Visual Impairment and Mortality in a Rural Adult Population (The Southern Harbin Eye Study)

Association Between Multimorbidity and Presence of Diagnosed Vision Problems Among the Middle-Aged and Older Population in India

PURPOSE

The aim of the study was to estimate the prevalence of diagnosed vision problems and to examine the association of single and multiple chronic conditions with vision problems among middle-aged and older adults in India.

METHODS

The study utilized data from the Longitudinal Ageing Study in India (LASI) Wave 1, (2017-18). Descriptive statistics along with bivariate and multivariable analyses were conducted to achieve the study objectives.

RESULTS

The prevalence of diagnosed vision problems in the sampled population was 48.2%. The older adults (60+ years) (55.3%) had shown a greater prevalence of vision problems than the middle-aged individuals (41%). Among chronic conditions, hypertension, diabetes, chronic lung diseases, chronic heart diseases, bone related diseases, psychiatric disorders, and high cholesterol were significantly associated with vision problems in the case of both middle-aged and older adults. Furthermore, odds of experiencing vision problems according to the presence of multimorbidity were higher in the middle-aged population [adjusted odds ratio (AOR) = 1.986; confidence interval (CI):1.855-2.126] than in the older population [AOR = 1.746; CI:1.644-1.854].

CONCLUSIONS

Middle-aged and older adults with chronic illnesses and multimorbidity were at greater risk of vision problems. Due to the high prevalence of vision problem, interventions aimed at prevention or early detection are warranted.

The association between disability and all-cause mortality in low-income and middle-income countries: a systematic review and meta-analysis

BACKGROUND

There are 1·3 billion people with disabilities globally. On average, they have poorer health than their non-disabled peers, but the extent of increased risk of premature mortality is unknown. We aimed to systematically review the association between disability and mortality in low-income and middle-income countries (LMICs).

METHODS

We searched MEDLINE, Global Health, PsycINFO, and EMBASE from Jan 1, 1990 to Nov 14, 2022. Longitudinal epidemiological studies in any language with a comparator group that measured the association between disability and all-cause mortality in people of any age were eligible for inclusion. Two reviewers independently assessed study eligibility, extracted data, and assessed risk of bias. We used a random-effects meta-analysis to calculate the pooled hazard ratio (HR) for all-cause mortality by disability status. We then conducted meta-analyses separately for different impairment and age groups.

FINDINGS

We identified 6146 unique articles, of which 70 studies (81 cohorts) were included in the systematic review, from 22 countries. There was variability in the methods used to assess and report disability and mortality. The meta-analysis included 54 studies, representing 62 cohorts (comprising 270 571 people with disabilities). Pooled HRs for all-cause mortality were 2·02 (95% CI 1·77-2·30) for people with disabilities versus those without disabilities, with high heterogeneity between studies (τ2=0·23, I2=98%). This association varied by impairment type: from 1·36 (1·17-1·57) for visual impairment to 3·95 (1·60-9·74) for multiple impairments. The association was highest for children younger than 18 years (4·46, [3·01-6·59]) and lower in people aged 15-49 years (2·45 [1·21-4·97]) and people older than 60 years (1·97 [1·65-2·36]).

INTERPRETATION

People with disabilities had a two-fold higher mortality rate than people without disabilities in LMICs. Interventions are needed to improve the health of people with disabilities and reduce their higher mortality rate.

FUNDING

UK National Institute for Health and Care Research; and UK Foreign, Commonwealth and Development Office.

Longitudinal associations between self-reported vision impairment and all-cause mortality: a nationally representative cohort study among older Chinese adults

OBJECTIVE

To compare the effects of pre-existing and new self-reported vision impairment (VI), and its correction, on all-cause mortality among Chinese adults aged 45 years and older.

METHODS

We used four waves of data from the China Health and Retirement Longitudinal Study. Our analytical cohort consists of 15 808 participants aged 45 years and older with an average follow-up of 6.4 years. Exposures included pre-existing self-reported VI and vision correction (time-independent exposures), new self-reported VI and vision correction (time-dependent exposures). Outcomes were measured as the risk of all-cause mortality and the risk stratification for pre-specified factors.

RESULTS

Compared with participants with normal vision, all-cause mortality was higher among those with pre-existing self-reported VI (crude HR (cHR)=1.29, 95% CI: 1.17 to 1.44; adjusted HR (aHR)=1.22, 95% CI: 1.09 to 1.37) and new self-reported VI (cHR=1.42, 95% CI: 1.28 to 1.58; aHR=1.36, 95% CI: 1.21 to 1.51). Mortality risk was lower among those with high school or higher education. Participants who were wearing eyeglasses/contact lenses or had cataract surgery at baseline did not have significantly higher all-cause mortality (eyeglasses: aHR=0.82, 95% CI: 0.65 to 1.02; cataract surgery: aHR=1.12, 95% CI: 0.74 to 1.69) compared with participants with normal vision. The same was true among participants with new correction of self-reported VI (glasses: aHR=1.01, 95% CI: 0.78 to 1.24; cataract surgery: aHR=0.95, 95% CI: 0.68 to 1.31).

