Refractive Errors in the Adult Pakistani Population: The National Blindness and Visual Impairment Survey

Prevalence of uncorrected distance refractive errors and associated risk factors in employees of an academic centre

BACKGROUND

Uncorrected refractive error (RE) may affect the work performance of adults in the workplace. The aim of current study was to determine the prevalence of corrected and uncorrected RE, and the determinants of uncorrected RE in adult employees of a university.

METHODS

This was a cross-sectional study of Tehran University Medical Sciences' staff. Besides demographic and some specific questionnaires, ophthalmic examinations including the measurement of uncorrected visual acuity (UCVA), best spectacles corrected visual acuity (BCVA), and presenting visual acuity were performed for all participants. The need for spectacles was defined as UCVA worse than 6/12 in the better eye that could be corrected to better than 6/12 with spectacles based on subjective refraction.

RESULTS

In total, 4460 individuals with mean age of 42.32 ± 8.80 were included in the study. The VA of the better eye was 0.01 ± 0.05 logMAR for BCVA, 0.13 ± 0.26 for UCVA, and 0.05 ± 0.12 for presenting VA. Prevalence of RE was 15.7%, including uncorrected RE of 5% and spectacles coverage (corrected RE) of 10.7%. The proportion of individuals with elementary education and poor-fair status of general health were 1.62 times higher in the uncorrected group. In the univariate analysis, type of occupation (office versus non-office workers), socioeconomic status, and insurance of employees were not related to uncorrected RE (all P > 0.4). Myopia was the only factor associated with uncorrected RE in logistic regression analysis (odds ratio = 2.73, 95%CI = 1.02-7.31, P = 0.04).

CONCLUSION

The prevalence of uncorrected RE and spectacle coverage were 5% and 10.7%, respectively. Myopia was almost three times more likely to be associated among employees with uncorrected RE.

Quality of refractive error care in Pakistan: an unannounced standardised patient study

OBJECTIVE

Undercorrected refractive errors are the primary cause of vision impairment worldwide, including in Pakistan. However, limited data exist on the quality of refractive error care. Our study assessed the quality of refractive error care in Punjab, Pakistan by estimating the proportion of spectacles that were optimally prescribed.

METHODS AND ANALYSIS

In this cross-sectional study, 12 unannounced standardised patients (USPs) from Jhang, Khanewal and Sahiwal districts were recruited. USPs underwent baseline subjective refraction and were trained to attend optical services, observe consultations, request spectacles and obtain prescriptions. The spectacles received were compared with baseline refraction to determine quality. We also examined the associations between spectacle quality, service and patient characteristics.

RESULTS

Out of 276 attempted visits to 69 optical services, 241 pairs of spectacles were dispensed. A population size-weighted percentage of 42.7% (95% CI 36.4% to 49.3%) of spectacles were optimal quality, with the range varying from 13.8% in Jhang to 67.0% in Khanewal. Half the suboptimal quality spectacles had horizontal prism deviations outside of tolerance limits. Optimal spectacles were associated with performing focimetry (unadjusted OR=7.15, 95% CI (3.02 to 16.94), p<0.001) and good communication (OR=2.23, 95% CI (1.06 to 4.67), p=0.03). Hyperopic USPs were less likely to receive optimal spectacles (OR=0.01 95% CI (0.00 to 0.11), p<0.001).

CONCLUSION

The quality of refractive error care in Pakistan requires improvement, particularly in the Jhang district. Key areas for enhancing refractive error care in Pakistan include refining dispensing and refraction skills for hyperopic prescriptions, providing training on the risks of using previous spectacles, and emphasising the importance of effective communication skills.

Exploring eye care pathways, patient priorities and economics in Pakistan: A scoping review and expert consultation study with thematic analysis

Purpose

As the prevalence of eye diseases increases, demand for effective, accessible and equitable eye care grows worldwide. This is especially true in lower and middle‐income countries, which have variable levels of infrastructure and economic resources to meet this increased demand. In the present study we aimed to review the literature on eye care in Pakistan comprehensively, with a particular focus on eye care pathways, patient priorities and economics.

Methods

A systematic scoping review was performed to identify literature relating to eye care in Pakistan. Searches of relevant electronic databases and grey literature were carried out. The results were analysed through a mixed methods approach encompassing descriptive numerical summary and thematic analysis. To consolidate results and define priority areas for future study, expert consultation exercises with key stakeholders were conducted using qualitative semi‐structured interviews.

Results

One hundred and thirty‐two papers (published and unpublished) were included in the final review. The majority (n = 93) of studies utilised a quantitative design. Seven interlinked themes were identified: eye care pathways, burden of eye disease, public views on eye‐related issues, workforce, barriers to uptake of eye care services, quality of eye care services and economic impact of blindness. Research priorities included investigating the eye care workforce, the quality and efficiency of current eye care services, eye care services available in rural Pakistan and the costs and benefits related to eye care provision and sustaining eye care programmes.

Conclusions

To the best of our knowledge, this is the first review to synthesise evidence from papers across the field relating to eye care in Pakistan. As such, this work provides new insights into the achievements of the national eye health programme, challenges in eye care in Pakistan and priority areas for future research.

Estimating need and coverage for five priority assistive products: a systematic review of global population-based research

INTRODUCTION

To improve access to assistive products (APs) globally, data must be available to inform evidence-based decision-making, policy development and evaluation, and market-shaping interventions.

METHODS

This systematic review was undertaken to identify studies presenting population-based estimates of need and coverage for five APs (hearing aids, limb prostheses, wheelchairs, glasses and personal digital assistants) grouped by four functional domains (hearing, mobility, vision and cognition).

RESULTS

Data including 656 AP access indicators were extracted from 207 studies, most of which (n=199, 96%) were cross-sectional, either collecting primary (n=167) or using secondary (n=32) data. There was considerable heterogeneity in assessment approaches used and how AP indicators were reported; over half (n=110) used a combination of clinical and self-reported assessment data. Of 35 studies reporting AP use out of all people with functional difficulty in the corresponding functional domains, the proportions ranged from 4.5% to 47.0% for hearing aids, from 0.9% to 17.6% for mobility devices, and from 0.1% to 86.6% for near and distance glasses. Studies reporting AP need indicators demonstrated >60% unmet need for each of the five APs in most settings.

CONCLUSION

Variation in definitions of indicators of AP access have likely led to overestimates/underestimates of need and coverage, particularly, where the relationship between functioning difficulty and the need for an AP is complex. This review demonstrates high unmet need for APs globally, due in part to disparate data across this sector, and emphasises the need to standardise AP data collection and reporting strategies to provide a comparable evidence base to improve access to APs.

