Cataract blindness in 4 regions of Guatemala: results of a population-based survey

Visual supplementation is an effective tool in cataract surgery counselling by eye-care practitioners

BACKGROUND

Informed consent constitutes an important aspect of eye care. However, patients often experience difficulties understanding and retaining information presented to them during consultations. This study investigates the efficacy of pictorial aids in supplementing preoperative counselling of patients undergoing cataract surgery.

METHODS

Patients attending routine pre-cataract surgery counselling were randomized to receive either a standard verbal consultation (control) or a verbal consultation with a digitalized pictorial aid illustrating key surgical steps (intervention). Patients were assessed after the consultation on their knowledge, satisfaction, anxiety and preparedness using an anonymous questionnaire.

RESULTS

Seventy-six patients were recruited and randomized into the control and intervention groups. The intervention group attained better Knowledge Scores (control: 5 [2-6] vs. intervention: 6 [6]), and more patients "strongly agreed" that they were more prepared (control: 78.9% vs. intervention: 97.4%, P=0.028). A higher proportion of patients in the control group either "disagreed" or "neither disagree nor agreed (neutral)" that they were less worried (control: 15.8% vs. intervention: 0.0%, Fisher's Exact Test P=0.025). Although the consultation duration was shorter in the intervention group (21±4mins vs. 27±6mins, P<0.001), the use of digital pictorial aids during consultation resulted in more effective counselling with increased patient knowledge, easier decision-making process and reduced patient anxiety.

CONCLUSION

Pictorial aids add to the repository of tools available to eye-care practitioners and are low-cost, easy to implement, and can effectively augment existing preoperative counselling processes to ensure accurate and effective preoperative counselling of patients.

Association of vision impairment and blindness with socioeconomic status in adults 50 years and older from Alto Amazonas, Peru

OBJECTIVE

To determine the relationship between socioeconomic status (SES) and visual impairment (VI) or blindness in the rural Peruvian Amazon, hypothesizing that higher SES would have a protective effect on the odds of VI or blindness.

METHODS

In this cross-sectional study of 16 rural communities in the Peruvian Amazon, consenting adults aged ≥ 50 years were recruited from ~30 randomly selected households per village. Each household was administered a questionnaire and had a SES score constructed using principal components analysis. Blindness and VI were determined using a ministry of health 3-meter visual acuity card.

RESULTS

Overall, 207 adults aged ≥ 50 were eligible; 146 (70.5%) completed visual acuity screening and answered the questionnaire. Of those 146 participants who completed presenting visual acuity screening, 57 (39.0%, 95% CI 30.2-47.1) were classified as visually impaired and 6 (4.1%, 95% CI 0.9-7.3) as blind. Belonging to the highest SES tercile had a protective effect on VI or blindness (OR 0.29, 95% CI 0.09 to 0.91, p = 0.034), with a linear trend across decreasing levels of SES (p = 0.019). This observed effect remained significant regardless of how SES groups were assigned.

CONCLUSION

Belonging to a higher SES group resulted in a lower odds of VI or blindness compared to those in the lowest SES group. The observation of a dose response provides confidence in the observed association, but causality remains unclear. Blindness prevention programs could maximize impact by designing activities that specifically target people with lower SES.

Pseudoexfoliation and Cataract Syndrome Associated with Genetic and Epidemiological Factors in a Mayan Cohort of Guatemala

