Prevalence and causes of low vision and blindness in an urban population: The Chennai Glaucoma Study

Aim:

To evaluate the prevalence and causes of low vision and blindness in an urban south Indian population.

Settings and Design:

Population-based cross-sectional study. Exactly 3850 subjects aged 40 years and above from Chennai city were examined at a dedicated facility in the base hospital.

Materials and Methods:

All subjects had a complete ophthalmic examination that included best-corrected visual acuity. Low vision and blindness were defined using World Health Organization (WHO) criteria. The influence of age, gender, literacy, and occupation was assessed using multiple logistic regression.

Statistical Analysis:

Chi-square test, t-test, and multivariate analysis were used.

Results:

Of the 4800 enumerated subjects, 3850 subjects (1710 males, 2140 females) were examined (response rate, 80.2%). The prevalence of blindness was 0.85% (95% CI 0.6–1.1%) and was positively associated with age and illiteracy. Cataract was the leading cause (57.6%) and glaucoma was the second cause (16.7%) for blindness. The prevalence of low vision was 2.9% (95% CI 2.4–3.4%) and visual impairment (blindness + low vision) was 3.8% (95% CI 3.2–4.4%). The primary causes for low vision were refractive errors (68%) and cataract (22%).

Conclusions:

In this urban population based study, cataract was the leading cause for blindness and refractive error was the main reason for low vision.     

Comprehensive vision care in urban communities: The pediatric outreach program

BackgroundThe Illinois College of Optometry's (ICO) Pediatric Outreach Program (POP) provides comprehensive vision care for high-risk children from birth to approximately 5 years of age in partnership with early intervention programs throughout the city of Chicago. Grant funds assisted in the ability to deliver vision services and spectacles to uninsured children. This report describes the structure and organization of the POP and presents the visual data.MethodsComprehensive eye examinations were performed on 4,298 children ages birth to approximately 5 years at 76 early intervention program sites. All of the children evaluated were enrolled from early intervention/Head Start programs. Visual acuity determination (by Lea method), assessment of binocular status, stereopsis evaluation, cycloplegic retinoscopy, and ocular health evaluations were performed. As necessary, eyeglasses were prescribed. Amblyogenic risk factors, strabismus, and ocular pathology were identified.ResultsOf the 4,298 children examined, 49% were boys and 51% were girls. Two percent were younger than 12 months old, 6% were 1.1 to 2 years old, 12% were 2.1 to 3 years, 30% were 3.1 to 4 years, 35% were 4.1 to 5 years, 14% were 5.1 to 6 years, and 1% were older than 6 years. Hyperopia and emmetropia were the most common refractive classifications among the children examined. Approximately 6.5% had risk factors for isometropic amblyopia, and 2.3% had risk factors for anisometropic amblyopia. Approximately 1% of the children had strabismus. Less than 1% of the children examined were identified with ocular pathology. Spectacles were dispensed to 16.6% of the children examined.ConclusionsThe Pediatric Outreach Program provides early identification and treatment of abnormal visual conditions, ensuring that children have maximal visual acuity and visual function. The educational aspects of the program have also contributed to its successes. Education for parents and early intervention agency staff promote the importance of comprehensive vision examinations for children 5 years of age and younger.     

Factors related to vision care in an older adult cohort.

