative of FLS.

Treatment coverage rates for refractive error in the National Eye Health survey

OBJECTIVE

To present treatment coverage rates and risk factors associated with uncorrected refractive error in Australia.

METHODS

Thirty population clusters were randomly selected from all geographic remoteness strata in Australia to provide samples of 1738 Indigenous Australians aged 40 years and older and 3098 non-Indigenous Australians aged 50 years and older. Presenting visual acuity was measured and those with vision loss (worse than 6/12) underwent pinhole testing and hand-held auto-refraction. Participants whose corrected visual acuity improved to be 6/12 or better were assigned as having uncorrected refractive error as the main cause of vision loss. The treatment coverage rates of refractive error were calculated (proportion of participants with refractive error that had distance correction and presenting visual acuity better than 6/12), and risk factor analysis for refractive correction was performed.

RESULTS

The refractive error treatment coverage rate in Indigenous Australians of 82.2% (95% CI 78.6-85.3) was significantly lower than in non-Indigenous Australians (93.5%, 92.0-94.8) (Odds ratio [OR] 0.51, 0.35-0.75). In Indigenous participants, remoteness (OR 0.41, 0.19-0.89 and OR 0.55, 0.35-0.85 in Outer Regional and Very Remote areas, respectively), having never undergone an eye examination (OR 0.08, 0.02-0.43) and having consulted a health worker other than an optometrist or ophthalmologist (OR 0.30, 0.11-0.84) were risk factors for low coverage. On the other hand, speaking English was a protective factor (OR 2.72, 1.13-6.45) for treatment of refractive error. Compared to non-Indigenous Australians who had an eye examination within one year, participants who had not undergone an eye examination within the past five years (OR 0.08, 0.03-0.21) or had never been examined (OR 0.05, 0.10-0.23) had lower coverage.

CONCLUSION

Interventions that increase integrated optometry services in regional and remote Indigenous communities may improve the treatment coverage rate of refractive error. Increasing refractive error treatment coverage rates in both Indigenous and non-Indigenous Australians through at least five-yearly eye examinations and the provision of affordable spectacles will significantly reduce the national burden of vision loss in Australia.

Effect of defocus on response time in different age groups: A pilot study

PURPOSE

To assess the response time associated with visual performance (VP) tasks in the presence of defocus in different presbyopic populations.

METHODS

58 eyes between the ages of 35 and 50 years were studied. Subjects were categorized as pre-presbyopic (35-39 years), early-presbyopic (40-45 years), and mid-presbyopic (46-50 years). VP measurements obtained monocularly included distance and near high contrast (HC) and low contrast (LC) optotype recognition, and contrast threshold at 12cpd for different defocus magnitudes between 0D and 3D in 1D steps. Response time defined as the time taken to recognize and verbalize an optotype, was compared among different presbyopic age groups.

RESULTS

From 58 eyes, mean (SD) response time for high contrast distance visual acuity for 0D through 3D ranged between 1.48 (0.23) and 1.87 (0.31)s, whereas low contrast distance visual acuity ranged between 1.5 (0.22) and 2.09 (0.49)s. Mean response time for high contrast near visual acuity for 0D through 3D ranged between 1.56 (0.19) and 2.23 (0.45)s. However, for low contrast near visual acuity it ranged between 1.75 (0.32) and 2.71 (0.94)s. Mean (SD) response time for 12cpd ranged between 2.11 (0.50) and 5.72 (1.09)s. ANOVA revealed a significant difference in response time for distance, near visual acuity and contrast sensitivity as a function of defocus for different age groups.

CONCLUSIONS

Response time is increased in the presence of increasing defocus for both distance and near visual acuity and could impact on performance for critical tasks. Full correction of visual acuity at distance and near in presbyopes is warranted always.

Uncorrected refractive errors, presbyopia and spectacle coverage in Kamuli District, Uganda

Background: Successful refractive error programmes arise from evidence that can be collected cost effectively and timely.Aim: To investigate the prevalence of uncorrected refractive error (URE), presbyopia and spectacle coverage in the Kamuli district, Uganda.Setting: The study was conducted in the Kamuli district in Uganda.Methods: The Rapid Assessment of Refractive Error (RARE) study design is a communitybased cross-sectional study using multistage cluster random sampling to gather information on refractive errors and presbyopia. Subjects aged 15 years and older were selected from the population in Kamuli district in Uganda. Vision impairment due to URE at distance and near and barriers to uptake of refractive error services were investigated.Results: Participants, N = 3281 (57.6% male), with an age range of 15–92 years were enumerated and the response rate was 100%. The prevalence of refractive errors was 4.6% (95% confidence interval [CI]: 3.7 – 5.5) and the spectacle coverage was 5.96% (95% CI 1.74% – 10.18%). The prevalence of uncorrected presbyopia was 50.3% (95% CI 47.6% – 53.0%) and the spectacle coverage was 0%. Thirty-three (or 1%) respondents were current spectacle users. One-hundred fourteen people (3.5%) had previously used spectacles; however, 50.9% of them discontinued spectacle use a year before the study because the spectacles were broken or scratched. The major barriers to spectacle uptake were accessibility of services and affordability of spectacles.Conclusion: The prevalence of URE and the barriers to uptake of refractive services will inform the implementation of refractive services in the study area. Key words: Uncorrected refractive errors; presbyopia and spectacle coverage

Population-based assessment of sensitivity and specificity of a pinhole for detection of significant refractive errors in the community

BACKGROUND

Measurements of refractive errors through subjective or automated refraction are not always possible in rapid assessment studies and community vision screening programs; however, measurements of vision with habitual correction and with a pinhole can easily be made. Although improvements in vision with a pinhole are assumed to mean that a refractive error is present, no studies have investigated the magnitude of improvement in vision with pinhole that is predictive of refractive error. The aim was to measure the sensitivity and specificity of 'vision improvement with pinhole' in predicting the presence of refractive error in a community setting.