Challenges in Eye Care in the Asia-Pacific Region

The Asia-Pacific region is home to a 4.3-billion population and one of the most rapidly aging regions. Addressing the eye care needs in the region would greatly boost the progress toward achieving universal eye health. Over 20 countries/regions have actively engaged in the "VISION 2020" initiative launched since 1999, and remarkable achievements have been witnessed as demonstrated by an increase in both the number and density of ophthalmologists in almost all countries. Nevertheless, formidable and emerging challenges are to be overcome in the coming century. From 1990 to 2015, the absolute number of blind people increased by 17.9%, largely due to population growth and aging. The Asia-Pacific region, the most populous continent with a rapidly aging population, would inevitably be left to tackle this challenge. Furthermore, a high prevalence of blinding eye diseases imposes great pressure on current eye care services, with South Asia having the highest age-standardized prevalence of moderate to severe visual impairment (17.5%) and mild vision impairment (12.2%) globally, and high-income countries having the highest overall prevalence of myopia, reaching 53.4% with East Asia having the second-highest overall prevalence (51.6%). Moreover, the availability of ophthalmic resources varies greatly in the region, with the density of ophthalmologists ranging from over 114 ophthalmologists per million population in Japan to 0 in Micronesia, and a highly disproportionate urban-rural distribution. This article aims to shed light on challenges faced by the Asia-Pacific ophthalmic community and propose corresponding strategies to tackle those challenges.

Prevalence and risk factor for refractive error in rural Chinese adults in Kailu, Inner Mongolia

PURPOSE

To investigate the prevalence of refractive error in adults 40 years of age and older in Kailu, Inner Mongolia.

METHODS

A population-based, cross-sectional study was conducted in Chinese adults. Spherical equivalent (S.E.) refractive error was determined from the right eye. Myopia and hyperopia were defined as a spherical equivalent (S.E.) < -0.5 dioptres (D) and >0.5 D, respectively. Since the prevalence of high myopia will vary with the precise criterion chosen, the prevalence of this condition was calculated for thresholds of both <-5.0 D and <6.0 D. Astigmatism was defined as cylinder power >0.5 D. Anisometropia was defined as a difference in S.E. between the two eyes >1.0 D.

RESULTS

The prevalence of myopia, high myopia (<-5.0 D/<-6.0 D) and hyperopia in Kailu adults was 60.3% (95%CI: 58.95-61.71), 5.5% (95%CI: 4.82-6.10) /4.0% (95%CI: 3.47-4.57) and 12.2% (95%CI: 11.26-13.11), respectively. The age- and gender-standardised prevalence of myopia, high myopia (-5.0 D/-6.0 D) and hyperopia were 62.5% (95%CI: 61.05-63.99), 5.0% (95%CI: 4.34-5.61) /3.5% (95%CI: 2.99-4.04) and 10.6% (95%CI: 9.71-11.49), respectively. 52.9% had refractive astigmatism >0.5 D and 18.8% of subjects had clinically significant anisometropia. Age was significantly associated with hyperopia, high myopia, astigmatism and anisometropia. Myopia was more prevalent in females. Individuals with a higher educational level had a greater and lesser likelihood of myopia and astigmatism, respectively.

CONCLUSIONS

Myopia affects around two-thirds of the rural Chinese population over 40 years of age in Kailu. This high prevalence highlights that rural populations should be included in epidemiological studies of refractive error. Further investigations are needed to clarify the role of environmental factors in myopia development.

Economic Inequality in Unmet Refractive Error Need in Deprived Rural Population of Iran

Purpose:

To determine economic inequality in unmet refractive error (RE) need and its determinants in deprived rural population of Iran.

Methods:

In this population-based study, two villages were randomly selected from among underserved villages of Iran. After selecting the participants, optometric examinations, including uncorrected and corrected visual acuity and subjective and manifest refraction, were done for all the participants. Then, unmet need for glasses was determined. Concentration index (C) was used to assess inequality, and Oaxaca–Blinder decomposition method was applied to decompose the gap between the two groups based on the determinants.

Results:

Of 3851 samples, 3314 participated in the study (response rate = 86.05%). The data of 3255 participants were used for analysis. The value of C and 95% confidence interval (CI) was −0.088 (−0.157 to −0.020), indicating a pro-poor inequality in unmet need. The prevalence (95% CI) of unmet need was 11.74% (9.25–14.22) in the poor and 6.51% (4.96–8.06) in the rich, with a gap of about 5% in favor of the rich (P < 0.001). A marked percentage of the gap was due to the explained portion (b = 5.73; P = 0.031). In the explained portion, the variable of economic status (b = 3.48; P = 0.004) and myopia (b = 0.88; P = 0.031) caused inequality in favor of the rich and against the poor, respectively. In the unexplained portion (b = −0.51; P = 0.372), the variables of education (P = 0.002) and place (P = 0.001) had statistically significant effects on inequality.

Conclusions:

There is a significant pro-poor economic inequality in the prevalence of unmet need in rural areas of Iran. Although part of this inequality is related to variables such as education and myopia, a major portion (two thirds) of this inequality may be due to the direct effect of economic inequality.

Use of spectacles for distance vision: coverage, unmet needs and barriers in a rural area of North India

Background

Uncorrected refractive errors contribute enormously to the burden of avoidable visual impairment worldwide. There is a huge disparity in different parts of the globe in context to spectacle coverage for distance vision. This study was undertaken with objectives of determining prevalence of spectacle coverage, unmet needs and associated factors among adults in a rural community of north India.

Methods

A community-based cross-sectional study was carried out within selected clusters of Jhajjar district of Haryana. All participants aged > 15 years underwent visual acuity assessment by LogMAR “E” screening chart. Participants with presenting visual acuity < 6/12 in any eye and all current spectacle users underwent detailed ophthalmic examination and refraction. Additional details about spectacles, barriers for their use and willingness to pay for them were collected. Participants with met and unmet need for spectacle use at visual acuity > 6/12 was computed. These are reported as proportions with 95% confidence intervals. Associated factors with unmet need were determined using bivariable and multivariable logistic regression analysis.

Results

A total of 6910 participants were examined. The current spectacle use was 7.5% (95% Confidence Interval CI: 6.5, 8.7). The spectacle coverage was found in 33.3% (95% CI: 30.0, 36.7) participants among those in need. The unmet need was found in 10.8% of participants (95% CI: 10.1, 11.6). On multivariable analysis, odds of unmet need was associated with age, gender, level of education and marriage status. The most common barrier for refractive correction was lack of perceived need for refraction and its correction.

Conclusion

There is substantial unmet need for distance vision spectacles in this population. It is imperative that multi-component intervention be implemented to improve spectacle coverage in this rural north Indian setting.

Progression of Myopic Maculopathy in Highly Myopic Chinese Eyes

Purpose

To evaluate the 2-year changes in myopic maculopathy and its associations in highly myopic eyes.