The Mayan population of Guatemala is understudied within eye and vision research. Studying an observational homogenous, geographically isolated population of individuals seeking eye care may identify unique clinical, demographic, environmental and genetic risk factors for blinding eye disease that can inform targeted and effective screening strategies to achieve better and improved health care distribution. This study served to: (a) identify the ocular health needs within this population; and (b) identify any possible modifiable risk factors contributing to disease pathophysiology within this population. We conducted a cross-sectional study with 126 participants. Each participant completed a comprehensive eye examination, provided a blood sample for genetic analysis, and received a structured core baseline interview for a standardized epidemiological questionnaire at the Salama Lions Club Eye Hospital in Salama, Guatemala. Interpreters were available for translation to the patients’ native dialect, to assist participants during their visit. We performed a genome-wide association study for ocular disease association on the blood samples using Illumina’s HumanOmni2.5-8 chip to examine single nucleotide polymorphism SNPs in this population. After implementing quality control measures, we performed adjusted logistic regression analysis to determine which genetic and epidemiological factors were associated with eye disease. We found that the most prevalent eye conditions were cataracts (54.8%) followed by pseudoexfoliation syndrome (PXF) (24.6%). The population with both conditions was 22.2%. In our epidemiological analysis, we found that eye disease was significantly associated with advanced age. Cataracts were significantly more common among those living in the 10 districts with the least resources. Furthermore, having cataracts was associated with a greater likelihood of PXF after adjusting for both age and sex. In our genetic analysis, the SNP most nominally significantly associated with PXF lay within the gene KSR2 (p < 1 × 10⁻⁵). Several SNPs were associated with cataracts at genome-wide significance after adjusting for covariates (p < 5 × 10⁻⁸). About seventy five percent of the 33 cataract-associated SNPs lie within 13 genes, with the majority of genes having only one significant SNP (5 × 10⁻⁸). Using bioinformatic tools including PhenGenI, the Ensembl genome browser and literature review, these SNPs and genes have not previously been associated with PXF or cataracts, separately or in combination. This study can aid in understanding the prevalence of eye conditions in this population to better help inform public health planning and the delivery of quality, accessible, and relevant health and preventative care within Salama, Guatemala.

Cataract blindness in Hungary

AIM

To estimate the prevalence of blindness and visual impairment resulting from cataract in the population aged ≥50y in Hungary, and to assess the cataract surgical services.

METHODS

A rapid assessment of avoidable blindness (RAAB) was conducted. A total of 3523 eligible people were randomly selected and examined. Each participant underwent surgery for cataract was interviewed with regard to the year, place, and costs of the surgery. Participants with obvious cataract were asked why they had not yet undergone surgery (barriers to surgery).

RESULTS

An estimated 12 514 people were bilaterally blind; the visual acuity (VA) in 19 293 people was <6/60, and the VA in 73 962 people was <6/18 in the better eye due to cataract. An estimated 77 933 eyes are blind; 98 067 eyes had a VA of <6/60, and an estimated 277 493 eyes had a VA of <6/18 due to cataract. Almost all cataract surgeries were conducted in government hospitals. The age- and sex-adjusted cataract surgical coverage with VA<3/60 in eyes was 90.0%. The rate of good visual outcome after surgery was 79.5%. Ocular comorbidity was the main cause of poor outcome (78.1%), followed by late complications (such as posterior capsule opacification) (17.2%), inadequate optical correction (3.1%), and surgical complications (1.6%). The main barrier to surgery in people with bilateral cataract and VA of <6/60 was 'need not felt'.

CONCLUSION

The prevalence of visual impairment resulting from cataract is slightly higher than expected. The quality of the cataract surgical service seems adequate in Hungary. However, the number of cataract operations per year should continue to increase due to the increasing patient demands and the aging population.

Field Testing Project to Pilot World Health Organization Eye Health Indicators in Latin America

PURPOSE

To develop and implement mechanisms to collect, report, and assess the World Health Organization (WHO) core eye health indicators in Chile, Honduras, Mexico, Peru, and Uruguay.

METHODS

Simple templates for a situational analysis (of data collection and reporting processes), a national data collection strategy, and a national work plan to implement the core eye health indicators were developed. Public and private sector representatives from the ministries of health (MOHs), national vision committees, and national societies of ophthalmology of each country used these tools with 2013 baseline data to improve their data collection processes and collected 2015 data. Final analysis and cross-validation were performed using intraocular lens sales data and last observation carried forward imputation.

