Population-based study of presbyopia in Shahroud, Iran

BCLA CLEAR Presbyopia: Epidemiology and impact

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies.

National sex- and age-specific burden of blindness and vision impairment by cause in Mexico in 2019: a secondary analysis of the Global Burden of Disease Study 2019

Background

Reliable national estimations for blindness and vision impairment are fundamental to assessing their burden and developing public health policies. However, no comprehensive analysis is available for Mexico. Therefore, in this observational study we describe the national burden of blindness and vision loss by cause and severity during 2019.

Methods

Using public data from the Global Burden of Disease (GBD) study 2019, we present national prevalence and years lived with disability (YLDs) counts and crude and age-standardized rates (per 100,000 people) of total, severity- and cause-specific blindness and vision impairment with 95% uncertainty intervals (UIs) by sex and age group.

Findings

In Mexico, the burden of blindness and vision impairment was estimated at 11.01 million (95% UI, 9.25-13.11) prevalent cases and 384.96 thousand (259.57-544.24) YLDs during 2019. Uncorrected presbyopia caused the highest burden (6.06 million cases, 4.36-8.08), whereas severe vision loss and blindness affected 619.40 thousand (539.40-717.73) and 513.84 thousand (450.59-570.98) people, respectively. Near vision loss and refraction disorders caused 78.7% of the cases, whereas neonatal disorders and age-related macular degeneration were among the least frequent. Refraction disorders were the main cause of moderate and severe vision loss (61.44 and 35.43%), and cataracts were the second most frequent cause of blindness (26.73%). Females suffered an overall higher burden of blindness and vision impairment (54.99% and 52.85% of the total cases and YLDs), and people >50 years of age suffered the highest burden, with people between 70 and 74 years being the most affected.

Interpretation

Vision loss represents a public health problem in Mexico, with women and older people being the most affected. Although the causes of vision loss contribute differentially to the severity of visual impairment, most of the impairment is avoidable. Consequently, a concerted effort at different levels is needed to alleviate this burden.

Funding

This study received no funding.

Non-Miotic Improvement in Binocular Near Vision with a Topical Compound Formula for Presbyopia Correction

INTRODUCTION

The aim of this case series was to examine the association between unaided binocular visual acuity for near vision and pupil change after the instillation of a special topical formulation for presbyopia treatment.

METHODS

This was a case series consisting of consecutive participants with presbyopia aged 40-70 years who were tested for visual acuity and pupil diameter before and 2 h after instillation of a formulation of pilocarpine and phenylephrine drops (FOV Tears) for presbyopia. Participants underwent subjective refraction, photopic and scotopic pupil diameter measurement and unaided monocular and binocular visual acuity testing by logMAR for distance and near vision both pre- and post-instillation of eye drops.

RESULTS

The study enrolled 363 subjects (n = 176 women, 48%) with a mean (± standard deviation) age of 50.4 ± 5.8 years. Mean spherical equivalent (SE) changed significantly (- 0.17 Diopters) after instillation of the FOV Tears formulation (p < 0.001). Post-instillation of eye drops, the scotopic pupil diameter decreased by 0.97 ± 0.98 mm, and the near visual acuity by logMAR improved significantly by nearly two lines (p < 0.01). In the linear regression analyses, age (p < 0.001) and SE pre-drop instillation (p < 0.001) were associated with unaided binocular visual acuity. The changes in photopic pupil diameter and the scotopic pupil diameter were not associated with unaided binocular visual acuity.

CONCLUSIONS

The use of the pilocarpine and phenylephrine formulation (FOV Tears) improved binocular visual acuity for near vision in presbyopic patients, and the effect was independent of pupil change.

Vision Impairment and Productivity Among Female Garment Workers in Bangladesh: A Cohort Study

PURPOSE

To assess the prevalence of near and correctable distance visual impairment among screened participants in the garment industry and to explore associations with income, age, and urban versus rural residence.