Methods

This was a longitudinal, observational cohort study involving 657 Chinese participants with bilateral high myopia (≤ -6.00 diopters spherical power), who were followed for 2 years. The worst eye of each participant was considered for the analysis. Myopic maculopathy was graded based on fundus photographs, using the International Photographic Classification and Grading System for Myopic Maculopathy.

Results

The mean baseline age was 21.6 ± 12.2 years (range, 6.8-69.7 years). Myopic maculopathy progressed in 97 (14.8%) of 657 eyes, of which 24 eyes progressed to a higher category of myopic maculopathy, including from no maculopathy to tessellated fundus in 17 eyes, from tessellated fundus to diffuse atrophy in 6 eyes, and from diffuse to patchy atrophy in 1 eye. Among 122 lesion changes identified, the most common changes were enlargement of diffuse atrophy (n = 50, 41.0%), appearance of lacquer cracks (n = 28, 23.0%), enlargement of patchy atrophy (n = 10, 8.2%) and development of additional lacquer cracks (n = 7, 5.8%). In addition, we identified 1 eye with enlargement of a Fuch's spot, and 1 eye with active choroidal neovascularization. In multiple logistic regression analysis, myopic maculopathy progression was associated with older age, longer axial length, greater change in myopic spherical equivalent and more severe myopic maculopathy at baseline.

Conclusions

Myopic maculopathy progressed in approximately 15% of highly myopic eyes over a 2-year period. Further studies with longer follow up periods are required to confirm identified risk factors for progression.

Potential Lost Productivity Resulting from the Global Burden of Myopia: Systematic Review, Meta-analysis, and Modeling

PURPOSE

We estimated the potential global economic productivity loss resulting from vision impairment (VI) and blindness as a result of uncorrected myopia and myopic macular degeneration (MMD) in 2015.

CLINICAL RELEVANCE

Understanding the economic burden of VI associated with myopia is critical to addressing myopia as an increasingly prevalent public health problem.

METHODS

We estimated the number of people with myopia and MMD corresponding to critical visual acuity thresholds. Spectacle correction coverage was analyzed against country-level variables from the year of data collection; variation in spectacle correction was described best by a model based on a human development index, with adjustments for urbanization and age. Spectacle correction and myopia data were combined to estimate the number of people with each level of VI resulting from uncorrected myopia. We then applied disability weights, labor force participation rates, employment rates, and gross domestic product per capita to estimate the potential productivity lost among individuals with each level and type of VI resulting from myopia in 2015 in United States dollars (US$). An estimate of care-associated productivity loss also was included.

RESULTS

People with myopia are less likely to have adequate optical correction if they are older and live in a rural area of a less developed country. The global potential productivity loss associated with the burden of VI in 2015 was estimated at US$244 billion (95% confidence interval [CI], US$49 billion-US$697 billion) from uncorrected myopia and US$6 billion (95% CI, US$2 billion-US$17 billion) from MMD. Our estimates suggest that the Southeast Asia, South Asia, and East Asia Global Burden of Disease regions bear the greatest potential burden as a proportion of their economic activity, whereas East Asia bears the greatest potential burden in absolute terms.

CONCLUSIONS

Even under conservative assumptions, the potential productivity loss associated with VI and blindness resulting from uncorrected myopia is substantially greater than the cost of correcting myopia.

Estimation of Spherical Refractive Errors Using Virtual Reality Headset

Refractive errors are the most common visual defects in humans. They are corrected using lenses whose power is determined using expensive and bulky devices operated by trained professionals. This limits the outreach of eye- health care. We exploit commercial virtual reality (VR) setup to create a portable and inexpensive system for subjective estimation of spherical refractive errors. In doing so, we aim to keep hardware additions simple and to a minimum. We add a plain reflecting mirror in a VR headset to project optotypes on programmable focal planes at varying distances from the subject's eye. An interactive interface uses feedback from the user to estimate accommodation range and spherical refractive errors automatically. We compute the range and precision of our system, and validate them in a user trial study. The proposed setup strongly agrees with clinical subjective refraction.

Refractive errors among patients attending the ophthalmology department of a medical college in North-East India

Purpose:

To determine the magnitude and pattern of refractive errors among patients attending the ophthalmology department of a new medical college in North-East India.

Materials and Methods:

A prospective study of the new patients (age ≥5 years), who were phakic and whose unaided visual acuities were worse than 20/20 but improved with pinhole, was done. Complete ophthalmic examination and refraction with appropriate cycloplegia for age were done for the 4582 eligible patients. Spherical equivalents (SE) of refractive errors of the right eyes were used for analysis.

Results:

Of the 4582 eligible patients, 2546 patients had refractive errors (55.56%). The proportion of emmetropia (SE − 0.50–+0.50 diopter sphere [DS]), myopia (SE <−0.50 DS), high myopia (SE >−5.0 DS), and hypermetropia (>+0.50 DS for adults and >+2.0 DS for children) were 53.1%, 27.4%, 2.6%, and 16.9%, respectively. The proportion of hyperopia increased till 59 years and then decreased with age (P = 0.000). The proportion of myopia and high myopia decreased significantly with age after 39 years (P = 0.000 and P = 0.004, respectively). Of the 1510 patients with astigmatism, 17% had with-the-rule (WTR), 23.4% had against-the-rule (ATR), and 19% had oblique astigmatisms. The proportion of WTR and ATR astigmatisms significantly decreased (P = 0.000) and increased (P = 0.000) with age, respectively.

Conclusions:

This study has provided the magnitude and pattern of refractive errors in the study population. It will serve as the initial step for conducting community-based studies on the prevalence of refractive errors in this part of the country since such data are lacking from this region. Moreover, this study will help the primary care physicians to have an overview of the magnitude and pattern of refractive errors presenting to a health-care center as refractive error is an established and significant public health problem worldwide.

Global and regional estimates of prevalence of refractive errors: Systematic review and meta-analysis

Purpose

The aim of the study was a systematic review of refractive errors across the world according to the WHO regions.

Methods

To extract articles on the prevalence of refractive errors for this meta-analysis, international databases were searched from 1990 to 2016. The results of the retrieved studies were merged using a random effect model and reported as estimated pool prevalence (EPP) with 95% confidence interval (CI).