RESULTS

Study tools were effectively implemented in all five countries and resulted in improved intersectoral stakeholder collaboration and communications, which improved the data collection and reporting processes. More complete and accurate data were reported by 2015 compared to the 2013 baseline.

CONCLUSIONS

Multisectoral stakeholders, including national professional societies and national vision committees, should collaborate with MOHs to improve the quality of data that are reported to WHO. This study involved these stakeholders in the data collection processes to better understand the realities of indicator implementation, better manage their expectations, and improve data quality. WHO Member States across the globe can feasibly adapt the study tools and methodologies to strengthen their data collection processes. Overall, the reliability and validity of the indicators is hampered with limitations that prevent fully accurate data from being collected.

The Effect of Counseling on Cataract Patient Knowledge, Decisional Conflict, and Satisfaction

PURPOSE

Cataract is the leading cause of non-refractive preventable blindness, and comprehensive strategies to increase cataract surgery rates are imperative, including high-quality supportive patient education. We evaluated the effectiveness of non-physician pre-surgical counselors teaching patients about cataract and cataract surgery in improving patient knowledge, decisional conflict, and satisfaction.

METHODS

A survey was given before and after 61 newly-diagnosed cataract patients underwent pre-surgical counseling at the Aravind Eye Hospital, Madurai, India. The survey measured change in cataract knowledge and decisional conflict, a measure of anxiety surrounding the decision to undergo surgery, along with patient satisfaction. Multiple regression was used to identify factors that influenced change in knowledge.

RESULTS

Both patient knowledge scores and decisional conflict scores improved following counseling (mean difference +2.0, p = 0.004 and +8.4, p < 0.0001, respectively). Multiple regression analysis identified female sex (β = 2.5, p < 0.001) and being illiterate (β = 1.7, p = 0.04) as important predictors of increased knowledge post-counseling.

CONCLUSION

Counseling both improved knowledge and reduced decisional conflict about cataract surgery, particularly among patients who had traditionally had more limited access to healthcare such as women and illiterate patients. Increased use of high quality counseling might help to further reduce the global burden of cataract and other forms of blindness.

The Correlation of Age and Postoperative Visual Acuity for Age-Related Cataract

Purpose. Clinically, what is the best time for age-related cataract (ARC) patients to receive surgeries and get the most benefits is important. We explored the relationship between age and presenting postoperative visual acuity (POVA) in patients from rural China. Methods. Three Lifeline Express Hospital Eye-Train missions of Peking University People's Hospital were chosen. At the first day after surgery, 3452 ARC eyes with the presenting POVA ≥ 6/60 were enrolled. The relationship between age and POVA was analyzed statistically. Results. In these three missions, there were more female patients than males; the ratio of females to males was 1.71. The average age of females was older than males. Overall, the percentages of patients with good visual outcomes (≥6/18) were significantly decreased with aging. Different regions had variations, but the trends were the same. There was weak linear correlation between age and POVA. The correlations of females were stronger than males in Yuncheng and Sanmenxia and weaker than males in Zhoukou. Conclusion. The good visual outcomes of presenting POVA were significantly decreased with aging and there were weak linear correlations between age and POVA in rural China. The linear correlation might be influenced by the difference of gender and region.

The first rapid assessment of avoidable blindness (RAAB) in Thailand

BACKGROUND

The majority of vision loss is preventable or treatable. Population surveys are crucial for planning, implementation, and monitoring policies and interventions to eliminate avoidable blindness and visual impairments. This is the first rapid assessment of avoidable blindness (RAAB) study in Thailand.

METHODS

A cross-sectional study of a population in Thailand age 50 years old or over aimed to assess the prevalence and causes of blindness and visual impairments. Using the Thailand National Census 2010 as the sampling frame, a stratified four-stage cluster sampling based on a probability proportional to size was conducted in 176 enumeration areas from 11 provinces. Participants received comprehensive eye examination by ophthalmologists.