METHODS

Vision and vision with pinhole were measured using a logMAR chart for 488 of 582 individuals aged 15 to 50 years. Refractive errors were measured using non-cycloplegic autorefraction and subjective refraction. The presence of refractive error was defined using spherical equivalent refraction (SER) at two levels: SER greater than ± 0.50 D sphere (DS) and SER greater than ±1.00 DS. Three definitions for significant improvement in vision with a pinhole were used: 1. Presenting vision less than 6/12 and improving to 6/12 or better, 2. Improvement in vision of more than one logMAR line and 3. Improvement in vision of more than two logMAR lines.

RESULTS

For refractive error defined as spherical equivalent refraction greater than ± 0.50 DS, the sensitivities and specificities for the pinhole test predicting the presence of refractive error were 83.9 per cent (95% CI: 74.5 to 90.9) and 98.8 per cent (95% CI: 97.1 to 99.6), respectively for definition 1. Definition 2 had a sensitivity 89.7 per cent (95% CI: 81.3 to 95.2) and specificity 88.0 per cent (95% CI: 4.4 to 91.0). Definition 3 had a sensitivity of 75.9 per cent (95% CI: 65.5 to 84.4) and specificity of 97.8 per cent (95% CI: 95.8 to 99.0). Similar results were found with spherical equivalent refraction greater than ±1.00 DS, when tested against the three pinhole-based definitions.

CONCLUSION

Refractive error definitions based on improvement in vision with the pinhole shows good sensitivity and specificity at predicting the presence of significant refractive errors. These definitions can be used in rapid assessment surveys and community-based vision screenings.

Age-related eye diseases and visual impairment among U.S. adults

BACKGROUND

Visual impairment is a common health-related disability in the U.S. The association between clinical measurements of age-related eye diseases and visual impairment in data from a national survey has not been reported.

PURPOSE

To examine common eye conditions and other correlates associated with visual impairment in the U.S.

METHODS

Data from the 2005-2008 National Health and Nutrition Examination Survey of 5222 Americans aged ≥40 years were analyzed in 2012 for visual impairment (presenting distance visual acuity worse than 20/40 in the better-seeing eye), and visual impairment not due to refractive error (distance visual acuity worse than 20/40 after refraction). Diabetic retinopathy (DR) and age-related macular degeneration (AMD) were assessed from retinal fundus images; glaucoma was assessed from two successive frequency-doubling tests and a cup-to-disc ratio measurement.

RESULTS

Prevalence of visual impairment and of visual impairment not due to refractive error was 7.5% (95% CI=6.9%, 8.1%) and 2.0% (1.7%, 2.3%), respectively. The prevalence of visual impairment not due to refractive error was significantly higher among people with AMD (2.2%) compared to those without AMD (0.8%), or with DR (3.5%) compared to those without DR (1.2%). Independent predictive factors of visual impairment not due to refractive error were AMD (OR=4.52, 95% CI=2.50, 8.17); increasing age (OR=1.09 per year, 95% CI=1.06, 1.13); and less than a high school education (OR=2.99, 95% CI=1.18, 7.55).

CONCLUSIONS

Visual impairment is a public health problem in the U.S. Visual impairment in two thirds of adults could be eliminated with refractive correction. Screening of the older population may identify adults at increased risk of visual impairment due to eye diseases.

Visual impairment and spectacle coverage rate in Baoshan district, China: population-based study

Background

To investigate the prevalence and risk factors of visual impairment associated with refractive error and the unmet need for spectacles in a special suburban senior population in Baoshan District of Shanghai, one of several rural areas undergoing a transition from rural to urban area, where data of visual impairment are limited.

Methods

The study was a population based survey of 4545 Chinese aged (age: >60 years or older ) at Baoshan, Shanghai, in 2009. One copy of questionnaire was completed for each subject. Examinations included a standardized refraction and measurement of presenting and best corrected visual acuity (BCVA) as well as tonometry, slit lamp biomicroscopy, and fundus photography.

Results

The prevalence of mild (6/12 to 6/18), moderate (6/18 to 6/60) and severe visual impairment was 12.59%, 8.38% and 0.44%, respectively, and 5.26%, 3.06% and 0.09% with refractive correction. Visual impairment was associated with age, gender, education and career, but not insurance . The prevalence of correctable visual impairment was 5.81% (using 6/18 cutoff) and 13.18% (using 6/12 cutoff). Senior people and women were significantly at a higher risk of correctable visual impairment, while the well-educated on the contrary. The prevalence of undercorrected refractive error (improves by 2 or more lines with refraction) was 24.84%, and the proportion with undercorrected refractive error for mild, moderate , severe and no visual impairment was 61.54%, 67.98%, 60.00% and 14.10%, respectively. The spectacle coverage rate was 44.12%. Greater unmet need for spectacles was observed among elderly people, females, non-peasant, and subjects with less education and astigmatism only.

Conclusions

High prevalence of visual impairment, visual impairment alleviated by refractive correction, and low spectacle coverage existed among the senior population in Baoshan District of Shanghai. Education for the public of the importance of regular examination and appropriate and accessible refraction service might be helpful to solve the problem.

Uncorrected refractive error in older British adults: the EPIC-Norfolk Eye Study

AIM

To investigate the prevalence of, and demographic associations with, uncorrected refractive error (URE) in an older British population.

