Socioeconomic inequality in the global burden of refraction disorders: results from the Global Burden of Diseases Study 2017.

PURPOSE: To explore socioeconomic inequality in global burden of refraction disorders using disability-adjusted life years (DALYs). METHODS: World Bank categorical and national DALY numbers, crude rates and age-standardized rates caused by refraction disorders between 1990 and 2017 were obtained. Gini coefficient and concentration index were computed to assess trends in global health inequality in refraction disorders burden. RESULTS: Lower middle-income countries had the highest burden of refraction disorders and greatest decline in age-standardized DALY rates of 15.9% (171.0 in 1990; 143.8 in 2017), followed by upper middle-income countries, with a 9.7% decline (103.7 in 1990; 93.7 in 2017). High-income countries had the lowest age-standardized DALY rates (70.4 in 1990; 65.7 in 2017), while low-income countries had the lowest DALY numbers. Between-country inequality decreased, with Gini coefficient declining from 0.203 in 1990 to 0.184 in 2017. Socioeconomic-associated inequality also decreased, with concentration index changing from -0.060 in 1990 to -0.041 in 2017. Small peaks of DALY numbers and crude rates occurred in the age group of 5-9 years in countries with different income levels. An earlier occurrence of high peaks of DALY estimates in older adults had been observed in countries with lower income. CONCLUSION: Middle-income countries are more burdened with refraction disorders but have achieved great progress in the last few decades. The global health improvement in refraction disorders has been accompanied by narrowing inequality. Older adults in lower income countries tend to suffer from refraction disorders at an earlier age, compared with older adults in higher income countries.

The cost-effectiveness of alternative vision screening models among preschool children in rural China.

PURPOSE: To explore the accuracy and cost-effectiveness of three vision screening models among preschool children in rural China. METHODS: Vision screening was carried out among children aged 4-5 years in 65 preschools in two counties in Northwest China, using Crowded Single Lea Symbols to test visual acuity. Children were assigned randomly by school to one of three screening models: screening by teachers (15 schools, 1835 children), local optometrists (30 schools, 1718 children) or volunteers (20 schools, 2183 children). Children identifying ≥2 symbols incorrectly in either eye failed screening. Accuracy of screening was compared with screenings executed by experienced optometrists among 141 children selected randomly from the three screening models. Direct and indirect costs for each model were assessed. Costs to detect a true case failed screening were estimated. RESULTS: The sensitivity for three models ranged from 76.9% to 87.5%, specificity from 84.9% to 86.7% and standardized positive predictive value from 83.7% to 85.7%. None differed significantly between models. The costs per case detected were $37.53, $59.14 and $52.19 for the teachers, local optometrists and volunteers. In producing the cost estimates for teacher screening and local optometrist screening models, we used a salary payment that was identical for both models (with the salary being equal to that of the optometrist). The teacher screening model was the most cost-effective. CONCLUSION: Accuracy of screening by teachers, local optometrists and volunteers was the same in this setting, but the use of teachers was most cost-effective, reducing the cost per case detected by almost 40%.

Cluster-randomized controlled trial of the effects of free glasses on purchase of children's glasses in China: The PRICE (Potentiating Rural Investment in Children's Eyecare) study.