METHODS

Vision screenings were conducted at 4 garment factories, 2 urban and 2 rural locations during September and October 2019. Distance vision impairment was the presence of uncorrected vision of <6/12 in either eye, correctable to ≥6/7.5 with distance refraction. Near vision impairment was defined as 1 or more of the following: 1) either eye with presenting near vision 6/12 in the same eye; 2) having been prescribed near add spectacle power in examination records; and/or 3) clinical diagnosis of presbyopia at the time of screening. Demographic information and monthly income were self-reported by questionnaire completion.

RESULTS

Among 915 participating workers (100% female, 18 to 70 years), 29.2% (n = 267) and 26.8% (n = 245) had correctable distance and near vision impairment respectively. Prevalence of near vision impairment was significantly higher among rural residents (34.2%, n = 160), compared to urban (19.0%, n = 85, P < 0.0001) with the largest differences in the 35 to 39 (68.2% vs 44.2%, P = 0.0019) and 40+ (85.9 vs 48.9%, P < 0.0001) year age ranges. Prevalence of near vision impairment was already high among urban (20.4%, n = 20) and rural (23.0%, n = 17) workers aged 30 to 34 years. In simple linear regression models, participants with near vision impairment earned $13.3 [standard error (SE) 2.44, P < 0.0001] less per month than those without, while urban residents earned $40.6 (SE 1.74, P < 0.0001) more than rural dwellers. In the final multivariate linear model, both near vision impairment ($6.51 lower monthly earnings, SE 1.84, P = 0.0004) and urban residence ($43.2 higher monthly earnings, SE 2.39, P < 0.0001) remained significantly associated with income.

CONCLUSIONS

This study found high rates of near vision impairment among female garment workers, particularly rural dwellers, and at a younger age than expected. The high prevalence and association between near vision impairment and lower income suggest that focusing on industries with a high proportion of female workers, such as readymade garments, may be effective in addressing gender disparities in vision impairment and its economic impact.

Prevalence and factors associated with uncorrected presbyopia in a rural population of Japan: the Locomotive Syndrome and Health Outcome in Aizu Cohort Study

PURPOSE

To investigate the prevalence and factors associated with uncorrected presbyopia among rural community dwellers in Japan.

STUDY DESIGN

A population-based cross-sectional study was conducted in 2011 among community dwellers aged 40-74 years who received specific health checkups in Minamiaizu and Tadami, Fukushima Prefecture, Japan.

METHODS

Uncorrected presbyopia was considered as when the distance-corrected visual acuity in the better eye was ≥0.5 and the near-presenting visual acuity in the better eye was <0.4, regardless of distance refractive status. Multiple logistic regression analysis was employed to calculate the odds ratios (ORs) for uncorrected presbyopia and to adjust for possible confounders.

RESULTS

A total of 2054 individuals participated in the specific health checkups. In the 1156 individuals (response rate: 56.28%) analyzed in the study, the mean (SD) age was 63.0 (8.7) years, the percentage of women was higher (57.87%), and the prevalence of uncorrected presbyopia was 26.38% (95% CI 23.86%-29.03%). Multivariate analysis revealed that the factors associated with uncorrected presbyopia were older age (adjusted OR: 1.054 [95% CI: 1.034-1.075]), female sex (adjusted OR: 1.388 [95% CI: 1.006-1.915]), and distance-presenting vision impairment (adjusted OR: 2.651 [95% CI: 1.697-4.143]).

CONCLUSION

Approximately one-quarter of the participants in this study from a rural population of Japan did not have adequate near vision. It is recommended that a public health intervention should be enacted to correct presbyopia, especially in the older age group, women, and those with uncorrected refractive errors.

Near vision impairment among the elderly in residential care-the Hyderabad Ocular Morbidity in Elderly Study (HOMES)

BACKGROUND/OBJECTIVE

To report on the prevalence and risk factors for near vision impairment (NVI) among the elderly in residential care in Telangana State in India.