CONCLUSIONS

Both pre-existing and new self-reported VI increase all-cause mortality among Chinese adults aged 45 years and older, though visual correction reduces this risk.

Cost-utility analysis of commonly used anti-glaucoma interventions for mild-to-moderate primary open-angle glaucoma patients in rural and urban China

OBJECTIVE

An increasing number of studies have explored the clinical effects of antiglaucoma surgical procedures; however, economic evidence was scarce. We aimed to compare the cost-effectiveness between maximal medical treatment (MMT) and commonly used surgical procedures (trabeculectomy, Ahmed glaucoma valve implantation, gonioscopy-assisted transluminal trabeculotomy and ab interno canaloplasty).

DESIGN AND SETTING

A Markov model study.

PARTICIPANTS

A hypothetical cohort of 100 000 patients with mild-to-moderate primary open-angle glaucoma (POAG).

OUTCOMES

Data were obtained from public sources. The main outcomes were incremental cost-utility ratios (ICURs) using quality-adjusted life-years (QALYs). Sensitivity analyses were conducted to verify the robustness and sensitivity of base-case results.

MAIN RESULTS

Both cumulative costs and QALYs gained from surgical procedures (US$6045-US$13 598, 3.33-6.05 QALYs) were higher than those from MMT (US$3117-US$6458, 3.14-5.66 QALYs). Compared with MMT, all surgical procedures satisfied the cost-effectiveness threshold (lower than US$30 501 and US$41 568 per QALY gained in rural and urban settings, respectively). During the 5-year period, trabeculectomy produced the lowest ICUR (US$21 462 and US$15 242 per QALY gained in rural and urban settings, respectively). During the 10-year-follow-up, trabeculectomy still produced the lowest ICUR (US$13 379 per QALY gained) in urban setting; however, gonioscopy-assisted transluminal trabeculotomy (US$19 619 per QALY gained) and ab interno canaloplasty (US$18 003 per QALY gained) produced lower ICURs than trabeculectomy (US$19 675 per QALY gained) in rural areas. Base-case results were most sensitive to the utilities and costs of initial treatment and maintenance.

CONCLUSIONS

The long-term cost-effectiveness of commonly used surgical procedures could be better than the short-term cost-effectiveness for mild-to-moderate POAG patients in China. Health economic studies, supported by more rigorous structured real-world data, are needed to assess their everyday cost-effectiveness.

Cost-Utility Analysis of Screening for Diabetic Retinopathy in China

Background. Diabetic retinopathy (DR) has been primarily indicated to cause vision impairment and blindness, while no studies have focused on the cost-utility of telemedicine-based and community screening programs for DR in China, especially in rural and urban areas, respectively.Methods. We developed a Markov model to calculate the cost-utility of screening programs for DR in DM patients in rural and urban settings from the societal perspective. The incremental cost-utility ratio (ICUR) was calculated for the assessment.Results. In the rural setting, the community screening program obtained 1 QALY with a cost of $4179 (95% CI 3859 to 5343), and the telemedicine screening program had an ICUR of $2323 (95% CI 1023 to 3903) compared with no screening, both of which satisfied the criterion of a significantly cost-effective health intervention. Likewise, community screening programs in urban areas generated an ICUR of $3812 (95% CI 2906 to 4167) per QALY gained, with telemedicine screening at an ICUR of $2437 (95% CI 1242 to 3520) compared with no screening, and both were also cost-effective. By further comparison, compared to community screening programs, telemedicine screening yielded an ICUR of 1212 (95% CI 896 to 1590) per incremental QALY gained in rural setting and 1141 (95% CI 859 to 1403) in urban setting, which both meet the criterion for a significantly cost-effective health intervention.Conclusions. Both telemedicine and community screening for DR in rural and urban settings were cost-effective in China, and telemedicine screening programs were more cost-effective.

Prevalence of cataract and cataract surgery in urban and rural Chinese populations over 50 years old: a systematic review and Meta-analysis

AIM

To summarize the data of epidemiological studies on cataract prevalence over 50 years old in urban and rural areas of China from 2000 to 2020, and to analyze the prevalence of cataract and operation rate in China.

METHODS

By searching PubMed, EMBASE, Web of Science, Wanfang Data and CNKI, Chinese and English literatures on the prevalence of cataract in China were retrieved, and the relevant characteristic data were extracted. Then, Stata v15SE software was used for Meta-analysis and heterogeneity test. According to the results of heterogeneity, the corresponding effect models were selected to combine the extracted data.

