Prevalence and risk factors for myopia and other refractive errors in an adult population in southern India

Wear Experiences with Two Soft Contact Lenses for Astigmatism of Different Modalities

Introduction

Patients expect to have excellent vision and comfort when wearing soft contact lenses. The purpose of this study was to compare the wear experiences of participants with astigmatism when wearing a daily disposable soft toric lens to an established, commonly used reusable toric lens.

Methods

In this crossover study, habitual soft toric lens wearers were fit with a daily replacement soft toric lens (delefilcon A) and a reusable, 1-month replacement soft toric lens (comfilcon A) in a randomized order. After 30 days of wear, Visual analog scale (VAS) surveys were used to assess wear experience, including vision and comfort, for overall wear and end-of-day wear. Scores were compared statistically with mixed-effects linear models. Participants also responded to questions about convenience, ease of use, and satisfaction with both lenses and preference questions based upon comfort, vision, and overall performance.

Results

Fifty-nine participants completed the multi-site crossover study. VAS scores [mean(std dev)] for overall quality of vision for the delefilcon A [80.4(16.4)] and comfilcon A [66.8(27.7)] lenses were statistically significant (P=0.002). The difference in the mean overall comfort scores for the delefilcon A lenses [71.6(26.3)] and comfilcon A lenses [63.2(28.9)] was 8.4, which exceeds the establish criteria for clinical significance, although not statistically significant (P=0.08). Overall satisfaction scores were 68.8(26.9) for the delefilcon A and 59.7(30.3) for the comfilcon A lenses (P=0.08). Both lenses provided mean binocular visual acuities better than 20/20 Snellen equivalent. Over half of the participants preferred the delefilcon A lenses based upon comfort, vision, and overall performance. Convenience, ease of use, and satisfaction all scored higher with delefilcon A lenses.

Conclusion

The results of this study show that wear experience with delefilcon A lenses for astigmatism can meet or exceed that of comfilcon A toric lenses while also providing healthy, daily disposable lens wear.

Methods for a population-based Comprehensive Eye care Workload Assessment (CEWA) study in Southern India

Eye care programs, in developing countries, are often planned using the prevalence of blindness and visual impairment, often estimated from Rapid Assessment of Avoidable Blindness (RAAB) surveys. A limitation of this planning approach is that it ignores the annual overall eye care requirements for a given population. Moreover, targets set are arbitrary, often influenced by capacity rather than need. To address this lacunae, we implemented a novel study design to estimate the annual need for comprehensive eye care in a 1.2 million populations. We conducted a population-based longitudinal study in Theni district, Tamil Nadu, India. All permanent residents of all ages were included. We conducted the study in three phases, (i) household-level enumeration and enrollment, (ii) basic eye examination (BEE) at household one-year post-enrollment, and (iii) assessment of eye care utilization and full eye examination (FEE) at central locations. All people aged 40 years and above were invited to the FEE. Those aged <40 years were invited to the FEE if indicated. In the main study, we enrolled 24,327 subjects (58% aged below 40 years and 42% aged 40 years and above). Of those less than 40 years, 72% completed the BEE, of whom 20% were referred for FEE at central location. Of the people aged ≥40 years, 70% underwent FEE. Our study design provides insights for appropriate long-term public health intervention planning, resource allocation, effective service delivery, and designing of eye care services for resource-limited settings.

Progression of myopia among undergraduate students in central China

AIM

To investigate the progression of myopia and risk factors among university students in central China.

METHODS

A total of 7359 first-year undergraduate students at Huazhong University of Science and Technology in central China were recruited to the study and invited to a centralized clinic for medical examination, including optometry, and re-examined after one year. Correlation analyses were performed to assess the associations between one-year myopia progression and various parameters.

RESULTS

The spherical equivalent refraction for the overall population was -3.14±2.28 D at baseline. The rate of myopia progression over 0.50 D after one year was 41.9%, and the 1-year progression of myopia was -0.47±0.58 D. There was no difference of mean 1-year myopia progression between male and female or difference among age group. The myopia progression of original myopia was severer than progression of new-onset myopia. There was also difference of mean myopia progression among different degrees of myopia at baseline. The under corrected eyes had a higher percentage of myopia progression than well corrected eyes (χ ²=7.90, P<0.01). There was no correlation between myopia progression and height, weight, body mass index, hemoglobin (Spearman correlation, ρ=-0.078, -0.152, -0.170, -0.096, respectively, all P>0.05).