METHODS

Data from 4428 participants, aged 48-89 years, who attended an eye examination in the third health check of the European Prospective Investigation into Cancer-Norfolk study and had also undergone an ophthalmic examination were assessed. URE was defined as ≥1 line improvement of visual acuity with pinhole-correction in the better eye in participants with LogMar presenting visual acuity (PVA) <0.3 (PVA <6/12). Refractive error was measured using an autorefractor without cycloplegia. Myopia was defined as spherical equivalent ≤-0.5 dioptre, and hypermetropia ≥0.5 dioptre.

RESULTS

Adjusted to the 2010 midyear British population, the prevalence of URE in this Norfolk population was 1.9% (95% CI 0.6% to 3.1%). Lower self-rated distance vision was correlated with higher prevalence of URE (p(trend)<0.001). In a multivariate logistic regression model adjusting for age, gender, retirement status, educational level and social class, independent significant associations with URE were increasing age (p(trend)<0.001) and having hypermetropic or myopic refractive error. Wearing distance spectacles was inversely associated with URE (OR 0.34, 95% CI 0.21 to 0.55, p<0.001). There were 3063 people (69.2%) who wore spectacles/contact lenses for distance vision. Spectacle wear differed according to type of refractive error (p<0.001), and use rose with increasing severity of refractive error (p(trend)<0.001).

CONCLUSION

Although refractive error is common, the prevalence of URE was found to be low in this population reflecting a low prevalence of PVA<0.3.

Frequency, course, and impact of correctable visual impairment (uncorrected refractive error)

Uncorrected refractive error has been identified by the World Health Organization (WHO) as one of the priorities for Vision 2020 and a frequent cause of visual impairment. In the past, only the terms presenting visual impairment (PVI) and visual impairment after best refractive correction (BCVI) were used, so that PVI also included BCVI cases. In the more recent literature, visual impairment has been subdivided into two mutually exclusive entities: that which is correctable by refraction (which we now term correctable visual impairment, CVI) and that which cannot be corrected by refraction due to ocular or neurological disease (which we now term non-correctable visual impairment, NCVI, and which is identical to BCVI). PVI remains a useful concept as it includes both types of impairment. Although CVI is reported to be the major form of visual impairment worldwide, its impacts are not yet well understood. CVI has a higher prevalence among vulnerable groups such as older people, less well educated people and those living alone or in rural areas. Systematic data on barriers to refractive correction remain scant, but these may be present at the individual level, within the health service context, or at a social level. Our review indicates that research on CVI is at a relatively early stage and that more detailed research, particularly determining whether it has impacts on independent living and quality of life, is needed before CVI can be justifiably prioritized in health policy.

Habitual vs optimal distance visual acuity

PURPOSE

The maintenance of a good level of vision is desirable for developmental and social reasons; it is also a requirement that should not be overlooked in the clinical research environment. This study set out to quantify and analyse any difference between 'habitual' (pre-sight test) and 'optimal' (post-refraction) distance visual acuity in an optometric population. It is intended that the outcome of this work will inform not only clinicians but also those undertaking vision research.

METHODS

Binocular logMAR visual acuity was determined at 6 m before and after optometric intervention in patients attending optometric practice for a routine sight test. Cases were recorded seriatim but restricted to the 'core' refraction range representative of typical optometric practice; three further exemption criteria included subject illiteracy, the necessity for a non-standard test distance and contact lens wear. Over a 12-month period, two-thirds of patients examined satisfied the study inclusion criteria; it is the clinical data of these 1288 individuals that are described and analysed here.

RESULTS

These data provide a quantitative demonstration that an optometric intervention will most likely improve the habitual distance visual acuity of subjects, irrespective of gender, age group, time interval since last test, refractive status and whether or not the subject is a habitual spectacle wearer. The improvement found was typically within one logMAR chart line (<5 letters), being greatest in spectacle-wearing teenagers and in individuals beyond retirement age (increasing to eight letters in elderly habitual non-spectacle wearers); also in non-wearers who left an interval of 2 years or more between sight tests.

CONCLUSIONS

Clinical and laboratory-based investigators are advised that a current and optimal refractive correction should be worn by subjects of all ages enrolled in vision-related studies. Refractive defocus may introduce or exaggerate test outcome variability.

The prevalence and risk indicators of uncorrected refractive error and unmet refractive need in Latinos: the Los AngelesLatino Eye Study

PURPOSE

To determine the age- and sex-specific prevalence and risk indicators of uncorrected refractive error and unmet refractive need among a population-based sample of Latino adults.

METHODS

Self-identified Latinos 40 years of age and older (n = 6129) from six census tracts in La Puente, California, underwent a complete ophthalmic examination, and a home-administered questionnaire provided self-reported data on potential risk indicators. Uncorrected refractive error was defined as a >or=2-line improvement with refraction in the better seeing eye. Unmet refractive need was defined as having <20/40 visual acuity in the better seeing eye and achieving >or=20/40 after refraction (definition 1) or having <20/40 visual acuity in the better seeing eye and achieving a >or=2-line improvement with refraction (definition 2). Sex- and age-specific prevalence and significant risk indicators for uncorrected refractive error and unmet refractive need were calculated.

RESULTS

The overall prevalence of uncorrected refractive error was 15.1% (n = 926). The overall prevalence of unmet refractive need was 8.9% (n = 213, definition 1) and 9.6% (n = 218, definition 2). The prevalence of uncorrected refractive error and either definition of unmet refractive need increased with age (P < 0.0001). No sex-related difference was present. Older age, <12 years of education, and lack of health insurance were significant independent risk indicators for uncorrected refractive error and unmet refractive need.