RESULTS

A total of 20 studies were included in this study, with a total of 111 434 cases. Meta-analysis showed heterogeneity. According to the random effect model, the overall prevalence of cataract in Chinese people over 50 years old was 27.45%, that in rural was 28.79%, and that in urban was 26.66%. The overall coverage rate of cataract surgery was 9.19%.

CONCLUSION

The prevalence of cataract is high in China, and there is still room for improvement in surgical coverage, so it is very important to promote cataract screening and prevention.

Visual Impairment, Major Eye Diseases, and Mortality in a Multi-Ethnic Asian Population and a Meta-analysis of Prospective Studies

PURPOSE

Vision impairment (VI) is associated with poor quality of life and increased risk of falls. Few prospective data are available on Asians. This study investigates the longitudinal impact of VI and the major eye diseases on mortality risk in Asians.

DESIGN

Prospective cohort study with meta-analysis.

METHODS

We conducted a multi-ethnic prospective study of adults (40-80 years old) in the Singapore Epidemiology of Eye Diseases Study (baseline: 2004-2011). All-cause mortality was obtained from the National Death Registry until May 2017. VI was defined by best-corrected visual acuity (BCVA) <20/40 in the better eye. Major eye diseases were assessed using standard protocols. We examined associations using multivariate-adjusted Cox proportional hazards regression models. Finally, we conducted a meta-analysis of the associations between VI and mortality.

RESULTS

Of 9,986 participants, 1,210 deaths occurred (12.1%) over a median follow-up of 8.8 years. Compared to participants with normal vision, persons with VI had increased risk of mortality (hazards ratio [HR]: 1.53; 95% confidence interval [CI:] 1.30-1.81) in multivariate models. In ethnicity-specific analyses, this association was significant across Chinese (HR: 1.63; 95% CI: 1.08-2.48); Malays (HR: 1.31; 95% CI: 1.06-1.62); and Indians (HR: 2.25; 95% CI: 1.61-3.15). Cataract, under-corrected refractive errors (URE), and diabetic retinopathy (DR) were significantly associated with mortality (HRs: 1.30, 1.22, and 1.54, respectively). In a meta-analysis of 12 studies including 58,034 persons, VI was associated with 30% increased risk of mortality (HR: 1.3; 95% CI: 1.2-1.5).

CONCLUSIONS

In this multi-ethnic Asian population, VI and preventable eye conditions (cataract, URE, and DR) were associated with mortality, emphasizing the need for early detection and intervention to prevent and treat VI and major eye diseases.

Short-wavelength blue light contributes to the pyroptosis of human lens epithelial cells (hLECs)

PURPOSE

The purpose of this study is to examine the effect of short-wavelength blue light (SWBL) on cultured human lens epithelial cells (hLECs). The pathogenesis of cataracts after SWBL exposure is discussed.

METHODS

HLE-B3 hLECs were randomly divided into 3 groups: the NC group, which was grown in a dark incubator; the acetyl (Ac)-Tyr-Val-Ala-Asp-chloromethyl ketone (AC-YVAD-CMK) treatment group; and the SWBL exposure group. After SWBL (2500 lux) irradiation (for 8, 16, 24, and 32 h), caspase-1 and gasdermin D (GSDMD) expression levels in HLE-B3 hLECs were examined using ELISA, immunofluorescence staining, and Western blotting analyses. Double-positive staining of hLECs for activated and inhibited caspase-1 was used to determine pyroptosis in HLE-B3 hLECs.

RESULTS

SWBL led to hLEC death, but a caspase-1 inhibitor suppressed cell death. The flow cytometry results also confirmed the dose-dependent effect of SWBL irradiation on the pyroptotic death of hLECs. Caspase-1 and GSDMD expression levels in all hLEC groups changed with blue light exposure times (8, 16, 24, and 32 h) and were higher in the AC-YVAD-CMK and SWBL exposure groups than in the NC group. The immunofluorescence results revealed higher GSDMD-N expression in the cell membrane of both the AC-YVAD-CMK and SWBL exposure groups than in the NC group.

CONCLUSIONS

Based on the data, SWBL induces pyroptotic programmed cell death by activating the GSDMD signalling axis in HLE-B3 hLECs. These results provide new insights into the exploitation of new candidates for the prevention of cataracts.

Visual impairment and ten-year mortality: the Liwan Eye Study

OBJECTIVES

To explore associations between visual impairment (VI) and mortality in an adult population in urban China.