CONCLUSION

Myopes still progress in undergraduate students, especially in high myopes.

Prevalence of Refractive Error in Vientiane Province, Lao People's Democratic Republic

PURPOSE

To determine the prevalence of adult refractive error and associated risk factors in the Vientiane Province of the Lao People's Democratic Republic.

METHODS

Population-based, cross-sectional ophthalmic survey of individuals ≥ 40 years of age in Vientiane Province. Suitable refractive data was available in 1058 individuals. Demographic data, which included age and gender, was obtained from all participants. Smoking status, presence of diabetes and hypertension was also recorded. The ophthalmic examination included autorefraction, grading of cataract, applanation tonometry and ultrasound pachymetry for ocular biometry, including axial length.

RESULTS

Mean refractive error measured -0.36 diopters (D) (standard deviation [SD], 1.41) and mean cylindrical error measured -0.33 D (SD 0.95). Myopia ≤ -0.5 D and ≤ -5.0 D occurred in 53.2% (95% confidence interval [CI]: 43.7 to 62.6) and 2.0% (95% CI: 0.4 to 3.6) of participants, respectively. There was a correlation between myopia and both age and higher grading of nuclear cataract (p < .001). Hyperopia ≥ +0.5 D was present in 26.4% of participants and was associated with increasing age (p < .001). Astigmatism was present in 55.8% (95% CI: 51.5 to 60.2) of the population and was associated with increased nuclear cataract (p < .001). Urban participants had a reduced prevalence of myopia compared with rural participants.

CONCLUSION

Myopia was associated with younger age and a higher grade of nuclear cataract. The prevalence of myopia in the adult population of Vientiane Province was higher than that reported in neighbouring Asian regions and contributed to low vision.

Astigmatism profile in the elderly population: Tehran Geriatric Eye Study

PURPOSE

To determine the prevalence of astigmatism and its associated factors and examine astigmatism symmetry patterns in an elderly population.

STUDY DESIGN

Population based cross-sectional study.

METHODS

The present population-based cross-sectional study was conducted on an elderly population above 60 years of age in Tehran, Iran in 2019. The sampling was done using the stratified multistage random cluster sampling method. All study participants underwent a complete optometric examination and slit-lamp biomicroscopy.

RESULTS

The prevalence of astigmatism higher than -0.50, -1.00, and -2.00 D was 83% (95% CI: 81 -84), 52 % (95% CI: 50 -54), and 19% (95% CI: 17-20), respectively. These prevalence was 79%(95% CI: 77-81), 46(95% CI: 44-49) and 14(95% CI: 13-16) in subjects without a history of ocular surgery, respectively. Based on cylinder power worse than -1.00 D, 10% (95% CI: 9-12), 20% (95% CI: 18-22), and 21% (95% CI:19-23) of study participants had with the rule, against the rule, and oblique astigmatism, respectively. According to the results of the multiple regression model, male gender, older age, low education level, pure posterior subcapsular cataract, pseudophakia, and myopia were independent factors associated with astigmatism. The prevalence of anisorule astigmatism was 57 % (95% CI: 56-59), the most common anisorule astigmatism was against the rule-oblique type with a prevalence of 36% (95% CI: 34-38).

CONCLUSION

The prevalence of astigmatism was high in the elderly population of Tehran. More than half of the participants in this study had anisorule astigmatism, and against the rule-oblique combination was more prevalent than other types. A posterior subcapsular cataract, a history of cataract surgery, and myopia were the associated factors of astigmatism in this study.

Accuracy of a low-cost, portable, refractive error estimation device: Results of a diagnostic accuracy trial

Purpose

To assess the accuracy of refraction measurements by ClickCheck^TM compared with the standard practice of subjective refraction at a tertiary level eye hospital.

Design

Diagnostic accuracy trial.