METHODS

Individuals aged ≥60 years were recruited from 41 'home for the aged' centres in Hyderabad, India. All participants had complete eye examinations including presenting and best-corrected visual acuity assessment for distance and near. NVI was defined as binocular presenting near vision worse than N8 (6/15) among those who had a normal presenting distance visual acuity of 6/18 in the better eye.

RESULTS

Of the 826 participants, the mean age was 74.4 years (standard deviation-8.4 years), 525 (63.6%) were women, 715 (86.6%) had at least school education. The prevalence of NVI was 51.2% (95% CI: 47.7-54.7) based on presenting vision. On applying multiple logistic regression analysis, the odds of NVI were higher in 80 years and older age (OR: 2.17; 95% CI: 3.44-13.6). Those with school education (OR: 0.58: 95% CI: 0.36-0.94) and higher education (OR: 0.38; 95% CI: 0.21-0.69) had lower odds for NVI. Similarly, those with self-reported diabetes (OR: 0.69; 95% CI: 0.49-0.97), those using spectacles (OR: 0.09; 95% CI: 0.05-0.16), and those who had undergone cataract surgery (OR: 0.51; 95% CI: 0.36-0.74) had lower odds for NVI.

CONCLUSIONS

NVI was common among the elderly in residential care in homes for the aged in Hyderabad, India. As most of this NVI is correctable, a routine screening programme and dispensing of spectacles can be undertaken to address this vision loss.

Patient and Economic Burden of Presbyopia: A Systematic Literature Review

Purpose

The objective of this systematic literature review (SLR) was to collate, report, and critique published evidence related to epidemiology and patient and economic burden of presbyopia.

Patients and Methods

A systematic literature search was conducted in MEDLINE^®, Embase^®, and Cochrane Library databases from the time of inception through October 2018 using Cochrane methodology. Studies published in English language reporting on epidemiology and patient and economic burden of presbyopia were included.

Results

Initial systematic literature search yielded 2,228 citations, of which 55 met the inclusion criteria (epidemiology, 44; patient burden, 14; economic burden, 1) and were included in this review. Globally, 1.09 billion people are estimated to be affected by presbyopia. The reported presbyopia prevalence varied across regions and by age groups, with the highest prevalence of 90% reported in the Latin America region in adults ≥35 years. Presbyopic patients report up to 22% decrease in quality-of-life (QoL) score, and up to 80% patients with uncorrected presbyopia report difficulty in performing near-vision related tasks. About 12% of presbyopes required help in performing routine activities, and these visual limitations reportedly induce distress and low self-esteem in presbyopia patients. Uncorrected presbyopia led to a 2-fold increased difficulty in near-vision-related tasks and a >8-fold increased difficulty in very demanding near-vision-related tasks. Further, uncorrected presbyopia leads to a decrement in patients’ QoL, evident by the low utility values reported in the literature. Annual global productivity losses due to uncorrected and under-corrected presbyopia in working-age population (<50 years) were estimated at US$ 11 billion (0.016% of the global domestic product (GDP) in 2011, which increased to US$ 25.4 billion if all people aged <65 years were assumed to be productive.

Conclusion

Uncorrected presbyopia affects patients’ vision-related quality of life due to difficulty in performing near-vision-related tasks. In addition, un-/under-corrected presbyopia could lead to productivity losses in working-age adults.

Repeatability of the amplitude of accommodation measured by a new generation autorefractor

Significance

This is the first study to validate the repeatability of objective measurements of amplitude of accommodation (AA) using the TONOREF III (NIDEK Co., Ltd., Japan), which can measure the AA in 30 seconds.

Purpose

To evaluate the repeatability of objective measurements of AA using the TONOREF III and explored the association between objectively measured AA and factors, including age, sex, spherical equivalent, baseline pupil size and pupil size change during accommodation.

Methods

This cross-sectional study recruited 35 healthy subjects aged 26 to 52 years. The Bland-Altman method and intraclass correlation coefficients (ICCs) were used to assess the repeatability of TONOREF III measurements. The relationships between AA and age, sex, baseline pupil size, changes in pupil size (ΔPS) during accommodation were analyzed using linear regression for univariate and multivariate analysis.