METHODS

The Liwan Eye Study was a population-based prevalence survey conducted in Guangzhou, Southern China. The baseline examination was carried out in 2003. All baseline participants were invited for the 10-year follow-up visit. VI was defined as the visual acuity of 20/40 or worse in the better-seeing eye with habitual correction if worn. Correctable VI was defined as the VI correctable to 20/40 or better by subjective refraction, and non-correctable VI was defined as the VI correctable to worse than 20/40. Mortality rates were compared using the log-rank test and Cox proportional hazards regression models.

RESULTS

Of the 1399 participants (mean age: 65.3 ± 9.93 years; 56.4% female) with available baseline visual acuity measurement, 320 participants (22.9%) had VI. After 10 years, 314 (22.4%) participants died. Visually impaired participants had a significantly increased 10-year mortality compared with those without VI (40.0% vs. 17.2%, P < 0.05). After adjusting for age, gender, income, educational attainment, BMI, history of diabetes and hypertension, both VI (HR, 1.55; 95% CI, 1.14-2.11) and non-correctable VI (HR, 2.72; 95% CI, 1.86-3.98) were significantly associated with poorer survival, while correctable VI (HR, 0.99; 95% CI, 0.66-1.49) was not an independent risk factor for 10-year mortality.

CONCLUSIONS

Our findings that VI, particularly non-correctable VI, predicting poorer survival may imply the underlying mechanism behind VI-mortality association and reinforce the importance of preventing and treating disabling ocular diseases to prevent premature mortality in the elderly.

Association between vision impairment and mortality: a systematic review and meta-analysis

BACKGROUND

The number of individuals with vision impairment worldwide is increasing because of an ageing population. We aimed to systematically identify studies describing the association between vision impairment and mortality, and to assess the association between vision impairment and all-cause mortality.

METHODS

For this systematic review and meta-analysis, we searched MEDLINE (Ovid), Embase, and Global Health database on Feb 1, 2020, for studies published in English between database inception and Feb 1, 2020. We included prospective and retrospective cohort studies that measured the association between vision impairment and all-cause mortality in people aged 40 years or older who were followed up for 1 year or more. In a protocol amendment, we also included randomised controlled trials that met the same criteria as for cohort studies, in which the association between visual impairment and mortality was independent of the study intervention. Studies that did not report age-adjusted mortality data, or that focused only on populations with specific health conditions were excluded. Two reviewers independently assessed study eligibility, extracted the data, and assessed risk of bias. We graded the overall certainty of the evidence using the Grading of Recommendations, Assessment, Development and Evaluations framework. We did a random-effects meta-analysis to calculate pooled maximally adjusted hazard ratios (HRs) for all-cause mortality for individuals with a visual acuity of <6/12 versus those with ≥6/12; <6/18 versus those with ≥6/18; <6/60 versus those with ≥6/18; and <6/60 versus those with ≥6/60.

FINDINGS

Our searches identified 3845 articles, of which 28 studies, representing 30 cohorts (446 088 participants) from 12 countries, were included in the systematic review. The meta-analysis included 17 studies, representing 18 cohorts (47 998 participants). There was variability in the methods used to assess and report vision impairment. Pooled HRs for all-cause mortality were 1·29 (95% CI 1·20-1·39) for visual acuity <6/12 versus ≥6/12, with low heterogeneity between studies (n=15; τ2=0·01, I2=31·46%); 1·43 (1·22-1·68) for visual acuity <6/18 versus ≥6/18, with low heterogeneity between studies (n=2; τ2=0·0, I2=0·0%); 1·89 (1·45-2·47) for visual acuity <6/60 versus ≥6/18 (n=1); and 1·02 (0·79-1·32) for visual acuity <6/60 versus ≥6/60 (n=2; τ2=0·02, I2=25·04%). Three studies received an assessment of low risk of bias across all six domains, and six studies had a high risk of bias in one or more domains. Effect sizes were greater for studies that used best-corrected visual acuity compared with those that used presenting visual acuity as the vision assessment method (p=0·0055), but the effect sizes did not vary in terms of risk of bias, study design, or participant-level factors (ie, age). We judged the evidence to be of moderate certainty.

INTERPRETATION

The hazard for all-cause mortality was higher in people with vision impairment compared with those that had normal vision or mild vision impairment, and the magnitude of this effect increased with more severe vision impairment. These findings have implications for promoting healthy longevity and achieving the Sustainable Development Goals.

FUNDING

Wellcome Trust, Commonwealth Scholarship Commission, National Institutes of Health, Research to Prevent Blindness, the Queen Elizabeth Diamond Jubilee Trust, Moorfields Eye Charity, National Institute for Health Research, Moorfields Biomedical Research Centre, Sightsavers, the Fred Hollows Foundation, the Seva Foundation, the British Council for the Prevention of Blindness, and Christian Blind Mission.