RESULTS

The age and sex adjusted prevalence of blindness (presenting visual acuity (VA) <20/400), severe visual impairment (VA <20/200 but ≥20/400), and moderate visual impairment (VA <20/70 but ≥20/200) were 0.6% (95% CI: 0.5-0.8), 1.3% (95% CI: 1.0-1.6), 12.6% (95% CI: 10.8-14.5). There was no significant difference among the four regions of Thailand. Cataract was the main cause of vision loss accounted for 69.7% of blindness. Cataract surgical coverage in persons was 95.1% for cut off VA of 20/400. Refractive errors, diabetic retinopathy, glaucoma, and corneal opacities were responsible for 6.0%, 5.1%, 4.0%, and 2.0% of blindness respectively.

CONCLUSION

Thailand is on track to achieve the goal of VISION 2020. However, there is still much room for improvement. Policy refinements and innovative interventions are recommended to alleviate blindness and visual impairments especially regarding the backlog of blinding cataract, management of non-communicative, chronic, age-related eye diseases such as glaucoma, age-related macular degeneration, and diabetic retinopathy, prevention of childhood blindness, and establishment of a robust eye health information system.

The cataract situation in Latin America: barriers to cataract surgery

PURPOSE

To provide an update of cataract data and barriers to cataract surgery in Latin America.

DESIGN

Review and longitudinal study.

METHODS

Cataract surgery rates and other related indicators that have been reported to the VISION 2020 Latin America program since 2005 were reviewed. PubMed was searched for publications concerning regional epidemiologic studies related to cataract, cataract surgery, barriers, outcomes, and cataract prevalence between January 2012 and October 2013 to obtain the most up-to-date data from 19 countries.

RESULTS

The weighted mean regional cataract surgery rate has increased by an impressive 70% since 2005, from 1562 to 2672 cataract surgeries per 1 million inhabitants. The weighted mean number of ophthalmologists per 1 million inhabitants in the region is approximately 62. Cataract surgery coverage varies widely in Latin America, from a meager 15% in El Salvador to a more satisfactory 77% in Uruguay. Five recent surveys indicate that lack of awareness of cataract and the surgery treatment option as well as the cost of the surgery are the main barriers to cataract surgery.

CONCLUSIONS

In spite of the increasing rates of cataract surgery and the more-than-adequate number of ophthalmologists in Latin America, it is not known how many ophthalmologists actually perform surgery. Coverage remains less than satisfactory across the region. Barriers to cataract surgery hinder the efforts of eye care programming. More comprehensive eye care programs and training centers are needed so that they can focus on reaching the underserved and unaware communities, increase surgery output and uptake, and improve outcomes.

Elimination of avoidable blindness due to cataract: where do we prioritize and how should we monitor this decade?

Background:

In the final push toward the elimination of avoidable blindness, cataract occupies a position of eminence for the success of the Right to Sight initiative.

Aims:

Review existing situation and assess what monitoring indicators may be useful to chart progress towards attaining the goals of Vision 2020.

Settings and Design:

Review of published papers from low and middle income countries since 2000.

Materials and Methods:

Published population-based data on prevalence of cataract blindness/visual impairment were accessed and prevalence of cataract blindness/visual impairment computed, where not reported. Data on prevalence of cataract blindness, cataract surgical coverage at different visual acuity cut offs, surgical outcomes, and prevalence of cataract surgery were analyzed. Scatter plots were used to look at relationships of some variables, with Human Development Index (HDI) rank. Available data on Cataract Surgical Rate (CSR) was plotted against prevalence of cataract surgery reported from surveys.

Results:

Worse HDI Ranks were associated with higher prevalence of cataract blindness. Most studies showed that a significant proportion of the blind were covered by surgery, while a fifth showed that a significant proportion, were operated before they went blind. A good visual outcome after surgery was positively correlated with higher surgical coverage. CSR was positively correlated with cataract surgical coverage.