PURPOSE: This study provides cross-sectional data on eye care utilization in a community-based adult population. METHODS: Data are from a questionnaire administered during the 7-year follow-up of the Epidemiology of Hearing Loss Study in 2000 to 2002. Participants in the population-based Beaver Dam Eye Study were eligible for the Epidemiology of Hearing Loss Study, which began in 1997. The primary outcome was self-reported vision testing within the past year. RESULTS: Subject ages ranged from 55 to 99 years (n = 2433), and 60.4% were female. Fifty-three percent of subjects reported they had their vision tested in the past year. Diabetes was self-reported by 11.5% of subjects, and 70.9% of diabetic participants had their vision tested in the past year. A current hospitalization or health insurance plan was reported by 98.6% of subjects. In multivariate analyses, self-reported factors significantly associated with having a vision test in the past year were female gender (odds ratio [OR] = 1.27; 95% confidence interval [CI] 1.06-1.52), current use of refractive correction for distance (OR = 1.98; 95% CI 1.56-2.52), glaucoma (OR = 3.52; 95% CI 2.37-5.24), cataract surgery (OR = 1.57; 95% CI 1.21-2.03), age-related macular degeneration (ARMD) (OR = 1.74; 95% CI 1.22-2.47), diabetes (OR = 2.46; 95% CI 1.83-3.31), visiting a primary care practitioner for any reason in the past year (OR = 1.72; 95% CI 1.32-2.25), having a hearing test in the past year (OR = 1.79; 95% CI 1.40-2.28), and the cessation of driving because of poor vision (OR = 1.64; 95% CI 1.16-2.52). In participants 65 years of age or older, having private insurance was associated with increased odds (OR = 3.39, 95% CI 1.82-6.31) of vision testing in the past year. CONCLUSION: This study suggests that chronic ocular conditions, diabetes, health insurance beyond government entitlements, and the use of other healthcare services are associated with increased eye care utilization.     

Cicatricial entropion and trichiasis in an urban Australian population

BACKGROUND: Cicatricial entropion and trichiasis may be caused by a variety of diseases, of which trachomatous entropion is the commonest worldwide. The spectrum of disease in the authors' community is quite different. The purpose of this study was to establish the aetiology of entropion and trichiasis in patients referred to a Melbourne-based subspecialty oculoplastics practice, excluding epiblepharon, congenital entropion and involutional entropion, and to compare the final diagnosis with the referring diagnosis. METHODS: All records of patients with cicatricial entropion and trichiasis presenting to the practice of one of the authors over the period 1990-2000 were analysed. Demographic data, referring diagnosis and final diagnosis were tabulated. RESULTS: The commonest final diagnosis was ocular cicatricial pemphigoid. In only a small proportion of cases was this diagnosis considered by the referring practitioners. In addition, two cases of undiagnosed conjunctival neoplasia presented with entropion and trichiasis. CONCLUSION: In all patients with entropion and trichiasis, a careful history and examination should be obtained and appropriate investigations performed to try and establish a firm diagnosis.     

Thirty years in an urban low vision clinic: changes in prescribing habits of low vision practitioners.

PURPOSES: The purposes of this study were to determine the types of low vision devices (LVDs) prescribed by clinicians in a large optometrist led hospital low vision clinic and to investigate changes in these prescribing habits between 1973 and 2003. METHODS: Data were collected from departmental records for all patients attending the low vision clinic at Moorfields Eye Hospital in London, U.K., during the month of June in 1973, 1978, 1983, 1988, 1993, 1998, and 2003. The primary outcome measure was the type or types of LVDs prescribed to patients attending the clinic for the first time. Data were collected on the age, sex, and diagnosis of all patients attending the clinic. RESULTS: One thousand four hundred thirty-eight patient visits were identified, of which 563 (39%) were first attendances. The median age of the patients examined did not change significantly over this time. Eighty-four percent of the patients attending the clinic for the first time were prescribed at least one LVD. The devices most frequently prescribed to new patients were nonilluminated hand magnifiers, illuminated hand magnifiers, and illuminated stand magnifiers. There was a linear increase in the proportion of hand magnifiers prescribed between 1973 and 2003 (r = 0.62, p < 0.05) and a corresponding decrease in the number of near spectacle-mounted telescopes prescribed (r = 0.70, p < 0.05). CONCLUSIONS: Between 1973 and 2003, the low vision clinic at Moorfields Eye Hospital provided nearly 100,000 low vision consultations. The demographics of patients attending the clinic remained remarkably constant over this time. The number of spectacle-mounted devices prescribed to new patients fell between 1973 and 2003. It is thought this is in part the result of the increased availability of electronic magnification devices and the development of illuminated hand magnifiers. The development of the acrylic bright field magnifier and LED-illuminated LVDs have had particular clinical impact.     