Visual acuity and risk of overall, injury-related, and cardiovascular mortality: the Kangbuk Samsung Health Study

AIMS 

The associations of visual impairment (VI) with cardio-metabolic risk factors have been reported but its association with cardiovascular mortality remains uncertain. Therefore, we evaluated the association of visual acuity (VA) with overall, injury-related, and cardiovascular mortality.

METHODS AND RESULTS

A cohort study was performed in 580 746 Korean adults (average age, 39.7 years) who were followed for a median of 8.1 years (maximum, 16 years). Presenting VA was measured by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Visual acuity in the better vision eye was categorized as normal vision (≥0.8), lowered vision (0.5-0.8), mild visual impairment (VI) (0.3-0.5), or moderate to severe VI (<0.3). Vital status and cause of death were ascertained through linkage to national death records. During 4 632 892.2 person-years of follow-up, 6585 overall deaths, 974 cardiovascular deaths, and 1163 injury-related deaths were identified. After adjustment for possible confounders, the multivariable-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for overall mortality among participants with lowered vision, minimal VI, and moderate to severe VI were 1.21 (1.13-1.29), 1.26 (1.15-1.37), and 1.54 (1.40-1.68), respectively, compared with those with normal vision. The corresponding HRs (95% CIs) for injury-related mortality were 1.12 (0.96-1.32), 0.98 (0.76-1.26), and 1.36 (1.04-1.79), respectively, and the corresponding HRs (95% CIs) for cardiovascular mortality were 1.32 (1.12-1.57), 1.43 (1.15-1.77), and 2.41 (1.94-2.99).

CONCLUSION 

In this large cohort of young and middle-aged individuals, VI was associated with increased risk of mortality especially due to cardiovascular disease.

Diabetic Retinopathy, Visual Impairment, and the Risk of Six-Year Death: A Cohort Study of a Rural Population in China

PURPOSE

The aim of this study was to explore the association between diabetic retinopathy (DR) and the risk of 6-year death, as well as the association between visual impairment (VI) and the risk of 6-year death in a rural Chinese population of age ≥30 years.

METHODS

This was a population-based cohort study. In 2006-2007, 6,830 subjects aged ≥30 years were recruited from 13 villages in Northern China through clustered randomization. In 2012-2013, a 6-year follow-up was further done. Six different proportional hazards models, with different confounders adjusted, were used to explore the association between baseline DR and risk of death.

RESULTS

5,570 subjects were included in this study by our inclusion and exclusion criteria. Four hundred and ten (7.36%) subjects died by follow-up. The median ages of the dead subjects and survived subjects were 67 (interquartile range [IQR]: 58-72) years and 52 (IQR: 42-58) years (Z = 21.979, p < 0.001). Male accounted for 62.20 and 44.92% among the dead and survived subjects (χ2 = 45.591, p < 0.001). Besides, compared with those survived, the dead were found to be with lower education (χ2 = 109.981, p < 0.001), lower marriage rate (χ2 = 101.341, p < 0.001), lower income (χ2 = 123.763, p < 0.001), higher proportion of smoking (χ2 = 8.869, p = 0.003), higher systolic blood pressure (Z = 10.411, p < 0.001), lower body mass index (Z = -3.302, p = 0.001), larger spherical equivalent error (Z = 4.248, p < 0.001), lower intraocular pressure (Z = -4.912, p < 0.001), smaller anterior chamber depth (Z = -9.186, p < 0.001), larger length thickness (Z = 11.069, p < 0.001), higher fast blood glucose level (Z = 5.650, p < 0.001), higher total cholesterols (Z = 2.015, p = 0.044), higher low-density lipoprotein (Z = 2.024, p = 0.043), and higher proportion of drug usage (χ2 = 56.108, p < 0.001). Besides, the dead subjects were more likely to be with VI, glaucoma, cataract, age-related macular degeneration, diabetes, and DR. Hundred and forty-eight subjects were diagnosed with DR at baseline, and 33 (22.30%) of them were dead before follow-up. By adjusting all relative confounders in a proportional hazards model, DR was found to be a risk factor of 6-year death, the hazard ratio was 1.739 (95% confidence intervals: 1.080, 2.803). Another 5 different statistical models with different confounders adjusted also revealed a statistically significant association between DR and 6-year death. The association between VI and 6-year death was not statistically significant.

CONCLUSIONS

DR increased the risk of 6-year death in a rural Chinese population aged ≥30 years, while VI did not.