Results

The mean difference in AA (ΔAA) between two sessions of TONOREF III measurements was 0.23 D (95% CI: -1.07 to +1.53 D), while no significant correlation was found between the mean and ΔAA (p = .14). The ICCs of the TONOREF III was 0.96. Age, sex, and ΔPS during accommodation were significant factors affecting the AA in multivariate analysis.

Conclusions

The repeatability of objective AA measurements using the TONOREF III was good. Measuring AA using the TONOREF^TM III in clinical practice is feasible.

Impact of Presbyopia and Its Correction in Low- and Middle-Income Countries

Presbyopia affects more than 1 billion people worldwide, and the number is growing rapidly due to the aging global population. Uncorrected presbyopia is the world's leading cause of vision impairment, and as with other causes. The burden falls unfairly on low- and middle-income countries (LMICs), in which rates of presbyopic correction are as low as 10%. The importance of presbyopia as a cause of vision impairment is further underscored by the fact that it strikes at the heart of the productive working years, although it can be safely and effectively treated with a pair of inexpensive glasses. To galvanize action for programs to address uncorrected presbyopia in the workplace and beyond LMICs, it is crucial to build a solid evidence base detailing the impact of presbyopia and its correction in important areas such as work productivity, activities of daily living, visual function, and quality of life. The aim of this review was to provide an up-to-date reference for program planners and policymakers seeking to build support for programs of presbyopia correction, particularly in low-resource settings.

Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia: Systematic Review, Meta-analysis, and Modelling

TOPIC

Presbyopia prevalence and spectacle-correction coverage were estimated by systematic review and meta-analysis of epidemiologic evidence, then modeled to expand to country, region, and global estimates.

CLINICAL RELEVANCE

Understanding presbyopia epidemiologic factors and correction coverage is critical to overcoming the burden of vision impairment (VI) from uncorrected presbyopia.

METHODS

We performed systematic reviews of presbyopia prevalence and spectacle-correction coverage. Accepted presbyopia prevalence data were gathered into 5-year age groups from 0 to 90 years or older and meta-analyzed within World Health Organization global burden of disease regions. We developed a model based on amplitude of accommodation adjusted for myopia rates to match the regionally meta-analyzed presbyopia prevalence. Presbyopia spectacle-correction coverage was analyzed against country-level variables from the year of data collection; variation in correction coverage was described best by a model based on the Human Development Index, Gini coefficient, and health expenditure, with adjustments for age and urbanization. We used the models to estimate presbyopia prevalence and spectacle-correction coverage in each age group in urban and rural areas of every country in the world, and combined with population data to estimate the number of people with near VI.

RESULTS

We estimate there were 1.8 billion people (prevalence, 25%; 95% confidence interval [CI], 1.7-2.0 billion [23%-27%]) globally with presbyopia in 2015, 826 million (95% CI, 686-960 million) of whom had near VI because they had no, or inadequate, vision correction. Global unmet need for presbyopia correction in 2015 is estimated to be 45% (95% CI, 41%-49%). People with presbyopia are more likely to have adequate optical correction if they live in an urban area of a more developed country with higher health expenditure and lower inequality.

CONCLUSIONS

There is a significant burden of VI from uncorrected presbyopia, with the greatest burden in rural areas of low-resource countries.

Distribution and progression of add power among people in need of near correction

IMPORTANCE

This study helps to better understand the need and trend in presbyopic add power in the aging society.

BACKGROUND

Distribution and progression of presbyopic add power in East Asian population is largely unknown.

DESIGN

Prospective cohort study.

PARTICIPANTS

About 303 participants from a population-based study of residents aged 35 years and older in Guangzhou, China.

METHODS

Visual acuity (VA) test and non-cycloplegic automated refraction were performed at baseline in 2008 and the 6-year follow-up per standardized protocol. Participants with presenting near VA ≤ 20/40 underwent distance subjective refraction and add power measurement by increasing plus lens at a standard distance of 40 cm at each visit.