BACKGROUND: Offering free glasses can be important to increase children's wear. We sought to assess whether "Upgrade glasses" could avoid reduced glasses sales when offering free glasses to children in China. METHODS: In this cluster-randomized, controlled trial, children with uncorrected visual acuity (VA)< = 6/12 in either eye correctable to >6/12 in both eyes at 138 randomly-selected primary schools in 9 counties in Guangdong and Yunnan provinces, China, were randomized by school to one of four groups: glasses prescription only (Control); Free Glasses; Free Glasses + offer of $15 Upgrade Glasses; Free Glasses + offer of $30 Upgrade Glasses. Spectacle purchase (main outcome) was assessed 6 months after randomization. RESULTS: Among 10,234 children screened, 882 (8.62%, mean age 10.6 years, 45.5% boys) were eligible and randomized: 257 (29.1%) at 37 schools to Control; 253 (28.7%) at 32 schools to Free Glasses; 187 (21.2%) at 31 schools to Free Glasses + $15 Upgrade; and 185 (21.0%) at 27 schools to Free Glasses +$30 Upgrade. Baseline ownership among these children needing glasses was 11.8% (104/882), and 867 (98.3%) children completed follow-up. Glasses purchase was significantly less likely when free glasses were given: Control: 59/250 = 23.6%; Free glasses: 32/252 = 12.7%, P = 0.010. Offering Upgrade Glasses eliminated this difference: Free + $15 Upgrade: 39/183 = 21.3%, multiple regression relative risk (RR) 0.90 (0.56-1.43), P = 0.65; Free + $30 Upgrade: 38/182 = 20.9%, RR 0.91 (0.59, 1.42), P = 0.69. CONCLUSIONS: Upgrade glasses can prevent reductions in glasses purchase when free spectacles are provided, providing important program income. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02231606. Registered on 31 August 2014.

Global Patterns in Health Burden of Uncorrected Refractive Error.

Purpose: To evaluate the global patterns in health burden of uncorrected refractive error (URE) by year, age and sex, region, and socioeconomic status, using disability-adjusted life years (DALYs). Methods: Global, regional, or national DALY numbers, crude DALY rates, and age-standardized DALY rates caused by URE, by year, or age and sex, were obtained from the Global Burden of Disease Study 2013. Human development index (HDI) in 2013 as a national socioeconomic indicator was obtained from the Human Development Report. Kruskal-Wallis test and linear regression were performed to explore the association between age-standardized DALY rates and HDI. Results: From 1990 to 2013, global DALY numbers caused by URE rose by 43.8%, crude rates remained relatively constant, and age-standardized rates fell by 8.8%. Global DALY rates increased with age, and older females had higher DALY numbers and rates than males of the same age. Age-standardized DALY rates in Eastern Mediterranean, South-East Asia, and Africa were higher than that at a global level. Multiple comparisons indicated higher age-standardized DALY rates in lower HDI countries. Age-standardized DALY rates were inversely related to HDI (standardized ß = -0.616, P < 0.001). Conclusions: The global health of URE is improving but crude DALY rates are keeping constant, implying that health progress does not mean fewer demands of refractive services. Worldwide, older age, female sex, and lower socioeconomic status are associated with higher URE burden. The findings of this study may raise public awareness of the global URE burden and are important for health policy making.

Efficient referral thresholds in autorefraction-based preschool screening.

PURPOSE: To determine economically efficient referral criteria for a preschool vision-screening program using autorefraction. DESIGN: Retrospective economic evaluation of a screening protocol. METHODS: Preschoolers in 2 cities received preschool-based Retinomax screening with a standard referral protocol and as-needed comprehensive eye examinations in 2012-2013. Positive predictive values and referral criteria that minimized cost per case detected were derived using data from San Francisco. These modeled referral criteria were then retrospectively tested for cost-effectiveness against other common criteria in Oakland with sensitivity analysis. Cases were defined by American Association for Pediatric Ophthalmology and Strabismus (AAPOS) criteria for amblyopia risk factors. The perspective was a third-party payer. Costs were obtained from a regional insurance provider. RESULTS: In San Francisco, 3974 children were screened, 631 referred, and 412 examined. Forty-eight percent of referrals, 301 children, met more than 1 of the referral criteria. Positive predictive values ranged from 7% for myopia to 56% for astigmatism. In Oakland, 2359 children were screened and 269 were examined. When applying the modeled referral criteria derived from San Francisco to the population of Oakland, the cost per case detected was $258. When compared in Oakland, the original referral criteria and criteria based on Vision in Preschoolers study cost, respectively, $424 and $371 per additional case detected. The modeled referral criteria had a lower cost per case detected across sensitivity analysis. CONCLUSIONS: More stringent referral criteria may reduce the cost per case detected in vision screening and allow more at-risk children to be detected with the same financial resources.

Vision screening by teachers in southern Indian schools: testing a new "all class teacher" model.