Methods

All participants, recruited consecutively, underwent auto-refraction (AR) and subjective refraction (SR) followed by refraction measurement using ClickCheck^TM (CR) by a trained research assistant. Eyeglass prescriptions generated using ClickCheck^TM and the resulting visual acuity (VA) was compared to SR for accuracy. Inter-rater reliability and agreement were determined using Intra-class correlation and Bland Altman analysis respectively.

Results

The 1,079 participants enrolled had a mean (SD) age of 39.02 (17.94) years and 56% were women. Overall, 45.3% of the participants had refractive error greater than ±0.5D. The mean (SD) spherical corrections were -0.66D (1.85) and -0.89D (2.20) in SR and CR respectively. There was high level of agreement between the spherical power measured using SR and CR (ICC: 0.940 (95% CI: 0.933 to 0.947). For the assessment of cylindrical correction, there was moderate level of agreement between SR and CR (ICC: 0.493 (0.100 to 0.715). There was moderate level of agreement between the VA measurements performed by using corrections from SR and CR (ICC: 0.577 (95% CI: 0.521–0.628). The subgroup analysis based on the age categories also showed high level of agreement for spherical corrections between the two approaches (ICC: 0.900). Bland Altman analysis showed good agreement for spherical corrections between SR and CR (Mean difference: 0.224D; 95% LoA: -1.647 D to 2.096 D) without evidence of measurement bias.

Conclusions

There was a high level of agreement for spherical power measurement between CR and SR. However, improvements are needed in order to accurately assess the cylindrical power. Being a portable, low-cost and easy-to-use refraction device, ClickCheck^TM can be used for first level assessment of refractive errors, thereby enhancing the efficiency of refractive services, especially in low- and-middle-income countries.

Common causes of visual impairment in the elderly

Background

Aging is not a disease; rather, it is a process. As people age, visual impairment (VI) becomes more common. In 2010, the overall prevalence rate of vision impairment in all races was 25.66% in individuals aged ≥ 80 years, according to the estimate of the National Eye Institute at the National Institutes of Health. This review aimed to address the common causes of VI in the elderly.

Methods

In this narrative review, an electronic search of the PubMed/MEDLINE database was conducted using "visual impairment" and "elderly" for the period between January 2010 and April 2021, to include randomized clinical trials and observational studies concerning VI in the elderly. The selected time period was chosen to provide an updated review.

Results

The search yielded 2955 articles published over the period of more than 11 years. The relevant randomized clinical trials or observational studies were included and reviewed. Cataracts, refractive errors, open-angle glaucoma, age-related macular degeneration, and diabetic retinopathy were the most common age-related ocular disorders leading to VI if untreated in the elderly. The loss of visual acuity can adversely affect quality of life in the elderly. Difficulty with activities of daily living related to VI can lead to social isolation, depression, and anxiety. Loss of vision in the elderly is linked to an increased risk of falls, hip fracture, depression, and poor quality of life.

Conclusions

The most common causes of VI in the elderly are cataracts and refractive errors. VI in most ocular diseases is more prevalent in women than in men due to longer lifespan. The overall prevalence of the main causes of VI in the elderly is expected to increase; therefore, health policymakers should consider this when planning for the health-enhancement program of the population.

Myopia in India

India is a culturally and geographically diverse nation. Its vast demographic nature does not allow a single definition for any of the given medical conditions in its territory. One important clinical condition which has created an uproar in the rest of the world is myopia. Its cause, prevalence, etiopathogenesis and other factors are being explored constantly; however, data with respect to Indian subcontinent are genuinely missing. Hence, in this review, we enumerate the country’s myopia journey from last 4 decades. The epidemiology, genetics, ocular/systemic association, quality of life, imaging, and management in myopia with necessary future directives are discussed to augment the overall management in future.