Need for eye and vision care in an underserved population: refractive errors and other ocular anomalies in the Sioux

The Native American population has a significant unmet need for eye and vision care. Beginning with the onset of continuous eye care on two reservations in North and South Dakota, a compilation was done of refractive errors and other clinical findings in 1886 Sioux Indians. The results are similar to previous findings in the Navajo, Cheyenne, and Zuni Indians. This paper contributes to the epidemiological characterization of an underserved population, demonstrates the degree of unmet needs before continuous eye care services, and hopefully will aid in the planning, implementation, and evaluation of optometric care for such groups.     

Unilateral visual impairment in an urban population in southern India

This study assessed the prevalence and causes of unilateral visual impairment in the urban population of Hyderabad city as part of the Andhra Pradesh Eye Disease Study. Stratified, random, cluster, systematic sampling was used to select 2,954 subjects from 24 clusters representative of the population of Hyderabad. Eligible subjects underwent detailed eye examination including logMAR visual acuity, refraction, slitlamp biomicroscopy, applanation tonometry, gonioscopy, dilatation, cataract grading, and stereoscopic evaluation of fundus. Automated threshold visual fields and slitlamp and fundus photography were done when indicated by standardised criteria. Unilateral visual impairment was defined as presenting distance visual acuity < 6/18 in the worse eye and > or = 6/12 in the better eye, which was further divided into unilateral blindness (visual acuity < 6/60 in the worse eye) and unilateral moderate visual impairment (visual acuity < 6/18-6/60 in the worse eye). A total of 2,522 subjects (85.4% of eligible), including 1,399 > or = 30 years old, participated in the study. In addition to the 1% blindness and 7.2% moderate visual impairment (based on bilateral visual impairment criteria) reported earlier in this sample, 139 subjects had unilateral visual impairment, an age-gender-adjusted prevalence of 3.8% (95% confidence interval 2.7-4.9%). The major causes of this visual impairment 39.9% were refractive error (42.9%), cataract (14.4%), corneal disease (11.5%), and retinal disease (11.2%). Of this unilateral visual impairment was blindness. The major causes of unilateral blindness were corneal disease (23.2%), cataract (22.5%), retinal disease (18%), and optic atrophy (12.9%). On the other hand, the predominant cause of unilateral moderate visual impairment was refractive error (67%) followed by cataract (9%). Of the total unilateral visual impairment, 34.3% was present in those < 30 years old and 36.2% in those 30-49 years old. Unilateral visual impairment afflicts approximately 1 in 25 persons in this urban population. A large proportion of this unilateral visual impairment is present in younger age groups. The causes of unilateral visual impairment, like those of bilateral visual impairment in this population, are varied, suggesting therefore, that in addition to the current focus of eye care in India predominantly on cataract, other causes of visual impairment need to be addressed as well.     

Refractive error in children in an urban population in New Delhi

PURPOSE: To assess the prevalence of refractive error and related visual impairment in school-aged children in an urban population in New Delhi, India. METHODS: Random selection of geographically defined clusters was used to identify a sample of children 5 to 15 years of age. From December 2000 through March 2001, children in 22 selected clusters were enumerated through a door-to-door survey and examined at a local facility. The examination included visual acuity measurements, ocular motility evaluation, retinoscopy and autorefraction under cycloplegia, and examination of the anterior segment, media, and fundus. Myopia was defined as spherical equivalent refractive error of at least -0.50 D and hyperopia as +2.00 D or more. Children with reduced vision and a sample of those with normal vision underwent independent replicate examinations for quality assurance in four of the clusters. RESULTS: A total of 7008 children from 3426 households were enumerated, and 6447 (92.0%) examined. The prevalence of uncorrected, baseline (presenting), and best corrected visual acuity of 20/40 or worse in the better eye was 6.4%, 4.9%, and 0.81%, respectively. Refractive error was the cause in 81.7% of eyes with vision impairment, amblyopia in 4.4%, retinal disorders in 4.7%, other causes in 3.3%, and unexplained causes in the remaining 5.9%. There was an age-related shift in refractive error from hyperopia in young children (15.6% in 5-year-olds) toward myopia in older children (10.8% in 15-year-olds). Overall, hyperopia was present in 7.7% of children and myopia in 7.4%. Hyperopia was associated with female gender. Myopia was more common in children of fathers with higher levels of education. CONCLUSIONS: Reduced vision because of uncorrected refractive error is a major public health problem in urban school-aged children in India. Cost-effective strategies are needed to eliminate this easily treated cause of vision impairment.     