AIM: To study the effectiveness and cost of a new school vision screening program involving all class teachers (ACTs) compared with the standard program involving a limited number of selected teachers (STs) in Southern India. METHODS: A total of 12 schools were selected for intervention and 12 schools were matched as controls, from in and around Pondicherry, India. Teachers in both the intervention arm (ACTs) and the standard arm (STs) were trained to identify students between the ages of 6 and 17 years with visual acuity ≤20/30 in either eye or obvious ocular abnormalities and refer them to an ophthalmic team. The ophthalmic team, including an ophthalmologist, visited the schools to examine all children referred by teachers, provided medical treatment or a prescription for glasses, or referred them to the base hospital if required. RESULTS: ACTs (761 teachers) screened 39,357 children (97.7%) and STs (156 teachers) screened 38,469 children (95.7%). ACTs found significantly fewer screen-positive children (n = 3806, 9.7%) than the STs (n = 6387, 16.6%; p < 0.001), but had a significantly larger number of children with actual vision loss and other ocular pathology (2231, 5.7% and 1554, 4.0%, respectively, p < 0.001). More children from ACTs than STs reached the base hospital for further investigation within 3 months (p < 0.001). The cost of screening per child with actual ocular pathology was estimated to be US$1.91 for ACTs and US$4.83 for STs. CONCLUSIONS: A school vision screening program involving ACTs resulted in more efficient screening than a program involving STs at about a third of the cost and also improved compliance with hospital referral.

Costs of eye care services: prospective study from a faith-based hospital in Zambia.

PURPOSE: To estimate the mean costs of cataract surgery and refractive error correction at a faith-based eye hospital in Zambia. METHODS: Out-of-pocket expenses for user fees, drugs and transport were collected from 90 patient interviews; 47 received cataract surgery and 43 refractive error correction. Overhead and diagnosis-specific costs were determined from micro-costing of the hospital. Costs per patient were calculated as the sum of out-of-pocket expenses and hospital costs, excluding user fees to avoid double counting. RESULTS: From the perspective of the hospital, overhead costs amounted to US$31 per consultation and diagnosis-specific costs were US$57 for cataract surgery and US$36 for refractive error correction. When including out-of-pocket expenses, mean total costs amounted to US$128 (95% confidence interval [CI] US$96--168) per cataract surgery and US$86 (95% CI US$67--118) per refractive error correction. Costs of providing services corresponded well with the user fee levels established by the hospital. CONCLUSION: This is the first paper to report on the costs of eye care services in an African setting. The methods used could be replicated in other countries and for other types of visual impairments. These estimates are crucial for determining resources needed to meet global goals for elimination of avoidable blindness.

Use of ready-made spectacles to meet visual needs in a low-resource adult population.

PURPOSE: In affluent societies, distance and near vision problems are typically corrected with custom-made eyeglasses. Many persons in less affluent areas do not have the resources for such. The purpose of this study was to assess the use of less expensive ready-made (RM) bifocals and readers to correct distance and near refractive error and presbyopia in an outreach clinic in Nicaragua. METHODS: This is a retrospective review of records of all patients older than 34 years who presented for an eye examination in an outreach clinic in Granada, Nicaragua, in 2010. A visual satisfaction questionnaire had been administered to patients before they were examined and after RM plus sphere bifocals or plus sphere reading spectacles were dispensed. The main outcome measures included pre- and post-distance and near visual acuities, vision satisfaction and difficulty ratings, and perceived cost and willingness to pay for replacement rating. RESULTS: Ready-made plus sphere spectacles (bifocals or single-vision readers) were dispensed to 95.4% of those examined. The remaining 4.6% required custom prescriptions because of astigmatism, myopia, or anisometropia. The RM bifocals were very well accepted, with high visual satisfaction ratings with the bifocals improving from a presenting value of 11 to 89.4% at distance and from 6.6 to 89.4% at near. Percentage of patients achieving visual acuity of 20/40 or better improved from 60 to 84.5% at distance and from 44 to 97% at near. Percentage achieving functionally good near vision (20/40 or better) improved from 38 to 97% with RM readers. Patients reporting highest satisfaction with near vision improved from 6.3 to 86.6%. Patients indicated that, on average, they would be willing to pay US$18.39 to replace the bifocals and US$16.67 to replace the readers. CONCLUSIONS: Ready-made bifocals and RM single-vision readers may be an acceptable and affordable alternative for many patients with hyperopia and/or presbyopia where access to custom-made eyeglasses is difficult.