Improving Access to Refractive Services in Adults: A Health Examination Center-Based Model

Purpose: To assess the potential of a health examination center-based screening model in improving service for uncorrected refractive error. Methods: Individuals aged ≥18 years undergoing the routine physical examinations at a tertiary hospital in the northeast China were invited. Presenting visual acuity, noncycloplegic autorefraction, noncontact tonometry, fundus photography, and slit-lamp examination were performed. Refractive error was defined as having spherical equivalent ≤ -0.75 D or ≥ +1 D and uncorrected refractive error was considered as refractive error combined with presenting visual acuity < 6/12 in the better eye. Costs for the screening were assessed. Results: A total of 5,284 participants (61 ± 14 years) were included. The overall prevalence of myopia and hyperopia was 38.7% (95% CI, 37.4-40.0%) and 23.5% (95% CI, 22.3-24.6%), respectively. The prevalence of uncorrected refractive error was 7.85% (95% CI, 7.13-8.58%). Women (p < 0.001 and p = 0.003), those with age ≥ 70 years (p < 0.001 and p = 0.003), and myopia (p < 0.001 and p < 0.001) were at higher risk of uncorrected refractive error and uncorrected refractive error-related visual impairment. Spectacle coverage rate was 70.6% (95% CI, 68.2-73.0%). The cost to identify a single case of refractive error and uncorrected refractive error was US$3.2 and US$25.2, respectively. Conclusion: The prevalence of uncorrected refractive error is high in the urban Chinese adults. Health examination center-based refractive error screening is able to provide an efficient and low-cost model to improve the refractive services in China.

Magnitude of astigmatism - A comparison between eyes

PURPOSE

Astigmatism is a highly prevalent refractive error and while studies typically focus to describe the axis symmetry between eyes, little is known about the refractive symmetry. Therefore, this study determined the astigmatic power symmetry between eyes in a large clinic population.

METHODS

A clinical chart review was conducted at three optometric practices in the United States, the United Kingdom and Canada and subjective refraction data from 88,891 patients 14-70 years of age who presented with at least -0.25DC refractive astigmatism in at least one eye were included in the analysis. Data were obtained at these practices between January 2014 and March 2017. The overall distribution (%) and magnitude (DC) of astigmatism was determined and refractive differences between eyes were identified.

RESULTS

The mean age of the patients was 42.1 ± 15.9 years and included 51,685 (58%) female and 37,206 (42%) male patients. In this data pool of 177,782 eyes, 10.9% required zero astigmatic correction, while 56.2% had astigmatism of -0.25 to -0.75DC. In total 23.9% of patients presented with astigmatism of at least -0.75DC in only one eye, while the other eye had 0 to -0.50DC. Overall, the difference in astigmatism between eyes was less than -0.75DC for 82.1% of astigmatic patients. For patients who presented with astigmatism of -1.00DC in the right eye, 80.8% of them had an astigmatic prescription of -1.00 ± 0.50DC in the left eye. For an astigmatic prescription of -4.00DC in the right eye, only 40.6% of patients exhibited astigmatism of -4.00DC ± 0.50DC in the left eye.

CONCLUSIONS

The majority of patients exhibited a difference in astigmatism between eyes of less than -0.75DC, however the refractive cylinder power symmetry was significantly lower in patients with higher refractive astigmatism.

Prevalence and risk factors of refractive error in Qinghai, China: a cross-sectional study in Han and Tibetan adults in Xining and surrounding areas

Background

Our study aimed to explore the prevalence and risk factors of refractive error (RE) in Han and Tibetan population aged 50–79 years in Xining and surrounding areas in Qinghai Province on Qinghai-Tibet Plateau.

Methods

As part of the China National Health Survey, our cross-sectional study compared the age-adjusted prevalence of RE in Han and Tibetan older adults aged 50–79 years in Xining and surrounding areas. A multivariate logistic regression model was used to identify risk factors for myopia and hyperopia.

Results

Among 769 Han participants and 476 Tibetan participants, the age-adjusted prevalence of myopia (spherical equivalent (SE) < − 0.5D), hyperopia (SE > + 0.5D), high myopia (SE < -6.0D) and astigmatism (cylindrical equivalent > = 0.5D) is 28.56, 22.82, 2.80, and 69.38%. Han participants have higher age-adjusted prevalence of myopia (32.93% vs 21.64%, p < 0.001), high myopia (3.93% vs 1.02%, p = 0.001) and astigmatism (72.14% vs 64.94%, p = 0.021) compared to Tibetan participants. Being Tibetan is the protective factor of myopia compared to being Han (OR 0.58, 95%CI 0.42–0.79, p < 0.001). Older age (p = 0.032), longer time length in rural area (p = 0.048), undergraduate/graduate education level (p = 0.031), lighter active level (p = 0.007) and lower BMI (p = 0.015) are risk factors for myopia. Older age (all p < 0.001) and pterygium status of the same eye (p = 0.013) also increase the hyperopia risk.