Results

In children, the EPP of myopia, hyperopia, and astigmatism was 11.7% (95% CI: 10.5–13.0), 4.6% (95% CI: 3.9–5.2), and 14.9% (95% CI: 12.7–17.1), respectively. The EPP of myopia ranged from 4.9% (95% CI: 1.6–8.1) in South–East Asia to 18.2% (95% CI: 10.9–25.5) in the Western Pacific region, the EPP of hyperopia ranged from 2.2% (95% CI: 1.2–3.3) in South-East Asia to 14.3% (95% CI: 13.4–15.2) in the Americas, and the EPP of astigmatism ranged from 9.8% in South-East Asia to 27.2% in the Americas. In adults, the EPP of myopia, hyperopia, and astigmatism was 26.5% (95% CI: 23.4–29.6), 30.9% (95% CI: 26.2–35.6), and 40.4% (95% CI: 34.3–46.6), respectively. The EPP of myopia ranged from 16.2% (95% CI: 15.6–16.8) in the Americas to 32.9% (95% CI: 25.1–40.7) in South-East Asia, the EPP of hyperopia ranged from 23.1% (95% CI: 6.1%–40.2%) in Europe to 38.6% (95% CI: 22.4–54.8) in Africa and 37.2% (95% CI: 25.3–49) in the Americas, and the EPP of astigmatism ranged from 11.4% (95% CI: 2.1–20.7) in Africa to 45.6% (95% CI: 44.1–47.1) in the Americas and 44.8% (95% CI: 36.6–53.1) in South-East Asia. The results of meta-regression showed that the prevalence of myopia increased from 1993 (10.4%) to 2016 (34.2%) (P = 0.097).

Conclusion

This report showed that astigmatism was the most common refractive errors in children and adults followed by hyperopia and myopia. The highest prevalence of myopia and astigmatism was seen in South-East Asian adults. The highest prevalence of hyperopia in children and adults was seen in the Americas.

The prevalence of refractive errors among adult rural populations in Iran

PURPOSE

The aim was to determine the prevalence of myopia and hyperopia and related factors in underserved rural areas in Iran.

METHODS

Under random cluster sampling, two rural regions were randomly selected in the north and southwest of the country, and 3,061 persons over 15 years of age were invited into the study. After selecting samples, all participants had refraction, measurement of uncorrected vision and visual acuity and ocular health examination by slitlamp biomicroscopy.

RESULTS

Of the 3,061 invitees, 2,575 participated in the study (response rate: 84.1 per cent). After excluding those who met the exclusion criteria or had missing refractive data, eventually there were 2,518 subjects available for this analysis. The mean age of the participants was 44.3 ± 17.5 years (range: 16 to 93 years) and 1,460 of them (58.0 per cent) were female. The overall prevalence of myopia and hyperopia in this study was 25.2 per cent (95 per cent CI: 23.2 to 27.2) and 22.5 per cent (95 per cent CI: 20.6 to 24.4), respectively. The prevalence of myopia increased from 20.9 per cent in participants 16 to 20 years to 32.9 per cent in the 21 to 30 years age group, declined up to the age of 60 years and increased again afterwards. The lowest prevalence was 6.8 per cent observed in the 16 to 20 years age group and the highest was 45.8 per cent in 61- to 70-year-olds. In the final logistic regression model, myopia significantly associated with age, higher education levels and cataracts, while hyperopia associated with age, lower education levels and male gender.

CONCLUSION

In our study, the prevalence of myopia was lower and the prevalence of hyperopia was higher compared to most previous studies. The findings of this study imply that refractive errors vary by age.

Reasons for Refusing Laser-Assisted in Situ Keratomileusis in a Pakistani Population

Purpose

To study and analyze the reasons for not performing laser-assisted in-situ keratomileusis (LASIK) surgery in Pakistan.

Methods

This is a retrospective observational review of the patients who presented for LASIK surgery during January 2014 to September 2016 at the Hashmanis Hospital refractive surgery facility in Karachi, Pakistan.

Results

A total of 6005 eyes in 3512 patients presented for LASIK surgery. Out of these, a total of 1795 eyes (29.9%) of 899 patients (25.6%) were rejected. The most common cause for not performing LASIK surgery was found to be increased risk of postoperative ectasia seen in 534 (29.75%) eyes. In 275 (15.32%) eyes, the surgery could not be performed because of affordability of procedure or unscientific apprehensions of the patient. Keratoconus was seen in 268 (14.93%) eyes.

Conclusion

The patients presenting for LASIK surgery need extensive screening as the large proportion of patients may have corneal structural for not performing this procedure. The cost of the procedure plays its role as does the unscientific beliefs amongst the patients.

Comparison of visual acuity, refractive outcomes, and satisfaction between LASIK performed with a microkeratome and a femto laser

Purpose

To compare refractive outcomes, visual acuities, and satisfaction of patients between those treated with laser-assisted in situ keratomileusis (LASIK) using a Hansatome microkeratome (HM) and femto-assisted laser (FAL).

Methods

This was a retrospective analysis of 1,366 eyes in 687 patients who underwent LASIK with an HM (n=1,137) and an FAL (n=229) at the two centers of Hashmanis Hospital, Karachi, Pakistan. Refractive outcomes, including sphere, cylinder, and spherical equivalent in diopters (D), and visual acuities were assessed both preoperatively and at 1 month follow-up. Patient satisfaction was gauged by contacting the patient at the time of chart review.

Results

The postoperative median sphere, cylinder, and spherical equivalent values for those treated with FAL were 0.3±0.7 (−5.5–1.8), −0.5±0.6 (−5.0–1.0), and 0.0±0.7 (−6.0–1.6), respectively. For the HM arm, they were 0.0±1.28 (−10.8–6.8), −0.5±0.5 (−4.5–1.5), and −0.3±1.3 (−11.6–6.8), respectively. All preoperative values were statistically insignificant between the groups, while postoperative values were significant with P-values <0.001. Predictability and efficacy index was higher for the FAL (92.1%, 1.00) than the HM group (82.2%, 0.84). Similarly, patient satisfaction was slightly higher for those treated with FAL (93.3%) than HM (91.4%).

Conclusion

Our large retrospective analysis of eyes that have undergone LASIK using HM and FAL shows superior refractive outcomes in the latter, with special regard to procedural efficacy and predictability.

Epidemiology of Myopia

Myopia is not a simple refractive error, but an eyesight-threatening disease. There is a high prevalence of myopia, 80% to 90%, in young adults in East Asia; myopia has become the leading cause of blindness in this area. As the myopic population increases globally, the severity of its impact is predicted. Approximately one fifth of the myopic population has high myopia (≥-6 diopters), which results in irreversible vision loss such as retinal detachment, choroidal neovascularization, cataracts, glaucoma, and macular atrophy. The increasing prevalence of school myopia in the past few decades may be a result of gene-environment interactions. However, earlier school myopia onset would accompany faster myopia progression and greater risk of high myopia later in life. Recently, there have been effective interventions to delay the onset of myopia, such as outdoor activity and decreasing the duration of near work. Hyperopia (≤0.5 diopters) is a predictor of myopia. Pharmacological agents and optic interventions such as low-concentration atropine and orthokeratology may slow progression in myopic children. Novel surgeries and anti-vascular endothelial growth factor drugs could deal with some myopic complications. From available evidence, the prevention, control, and treatment of myopia seem to be promising. However, to reduce the impact of myopia in future decades, more work and effort are still needed, including that by governments and intercountry eye health organizations.

