Prevalence of uncorrected binocular distance visual acuity in Hispanic and non-Hispanic adults. Results from the HHANES and the NHANES I

The Effect of Self-Reported Visual Impairment and Sleep on Cognitive Decline: Results of the Hispanic Community Health Study/Study of Latinos

BACKGROUND

Visual impairment could worsen sleep/wake disorders and cognitive decline.

OBJECTIVE

To examine interrelations among self-reported visual impairment, sleep, and cognitive decline in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Miami-site.

METHOD

HCHS/SOL Miami-site participants ages 45-74 years (n = 665) at Visit-1, who returned for cognitive test 7-years later (SOL-INCA). Participants completed the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ), validated sleep questionnaires and test for obstructive sleep apnea (OSA) at Visit-1. We obtained verbal episodic learning and memory, verbal fluency, processing speed, and executive functioning at Visit-1 and at SOL-INCA. Processing speed/executive functioning were added to SOL-INCA. We examined global cognition and change using a regression-based reliable change index, adjusting for the time lapse between Visit-1 and SOL-INCA. We used regression models to test whether 1) persons with OSA, self-reported sleep duration, insomnia, and sleepiness have an increased risk for visual impairment, 2a) visual impairment is associated with worse cognitive function and/or decline, and 2b) sleep disorders attenuate these associations.

RESULT

Sleepiness (β= 0.04; p < 0.01) and insomnia (β= 0.04; p < 0.001) were cross-sectionally associated with visual impairment, adjusting for sociodemographic characteristics, behavioral factors, acculturation, and health conditions. Visual impairment was associated with lower global cognitive function at Visit-1 (β= -0.16; p < 0.001) and on average 7-years later (β= -0.18; p < 0.001). Visual impairment was also associated with a change in verbal fluency (β= -0.17; p < 0.01). OSA, self-reported sleep duration, insomnia, and sleepiness did not attenuate any of the associations.

CONCLUSION

Self-reported visual impairment was independently associated with worse cognitive function and decline.

Longitudinal relationships among visual acuity, daily functional status, and mortality: the Salisbury Eye Evaluation Study

IMPORTANCE

Determination of the mechanisms by which visual loss increases mortality risk is important for developing interventional strategies.

OBJECTIVE

To evaluate the direct and indirect effects of loss of visual acuity (VA) on mortality risk through functional status changes among aging adults.

DESIGN, SETTING, AND PARTICIPANTS

Prospective longitudinal study of a population-based sample of 2520 noninstitutionalized adults aged 65 to 84 years from September 16, 1993, through July 26, 2003, in the greater Salisbury area of Maryland. Participants underwent reassessment 2, 6, and 8 years after baseline. Mortality status was ascertained from linkage with the National Death Index through 2009.

EXPOSURES

Results of VA testing and self-reported functional status based on activities of daily living (ADL) and instrumental ADL (IADL).

MAIN OUTCOMES AND MEASURE

Mortality.

RESULTS

Worse VA levels at baseline were associated with an increased the risk for mortality (hazard ratio [HR], 1.16 [95% CI, 1.04-1.28]; P < .01) through their effect on lower IADL levels at baseline. Declines in VA over time were associated with increased mortality risk (HR, 1.78 [95% CI, 1.27-2.51]; P < .001) by way of decreasing IADL levels over time. Participants experiencing the mean linear decline in VA of 1 letter on the Early Treatment Diabetic Retinopathy Study acuity chart per year are expected to have a 16% increase in mortality risk during the 8-year study exclusively through associated declines in IADL levels.

CONCLUSIONS AND RELEVANCE

In this longitudinal study of older adults, VA loss adversely affected IADL levels, which subsequently increased the risk for mortality. Prevention of disabling ocular conditions, treatment of correctable visual impairment, and interventions designed to prevent the effect of visual impairment on IADL declines may all reduce mortality risk in aging adults.

Causes of blindness and visual impairment in Latin America

We review what is known in each country of the Latin American region with regards to blindness and visual impairment and make some comparisons to Hispanic populations in the United States. Prevalence of blindness varied from 1.1% in Argentina to 4.1% in Guatemala in people 50 years of age and older, with the major cause being cataract. Diabetic retinopathy and glaucoma are starting to make serious inroads, although epidemiological data are limited, and age-related macular degeneration is now a concern in some populations. Infectious diseases such as trachoma and onchocerciasis are quickly diminishing. Although progress has been made, retinopathy of prematurity remains the major cause of childhood blindness. If VISION 2020 is to succeed, many more epidemiological studies will be needed to set priorities, although some can be of the Rapid Assessment of Avoidable Blindness design. Developing the infrastructure for screening and treatment of ophthalmic disease in Latin America continues to be a challenge.