Mortality and causes of death in a population with blindness in Korea: A longitudinal follow-up study using a national sample cohort

The influence of visual impairment and blindness on the risk of mortality has been reported in diverse cohort studies. However, the results reported have varied from nonsignificant to significant associations. In the present study, we evaluated the influence of blindness on the risk of mortality from 2002 to 2013 using a longitudinal database with a national sample cohort provided by the Korean National Health Insurance Service. Of a total of 1,125,691 subjects, 1,279 subjects who were registered as blind were enrolled, and 5,116 control participants were matched at a 1:4 ratio for age, sex, income, region of residence, and medical histories of hypertension, diabetes mellitus and dyslipidemia. The life/death information contained in this dataset was used for the analysis; this information was originally recorded by the medical doctors on the death certificates of the participants. The percentage of total deaths during the mean follow-up period of 111.0 ± 41.6 months was 28.1% in the blindness group and 19.7% in the matched control group. The risk of mortality was significantly higher in the blindness group than in the control group according to the Cox proportional hazards model with additional adjustments for ischemic heart disease, stroke, and depression (adjusted hazard ratio [HR] of mortality = 1.54, 95% confidence interval [CI] = 1.37–1.74, P < 0.001). In the subgroup analyses, the adjusted HRs for mortality were significantly higher in the blindness group than in the control group regardless of age (young defined as <60 years old vs old defined as ≥60 years old) and sex. The percentage of death due to metabolic diseases and genitourinary diseases was higher in the blindness group than in the matched control group.

Cost-effectiveness and cost-utility of population-based glaucoma screening in China: a decision-analytic Markov model

BACKGROUND

Glaucoma, particularly primary angle closure glaucoma (PACG), is a leading cause of global blindness. Nearly half of all people with PACG are of Chinese descent. Population-level glaucoma screening has generally not been found to be cost-effective in high-income countries; however, this assessment has rarely been done in low-income or middle-income countries. We aimed to assess the cost-effectiveness and cost-utility of population-level glaucoma screening in China.

METHODS

We developed decision-analytic Markov models for separate and combined screening for PACG and primary open angle glaucoma (POAG) to evaluate costs and benefits of community-level screening versus opportunistic case finding from a societal perspective. A cohort of individuals was followed in the model from age 50 years through a total of 30 1-year Markov cycles. Analyses were done separately for rural and urban settings. We did a meta-analysis of glaucoma prevalence studies in China to obtain prevalence estimates for PACG and POAG. Screening costs were taken from a Chinese screening programme and treatment costs from a tertiary Chinese eye hospital. Main outcomes were incremental cost-utility ratios (ICURs) using quality-adjusted life-years and incremental cost-effectiveness ratios (ICERs) using years of blindness avoided. We did one-way deterministic and simulated probabilistic sensitivity analyses to reflect uncertainty around ICURs and ICERs.

FINDINGS

Compared with no screening, combined screening of POAG and PACG in rural China is predicted to result in an ICUR of US$569 (95% CI 17 to 4180) and an ICER of $1280 (-58 to 7940), both of which are below the WHO cost-effectiveness threshold of one to three times rural gross domestic product. For the urban China setting, combined screening is predicted to result in fewer net costs and greater gain in health benefits than no screening. Findings were robust in all sensitivity analyses. Over 30 years, a total of 246 (95% CI 63 to 628) and 1325 (510 to 2828) years of blindness are predicted to be avoided for every 100 000 rural and urban residents screened, respectively.

INTERPRETATION

Population screening for glaucoma (POAG and PACG combined) is likely to be cost-effective in both urban and rural China. Future studies should investigate the effectiveness of interventions to improve acceptance of definitive care among people screened.

FUNDING

Ulverscroft Foundation, Wenzhou Medical University Research Fund, Zhejiang Province Health Innovation Talents Project, and Wenzhou's Ten Major Livelihood Issues 2015.

Mortality during 6 years of follow-up in relation to visual impairment and eye disease: results from a population-based cohort study of people aged 50 years and above in Nakuru, Kenya

OBJECTIVE

To estimate the association between (1) visual impairment (VI) and (2) eye disease and 6-year mortality risk within a cohort of elderly Kenyan people.

DESIGN, SETTING AND PARTICIPANTS

The baseline of the Nakuru Posterior Segment Eye Disease Study was formed from a population-based survey of 4318 participants aged ≥50 years, enrolled in 2007-2008. Ophthalmic and anthropometric examinations were undertaken on all participants at baseline, and a questionnaire was administered, including medical and ophthalmic history. Participants were retraced in 2013-2014 for a second examination. Vital status was recorded for all participants through information from community members. Cumulative incidence of mortality, and its relationship with baseline VI and types of eye disease was estimated. Inverse probability weighting was used to adjust for non-participation.

PRIMARY OUTCOME MEASURES

Cumulative incidence of mortality in relation to VI level at baseline.