MAIN OUTCOME MEASURES

Add power at baseline and follow-ups.

RESULTS

Mean (standard deviation) age of the study participants was 57.6 (11.1) years and 50.2% were female. The mean add power at baseline was 1.43, 1.73, 2.03 and 2.20 diopters (D) for individuals in the age groups of 35-44, 45-54, 55-64 and 65+ years, respectively. Participants with older age and lower educational level had significantly higher add power requirements (P < 0.001). The overall 6-year increase in add power was 0.15D (95% CI: 0.06 to 0.25), and was smaller in myopic subjects (P = 0.03). Baseline age and add power, but not changes in biometric factors, were associated with longitudinal change in add power (P < 0.001).

CONCLUSIONS AND RELEVANCE

Distribution and progression of add power in Chinese was different from that previously suggested by Caucasian studies. More studies are needed to establish up-to-date age-related add power prescription norms for population of different ethnicities.

Fundamentals of Presbyopia: visual processing and binocularity in its transformation

Background

The accommodation has considerable interactions with the pupil response, vergence response and binocularity. The transformation of visual reception processing and the changes of the binocular cooperation during the presbyopia development are still poorly studied. So, the regularities of visual system violation in the presbyopia formation need to be characterized. This study aims to reveal the transformation of visual reception processing and to determine the role of disturbances in binocular interactions in presbyopia formation.

Methods

This study included 60 people with emmetropic refraction, uncorrected distance visual acuity 1.0 or higher (decimal scale), normal color perception, without concomitant ophthalmopathology. The first group consisted of 30 people (from 18 to 27 years old) without presbyopia, the second cohort comprised 30 patients (from 45 to 55 years old) with presbyopia. The eyeball anatomy and optics were evaluated using ultrasound biomicroscopy, aberrometry, and pupillometry. The functional state of the visual system was investigated under monocular and binocular conditions. The registration of the disparate fusional reflex limits was performed by the original technic using a diploptic device which facilitated investigation of the binocular interaction under natural conditions without the accommodation response, but with the different vergence load. The disparate fusional reflex was analyzed using the proximal and distal fusion borders, and the convergence and divergence fusion borders. The calculation of the area of binocularity field was performed in cm².

Results

The presbyopia formation is characterized by a change in an intraocular anatomy, optics, visual processing, and binocularity. The processes of binocular interaction inhibition make a significant contribution to the misalignment of the visual perception. The modification of the proximal, distal and convergence fusion borders was determined. It was revealed that 87% of the presbyopic patients had binocularity shortage, whereas the reduction of binocularity field area in extreme grade was seen in 6% of cases.

Conclusions

The presbyopia formation is accompanied by a significant reorganization of the visual system activity and by the creation of the new visual processing interactions. These data may be useful in presbyopia surgery.

Prevalence and incidence of presbyopia in urban Southern China

AIMS

To investigate the prevalence and incidence of presbyopia in an urban Chinese population.

METHODS

1817 subjects aged ≥35 years were identified by random cluster sampling in Yuexiu District, Guangzhou, China, at baseline in 2008, and all were invited for the follow-up examination in 2014. Distance and near visual acuity (VA) tests, as well as non-cycloplegic automated refraction were performed at each examination as per standardised protocol. Participants with presenting near VA ≤20/40 were further tested with add power at a standard distance of 40 cm to obtain their best-corrected near VA. Functional presbyopia was defined as near VA under presenting distance refraction correction of <20/50 and could be improved by at least one line with add power.

RESULTS

A total of 1191 (83.5% of the 2014 follow-up) participants were included in the current analysis with a mean (SD) age of 50.4 (9.7) years, and 52.9% were female. Prevalence of functional presbyopia at baseline was 25.2% (95% CI 21.5 to 28.9) and the 6-year incidence was 42.8% (95% CI 39.4 to 50.1). Older and more hyperopic subjects had both higher prevalence and incidence of presbyopia (P<0.001). Average presbyopic correction coverage (PCC) was 87.7% at baseline and was significantly lower in myopic participants (P=0.006).