Self-reported age-related eye diseases and visual impairment in the United States: results of the 2002 national health interview survey

OBJECTIVES

We sought to establish national data on the prevalence of visual impairment, blindness, and selected eye conditions (cataract, diabetic retinopathy, glaucoma, and macular degeneration) and to characterize these conditions within sociodemographic subgroups.

METHODS

Information on self-reported visual impairment and diagnosed eye diseases was collected from 31,044 adults. We calculated weighted prevalence estimates and odds ratios with logistic regression using SUDAAN.

RESULTS

Among noninstitutionalized US adults 18 years and older, the estimated prevalence for visual impairment was 9.3% (19.1 million Americans), including 0.3% (0.7 million) with blindness. Lifetime prevalence of diagnosed diseases was as follows: cataract, 8.6% (17 million); glaucoma, 2.0% (4 million); macular degeneration, 1.1% (2 million); and diabetic retinopathy, 0.7% (1.3 million). The prevalence of diabetic retinopathy among persons with diagnosed diabetes was 9.9%.

CONCLUSIONS

We present the most recently available national data on self-reported visual impairment and selected eye diseases in the United States. The results of this study provide a baseline for future public health initiatives relating to visual impairment.

The prevalence and causes of visual impairment in Tehran: the Tehran Eye Study

AIMS

To determine the prevalence and causes of visual impairment in Tehran, Iran, through a population based study.

METHODS

In a population based, cross sectional study, 6497 Tehran citizens were sampled from 160 clusters using a stratified, random, cluster sampling strategy. The eligible people were enumerated through a door to door household survey in the selected clusters and were invited. All participants were transferred to a clinic for an extensive eye examination and interview. Visual impairment was determined using presenting and best corrected visual acuity (low vision: visual acuity of less than 6/18 to 3/60 in the better eye; blindness: visual acuity of less than 3/60 in the better eye).

RESULTS

Of those sampled, 4565 (70.3%) people participated in the study. The age and sex standardised prevalences of visual impairment on the basis of best corrected and presenting visual acuity were 1.39% (95% confidence interval (CI), 1.07 to 1.71) and 2.52% (95% CI, 2.07 to 2.97), respectively. 15 people (0.28%; 95% CI, 0.14 to 0.42) were blind with corrected vision while 22 (0.39%; 95% CI, 0.23 to 0.56) were blind with presenting vision. Using the corrected and presenting vision, the prevalence of low visual impairment was 1.11% (95% CI, 0.84 to 1.39) and 2.13% (95% CI, 1.71 to 2.55), respectively. The causes of visual impairment according to the best corrected vision were cataract (36.0%), macular degeneration (20.0%), and amblyopia (10.7%). However, according to the presenting vision, uncorrected refractive errors were the most frequent primary cause (33.6%) and cataract (25.4%), macular degeneration (12.7%), and amblyopia (8.2%) were the other main causes of visual impairment in the study sample. The prevalence of visual impairment was associated with advancing age and lower education.

CONCLUSION

The results indicate that the burden of visual impairment is important and, although easily preventable, uncorrected refractive errors and cataract have a major role as causes of visual impairment in this population. Results also highlight the need for visual impairment prevention programmes, with emphasis on treatment of refractive errors and cataract.

The Tehran Eye Study: research design and eye examination protocol

BACKGROUND

Visual impairment has a profound impact on society. The majority of visually impaired people live in developing countries, and since most disorders leading to visual impairment are preventable or curable, their control is a priority in these countries. Considering the complicated epidemiology of visual impairment and the wide variety of factors involved, region specific intervention strategies are required for every community. Therefore, providing appropriate data is one of the first steps in these communities, as it is in Iran. The objectives of this study are to describe the prevalence and causes of visual impairment in the population of Tehran city; the prevalence of refractive errors, lens opacity, ocular hypertension, and color blindness in this population, and also the familial aggregation of refractive errors, lens opacity, ocular hypertension, and color blindness within the study sample.