RESULTS

Of the baseline sample, 2170 (50%) were re-examined at follow-up and 407 (10%) were known to have died (adjusted risk of 11.9% over 6 years). Compared to those with normal vision (visual acuity (VA) ≥6/12, risk=9.7%), the 6-year mortality risk was higher among people with VI (<6/18 to ≥6/60; risk=28.3%; risk ratio (RR) 1.75, 95% CI 1.28 to 2.40) or severe VI (SVI)/blindness (<6/60; risk=34.9%; RR 1.98, 95% CI 1.04 to 3.80). These associations remained after adjustment for non-communicable disease (NCD) risk factors (mortality: RR 1.56, 95% CI 1.14 to 2.15; SVI/blind: RR 1.46, 95% CI 0.80 to 2.68). Mortality risk was also associated with presence of diabetic retinopathy at baseline (RR 3.18, 95% CI 1.98 to 5.09), cataract (RR 1.26, 95% CI 0.95 to 1.66) and presence of both cataract and VI (RR 1.57, 95% CI 1.24 to 1.98). Mortality risk was higher among people with age-related macular degeneration at baseline (with or without VI), compared with those without (RR 1.42, 95% CI 0.91 to 2.22 and RR 1.34, 95% CI 0.99 to 1.81, respectively).

CONCLUSIONS

Visual acuity was related to 6-year mortality risk in this cohort of elderly Kenyan people, potentially because both VI and mortality are related to ageing and risk factors for NCD.

Blindness, cataract surgery and mortality in Ethiopia

PURPOSE

To examine the relationships between blindness, the intervention of cataract surgery and all-cause mortality in a rural Ethiopian population.

DESIGN

Population-based, interventional prospective study.

METHODS

Community-based detection methods identified blind Ethiopian persons from two selected kebeles in Amhara region, Ethiopia. Data from 1201 blind patients were collected-628 cataract-blind and 573 blind from other conditions. Free cataract surgery was provided for consenting, cataract-blind patients. Follow-up surveys were conducted after 12 months (±1 month)-the main outcome measure for this report is all-cause mortality at 1 year.

RESULTS

During the follow-up period, 110 persons died from the selected population (mortality 9.2%), which consisted of those cataract-blind patients who received cataract surgery (N=461), cataract-blind patients who did not receive surgery (N=167) and all non-cataract-blind patients (N=573). Of the 461 patients who received cataract surgery, 44 patients died (9.5%). Of the 740 patients who did not receive surgery, 66 died (8.9%)-28 patients from the cohort of cataract-blind patients who did not receive surgery (16.8%) and 38 patients from the cohort of non-cataract blind (6.6%). Subgroup analysis revealed significantly increased odds of mortality for cataract-blind patients over 75 years of age who did not receive surgery and for unmarried patients of all age groups.

CONCLUSIONS

In this population, mortality risk was significantly elevated for older cataract-blind patients when compared with non-cataract-blind patients-an elevation of risk that was not noted in an age-matched cohort of cataract-blind patients who underwent cataract surgery as early as 1-year follow-up.

Age-related cataract, cataract surgery and subsequent mortality: a systematic review and meta-analysis

PURPOSE

Changes in lens may reflect the status of systemic health of human beings but the supporting evidences are not well summarized yet. We aimed to determine the relationship of age-related cataract, cataract surgery and long-term mortality by pooling the results of published population-based studies.

METHODS

We searched PubMed and Embase from their inception till March, 2014 for population-based studies reporting the associations of any subtypes of age-related cataract, cataract surgery with all-cause mortality. We pooled the effect estimates (hazards ratios [HRs]) under a random effects model.

RESULTS

Totally, we identified 10 unique population-based studies including 39,659 individuals at baseline reporting the associations of any subtypes of cataract with all-cause mortality from 6 countries. The presence of any cataract including cataract surgery was significantly associated with a higher risk of death (pooled HR: 1.43, 95% CI, 1.21, 2.02; P<0.001; I(2) = 64.2%). In the meta-analysis of 9 study findings, adults with nuclear cataract were at higher risks of mortality (pooled HR: 1.55, 95% CI, 1.17, 2.05; P = 0.002; I(2) = 89.2%). In the meta-analysis of 8 study findings, cortical cataract was associated with higher risks of mortality (pooled HR: 1.26, 95% CI, 1.12, 1.42; P<0.001, I(2) = 29.7%). In the meta-analysis of 6 study findings, PSC cataract was associated with higher risks of mortality (pooled HR: 1.37, 95% CI, 1.04, 1.80; P = 0.03; I(2) = 67.3%). The association between cataract surgery and mortality was marginally non-significant by pooling 8 study findings (pooled HR: 1.27, 95% CI, 0.97, 1.66; P = 0.08; I(2)= 76.6%).