CONCLUSIONS

The data suggest that the prevalence of uncorrected refractive error and unmet refractive need is high in Latinos of primarily Mexican ancestry. Better education and access to care in older Latinos are likely to decrease the burden of uncorrected refractive error in Latinos.

Age-specific changes in the prevalence and management of optically correctable visual impairment between 1988 and 2000: the Ponza Eye Study

PURPOSE

To obtain age-specific data on changes in the prevalence and management of optically correctable visual impairments (OCVIs) in Ponza, Italy.

METHODS

Ophthalmologic examinations were carried out to 1000 Ponzans aged 40-87 years in 1988 and to 836 persons in 2000. Visual acuity (VA) was evaluated under uncorrected (VA(UC)), presenting (VA(PR)), and best-corrected (VA(BC)) conditions. We calculated the prevalence of total OCVIs (subjects with VA(UC)>0.5 logMAR and VA(BC)<or=0.5 logMAR in the better eye), uncorrected OCVIs (VA(PR)>0.5 logMAR), and corrected OCVIs (VA(PR)<or=0.5 logMAR) as well as the OCVI correction rate ((corrected OCVI/total OCVI) x 100). Subjects with uncorrected OCVIs were compared to those with corrected OCVIs to evaluate possible associations with some risk factors.

RESULTS

Among 52- to 63-year olds there were increases in the prevalence of total OCVI (from 15.7 to 22.7%, P=0.051), corrected OCVI (from 10.9 to 19.9%, P=0.005), and OCVI correction rate (from 69.2 to 87.8%, P=0.045). Among 64- to 75-year olds decreases were observed in the prevalence of total OCVI (from 28.5 to 20.0%, P=0.029) and uncorrected OCVI (from 12.6 to 4.8%, P=0.003) while the OCVI correction rate increased from 55.9 to 76.1% (P=0.033). The overall prevalence of uncorrected OCVIs dropped from 7.5 to 4.1%. In 2000, uncorrected OCVI was associated with limited education, very advanced age, retirement, and refractive error associated with eye diseases.

CONCLUSIONS

Refractive error management has improved in Ponza since 1988, and these changes may be, in part, due to higher education levels, increased frequency of cataract surgery, and slower progression of cataract-related disability.

Vision screening of older people

A recent systematic review found that between 20% and 50% of older people in the UK have undetected reduced vision and in most cases this is caused by refractive error or cataracts, and is correctable. Two approaches to improve the detection of these problems are to better publicise optometric services and to carry out community-based vision screening of older people. Screening programmes should pass the Wilson criteria and a consideration of these highlights three inter-related questions: 'Is vision screening effective at detecting correctable low vision in older people?'; 'Which tests should be included?' and 'Which venues are most appropriate?' We carried out a systematic review to investigate these questions. For the first question, only one study was found which met our selection criteria. The 'gold standard' eye examination in this study lacked several important components, and the vision screening method that was used was not found to be very effective. The review revealed other studies, which, although not meeting our selection criteria, included relevant information. The screening studies highlight the lack of agreement on the content of a gold standard eye examination and of the test(s) that should be used to screen vision. Visual function in older people is not adequately described by high contrast visual acuity (VA), nor by self-reports of visual difficulties. Other tests that may be relevant include visual field testing, low contrast VA, contrast sensitivity and stereo-acuity. The pinhole test has often been used in attempts to detect uncorrected refractive errors, but results from this test can be problematic and possible reasons for this are discussed. Appropriate venues for vision screening are contingent upon the format of the vision screening programme. There is still uncertainty over the battery of vision tests that are most appropriate. This, and optimum venues for screening, require further research before it can be fully determined whether vision screening of older people meets the Wilson criteria. If a vision screening programme using a battery of vision tests, perhaps computerised, can be established, then this should be tested to determine the sensitivity and specificity for detecting the target conditions. Ultimately, longitudinal studies are necessary to determine whether such a screening programme will lead to improved visual performance and quality of life in older people.

Uncorrected refractive errors and spectacle utilisation rate in Tehran: the unmet need

AIM

To determine the prevalence of the met and unmet need for spectacles and their associated factors in the population of Tehran.

METHODS

6497 Tehran citizens were enrolled through random cluster sampling and were invited to a clinic for an interview and ophthalmic examination. 4354 (70.3%) participated in the survey, and refraction measurement results of 4353 people aged 5 years and over are presented. The unmet need for spectacles was defined as the proportion of people who did not use spectacles despite a correctable visual acuity of worse than 20/40 in the better eye.

RESULTS

The need for spectacles in the studied population, standardised for age and sex, was 14.1% (95% confidence interval (CI), 12.8% to 15.4%). This need was met with appropriate spectacles in 416 people (9.3% of the total sample), while it was unmet in 230 people, representing 4.8% of the total sample population (95% CI, 4.1% to 5.4%). The spectacle coverage rate (met need/(met need + unmet need)) was 66.0%. Multivariate logistic regression showed that variables of age, education, and type of refractive error were associated with lack of spectacle correction. There was an increase in the unmet need with older age, lesser education, and myopia.

CONCLUSION

This survey determined the met and unmet need for spectacles in a Tehran population. It also identified high risk groups with uncorrected refractive errors to guide intervention programmes for the society. While the study showed the unmet need for spectacles and its determinants, more extensive studies towards the causes of unmet need are recommended.

What is the global burden of visual impairment?

BACKGROUND

A recent estimate by the World Health Organization (WHO) suggests that 161 million persons worldwide have visual impairment, including 37 million blind (best-corrected visual acuity less than 3/60 in the better eye) and 124 million with visual impairment less severe than blindness (best-corrected acuity less than 6/18 to 3/60 in the better eye). This estimate is quoted widely, but because it is based on definitions using best-corrected visual acuity, uncorrected refractive error as a cause of visual impairment is excluded.