METHODS DESIGN

Through a population-based, cross-sectional study, a total of 5300 Tehran citizens will be selected from 160 clusters using a stratified cluster random sampling strategy. The eligible people will be enumerated through a door-to-door household survey in the selected clusters and will be invited. All participants will be transferred to a clinic for measurements of uncorrected, best corrected and presenting visual acuity; manifest, subjective and cycloplegic refraction; color vision test; Goldmann applanation tonometry; examination of the external eye, anterior segment, media, and fundus; and an interview about demographic characteristics and history of eye diseases, eye trauma, diabetes mellitus, high blood pressure, and ophthalmologic cares. The study design and eye examination protocol are described.

CONCLUSION

We expect that findings from the TES will show the status of visual problems and their causes in the community. This study can highlight the people who should be targeted by visual impairment prevention programs.

Blindness and visual impairment in the Americas and the Caribbean

AIM

To summarise available data on the prevalence and causes of visual impairment and blindness in the Americas and the Caribbean.

METHODS

The published literature was searched in Medline and LILACS using the following key words: blindness, visual impairment, prevalence. Articles were reviewed, and the references of the articles were also searched for relevant articles, which were also reviewed.

RESULTS

Using the mortality in children under the age of 5 as an indicator, the overall prevalence of childhood blindness (in the under age 15 group) for the region was estimated at 0.45/1000, with the majority (67%) living in countries with mortality of children under age 5 above 30/1000 live births. Corneal opacities were more common in countries where the under 5 year mortality are above 30/1000 live births and retinopathy of prematurity (ROP) was an important cause in countries with intermediate death rates. For adults, overall blindness rates were not estimated because of the social, economic, and ethnic diversity in the region. The primary causes of visual loss in adults in the Americas were age related eye diseases, notably cataract and glaucoma in the African-American and Hispanic populations, and age related macular degeneration in the white population. Uncorrected refractive error was a significant cause of decreased vision across ages, ethnic groups, and countries.

CONCLUSION

More data are needed on the magnitude and causes of visual loss for the Caribbean and Latin American countries. Rates of blindness and visual loss from available data within these countries are widely disparate. Prevention and control of avoidable blindness needs to be an ongoing focus in this region.

Prevalence [correction of prevalance] of functional blindness, visual impairment, and related functional deficits among elderly Mexican Americans

BACKGROUND

This report describes the prevalence and correlates of functional blindness and visual impairment among older Mexican Americans, using data on 2800 respondents from the Hispanic Established Populations for the Epidemiological Study of the Elderly.

METHODS

Bivariate and multivariate logistic regression analyses were used to examine the associations between corrected bilateral distant vision and sociodemographic characteristics, selected health conditions, self-reported health status, health care utilization, and functional dependence on the basis of assistance needed for basic and instrumental activities of daily living (ADLs).

RESULTS

Using a modified Snellen test for distance visual acuity, 5% of older Mexican Americans were found to be functionally blind, and 13.5% were found to be visually impaired. Vision loss was significantly associated with older age, lower education, hypertension, diabetes, poor self-rated health, and hospitalization during the year prior to the interview. Over 50% of functionally blind subjects required assistance with at least one basic ADL, compared with 15% of those who were visually impaired and 8% of those who were not visually impaired.

CONCLUSIONS

The prevalence of functional blindness in this sample of elderly Mexican Americans was higher than reported for the general elderly population, yet they also have higher rates of adequate vision because of the low prevalence of visual impairment. The results suggest a need for more research on the prevalence and impact of functional blindness and visual impairment on the health of older Mexican Americans.

Current Depression, Lifetime History of Depression, and Visual Acuity in Hispanic Adults

This study used data from the Hispanic Health and Nutrition Examination Survey to examine associations between bilateral visual acuity and depression among Cuban American, Mexican American, and Puerto Rican adults. Among Mexican Americans, the odds of current depression were significantly higher for those with moderate and greater impairment distance acuity (20/80 or worse). Among Cuban Americans, the odds of lifetime history of major depressive disorder were significantly higher for those with a distance visual acuity worse than 20/50. There were no significant associations between either past or current depression and impaired visual acuity in Puerto Ricans. These findings provide only limited support for the hypothesis that odds of past and current depression are greater in Hispanics with impaired visual acuity than in Hispanics who are fully sighted.