Epidemiology of Pathologic Myopia in Asia and Worldwide

The myopia epidemic in Asia is evident because the prevalence of high myopia among young adults is higher among Asian (6.8%-21.6%) compared with non-Asian populations (2.0%-2.3%). High myopia is linked to pathologic myopia (PM), which may cause irreversible visual impairment (VI). This review will highlight updates on the prevalence of PM and the associated VI from PM. The prevalence of PM among the middle-aged and elderly (0.9%-3.1%) is higher than the prevalence among children and adolescents (<0.2%). The PM lesions detected among older adults include advanced lesions, such as posterior staphyloma, chorioretinal atrophy, lacquer cracks, and Fuchs spot (in descending frequency of occurrence). A relatively high prevalence of PM (8%) was recently reported among highly myopic young adults. As young individuals grow older, the early grades of PM lesions are likely to progress to advanced grades. Two longitudinal changes that occur frequently in PM include the enlargement of beta peripapillary atrophy and the development of chorioretinal atrophy. The lack of longitudinal changes in PM limits the causal inferences of PM. The prevalence of VI attributed to PM seems to be higher among Asian populations compared with Western and European populations. Pathologic myopia is ranked as a more important cause of blindness and low vision in Asian populations compared with Western and European populations. With the lack of effective treatment strategies and poor prognosis, PM threatens the vision health of populations in Asia and worldwide. To control this future epidemic, the prevention of myopia onset and progression is necessary.

Prevalence and Causes of Visual Impairment and Blindness among Cocoa Farmers in Ghana

PURPOSE

To determine the prevalence and causes of visual impairment and blindness among cocoa farmers in Ghana in order to formulate early intervention strategies.

METHODS

A cross-sectional study using multistage random sampling from four cocoa growing districts in Ghana was conducted from November 2013 to April 2014. A total of 512 cocoa farmers aged 40 years and older were interviewed and examined. The brief interview questionnaire was administered to elicit information on the demographics and socioeconomic details of participants. The examination included assessment of visual acuity (VA), retinoscopy, subjective refraction, direct ophthalmoscopy, slit-lamp biomicroscopy and intraocular pressure (IOP). For quality assurance, a random sample of cocoa farmers were selected and re-examined independently.

RESULTS

Moderate to severe visual impairment (VA <6/18 to 3/60 in the better-seeing eye) was present in 89 participants (17.4%) and 27 (5.3%) were blind (presenting VA <3/60 in the better eye) defined using presenting VA. The main causes of visual impairment were cataract (45, 38.8%), uncorrected refractive error (42, 36.2%), posterior segment disorders (15, 12.9%), and corneal opacity (11, 9.5%).

CONCLUSION

The prevalence of visual impairment and blindness among cocoa farmers in Ghana is relatively high. The major causes of visual impairment and blindness are largely preventable or treatable, indicating the need for early eye care service interventions.

A situational analysis of ocular health promotion in the South African primary health-care system

BACKGROUND

South Africa has a serious burden of avoidable blindness and visual impairment, which may be due to poor ocular health promotional policies and programs or implementation. Therefore, this paper sought to critically analyse the South African primary health-care policies and programs, to identify the components of ocular health promotional policies and programs as well as how they are currently being implemented and to suggest areas that can be improved in order to minimise the burden of blindness and visual impairment.

METHODS

Triangulated quantitative and qualitative research methods were used in the study. Questionnaire and interviews were used to solicit data from national and provincial managers of different health directorates. Eye-care managers from each province also completed the questionnaire. Furthermore, relevant health policy and program documents from national and provincial departments of health were studied to identify areas relating to ocular health promotion.

RESULTS

The study found varying degrees of implementation of various ocular health promotional activities in the provinces with the majority of respondents (62 per cent) indicating that ocular health promotion was not part of their responsibility and another 81 per cent revealing that vision screening does not form part of their health promotional programs. It further revealed a lack of a dedicated directorate for ocular health-care issues and the absence of an integrated ocular health promotional policy.

CONCLUSION

Ocular health promotional activities were absent in other provinces. This may be a major contributing factor to poor ocular health promotion in South Africa and hence, the high prevalence of blindness and visual impairment. Therefore, it is recommended that an integrated ocular health promotional model (directorate and policies) be developed and be part of the South African primary health-care system.

Prevalence of Refractive Errors in the INK Area, Durban, South Africa

PURPOSE

To determine the prevalence and types of refractive errors in persons aged 35 years and older in the Inanda, Ntuzuma, and KwaMashu (INK) area of Durban, KwaZulu-Natal Province, South Africa.

METHODS

Refractive error data were obtained by autorefraction (Retinomax K-Plus; Nikon, Tokyo, Japan), retinoscopy, and subjective refraction. Refractive error was defined using spherical equivalents as myopia (<-0.5D) and hyperopia (>+0.5D). Astigmatism was defined as cylinder equal to or greater than -0.5D in either eye.

RESULTS

Participants' ages ranged from 35 to 90 years, with a mean of 53.05 ± 11.4 years. Women comprised 75% of the subjects. The prevalence of refractive error was 57.3%, with myopia 11.4%, hyperopia 37.7%, and astigmatism 25.7%. Myopia and astigmatism were significantly more prevalent in men (p < 0.01), whereas hyperopia was more prevalent in women (p < 0.01). Hyperopia was significantly associated with education (p < 0.01), whereas myopia and astigmatism were not (p = 0.09 and p = 0.15, respectively).

CONCLUSIONS

Approximately 57.3% of the population 35 years and older in the INK area of Durban were affected by refractive errors, with myopia, hyperopia, and astigmatism being significantly associated with sex. This study suggests that there is a need for interventions to alleviate refractive error in the INK area as well as in other communities affected by the lack of access to affordable services.

Biometry and visual function of a healthy cohort in Leipzig, Germany

Background

Cross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany.

Methods

Measurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies.

Results

The results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL −0.19 (0.006), ACD −0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (−0.66 (< 0.001)), ACD (−0.52 (< 0.001)) and ACV (−0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = −0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF −0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age.

Conclusion

Biometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research.

Trial registration

ClinicalTrials.gov # NCT01173614 July 28, 2010

Is myopia another clinical manifestation of insulin resistance?