METHODS

We reviewed data from population-based surveys of visual impairment worldwide published 1996 onwards that included presenting visual acuity, and estimated the proportion of visual impairment caused by uncorrected refractive error in different sub-regions of the world. We then extrapolated these data to estimate the worldwide burden of visual impairment including that caused by uncorrected refractive error.

RESULTS

The total number of persons with visual impairment worldwide, including that due to uncorrected refractive error, was estimated as 259 million, 61% higher than the commonly quoted WHO estimate. This includes 42 million persons with blindness defined as presenting visual acuity less than 3/60 in the better eye, and 217 million persons with less severe visual impairment level defined as presenting visual acuity less than 6/18 to 3/60 in the better eye, 14% and 75% higher, respectively, than the WHO estimates based on best-corrected visual acuity. Sensitivity analysis, taking into account the uncertainty of the proportion of visual impairment caused by refractive error, revealed that the number of persons in the world with visual impairment due to uncorrected refractive error could range from 82 to 117 million.

CONCLUSION

The actual burden of visual impairment worldwide, including that caused by uncorrected refractive error, is substantially higher than the commonly quoted WHO estimate that is based on best-corrected visual acuity. We suggest that the indicative estimate of 259 million persons with visual impairment worldwide, which includes 42 million blind with visual acuity less than 3/60 in the better eye, be used for further planning of the VISION 2020 initiative instead of the often quoted 161 million estimate that includes 37 million blind.

Uncorrected refractive error in Singapore teenagers

AIM

To study the prevalence rate of uncorrected refractive error and associated risk factors among Singapore schoolchildren aged 12-16 years (grade 7).

METHODS

A cross sectional study of 628 participants (participation rate 99.8%) was conducted in two schools. An interviewer led questionnaire asking about sociodemographic variables and risk factors was administered. Refractive errors were measured using a table mounted autorefractor. Participants with habitual visual acuity (VA) of 0.2 logMAR or worse underwent subjective refraction. Uncorrected refractive error was defined as improvement of at least 0.2 logMAR in best corrected visual acuity after subjective refraction.

RESULTS

The prevalence rate of uncorrected refractive error was 22.3% (95% confidence interval (CI) 19.0% to 25.5%). The multivariate adjusted odds ratio of uncorrected refractive error in students with the lowest academic ability was 2.24 (95% CI 1.34 to 3.73). Increasing time interval since the last visit to an eye care provider increased the risk of uncorrected refractive error (trend p = 0.001).

CONCLUSION

Uncorrected refractive error was a significant problem among Singapore students aged 12-16 years (grade 7). Uncorrected refractive error was more common among students with low academic ability or those who had not visited an eye care provider for a long time.

Frequency of under-corrected refractive errors in elderly Chinese in Beijing

PURPOSE

The aim of the study was to evaluate the prevalence of under-corrected refractive error among elderly Chinese in the Beijing area.

METHODS

The population-based, cross-sectional, cohort study comprised 4,439 subjects out of 5,324 subjects asked to participate (response rate 83.4%) with an age of 40+ years. It was divided into a rural part [1,973 (44.4%) subjects] and an urban part [2,466 (55.6%) subjects]. Habitual and best-corrected visual acuity was measured. Under-corrected refractive error was defined as an improvement in visual acuity of the better eye of at least two lines with best possible refractive correction.

RESULTS

The rate of under-corrected refractive error was 19.4% (95% confidence interval, 18.2, 20.6). In a multiple regression analysis, prevalence and size of under-corrected refractive error in the better eye was significantly associated with lower level of education (P<0.001), female gender (P<0.001), and age (P=0.001).

CONCLUSIONS

Under-correction of refractive error is relatively common among elderly Chinese in the Beijing area when compared with data from other populations.

Vision and falls

Falls occur in about one third of older people living independently in the community every year. This can lead to significant physical, psychological and financial costs to the individual and the community. While the risk factors for falls in older people are multifactorial, poor vision is considered to be an important contributing factor. The aim of this review is to evaluate current research linking impaired visual function with falls and to review current intervention strategies for the prevention of falls in older individuals. The evidence from the current literature indicates that impairment of visual functions, such as visual acuity, contrast sensitivity, visual fields and depth perception, is associated with an increased risk of falls. Recent studies have also demonstrated that falls can be reduced following cataract surgery as a visual intervention. Optometrists need to be aware of these associations and through appropriate treatment, referral and/or education, they can play a major role in optimising visual function in older people, as part of a multidisciplinary approach to falls prevention.

Gender differences in the utilisation of optometric services in Victoria

Medicare and population data demonstrate clear gender differences in utilisation of health services. There are three broad hypotheses that may explain different utilisation rates of health services by gender: differences in access, differences in incidence and differences in attitudes in seeking health care between the genders. Men are 28 per cent less likely than women to see an optometrist in Victoria. Both women's and men's utilisation of optometric services in Victoria increase with age but there are clear gender differences apparent at every stage of life after childhood. These utilisation rates between genders are tested against incidence rates between genders for eye conditions. There are few noted gender differences apparent in the incidence or prevalence of ocular conditions. The data on the incidence of health conditions often has limitations, either in measurement tools or in differences in incidence between genders. These limitations are not as evident in eye care incidence data. Access and incidence differences do not adequately explain the differences in optometric service utilisation rates. This promotes the hypothesis that attitudinal differences in seeking health care between men and women are significant.