Literature and information in vision care and vision science

The explosion of information in vision care and vision science makes keeping up with the literature and information in the field challenging. This report examines the nature of literature and information in vision care and vision science. A variety of topics are discussed, including the general nature of scientific and clinical journals, journals in vision science and vision care, resources available for searches for literature and information, and issues involved in the evaluation of journals and other information sources. Aspects of the application of citation analysis to vision care and vision science are reviewed, and a new citation analysis of a leading textbook in vision care (Borish's Clinical Refraction) is presented. This report is directed toward anyone who wants to be more informed about the literature of vision care and vision science, whether they are students, clinicians, educators, or librarians.     

Awareness of eye donation in an urban population in India.

PURPOSE: Awareness of eye donation and willingness to pledge eyes for donation was assessed in the urban population of Hyderabad, India, where corneal blindness is a significant problem. METHODS: A total of 2522 subjects of all ages, representative of the Hyderabad population, participated in the Andhra Pradesh Eye Disease Study. Subjects >15 years old were interviewed regarding awareness of eye donation and willingness to pledge eyes for donation. RESULTS: Age-gender-adjusted prevalence of awareness of eye donation was 73.8% (95% CI: 66.5-81.0%) but only 1.9% (95% CI: 0.16-3.66%) had pledged eyes. With multivariate analysis, significantly less awareness of eye donation was found in illiterate subjects (OR 0.1; 95% CI: 0.1-0.14), subjects > or =70 years old (OR 0.3; 95% CI: 0.2-0.6), subjects of lower socio-economic status (OR 0.4; 95% CI: 0.3-0.6), females (OR 0.6; 95% CI: 0.5-0.8) and Muslims (OR 0.7; 95% CI: 0.6-0.9). Media was the major source of information about eye donation. Of those aware of eye donation, 44.9% were willing to pledge eyes. Willingness to pledge eyes for donation was significantly lower in Muslims (OR 0.18; 95% CI: 0.13-0.24) than in Hindus and in subjects > or =60years old (OR 0.3; 95% CI: 0.2-0.5). CONCLUSIONS: These data show that although only a few had pledged eyes there is enough potential in this population for obtaining many more corneas for transplantation. The information about distribution and demographic associations of awareness and willingness for eye donation could help in developing strategies to increase procurement of corneas for dealing with corneal blindness.     

Ocular trauma in an urban population. Review of 1132 cases

A retrospective survey was done of all ocular and adnexal trauma cases seen at a large metropolitan hospital during a 6-month period. By determining patient demographics, causes of the eye injuries, and extent of ocular damage, the authors hoped to delineate areas where preventive measures might decrease such trauma. Demographic and clinical data on 1132 patients were analyzed. Most patients were in the first three decades of life and were male. Blunt trauma was the most common type of injury. Assault was the most common cause and accounted for the highest number of serious injuries. Eye injuries associated with violence are difficult to prevent using conventional strategies that are usually effective in the home and workplace.     

Prevalence of blindness and visual impairment in an elderly urban population

Background: Accurate data on the prevalence of blindness in urban populations is not readily available. The Australian Longitudinal Study of Ageing is a prospective multidimensional study examining a broad range of age-related health issues, including visual function.
Methods: A population-based sample of 1466 persons, 70 years of age and over, from the Adelaide metropolitan area underwent visual acuity measurements.
Results: Approximately 1% were legally blind by Australian definitions.
Conclusions: This percentage is low by world standards, however projections indicate that the absolute number of blind elderly people is rapidly increasing. Data such as this are crucial for the planning of adequate ophthalmic care.