Conclusions

Our study found an overall prevalence of myopia of 28.56% in Xining and surrounding areas in adults older than 50 years. Han population has higher myopia risk than Tibetan population. More medical and social resources should be allocated to improve the vision and life quality of older adults.

Investigation of the Accuracy of a Low-Cost, Portable Autorefractor to Provide Well-Tolerated Eyeglass Prescriptions: A Randomized Crossover Trial

PURPOSE

To compare patient preferences for eyeglasses prescribed using a low-cost, portable wavefront autorefractor versus standard subjective refraction (SR).

DESIGN

Randomized, cross-over clinical trial.

PARTICIPANTS

Patients aged 18 to 40 years presenting with refractive errors (REs) to a tertiary eye hospital in Southern India.

METHODS

Participants underwent SR followed by autorefraction (AR) using the monocular version of the QuickSee device (PlenOptika Inc). An independent optician, masked to the refraction approach, prepared eyeglasses based on each refraction approach. Participants (masked to refraction source) were randomly assigned to use SR- or AR-based eyeglasses first, followed by the other pair, for 1 week each. At the end of each week, participants had their vision checked and were interviewed about their experience with the eyeglasses.

MAIN OUTCOME MEASURES

Patients preferring eyeglasses were chosen using AR and SR.

RESULTS

The 400 participants enrolled between March 26, 2018, and August 2, 2019, had a mean (standard deviation) age of 28.4 (6.6) years, and 68.8% were women. There was a strong correlation between spherical equivalents using SR and AR (r = 0.97, P < 0.001) with a mean difference of -0.07 diopters (D) (95% limits of agreement [LoA], -0.68 to 0.83). Of the 301 patients (75.2%) who completed both follow-up visits, 50.5% (n = 152) and 49.5% (n = 149) preferred glasses prescribed using SR and AR, respectively (95% CI, 45.7-56.3; P = 0.86). There were no differences in demographic or vision characteristics between participants with different preferences (P > 0.05 for all).

CONCLUSIONS

We observed a strong agreement between the prescriptions from SR and AR, and eyeglasses prescribed using SR and AR were equally preferred by patients. Wider use of prescribing based on AR alone in resource-limited settings is supported by these findings.

Sleep time and homework hours/daily are associated with reduced visual acuity among school students aged 9-18 in Shenyang in 2016

PURPOSE

The purpose of this survey was to explore the prevalence of reduced visual acuity and its associated factors among school students in Shenyang in 2016.

METHODS

This was a cross-sectional study using data from the Ministry of Education' Student Physical Fitness (MESPF) monitoring in 2016. A total of 13,642 students aged 9-18 years were surveyed in Shenyang. The unaided distance visual acuity was measured, and questionnaire on lifestyle behaviors that may affect visual acuity was investigated among students. The prevalence of reduced visual acuity and its associated factors were analyzed.

RESULTS

The average prevalence of reduced visual acuity among students aged 9-18 years was 65.8%, and severe reduced visual acuity was main (42.9%), and there were statistical effect of age, gender, and region on the prevalence of reduced visual acuity. Binary and multi variable logistic regression results revealed that students sleeping <8 h, homework hours ⩾1 h, and parental myopia had an increased risk of reduced visual acuity.

CONCLUSIONS

Sleep time <8 h and homework time ⩾1 h may be associated with reduced visual acuity among students in Shenyang. Therefore, it is benefit for student to get enough sleep and decreasing studying time in order to prevent and reduce poor vision.

Prevalence of refractive errors, uncorrected refractive error, and presbyopia in adults in India: A systematic review

Purpose:

The objective of this review is to estimate the prevalence of refractive errors, uncorrected refractive error (URE), and uncorrected presbyopia in adults aged ≥30 years in India.

Methods:

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. A detailed literature search was performed to include all studies published from India from the year 1990 using the Cochrane Library, Medline, and Embase. Refractive error was defined by >0.50 D ametropia. URE was defined by presenting visual acuity (PVA) worse than 6/18 improving with pinhole or spectacle correction, and uncorrected presbyopia by near vision <N8 improving with correction in the absence of distance URE.