Undercorrected refractive error in Singaporean Chinese adults: the Tanjong Pagar survey

OBJECTIVE

To study the prevalence of undercorrected refractive error and associated sociodemographic factors among Singaporean Chinese adults.

DESIGN

Cross-sectional, population-based survey.

PARTICIPANTS

Singaporean Chinese adults aged 40 to 79 years (n = 1152).

METHODS

The Singapore electoral register of Tanjong Pagar was used as a sampling frame, and disproportionate, stratified, clustered, random sampling was performed. There were 1717 eligible adults and 1232 (71.8%) participated. Analysis was performed among 1152 adults with complete habitual and best-corrected visual acuity data.

MAIN OUTCOME MEASURE

Undercorrected refractive error was defined as improvement of better eye visual acuity of at least 2 lines or more with best possible refractive correction.

RESULTS

The age- and gender-adjusted rate of undercorrected refractive error standardized directly by age and gender was 17.3% (95% confidence interval, 15.0, 19.5). Undercorrected refractive error rates were more common in older adults who had completed fewer years of education and in those who had cataract. People who did not wear spectacles tended to have poorer vision.

CONCLUSIONS

The undercorrected refractive error rate among Singaporean Chinese is relatively common compared with data from other populations.

Correctable visual impairment in older people: a major unmet need

This review seeks to determine the prevalence of correctable visual impairment (VI) in older people in the UK, to discover what proportion of these cases are undetected, to suggest reasons for the poor detection and to make recommendations for improving the detection. To establish the context of these issues, the review will also touch on the general prevalence and causes of VI in older people in developed countries and on the impact of VI in older people. Typically, studies suggest that VI affects about 10% of people aged 65-75, and 20% of those aged 75 or older. There is a strong relationship between impaired vision in older people and both reduced quality of life and increased risk of accidents, particularly falls. The literature suggests that those with low vision are about two times more likely to have falls than fully sighted people, and the annual UK cost of treating falls directly attributable to VI is pound 128 million. The literature on the prevalence of undetected reduced vision in older people reveals that between 20 and 50% of older people have undetected reduced vision. The majority of these people have correctable visual problems (refractive errors or cataract). It is particularly startling that, in 'developed countries', between 7 and 34% of older people have VI that could simply be cured by appropriate spectacles. The reasons why so many cases of treatable VI remain untreated are discussed, and suggestions are made for improving the detection of these cases. We conclude that there should be better publicity encouraging older people to attend for regular optometric eye examinations. A complementary approach is annual visual screening of the elderly, possibly as part of GPs annual health check on people aged 75 years and older. Recommendations are made for evaluating new approaches to screening and for improving the management of cases detected by screening.

Five-year refractive changes in an older population: the Blue Mountains Eye Study

PURPOSE

To examine 5-year changes in refractive error and astigmatism in an older population.

DESIGN

Population-based cohort study.

PARTICIPANTS

The Blue Mountains Eye Study examined 3654 residents aged 49 years or older from 1992 to 1994. After excluding 543 persons who died since baseline, 2335 (75.1%) attended 5-year examinations from 1997 to 1999.

METHODS

Both examinations included a detailed eye assessment, with subjective refraction performed according to a modified Early Treatment of Diabetic Retinopathy Study protocol.

MAIN OUTCOME MEASURES

Spherical equivalent (sum of sphere + cylinder) was used as the measure of refractive error. Only phakic eyes with best-corrected visual acuity >20/40 were included (n = 3701).

RESULTS

Similar changes in refractive error were observed for the two eyes. Symmetric changes were found in 72% of participants when the difference between eyes was within 0.5 diopters (D) and in 91% when the difference was within 1.0 D. The 5-year change in spherical power was in a hyperopic direction for younger age groups and in a myopic direction for older subjects, P < 0.0001. The gender-adjusted mean change in refractive error in right eyes of persons aged 49 to 54, 55 to 64, 65 to 74, and 75 years or older at baseline was +0.41 D, +0.30 D, +0.05 D, and -0.22D, respectively. Refractive change was strongly related to baseline nuclear cataract severity; grades 4 to 5 were associated with a myopic shift (-0.33 D, P < 0.0001). Education level and age of onset of myopia, but not gender or diabetes, also predicted refractive change. The mean age-adjusted change in refraction was +0.14 D for hyperopic eyes, +0.32 D for emmetropic eyes, and +0.15 D for myopic eyes. The mean change in cylinder power over the 5-year period was small, irrespective of baseline refraction. The axis of astigmatism remained stable in most cases (64%), whereas 12% changed to "against the rule" and 11% to "with the rule."

CONCLUSIONS

This report has documented refractive error changes in an older population and confirmed reported trends of a hyperopic shift before age 65 years and a myopic shift thereafter associated with the development of nuclear cataract.

Correctable visual impairment in an older population: the blue mountains eye study

PURPOSE

To describe temporal changes in the characteristics of older persons with visual impairment in their better eye correctable by refraction.

DESIGN

Study of two cross sections of a community 6 years apart.

METHODS

The Blue Mountains Eye Study examined 3654 persons aged 49 to 97 during 1992 to 1994 (cross-section 1) and 3509 persons (2335 cohort survivors plus 1174 persons who moved to the area and age group) during 1997 to 2000 (cross-section 2). Logarithm of minimal angle of resolution visual acuity was measured before and after refraction. Correctable visual impairment was defined as visual impairment < 20/40 in the better eye before refraction that improved after refraction to no impairment (>/= 20/40). Factors associated with correctable visual impairment and persistent correctable impairment were determined.