Myopia is a multifactorial visual refraction disease, in which the light rays from distant objects are focused in front of retina, causing blurry vision. Myopic eyes are characterized by an increased corneal curvature and/or ocular axial length. The prevalence of myopia has increased in recent decades, a trend that cannot be attributed exclusively to genetic factors. Low and middle income countries have a higher burden of refractive error, which we propose could be a consequence of a shorter exposure time to a westernized lifestyle, a phenomenon that may also explain the rapid increase in cardiometabolic diseases, such as diabetes, among those populations. We suggest that interactions between genetic, epigenetic and a rapidly changing environment are also involved in myopia onset and progression. Furthermore, we discuss several possible mechanisms by which insulin resistance may promote abnormal ocular growth and myopia to support the hypothesis that insulin resistance and hyperinsulinemia are involved in its pathogenesis, providing a link between trends in myopia and those of cardiometabolic diseases. There is evidence that insulin have direct ocular growth promoting effects as well an indirect effect via the induction of insulin-like growth factors leading to decreases insulin-like growth factor-binding protein, also implicated in ocular growth.

Prevalence of Myopia in France: A Cross-Sectional Analysis

Refractive error (RE), particularly myopia, is the first cause of visual impairment throughout the world. This study aimed to depict the prevalence of myopia in a multicentric series of French individuals.This cross-sectional analysis was carried out between January 2012 and November 2013 in eye clinics dedicated to REs. Data collection included age, gender, best-corrected visual acuity, RE, and any relevant medical history involving laser refractive surgery and cataract surgery. Exclusion criteria consisted of monophthalm patients or those with incomplete demographic data.Prevalences in the overall population, by gender and by age groups were reported for mild myopia (-0.50 to -2.75 diopter [D]), moderate myopia (-3 to -5.75 D), high myopia (less than -6 D), and very high myopia (less than -10 D).The analysis included 100,429 individuals, mean age 38.5 years (± 16.9). Overall prevalence of myopia was 39.1% (95% CI 38.8-39.4). Prevalences of mild, moderate, high and very high myopia were respectively 25.1% (95% CI 25.4-24.9), 10.6% (95% CI 10.4-10.8), 3.4% (95% CI 3.3-3.5) and 0.5% (95% CI 0.48-0.57).Even if possible bias occurred in recruitment, our results are similar to RE data collected in nationally representative samples of Caucasians in other studies. This is to our knowledge, one of the largest European series of individuals dedicated to myopia prevalences in different age groups. These results confirm the importance of myopia as a major health issue in Western countries.

The age-specific prevalence of myopia in Asia: a meta-analysis

PURPOSE

To estimate the age-specific prevalence of myopia in Asia.

METHODS

We searched PubMed, Embase, and Web of Science from their inception through September 2013 for population-based surveys reporting the prevalence of myopia in adults or children in Asia. We pooled the prevalence estimates for myopia by age groups and by year of birth using a random-effects model.

RESULTS

We identified 50 eligible population-based studies including 215,672 subjects aged 0 to 96 years reporting the prevalence of myopia from 16 Asian countries or regions. Myopia was found to be most prevalent (96.5%; 95% confidence interval, 96.3 to 96.8) in Koreans aged 19 years. There was no significant linear age group effect on the prevalence of myopia in the whole Asian population but there was a U-shaped relationship between both age and year of birth and the prevalence of myopia. The prevalence of myopia was also higher in those older than 70 years (36.3%; 95% confidence interval, 27.6 to 45.0) compared with other age groups, which revealed nuclear cataract-myopia shifts in refraction.

CONCLUSIONS

There is a large variation in the age-specific prevalence of myopia in Asia. A U-shaped relationship between age and the prevalence of myopia was found in the whole Asian population. The analysis is essential to guide future eye health care, intervention, and clinical management in Asia.

Self-adjustable glasses in the developing world

Uncorrected refractive errors are the single largest cause of visual impairment globally. Refractive errors are an avoidable cause of visual impairment that are easily correctable. Provision of spectacles is a cost-effective measure. Unfortunately, this simple solution becomes a public health challenge in low- and middle-income countries because of the paucity of human resources for refraction and optical services, lack of access to refraction services in rural areas, and the cost of spectacles. Low-cost approaches to provide affordable glasses in developing countries are critical. A number of approaches has been tried to surmount the challenge, including ready-made spectacles, the use of focometers and self-adjustable glasses, among other modalities. Recently, self-adjustable spectacles have been validated in studies in both children and adults in developed and developing countries. A high degree of agreement between self-adjustable spectacles and cycloplegic subjective refraction has been reported. Self-refraction has also been found to be less prone to accommodative inaccuracy compared with non-cycloplegic autorefraction. The benefits of self-adjusted spectacles include: the potential for correction of both distance and near vision, applicability for all ages, the empowerment of lay workers, the increased participation of clients, augmented awareness of the mechanism of refraction, reduced costs of optical and refraction units in low-resource settings, and a relative reduction in costs for refraction services. Concerns requiring attention include a need for the improved cosmetic appearance of the currently available self-adjustable spectacles, an increased range of correction (currently −6 to +6 diopters), compliance with international standards, quality and affordability, and the likely impact on health systems. Self-adjustable spectacles show poor agreement with conventional refraction methods for high myopia and are unable to correct astigmatism. A limitation of the fluid-filled adjustable spectacles (AdSpecs, Adaptive Eyecare Ltd, Oxford, UK) is that once the spectacles are self-adjusted and the power fixed, they become unalterable, just like conventional spectacles. Therefore, they will need to be changed as refractive power changes over time. Current costs of adjustable spectacles are high in developing countries and therefore not affordable to a large segment of the population. Self-adjustable spectacles have potential for “upscaling” if some of the concerns raised are addressed satisfactorily.

Population-based survey of refractive error among school-aged children in rural northern China: the Heilongjiang eye study

BACKGROUND

The prevalence of refractive error in the north of China is unknown. The study aimed to estimate the prevalence and associated factors of refractive error in school-aged children in a rural area of northern China.

DESIGN

Cross-sectional study.

PARTICIPANTS OR SAMPLES

The cluster random sampling method was used to select the sample.

METHODS

A total of 1700 subjects of 5 to 18 years of age were examined. All participants underwent ophthalmic evaluation. Refraction was performed under cycloplegia. Association of refractive errors with age, sex, and education was analysed.

MAIN OUTCOME MEASURES

The main outcome measure was prevalence rates of refractive error among school-aged children.

RESULTS

Of the 1700 responders, 1675 were eligible. The prevalence of uncorrected, presenting, and best-corrected visual acuity of 20/40 or worse in the better eye was 6.3%, 3.0% and 1.2%, respectively. The prevalence of myopia was 5.0% (84/1675, 95% CI, 4.8%-5.4%) and of hyperopia was 1.6% (27/1675, 95% CI, 1.0%-2.2%). Astigmatism was evident in 2.0% of the subjects. Myopia increased with increasing age, whereas hyperopia and astigmatism were associated with younger age. Myopia, hyperopia and astigmatism were more common in females. We also found that prevalence of refractive error were associated with education. Myopia and astigmatism were more common in those with higher degrees of education.