Results:

Fifteen studies were included from South India, one each from Western and Central India, and one study covered 15 states across India. The prevalence of RE of at least 0.50 D of spherical equivalent ametropia was 53.1% [(95% confidence interval (CI): 37.2–68.5), of which myopia and hyperopia was 27.7% and 22.9%, respectively. The prevalence of URE was 10.2% (95% CI: 6.9–14.8), but heterogeneity in these estimates was very high. The prevalence of uncorrected presbyopia was 33% (95% CI: 19.1–51.0).

Conclusion:

This review highlights the magnitude of refractive errors among adults in India. More studies are needed using standard methods in regions where there is a lack of information on UREs. Programs delivering spectacles for adults in India will need to primarily focus on reading glasses to correct presbyopia along with spectacles for hyperopia and myopia.

Cytokine fibroblast growth factor 10 (FGF10) polymorphisms are associated with risk of myopia in young children

Myopia has become a major public health issue worldwide. Identification of genetic loci related to myopia in young children may advance our knowledge of the pathogenesis of myopia. Fibroblast growth factor 10 (FGF10) plays essential roles for the development of myopia through modulating extracellular matrix-associated genes. Studies revealed that genetic variants of FGF10 were associated with extreme myopia in adults. However, their associations with susceptibility of myopia in young children, which are less affected by confounding factors and more suitable for studying genetic factors of myopia, have not been explored. In the current study, we evaluated 13 tagSNPs that captured 100% of genetic variation in the FGF10 gene region for their associations with myopia in a large Chinese case-control study with 900 myopia children and 900 nonmyopia children. We found rs2973644 was significantly associated with increased risk of myopia (odds ratio [OR]: 1.26; 95% confidence intervals [CI]: 1.06-1.49; P = 0.009). furthermore, rs339501 (OR: 1.73; 95% CI: 1.18-2.53; P = 0.005), rs2973644 (OR: 1.57; 95% CI: 1.13-2.19; P = 0.007), and rs79002828 (OR: 1.83; 95% CI: 1.20-2.77; P = 0.005) were significantly associated with increased risk of high myopia in young children. Functional assessment of rs2973644 by luciferase assays revealed the risk G allele causes a higher expression level of FGF10 than the protective A allele. Our results do support that genetic variants of cytokine FGF10 are associated with susceptibility of myopia (as well as high myopia) in young children and further exploration are needed for myopia in children.

Prevalence and risk factors for myopia and other refractive errors in an adult population in southern India

PURPOSE

To investigate prevalence and risk factors for myopia, hyperopia and astigmatism in southern India.

METHODS

Randomly sampled villages were enumerated to identify people aged ≥40 years. Participants were interviewed for socioeconomic and lifestyle factors and attended a hospital-based ophthalmic examination including visual acuity measurement and objective and subjective measurement of refractive status. Myopia was defined as spherical equivalent (SE) worse than -0.75 dioptres (D), hyperopia as SE ≥+1D and astigmatism as cylinder <-0.5.

RESULTS

The age-standardised prevalences of myopia, hyperopia and astigmatism were 35.6% (95% CI: 34.7-36.6), 17.0% (95% CI: 16.3-17.8) and 32.6 (29.3-36.1), respectively. Of those with myopia (n = 1490), 70% had advanced cataract. Of these, 79% had presenting visual acuity (VA) less than 6/18 and after best correction, 44% of these improved to 6/12 or better and 27% remained with VA less than 6/18. In multivariable analyses (excluding patients with advanced cataract), increasing nuclear opacity score, current tobacco use, and increasing height were associated with higher odds of myopia. Higher levels of education were associated with increased odds of myopia in younger people and decreased odds in older people. Increasing time outdoors was associated with myopia only in older people. Increasing age and female gender were associated with hyperopia, and nuclear opacity score, increasing time outdoors, rural residence and current tobacco use with lower odds of hyperopia. After controlling for myopia, factors associated with higher odds of astigmatism were age, rural residence, and increasing nuclear opacity score and increasing education with lower odds.

CONCLUSIONS

In contrast to high-income settings and in agreement with studies from low-income settings, we found a rise in myopia with increasing age reflecting the high prevalence of advanced cataract.