Conclusions:

Cataract surgical coverage is increasing in most countries at vision <3/60 and visual outcomes after cataract surgery are improving. Establishing population-based surveillance of cataract surgical need and performance is a strong monitoring tool and will help program planners immensely.

The challenges in improving outcome of cataract surgery in low and middle income countries

Cataract is the leading cause of blindness globally and surgery is the only known measure to deal with it effectively. Providing high quality cataract surgical services is critical if patients with cataract are to have their sight restored. A key focus of surgery is the outcome of the procedure. In cataract surgery this is measured predominantly, using visual acuity. Population- and hospital-based studies have revealed that the visual outcome of cataract surgery in many low and middle income settings is frequently sub-optimal, often failing to reach the recommended standards set by the World Health Organization (WHO). Another way of measuring outcome of cataract surgery is to ask patients for their views on whether surgery has changed the functioning of their eyes and their quality of life. There are different tools available to capture patient views and now, these patient-reported outcomes are becoming more widely used. This paper discusses the visual outcome of cataract surgery and frames the outcome of surgery within the context of the surgical service, suggesting that the process and outcome of care cannot be separated. It also discusses the components of patient-reported outcome tools and describes some available tools in more detail. Finally, it describes a hierarchy of challenges that need to be addressed before a high quality cataract surgical service can be achieved.

An estimation of the worldwide economic and health burden of visual impairment

This study aims to provide a rigorous estimate of the worldwide costs of visual impairment (VI), and the associated health burden. The study used a prevalence-based model. Prevalence rates for mild VI (visual acuity (VA) worse than 6/12 but not worse than 6/18), moderate VI (VA worse than 6/18 but not worse than 6/60) and blindness (VA worse than 6/60) were applied to population forecasts for each World Health Organisation (WHO) subregion. The limited available country cost data were extrapolated between subregions using economic and population health indicators. Age and gender subgroup population numbers were derived from United Nations' data. Costs and the health burden of VI were estimated for each world subregion using published disease prevalence rates, health care expenditures and other economic data. The study includes direct health care costs, indirect costs and the health burden of VI. The total cost of VI globally was estimated at $3 trillion in 2010, of which $2.3 trillion was direct health costs. This burden is projected to increase by approximately 20% by 2020. VI is associated with a considerable disease burden. Unless steps are taken to reduce prevalence through prevention and treatment, this burden will increase alongside global population growth.

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.

Cataract surgery outcome at a rural eye care hospital in India

We report the final outcomes, based on final visual acuity, of patients who underwent cataract surgery at an outreach rural ophthalmology unit and document the details of the ophthalmic examination, type of surgery, intra- and postoperative complications and the final visual acuity. Of 208 eyes (198 patients), 81.3% had small incision cataract surgery and 18.7% had phacoemulsification. We believe that, with good planning and the proper utilization of available resources, it is possible to achieve a good visual outcome in the great majority of cases.

Cataract surgery rates in latin america: a four-year longitudinal study of 19 countries

PURPOSE

To collect cataract surgery rates data in 19 Latin American countries over a 4-year period as data published to date have been limited.

METHODS

Cataract surgery rates were obtained from National Society of Ophthalmology, National VISION 2020/Prevention of Blindness Committee and Ministry of Health representatives for each country for 2005 to 2008. Economic (gross national income per capita) and other data were collected from publicly available databases. Linear and power correlations between gross national incomes and cataract surgery rates were calculated.

RESULTS

Over the study period, most countries increased their cataract surgery rates, with the largest increases observed for Venezuela (186%), Nicaragua (183%), Costa Rica (100%), Uruguay (97%), and Peru (88%). Mean cataract surgery rates for 2005, 2006, 2007, and 2008 for the ensemble of countries were 1545, 1684, 1660, and 1822 per million population, respectively, with a growth over the study period of 17.9%, concurrent with an increase of 57 million (11.5%) in the population. A good correlation between cataract surgery rate and gross national income per capita was found (P < .001).