RESULTS

Cross-sections 1 and 2 had similar age-gender distributions. In cross-section 1, 7.5% of participants had correctable visual impairment, 3.6% had noncorrectable visual impairment, and 88.9% had no impairment. Corresponding rates in cross-section 2 were 5.6%, 2.7%, and 91.7%. In both cross sections, similar proportions (around 68%) of those visually impaired had correctable visual impairment and similar sociodemographic measures predicted correctable visual impairment. Cross-section 1 participants who were married, owned their home, had high job prestige, gained qualifications after high school, or were current drivers were less likely to have correctable visual impairment after controlling for age and gender. Adjusted odds for correctable visual impairment increased in those living alone, using community support services, dependent on others, with myopia, wearing distance glasses, or with low perceived health and heart disease. Histories of stroke, cancer, and diabetes were similar between groups with correctable and no visual impairment.

CONCLUSION

Socioeconomic parameters, myopia, wearing distance glasses, reported health problems, and poor perceived health were associated with correctable visual impairment in this older population.

Vision impairment and older drivers: who's driving?

AIM

To establish the association between impaired vision and drivers' decisions to stop driving, voluntarily restrict driving, and motor vehicle accidents.

METHODS

Driving related questions were included in a population based study that determined the prevalence and incidence of eye disease. Stratified random cluster samples based on census collector districts were selected from the Melbourne Statistical Division. Eligible participants aged 44 years and over were interviewed and underwent a comprehensive ophthalmic examination. The outcomes of interest were the decision to stop driving, limiting driving in specified conditions, and driving accidents. The associations between these outcomes and the legally prescribed visual acuity (<6/12) for a driver's licence were investigated.

RESULTS

The mean age of the 2594/3040 (85%) eligible participants was 62.5 (range 44-101). People with visual acuity less than 6/12 were no more likely to have an accident than those with better vision (chi(2) = 0.175, p>0.9). Older drivers with impaired vision, more so than younger adults, restrict their driving in visually demanding situations (p<0.05). Of the current drivers, 2.6% have vision less than that required to obtain a driver's licence. The risk of having an accident increased with distance driven (OR 2.57, CL 1.63, 4.04 for distance >31 000 km) but not with age.

CONCLUSION

There was no greater likelihood of self reported driving accidents for drivers with impaired vision than those with good vision. While many older drivers with impaired vision limit their driving in adverse conditions and some drivers with impaired vision stop driving, there are a significant number of current drivers with impaired vision.

Eye health in rural Australia

A review of the current literature relating to eye health in rural Australia was conducted. Few studies have been undertaken, with most information provided by the Australian Institute of Health and Welfare databases, The National Trachoma and Eye Health Program of 1980 and the Visual Impairment Project in Victoria in the mid 1990s. Key findings were that the rural population has an increased prevalence of pterygium, cataract, ocular trauma and glaucoma, but no difference in refractive error or diabetic retinopathy (although data are limited). Rural residents are more likely to have seen an optometrist but less likely to have seen an ophthalmologist. Interventions have been undertaken in ophthalmologist training to increase the rural workforce and tele-ophthalmology to provide city-based metropolitan ophthalmological support for rural practitioners. Further epidemiological data and evaluated interventions are urgently required to help identify and address the needs of rural Australian communities.

Factors associated with undercorrected refractive errors in an older population: the Blue Mountains Eye Study

AIMS

To identify characteristics of people with clinically relevant undercorrected refractive errors.

METHODS

The Blue Mountains Eye Study was a population based survey of 3654 Australians aged 49-97 years. Examinations included a standardised refraction and measurement of presenting and best corrected visual acuity. Clinically relevant undercorrected refractive error was defined as improvement of >/=10 letters (2+ lines on the logMAR chart) in subjects with presenting acuity 6/9 or worse. Associations with a range of demographic and ocular variables were explored, adjusting for age and sex, presented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Undercorrected refractive error was present in 814/3654 subjects (10.2%). Older age (p <0.001), hyperopia (OR 1.45, CI 1.15 to 1.83), longer interval from last eye examination (p <0.001), past occupation as tradesperson (OR 1.64, 1.13 to 3.29) or labourer (OR 2.00, CI 1.39 to 2.89), receipt of government pension (OR 1.47, CI 1.12 to 1.94), and living alone (OR 1.34, CI 1.05 to 1.72) were all associated with undercorrected refractive error. Past or current use of distance glasses (OR 0.25, CI 0.20 to 0.32) and driving (OR 0.67, CI 0.52 to 0.86) were associated with a lower prevalence.

CONCLUSIONS

Increasing age and measures of socioeconomic disadvantage and isolation were found to predict undercorrected refractive error. Given the documented impacts from correctable visual impairment, these findings suggest a need to target education and eye care services.

Fred Hollows lecture. Eye care for the community

Eye disease is a huge and largely unrecognized problem in our community, especially in the elderly. The Visual Impairment Project, an intensive epidemiological study conducted by the Centre for Eye Research Australia (CERA) from 1991 to 1999, determined the prevalence, causes and risk factors for eye disease in Australia, and helped identify a series of specific, often simple, steps and strategies to significantly reduce its impact. A distillation of CERA"s findings has highlighted the growing problem of eye disease in our community. In addition, CERA has joined with other interested bodies to form Vision 2020: the Right to Sight Australia. This partnership was established in response to the Global Initiative to Eliminate Avoidable Blindness by the year 2020 - Vision 2020: the Right to Sight. This Global Initiative was established by the World Health Organization and the International Agency for the Prevention of Blindness. Vision 2020 Australia aims to be the peak body for all those involved in vision care in its broadest sense in Australia, and to put vision on the national agenda.