CONCLUSIONS

All subtypes of age-related cataract were associated with an increased mortality with nuclear cataract having the strongest association among the 3 cataract subtypes. However, cataract surgery was not significantly related to mortality. These findings indicated that changes in lens may serve as markers for ageing and systemic health in general population.

Cataract, visual impairment and long-term mortality in a rural cohort in India: the Andhra Pradesh Eye Disease Study

BACKGROUND

A large-scale prevalence survey of blindness and visual impairment (The Andhra Pradesh Eye Diseases Study [APEDS1]) was conducted between 1996-2000 on 10,293 individuals of all ages in three rural and one urban clusters in Andhra Pradesh, Southern India. More than a decade later (June 2009-March 2010), APEDS1 participants in rural clusters were traced (termed APEDS2) to determine ocular risk factors for mortality in this longitudinal cohort.

METHODS AND FINDINGS

Mortality hazard ratio (HR) analysis was performed for those aged >30 years at APEDS1, using Cox proportional hazard regression models to identify associations between ocular exposures and risk of mortality. Blindness and visual impairment (VI) were defined using Indian definitions. 799/4,188 (19.1%) participants had died and 308 (7.3%) had migrated. Mortality was higher in males than females (p<0.001). In multivariable analysis, after adjusting for age, gender, diabetes, hypertension, body mass index, smoking and education status the mortality HR was 1.9 (95% CI: 1.5-2.5) for blindness; 1.4 (95% CI: 1.2-1.7) for VI; 1.8 (95% CI: 1.4-2.3) for pure nuclear cataract, 1.5 (95% CI: 1.1-2.1) for pure cortical cataract; 1.96 (95% CI: 1.6-2.4) for mixed cataract, 2.0 (95% CI: 1.4-2.9) for history of cataract surgery, and 1.58 (95% CI: 1.3-1.9) for any cataract. When all these factors were included in the model, the HRs were attenuated, being 1.5 (95% CI: 1.1-2.0) for blindness and 1.2 (95% CI: 0.9-1.5) for VI. For lens type, the HRs were as follows: pure nuclear cataract, 1.6 (95% CI: 1.3-2.1); pure cortical cataract, 1.5 (95% CI: 1.1-2.1); mixed cataract, 1.8 (95% CI: 1.4-2.2), and history of previous cataract surgery, 1.8 (95% CI: 1.3-2.6).

CONCLUSIONS

All types of cataract, history of cataract surgery and VI had an increased risk of mortality that further suggests that these could be potential markers of ageing.

Prevalence and associated factors for pterygium in a rural adult population (the Southern Harbin Eye Study)

PURPOSE

To estimate the prevalence of pterygium and identify associated risk factors in a Southern Harbin population at low altitude in a cold climate.

METHODS

A prospective population-based survey was conducted in 2006. A stratified, clustered, randomized sampling procedure was used to select 5057 subjects aged 50 years and older. Pterygia were diagnosed and graded, and the association between pterygium and astigmatism was investigated. Risk factors associated with pterygium were evaluated with logistic regression models.

RESULTS

A total of 5057 persons aged 50 to 96 years (91.0% of the eligible population) who were residents of Southern Harbin, Heilongjiang Province, China, participated in the study, and 323 (6.4%) had at least 1 pterygium. The prevalence of pterygium in the unilateral and bilateral eyes of the participants was 3.7% and 2.6%, respectively. The presence of a pterygium was significantly associated with the presence of astigmatism (cylinder ≥ ± 0.5 diopters, P < 0.001). Pterygium was independently associated with male sex (odds ratio 1.73; 95% confidence interval, 1.37-2.19) and smoking (odds ratio 1.90; 95% confidence interval, 1.51-2.35) (P < 0.001).

CONCLUSIONS

This study details pterygium in a rural population of Harbin at low altitude in a cold climate. The prevalence of pterygium in the population is lower than that reported in other regions of the world. The primary causative factors were related to male sex and smoking, the latter of which is easily preventable. Public health schemes to address this serious health issue are urgently needed.

Age differential effects of severity of visual impairment on mortality among older adults in China

We use a population-based longitudinal survey in China from 2002 to 2005 to examine age differentials in the association between severity of visual impairment and mortality risk in older adults. Controlling for numerous factors and baseline health, a substantial age difference is found. Young-old women and men aged 65 to 79 with severe visual impairments have 161% (hazard ratio = 2.61) and 52% (hazard ratio = 1.52) higher risk of death respectively as compared to their unimpaired counterparts. Mild impairment does not increase mortality risk among young-old adults, while both mild and severe impairment increase mortality risk by 33% and 32% for women and 24% and 34% for men among the oldest-old as a whole when all factors are controlled for. We conclude that visual impairment is an independent predictor of mortality and severe visual impairment likely plays a stronger role in determining mortality risk among young-old adults than among the oldest-old.