CONCLUSIONS

Although progress is being made in the region, the cataract surgery rates represent only one parameter. When they are examined in the context of cataract surgical coverage it is clear that substantial proportions of bilaterally blind persons are still not receiving surgery.

Prevalence and causes of visual impairment in a Brazilian population: the Botucatu Eye Study

Background

This paper reports population-based data on the prevalence and causes of visual impairment among children and adults in Botucatu, Brazil.

Methods

A population-based cross-sectional study was conducted involving a random start point and then systematic sampling of an urban Brazilian population in the city of Botucatu. There were approximately 3 300 individuals aged 1 to 91 years who were eligible to participate in the study. Of this sample, 2485 (75.3%) underwent ophthalmic examination. The ophthalmic examination included uncorrected (presenting) and best corrected distance visual acuity using standardized protocols. The primary cause of decreased visual acuity was identified for all patients with visual impairment.

Results

Presenting low vision and presenting blindness were found in 5.2% (95% CI: 4.3–6.1) and 2.2% (95% CI: 1.6–2.8) of the population, respectively. Unilateral presenting low vision and unilateral presenting blindness were found in 8.3% (95% CI: 7.2–9.5) and 3.7% (95% CI: 2.9–4.4) of the population respectively. Best corrected low vision was found in 1.3% of the population (95% CI: 0.9–1.7) and best corrected blindness was discovered in 0.4% of people (95% CI: 0.2–0.7). The main cause of presenting low vision was refractive error (72.3%) and cataract was the most prevalent cause of blindness (50%).

Conclusion

The main causes of low vision and blindness in this Brazilian city were uncorrected refractive errors, cataract, and retinal diseases. Programs to further reduce the burden of visual impairment need to be targeted toward the correction of refractive error and surgery for cataracts.

Rapid Assessment of Avoidable Blindness in India

BACKGROUND

Rapid assessment of avoidable blindness provides valid estimates in a short period of time to assess the magnitude and causes of avoidable blindness. The study determined magnitude and causes of avoidable blindness in India in 2007 among the 50+ population.

METHODS AND FINDINGS

Sixteen randomly selected districts where blindness surveys were undertaken 7 to 10 years earlier were identified for a follow up survey. Stratified cluster sampling was used and 25 clusters (20 rural and 5 urban) were randomly picked in each district.. After a random start, 100 individuals aged 50+ were enumerated and examined sequentially in each cluster. All those with presenting vision <6/18 were dilated and examined by an ophthalmologist. 42722 individuals aged > = 50 years were enumerated, and 94.7% examined. Based on presenting vision,, 4.4% (95% Confidence Interval[CI]: 4.1,4.8) were severely visually impaired (vision<6/60 to 3/60 in the better eye) and 3.6% (95% CI: 3.3,3.9) were blind (vision<3/60 in the better eye). Prevalence of low vision (<6/18 to 6/60 in the better eye) was 16.8% (95% CI: 16.0,17.5). Prevalence of blindness and severe visual impairment (<6/60 in the better eye) was higher among rural residents (8.2%; 95% CI: 7.9,8.6) compared to urban (7.1%; 95% CI: 5.0, 9.2), among females (9.2%; 95% CI: 8.6,9.8) compared to males (6.5%; 95% CI: 6.0,7.1) and people above 70 years (20.6%; 95% CI: 19.1,22.0) compared to people aged 50-54 years (1.3%; 95% CI: 1.1,1.6). Of all blindness, 88.2% was avoidable. of which 81.9% was due to cataract and 7.1% to uncorrected refractive errors/uncorrected aphakia.

CONCLUSIONS

Cataract and refractive errors are major causes of blindness and low vision and control strategies should prioritize them. Most blindness and low vision burden is avoidable.