Global cost of correcting vision impairment from uncorrected refractive error.

OBJECTIVE: To estimate the global cost of establishing and operating the educational and refractive care facilities required to provide care to all individuals who currently have vision impairment resulting from uncorrected refractive error (URE). METHODS: The global cost of correcting URE was estimated using data on the population, the prevalence of URE and the number of existing refractive care practitioners in individual countries, the cost of establishing and operating educational programmes for practitioners and the cost of establishing and operating refractive care facilities. The assumptions made ensured that costs were not underestimated and an upper limit to the costs was derived using the most expensive extreme for each assumption. FINDINGS: There were an estimated 158 million cases of distance vision impairment and 544 million cases of near vision impairment caused by URE worldwide in 2007. Approximately 47 000 additional full-time functional clinical refractionists and 18 000 ophthalmic dispensers would be required to provide refractive care services for these individuals. The global cost of educating the additional personnel and of establishing, maintaining and operating the refractive care facilities needed was estimated to be around 20 000 million United States dollars (US$) and the upper-limit cost was US$ 28 000 million. The estimated loss in global gross domestic product due to distance vision impairment caused by URE was US$ 202 000 million annually. CONCLUSION: The cost of establishing and operating the educational and refractive care facilities required to deal with vision impairment resulting from URE was a small proportion of the global loss in productivity associated with that vision impairment.

Unmet refractive need and its determinants in Shahroud, Iran.

Uncorrected refractive error plays a significant role in poor vision and blindness, and its correction is the most cost-effective intervention in eye care. In this study, we report the status of the unmet refractive need and the role of economic inequality in determining the level of this need in Shahroud, Iran. This cross-sectional nested case-control study was performed on 5,190 individuals aged 40-64 years. Cases and controls were individuals with uncorrected visual acuity worse than 0.3 LogMAR in the better eye who showed at least 0.2 LogMAR improvement after correction. Cases were individuals whose presenting vision was worse than 0.3 in the better eye but improved by at least 0.2 LogMAR after correction. Controls were individuals in whom the difference between the presenting and corrected vision was less than 0.2 LogMAR. The prevalence of the unmet need was 5.7 % and it was more prevalent in women (6.5 %) than in men (4.6 %) (p = 0.003). There was a gap of 19.6 % between the two groups of high and low economic status. The Oaxaca-Blinder decomposition method revealed that differences in the education level of the two groups accounted for half of this gap. Spectacle usage is better in Iran than in some other developing countries; however, in this study, about 40 % of those who required spectacles did not have them.

Unmet need for corrective eyeglasses: results from a Los Angeles County Hospital survey.

To investigate the socioeconomic challenges encountered by patients from Los Angeles County Ophthalmology Clinic, California, United States, in obtaining prescription eyeglasses. A retrospective survey study. Patients sent for refraction in June 2009 were asked to rate their satisfaction with their eyeglasses. If they did not obtain eyeglasses, they were asked the reason e.g., cost, lost prescription, etc. Fifty-five percent (54/99) of patients who received a prescription did not obtain eyeglasses. The most common reason was cost (67 %). Eighty-eight percent of patients had some form of health insurance; however, 100 % were lacking eyeglasses coverage. The mean visual acuity pre-refraction was 20/80 versus 20/30 post-refraction (p < 0.001). It is well known that refractive error is a major cause of blindness worldwide, which negatively impacts the patient and their community. However, it is infrequently addressed that these conditions persist in parts of the develop world, including the United States. Los Angeles County Hospital is an example of an environment with many low-income patients in need of refractive correction who are limited mainly by cost in attaining eyeglasses. Furthermore, insurance organizations that cover low-income patients provide minimal or no coverage for prescription eyeglasses.