CONCLUSION

This report has provided details of the refractive status in a rural school-aged population. Although the prevalence of refractive errors is lower in the population, the unmet need for spectacle correction remains a significant challenge for refractive eye-care services.

High prevalence of refractive errors in a rural population: 'Nooravaran Salamat' Mobile Eye Clinic experience

BACKGROUND

The prevalence of myopia and hyperopia and determinants were determined in a rural population of Iran.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

Using random cluster sampling, 13 of the 83 villages of Khaf County in the north east of Iran were selected. Data from 2001 people over the age of 15 years were analysed.

METHODS

Visual acuity measurement, non-cycloplegic refraction and eye examinations were done at the Mobile Eye Clinic.

MAIN OUTCOME MEASURES

The prevalence of myopia and hyperopia based on spherical equivalent worse than -0.5 dioptre and +0.5 dioptre, respectively.

RESULTS

The prevalence of myopia, hyperopia and anisometropia in the total study sample was 28% (95% confidence interval: 25.9-30.2), 19.2% (95% confidence interval: 17.3-21.1), and 11.5% (95% confidence interval: 10.0-13.1), respectively. In the over 40 population, the prevalence of myopia and hyperopia was 32.5% (95% confidence interval: 28.9-36.1) and 27.9% (95% confidence interval: 24.5-31.3), respectively. In the multiple regression model for this group, myopia strongly correlated with cataract (odds ratio = 1.98 and 95% confidence interval: 1.33-2.93), and hyperopia only correlated with age (P < 0.001). The prevalence of high myopia and high hyperopia was 1.5% and 4.6%. In the multiple regression model, anisometropia significantly correlated with age (odds ratio = 1.04) and cataract (odds ratio = 5.2) (P < 0.001).

CONCLUSION

The prevalence of myopia and anisometropia was higher than that in previous studies in urban population of Iran, especially in the elderly. Cataract was the only variable that correlated with myopia and anisometropia.

High prevalence of myopia in an adult population, Shahroud, Iran

PURPOSE

To determine the prevalence of myopia and hyperopia and the associated risk factors in the presbyopic age group of the population in Shahroud, Iran.

METHODS

Through a multistage random cluster sampling approach, 6311 people of the 40- to 64-year-old population residing in Shahroud were invited to this study. The prevalence of a cycloplegic spherical equivalent (SE) ≥-0.5 diopter (D) and hyperopia >+0.50 D was determined by age and gender.

RESULTS

Of the invitees, 5190 (82.2%) participated in the study and data from 4864 people was used in the analyses. On the basis of cycloplegic refraction, the prevalence of myopia and hyperopia was 30.2% [95% confidence interval (CI): 28.9 to 31.5] and 35.6 (95% CI: 34.1 to 37.1), respectively. In the multiple logistic regression model, the odds of myopia significantly increased with higher education [odds ratio (OR) = 1.02, p < 0.001] and nuclear cataract (OR = 3.23, p < 0.001). After the age of 54 years, the odds of hyperopia significantly increased compared with the 40- to 44-year age group, whereas higher education and nuclear cataract had negative association with hyperopia. The prevalence of high myopia (SE >-6.0 D) and high hyperopia (SE > 4.0 D) was 1.9% (95% CI: 1.5 to 2.3) and 1.1% (95% CI: 0.8 to 1.4), respectively. Nuclear cataract significantly correlated with high myopia (OR = 6.44) and older age significantly correlated with high hyperopia (OR = 1.12).

CONCLUSIONS

The prevalence of myopia was unexpectedly higher than that found in other parts of the Middle East. The prevalence of hyperopia was lower than that previously reported in Iran. Education correlated directly with myopia and inversely with hyperopia; however, nuclear cataract was the most important risk factor for myopia. Adjusted for other variables, the prevalence of hyperopia still increased with age.

Validity of noncycloplegic refraction in the assessment of refractive errors: the Tehran Eye Study

PURPOSE

To determine the sensitivity and specificity of noncycloplegic autorefraction for determining refractive status compared to cycloplegic autorefraction.

METHODS

The target population was noninstitutionalized citizens of all ages, residing in Tehran in 2002, selected through stratified cluster sampling. From 6497 eligible residents, 70.3% participated in the study, from August to November 2002. Here, we report data on 3501 people over the age of 5 years who had autorefraction with and without cycloplegia (two drops of cyclopentolate 1.0% 5 min apart, with autorefraction 25 min after the second drop).

RESULTS

Overall, the sensitivity of noncycloplegic autorefraction for myopia was 99%, but the specificity was only 80.4%. In contrast, the sensitivity for hyperopia was only 47.9%, but the specificity was 99.4%. At all ages, noncycloplegic autorefraction overestimated myopia and underestimated hyperopia. Overestimation of myopia was highest in the 21-30 and 31-40 year groups. Underestimation of hyperopia was high up to the age of 50 (20-40%), but decreased with age, to about 8% after the age of 50, down to almost 0% after 70. The difference in mean spherical equivalent with and without cycloplegia fell from 0.71 dioptres (D) in the 5-10 age group to 0.14D in those over 70.

CONCLUSION

Use of noncycloplegic autorefraction in epidemiological studies leads to considerable errors relative to cycloplegic measurements, except in those over 50-60. The difference between cycloplegic and noncycloplegic measurements varies with age and cycloplegic refractive category, and there is considerable individual variation, ruling out adjusting noncycloplegic measurements to obtain accurate cycloplegic refractions.

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.

Worldwide prevalence and risk factors for myopia

BACKGROUND

Myopia, the most common type of refractive error, is a complex trait including both genetic and environmental factors. Numerous studies have tried to elucidate the aetiology of myopia. However, the exact aetiology of myopia is still unclear.

PURPOSE

To summarize the worldwide patterns and trends for the prevalence of myopia and to evaluate the risk factors for myopia in population-based studies.

RECENT FINDINGS

The prevalences of myopia vary across populations of different regions and ethnicities. In population-based studies on children, the prevalence of myopia has been reported to be higher in urban areas and Chinese ethnicity. The regional and racial difference is not so obvious in adult populations aged over 40 years. More time spent on near work, less time outdoors, higher educational level and parental history of myopia have been reported to increase the risk of myopia.

CONCLUSIONS

Environmental factors play a crucial role in myopia development. The effect of gene-environment interaction on the aetiology of myopia is still controversial with inconsistent findings in different studies. A relatively hyperopic periphery can stimulate compensating eye growth in the centre. Longitudinal cohort studies or randomized clinical trials of community-based health behaviour interventions should be conducted to further clarify the aetiology of myopia.

Prevalence of the refractive errors by age and gender: the Mashhad eye study of Iran

BACKGROUND

Refractive errors are a common eye problem. Considering the low number of population-based studies in Iran in this regard, we decided to determine the prevalence rates of myopia and hyperopia in a population in Mashhad, Iran.