CONCLUSIONS

Prevalence of functional presbyopia in urban China is relatively lower along with a higher PCC compared with previous population-based rural cohorts. We identified a high presbyopia incidence, and further studies are needed to understand longitudinal presbyopia progression as well as the urban-rural gap in presbyopia to throw light on future strategic planning.

Evaluating Three Different Methods of Determining Addition in Presbyopia

Purpose:

To compare three different methods for determining addition in presbyopes.

Methods:

The study included 81 subjects with presbyopia who aged 40-70 years. Reading addition values were measured using 3 approaches including the amplitude of accommodation (AA), dynamic retinoscopy (DR), and increasing plus lens (IPL).

Results:

IPL overestimated reading addition relative to other methods. Mean near addition obtained by AA, DR and IPL were 1.31, 1.68 and 1.77, respectively. Our results showed that IPL method could provide 20/20 vision at near in the majority of presbyopic subjects (63.4%).

Conclusion:

The results were approximately the same for 3 methods and provided comparable final addition; however, mean near additions were higher with increasing plus lens compared with the other two methods. In presbyopic individuals, increasing plus lens is recommended as the least time-consuming method with the range of ±0.50 diopter at the 40 cm working distance.

National Burden of Eye Diseases in Iran, 1990-2010; Findings from the Global Burden of Diseases Study 2010

Purpose:

The disability-adjusted life-years (DALYs) lost due to eye diseases and trends in DALYs in Iran has not been previously reported. The object of this study is to report the burden of eye diseases in Iran and to compare changes from 1990 to 2010 based on age and gender.

Methods:

Data from the Global Burden of Disease Study 2010 (GBD 2010) are used to report DALYs for cataract, refraction/accommodation (functional) disorders, macular degeneration, and glaucoma.

Results:

Cataract, refraction/accommodation (functional) disorders, macular degeneration, and glaucoma were the 84^th, 87^th, 138^th, and 151^st causes of DALY in 1990 and the 89^th, 72^nd, 99^th, and 137^th in 2010, respectively. Cataract accounted for 0.085% of national DALY in 1990 and 0.09% in 2010, refraction/accommodation (functional) disorders accounted for 0.42% in 1990 and 0.47% in 2010, macular degeneration accounted for 0.017% in 1990 and 0.071% in 2010 and glaucoma accounted for 0.0099% in 1990 and 0.025% in 2010. There was a steady increase in DALY with age for each eye disease for both genders and dichotomized for males and females from 1990 to 2010.

Conclusions:

Epidemiologic transition is reflected in major ophthalmic and blinding diseases in the GBD data for Iran. The burden of macular degeneration is rising, followed by glaucoma. The burden of presbyopia affected individuals past their middle age. The burden of cataract manifested as a slower increase that could be attributable to better access to treatment.

Apparent progression of presbyopia after laser in situ keratomileusis in patients with early presbyopia

PURPOSE

To assess the effect of laser in situ keratomileusis (LASIK) on near visual function in presbyopic patients.

DESIGN

Retrospective cohort study.

METHODS

Fifty-three eyes of 40 patients 45 years of age and older who had undergone LASIK for high myopia (-6 diopters [D] and over) were included. The minimal add powers for obtaining the best-corrected near visual acuity (add powers) were measured preoperatively and 3 months postoperatively, and the correlations with the powers corrected by LASIK, corneal higher-order aberrations (HOAs), ocular HOAs, and patient ages were evaluated using univariate analysis. Factors correlated with the changes in add powers were evaluated further by multivariate analysis.

RESULTS

The mean ± standard deviation patient age was 50.0 ± 4.1 years; the power corrected by LASIK was -7.56 ± 1.06 D. The mean add power was 1.80 ± 0.60 D preoperatively, which increased significantly (P < .001) to 2.18 ± 0.69 D postoperatively. Significant correlations with the increased add powers were detected with age (P = .01) and the power corrected by LASIK (P = .04) but not with corneal and ocular HOAs (P > .05). Multivariate analysis showed that only age was correlated significantly (P = .01). The percentage of eyes with increased add powers of 0.5 D or more was 60.4%, which was significantly (P = .02) higher in younger patients.