Vision impairment in the Pacific region

The Western Pacific region is one of great diversity, containing the most populous country, China, and many small Pacific island countries. This review describes the prevalence of blindness and vision loss, illustrates the changing trends in the important causes of vision loss and blindness, and the stages of development of the delivery of eye care services across this region.

Five-year outcome of correctable visual impairment: the Blue Mountains Eye Study

This report aims to describe the outcome and socio-economic characteristics of older persons attending the Blue Mountains Eye Study (BMES) with persistent correct-able visual impairment (VI). The BMESI examined 3654 persons aged 49+ during 1992-1994 and re-examined 2335 survivors during 1997-1999 (BMES II). Visual acuity was measured before and after standardized refraction. Participants had correctable VI if their better eye was visually impaired <6/12 before refraction (with distance glasses if worn) and was unimpaired after refraction. In BMES I,274 persons (7.5%) had correctable VI, of whom 127 returned to BMES II. Of this group of 127, 34 had persistent correctable VI and 74 were no longer impaired. Fewer persons with correctable VI returned and more died prior to BMES II, compared to persons with no or non-correctable VI. This study showed that persistent correctable impairment was more frequent with increasing age, among women, in those living alone, using community support services,or with a history of heart disease.

Utilisation of eye care services by urban and rural Australians

AIM

To investigate factors related to the use of eye care services in Australia.

METHODS

Health, eye care service use, and sociodemographic data were collected in a structured interview of participants in a population based study. All participants had a standard eye examination.

RESULTS

Men (OR 1.3 CL 1.02, 1.7), those who spoke Greek (OR 2.1 CL 1.1, 3.8) or Italian (OR 1.9 CL 1.0, 3.3), and those without private health insurance (OR 1.59 CL 1.22, 2.04) were more likely to have not used eye care services. Ophthalmology services were utilised at lower rates in rural areas (OR 0.14 CL 0.09, 0.2). Approximately 40% of participants with undercorrected refractive error, cataract, and undiagnosed glaucoma had seen either an ophthalmologist, optometrist, or both within the last year.

CONCLUSION

Despite the similarity in prevalence of eye disease in urban and rural areas, significant differences exist in the utilisation of eye care services. Sex, private health insurance, urban residence, and the ability to converse in English were significant factors associated with eye healthcare service use. Many participants had undiagnosed eye disease despite having seen an eye care provider in the last year.

The Auckland Cataract Study: demographic, corneal topographic and ocular biometric parameters

PURPOSE

To determine patient demographics and the ocular biometric parameters in patients presenting for cataract surgery within the public hospital system, in a defined New Zealand population.

METHOD

Prospective study of 502 eyes of 488 consecutive patients undergoing cataract surgery. A clinical assessment, including refraction, keratometry (K), A-scan ultrasound and Orbscan II computerized topography was performed on each eye.

RESULTS

The mean age of the group was 74.9 +/- 9.8 years (mean +/- SD) with a female predominance (62%). Ethnic origin included 72% European, 8% Maori, 10% Pacific Islander, 4% Asian, 3% Indian and 3% other ethnic origins. The mean Log MAR visual acuity of eyes prior to cataract surgery was 0.88 +/- 0.57 (approximately 6/48(-1)). Corneal topographic (keratometric) maps were classified into five groups: 34% round, 10% oval, 31% symmetrical bow tie, 12% asymmetrical bow tie and 13% irregular. The mean steepest K measurement was 44.1 +/- 1.7 D, the median keratometric astigmatism 0.89 D (range 0.0-6.5 D) and the steepest corneal meridian was horizontal in 50% and vertical in 43%. Seven per cent of corneas were spherical. Refraction revealed a mean sphere of 0.0 +/- 3.1 D and a mean cylinder of -1.2 (range 0.0-7.5 D). Refractive astigmatism was with-the-rule in 15%, against-the-rule in 50% and oblique in 15%, with 20% spherical. Axial length was a mean of 23.14 +/- 1.03 mm.

CONCLUSION

Patients presenting for cataract surgery in this study were predominantly elderly, female, of European Caucasian ethnicity and exhibited relatively poor corrected visual acuity in the affected eye. Interestingly, 41% of eyes demonstrated bow-tie topographic patterns, largely exhibiting with-the-rule astigmatism. However, assessment by keratometry or refraction highlighted against-the-rule more frequently; this may have implications for combined cataract and astigmatic surgery. The mean axial length was slightly shorter than expected for a group of predominantly European ethnic origin, although the mean refractive error was emmetropic.

Correction of refractive error in the Victorian population: the feasibility of "off the shelf" spectacles

AIMS

To assess the feasibility of providing a stock of ready made spectacles for correction of refractive error in the general population.

METHODS

Data were collected in the Visual Impairment Project, a population based survey of Victorian residents aged 40 years or older in randomly selected urban and rural sample areas. This included a refractive eye examination and the proportion of subjects with hypermetropia, emmetropia (defined as -1.0 to +1.0D spherical equivalent), and myopia documented in the 40-60 year age group.

RESULTS

2595 (54.8%) participants were aged between 40 and 60 years. Those with a best corrected visual acuity of less than 6/12, astigmatism of more than 1.25D, and anisometropia of more than 0.5D were excluded. 516 participants had refractive error which was deemed suitable for correction by "off the shelf" spectacles. This represents 19.9% of all participants between 40 and 60 years of age. Provision of spectacles in 0.5D increments would provide suitable stock spectacles for 85.5% of a -3.0 to +3.0D range or 89.2% of a -3.50 to +3.50D range.

CONCLUSIONS

Ready made "off the shelf" spectacles could significantly alleviate visual morbidity due to refractive error in up to 20% of an urban population in Australia. This approach may also be useful in developing countries with poor access to optometric services.