DESIGN

Cross-sectional population-based study.

PARTICIPANTS

Random cluster sampling. Of 4453 selected individuals from the urban population of Mashhad, 70.4% participated.

METHODS

Refractive error was determined using manifest (age > 15 years) and cycloplegic refraction (age ≤ 15 years). Myopia was defined as a spherical equivalent of -0.5 diopter or worse. An spherical equivalent of +0.5 diopter or worse for non-cycloplegic refraction and an spherical equivalent of +2 diopter or worse for cycloplegic refraction was used to define hyperopia.

MAIN OUTCOME MEASURES

Prevalence of refractive errors.

RESULTS

The prevalence of myopia and hyperopia in individuals ≤ 15 years old was 3.64% (95% CI: 2.19-5.09) and 27.4% (95% CI: 23.72-31.09), respectively. The same measurements for subjects > 15 years of age was 22.36% (95% CI: 20.06-24.66) and 34.21% (95% CI: 31.57-36.85), respectively. Myopia was found to increase with age in individuals ≤ 15 years and decrease with age in individuals > 15 years of age. The rate of hyperopia showed a significant increase with age in individuals > 15 years. The prevalence of astigmatism was 25.64% (95% CI: 23.76-27.51).

CONCLUSIONS

In children and the elderly, hyperopia is the most prevalent refractive error. After hyperopia, astigmatism is also of importance in older ages. Age is the most important demographic factor associated with different types of refractive errors.

Risks and sequelae of scleral perforation during peribulbar or retrobulbar anesthesia

PURPOSE

To assess the risk for and circumstances of serious complications during peribulbar and retrobulbar anesthesia.

SETTING

University eye departments, Freiburg and Würzburg, Germany, and Skopje, Macedonia.

METHODS

This retrospective analysis comprised patients who received secondary care for complications of inadvertent globe perforation during peribulbar or retrobulbar injections over a 17-year period.

RESULTS

The review identified 9 inadvertent globe perforations that led to a variety of complications, ranging from subretinal hemorrhage to a globe rupture. Two cases were minor (subretinal hemorrhage with spontaneous resorption and retinal break requiring photocoagulation). All other cases required 1 or more vitrectomies to resolve intraocular hemorrhage and retinal detachment. Most cases still had significant functional impairment after treatment. Two of the 9 eyes regained reading ability, 1 eye maintained no light perception acuity, and 6 eyes had ambulatory vision only.

CONCLUSIONS

Although perforation is a rare complication of peribulbar anesthesia in normal eyes, the severity of complications in this study point to the importance of giving all patients, not only those with risk factors (eg, myopia, scar formation), detailed information about the possible risks and complications of peribulbar injections compared with those of other methods such as topical anesthesia and general anesthesia.

The challenge of uncorrected refractive error: driving the agenda of the Durban Declaration on refractive error and service development

The purpose of this article is to highlight the challenge of uncorrected refractive error globally, as well as to discuss recent advocacy successes and innovative programs designed to address the need for broader refractive error service development, particularly in developing countries. The World Health Organization's VISION 2020: The Right to Sight program first posed the challenge to national governments to give priority to strategies and resources targeted towards avoidable causes of blindness and visual impairment, so that these unnecessary forms of blindness or visual impairment can be eliminated globally by the year 2020. The blindness prevention community is challenged to increase in scale its initiatives, which support the attainment of VISION 2020: The Right to Sight goals primarily and the United Nation's Millennium Development Goals indirectly. The Durban Declaration on Refractive Error and Service Development was the outcome of a meeting of eye-care professionals, researchers, governments, civil society and industry in March 2007 and still stands as a guiding document to the blindness prevention community for the elimination of avoidable blindness due to uncorrected refractive error.

Refractive error among the elderly in rural Southern Harbin, China

PURPOSE

To estimate the prevalence and associated factors of refractive errors among the elderly in a rural area of Southern Harbin, China.

METHODS

Five thousand and fifty seven subjects (age > or = 50 years) were enumerated for a population-based study. All participants underwent complete ophthalmic evaluation. Refraction was performed by ophthalmic personnel trained in the study procedures. Myopia was defined as spherical equivalent worse than -0.50 diopters (D) and hyperopia as spherical equivalent worse than +0.50 D. Astigmatism was defined as a cylindrical error worse than 0.75D. Association of refractive errors with age, sex, and education were analyzed.

RESULTS

Of the 5,057 responders (91.0%), 4,979 were eligible. The mean age was 60.5 (range 50-96) years old. The prevalence of myopia was 9.5% (95% confidence interval [CI], 8.5-10.1) and of hyperopia was 8.9% (95% CI, 7.9-9.5). Astigmatism was evident in 7.6% of the subjects. Myopia, hyperopia and astigmatism increased with increasing age (p<0.001, respectively). Myopia and astigmatism were more common in males, whereas hyperopia was more common in females. We also found that prevalence of refractive error weas associated with education. Myopia was more common in those with higher degrees of education, whereas hyperopia and astigmatism were more common in those with no formal education.

CONCLUSIONS

This report has provided details of the refractive status in a rural population of Harbin. The prevalence of refractive errors in this population is lower than those reported in other regions of the world.

The prevalence of refractive errors and its determinants in the elderly population of Mashhad, Iran

PURPOSE

To determine the prevalence rates of refractive errors in elderly people in Mashhad, Iran.

METHODS

In a cross-sectional study with a cluster sampling method, the sample population was selected proportionate to the total population of Mashhad. The selected citizens were then invited for eye examinations at the clinic. After an interview, refractive data were collected using objective and subjective refractions. Refractive error data were converted into spherical equivalent (SE), and myopia was defined as an SE worse than -0.50 diopters (D) and hyperopia worse than +0.50 D.

RESULTS

Of the 1540 selected samples, 93.5% participated in the study. Data were analyzed for 1367 adults without previous cataract surgery who had right eye refraction data; 35.4% were women, and 64.6% were men. The mean age was 63.7 +/- 7.1 years. The prevalence of myopia was 27.2% (95% confidence interval (CI) 24.8-29.5); 29.6% in men and 22.5% in women (P < 0.001). The rate of myopia showed an increase with age (P < 0.001). The prevalence of hyperopia was 51.6% (95% CI, 48.9% to 54.3%); 57.6% in women and 48.3% in men (P < 0.001). The rate of hyperopia showed a significant decrease with age. The prevalence of astigmatism in the studied sample was 37.5% (95% CI, 34.9% to 40.0%).

CONCLUSIONS

Refractive errors are a major issue among the elderly and their prevalence rates vary greatly depending on age and gender. The present study was able to examine this public health issue among the elderly in Mashhad.