CONCLUSIONS

This study verified the apparent progression of presbyopia after LASIK and the importance of obtaining informed consent from patients, especially those with early presbyopia.

Presbyopia, spectacles use and spectacle correction coverage for near vision among cloth weaving communities in Prakasam district in South India

PURPOSE

To assess the prevalence of presbyopia, spectacles use and spectacle correction coverage for near vision among weaving communities in Prakasam district in the South Indian state of Andhra Pradesh.

METHODS

A population based cross sectional study was conducted among a population aged ≥40 years. Distance visual acuity was assessed at 6 m. Near vision was assessed using N notation charts at a fixed distance of 40 cm. Presbyopia was defined as binocular unaided near vision <N8 and improving to ≥N8 with near addition lenses. Functional presbyopia was defined as presenting near vision <N8 and improving to ≥N8 with near addition lenses. A questionnaire was used to collect information on spectacles use. In order to calculate spectacle correction coverage for presbyopia, met presbyopia need was defined as the percentage of people who presented with presbyopia correction and achieved binocular N8 using it. Unmet presbyopia need was defined as the percentage of people who had either under corrected or uncorrected binocular near vision worse than N8 that would improve with correction to at least N8.

RESULTS

Of 2848/3000 enumerated subjects (94.0%) participated. Four hundred individuals with distance visual impairment were excluded from the analysis. Among the remaining 2448 individuals, 46% were male and 49.1% had no formal education. The mean age among males was higher compared to females (p < 0.01). Based on unaided near vision, the prevalence of presbyopia was 61.8% (95% CI: 59.9-63.7) and the prevalence of functional presbyopia was 35.1% (95% CI: 33.2-37.0). Using multivariable analysis, it was found that functional presbyopia was significantly associated with female gender, no education and lack of spectacle use. Spectacle correction coverage was 43.2%. Among the 781 individuals who had no correction at the time of examination, 122 (15.6%) subjects reported having used spectacles previously. The reasons for discontinuation of spectacles were discomfort with spectacles (n = 57; 46.7%), damaged or lost spectacles (n = 45; 36.9%), ability to see clearly even without spectacles (n = 12; 9.8%) and other reasons (n = 8; 6.6%).

CONCLUSION

Although the prevalence of presbyopia (61.8%) was comparable with other studies, the prevalence of functional presbyopia (35.1%) was lower and linked with higher spectacle correction coverage (43.2%) in this weaving community. However, it still highlights a large unmet need and spectacle correction coverage that could be improved by the provision of good quality, affordable spectacles, which may also improve spectacles use.

Economic inequality in presenting near vision acuity in a middle-aged population: a Blinder-Oaxaca decomposition

PURPOSE

To investigate economic inequality and its determinants in near vision, in a middle-aged population.

METHODS

In this population-based study, the presenting near vision in the better eye was investigated as the main outcome. If this vision revealed a value ≥1.6 M, the participant was considered to have presenting near vision impairment (PNVI). The effect of variables studied on PNVI was investigated using logistic regression. Economic inequality in PNVI was investigated using the Oaxaca-Blinder decomposition method.

RESULTS

PNVI in the better eye was observed in 18.2% (95% CI 16.8 to 19.6) of participants. The prevalence of PNVI in the high and low economic groups was 11.7% (95% CI 10.3 to 13.0) and 28.5% (95% CI 26.0 to 31.0), respectively. Age and education were observed as the main factors in the explained portion of this gap and were in favour of the high economic group. Gender and eye care utilisation were factors affecting the unexplained portion of this gap and were in favour of the low economic group.

CONCLUSIONS

Economic inequality plays a significant role in PNVI, while age and education are among the main factors affecting this gap. The effect caused by any change in these two factors was found to have a greater effect on women with low economic status.