Real cost of recycled spectacles.

PURPOSE: Many programs aimed at mitigating the problem of uncorrected refractive error and the resulting avoidable blindness use recycled (donated) spectacles as a seemingly inexpensive expedient. This article analyses the costs and benefits of recycled spectacles and compares them with alternative methodologies. Although well intentioned, it is argued that recycled spectacles will neither suit many of those affected by uncorrected refractive error nor provide a cost saving solution to the problem. Although this is not the first argument against the use of recycled spectacles, there has been no accurate costing of their delivery. This article assesses the real cost of delivery of recycled spectacles. METHODS: The useable quantity of recycled spectacles was determined by examining two separate batches of donated spectacles. These data were used in the calculation of the cost of delivery. The metric used for comparison was only cost (i.e., it was a cost minimization analysis) because it was deemed that recycled spectacles and ready-made spectacles were the same mode of correction fundamentally. RESULTS: Only 7% of the 275 recycled spectacles analyzed were suitable for use. The relatively small proportion of useable spectacles contributed to the high societal cost of delivering recycled spectacles, which was found to be U.S.$20.49, more than twice the cost of supplying ready-made spectacles. CONCLUSIONS: Recycled spectacles are not a cost-saving method of correcting refractive error and should be discouraged as a strategy for eliminating uncorrected refractive error in developing countries.

Safety and compliance of prescription spectacles ordered by the public via the Internet.

BACKGROUND: This study investigated prescription spectacles ordered from online vendors and delivered directly to the public for compliance with the optical tolerance and impact resistance requirements for eyewear dispensed in the United States. METHODS: Ten individuals ordered 2 pairs of spectacles from each of 10 of the most visited Internet vendors, totaling 200 eyewear orders. Spectacles ordered consisted of ranges of lens and frame materials, lens styles, and refractive corrections reflecting current distributions in the United States. Evaluations included measurement of sphere power, cylinder power and axis, add power (if indicated), horizontal prism imbalance, and impact testing. RESULTS: We received and evaluated 154 pairs of spectacles, comprising 308 lenses. Several spectacles were provided incorrectly, such as single vision instead of multifocal and lens treatments added or omitted. In 28.6% of spectacles, at least 1 lens failed tolerance standards for at least 1 optical parameter, and in 22.7% of spectacles, at least 1 lens failed impact testing. Overall, 44.8% of spectacles failed at least 1 parameter of optical or impact testing. CONCLUSION: Nearly half of prescription spectacles delivered directly by online vendors did not meet either the optical requirements of the patient's visual needs or the physical requirements for the patient's safety.

Screening for refractive error and fitting with spectacles in rural and urban India: cost-effectiveness.

OBJECTIVES: To assess the cost-effectiveness of screening for refractive error and fitting with glasses in India. METHODS: We populated a decision tree with the costs of screening and spectacles, prevalence of varying levels of presenting and best corrected visual acuity (BCVA) from two studies, and sensitivity and specificity of screening. We calculated dollars spent per disability adjusted life year (DALY) averted separately in urban and rural areas for school-based screening (SBS) and primary eye care (PEC) programs that fit spectacles to individuals presenting for care. We conducted a series of univariate and probabilistic sensitivity analyses. An intervention was inferred to be highly cost-effective if the incremental cost-effectiveness ratio (ICER) was less than the gross domestic product (GDP) per capita and moderately cost-effective if the ICER was less than three times this level. RESULTS: Compared with no screening, urban SBS was highly cost-effective; rural SBS was moderately cost-effective for ages 5-15 and highly cost-effective for ages 7-15. Both urban and rural PEC were moderately cost-effective in comparison to SBS. Probabilistic sensitivity analysis suggested that SBS is likely the most cost-effective solution for refractive error in India if the 5-15 year old age group is targeted; primary eye care is the best choice if a high value is placed on DALYs and the 7-15 year old age group is targeted. CONCLUSION: Both SBS and PEC Interventions for refractive error can be considered cost-effective in India. Which is the more cost-effective depends on the choice of targeted age group and area of the intervention.

Economics and attitudes regarding spectacles in daily life: a European perspective.

PURPOSE: The objectives of this survey were to collect data from five European countries (France, Germany, Italy, Spain, and the United Kingdom) on the societal costs of spectacle dependence and respondents' willingness to pay (WTP) for freedom from spectacles. METHODS: Samples of citizens age >or=45 years and currently wearing spectacles were selected according to a quota method (age, gender, occupation) and interviewed (22 questions) using a Computer-Assisted Telephone Interviewing system. RESULTS: In total, 4,157 respondents were interviewed across the 5 countries; 38.4% were age >or=65 years and 55.8% female. Most prescribed lenses were monofocal (49.7-72.8%) in all countries, except in France (29.8%). The most frequent replacement interval (70.4%) was >or=2 years and the average cost was > euro 145 per pair (62.9%). Replacements were most frequent in the UK and expenditure was highest in France. The three most common everyday tasks requiring spectacles were reading (60.4%), watching TV (33.6%) and shopping (28.8%). Willingness to pay varied across countries, the UK subjects expressing the lowest values; this was especially true for men and persons aged < 64 years. CONCLUSION: Respondents in France bought mostly expensive spectacles while Italians acquired the least expensive eyeglasses. The spectacle frequency of replacement rate is inversely related to prices. About half of all respondents expressed a WTP, at least partially, for freedom from spectacles.

Stated and actual willingness to pay for spectacles in Timor-Leste.

PURPOSE: To conduct a survey of willingness to pay for ready-made spectacles in the low-resource country of Timor-Leste, and, uniquely, subsequent validation with actual payment information. METHODS: A systematic random sampling strategy was used to apply a binary with follow-up stated willingness to pay methodology. Findings were validated by comparing the amount declared willing to pay with the actual price paid at a subsequent visit. RESULTS: Of the 152 participants (96.2%; mean age 50.9 +/- 13.2 years; 50.0% female) agreeable to wearing spectacles if required, 84.9% were willing to pay for them, with 82.9% of these willing to pay at least United States dollars (USD) 0.10. By multivariate analysis, increasing age and owning fewer animals were significantly and independently associated with unwillingness to pay at least USD 0.10. Of the survey participants agreeable to wearing spectacles who attended a later visit (113/152; 74.3%; 53.1% female), the 80.5% who would benefit were offered spectacles, first for USD 1.00. If declined, this was revised to USD 0.10. If this was declined, the spectacles were dispensed, unknown to subsequent attendees, at no charge. The predictive value of stated willingness to pay at least USD 0.10 was 96.3%. CONCLUSIONS: Binary with follow-up stated willingness to pay with validation against actual payment was successfully applied to spectacles in Timor-Leste.

Potential lost productivity resulting from the global burden of uncorrected refractive error.

OBJECTIVE: To estimate the potential global economic productivity loss associated with the existing burden of visual impairment from uncorrected refractive error (URE). METHODS: Conservative assumptions and national population, epidemiological and economic data were used to estimate the purchasing power parity-adjusted gross domestic product (PPP-adjusted GDP) loss for all individuals with impaired vision and blindness, and for individuals with normal sight who provide them with informal care. FINDINGS: An estimated 158.1 million cases of visual impairment resulted from uncorrected or undercorrected refractive error in 2007; of these, 8.7 million were blind. We estimated the global economic productivity loss in international dollars (I$) associated with this burden at I$ 427.7 billion before, and I$ 268.8 billion after, adjustment for country-specific labour force participation and employment rates. With the same adjustment, but assuming no economic productivity for individuals aged > 50 years, we estimated the potential productivity loss at I$ 121.4 billion. CONCLUSION: Even under the most conservative assumptions, the total estimated productivity loss, in $I, associated with visual impairment from URE is approximately a thousand times greater than the global number of cases. The cost of scaling up existing refractive services to meet this burden is unknown, but if each affected individual were to be provided with appropriate eyeglasses for less than I$ 1000, a net economic gain may be attainable.