Epidemiology of refractive errors and presbyopia

Adenosine Triphosphate (ATP) and Protein Aggregation in Age-Related Vision-Threatening Ocular Diseases

Protein aggregation is the etiopathogenesis of the three most profound vision-threatening eye diseases: age-related cataract, presbyopia, and age-related macular degeneration. This perspective organizes known information on ATP and protein aggregation with a fundamental unrecognized function of ATP. With recognition that maintenance of protein solubility is related to the high intracellular concentration of ATP in cells, tissues, and organs, we hypothesize that (1) ATP serves a critical molecular function for organismal homeostasis of proteins and (2) the hydrotropic feature of ATP prevents pathological protein aggregation while assisting in the maintenance of protein solubility and cellular, tissue, and organismal function. As such, the metabolite ATP plays an extraordinarily important role in the prevention of protein aggregation in the leading causes of vision loss or blindness worldwide.

Refractive development I: Biometric changes during emmetropisation

PURPOSE

Although there are many reports on ocular growth, these data are often fragmented into separate parameters or for limited age ranges. This work intends to create an overview of normal eye growth (i.e., in absence of myopisation) for the period before birth until 18 years of age.

METHODS

The data for this analysis were taken from a search of six literature databases using keywords such as "[Parameter] & [age group]", with [Parameter] the ocular parameter under study and [age group] an indication of age. This yielded 34,409 references that, after screening of title, abstract and text, left 294 references with usable data. Where possible, additional parameters were calculated, such as the Bennett crystalline lens power, whole eye power and axial power.

RESULTS

There were 3422 average values for 17 parameters, calculated over a combined total of 679,398 individually measured or calculated values. The age-related change in refractive error was best fitted by a sum of four exponentials (r²  = 0.58), while all other biometric parameters could be fitted well by a sum of two exponentials and a linear term ('bi-exponential function'; r² range: 0.64-0.99). The first exponential of the bi-exponential fits typically reached 95% of its end value before 18 months, suggesting that these reached genetically pre-programmed passive growth. The second exponentials reached this point between 4 years of age for the anterior curvature and well past adulthood for most lenticular dimensions, suggesting that this part represents the active control underlying emmetropisation. The ocular components each have different growth rates, but growth rate changes occur simultaneously at first and then act independently after birth.

CONCLUSIONS

Most biometric parameters grow according to a bi-exponential pattern associated with passive and actively modulated eye growth. This may form an interesting reference to understand myopisation.

Prevalence of refractive errors in Hungary reveals three-fold increase in myopia

AIM

To examine the prevalence and composition of refractive errors in Hungary.

METHODS

Nationwide cross-sectional data collected between 2014 and 2019 were analysed from the Comprehensive Health Screening Program of Hungary, which provided spectacle dioptric power and autorefractometry data for 68 227 people (35 850 women and 32 377 men). Their age distribution, 18-99y, was similar to the national demographic distributions.

RESULTS

Of the total population, 16.50% of the refractive errors exhibited hyperopia, 40.05% emmetropia, and 43.45% myopia. Myopia was 3 times more frequent (58.7%) in younger ages (18-35y of age) compared to older age groups (19.4% of those 56-70y of age; P<0.001). High myopia showed a low prevalence (0.21%), and an increase parallel with ageing (r=0.716; P=0.009).

CONCLUSION

Myopia is the most frequent refractive error in Hungary. The prevalence of myopia is especially increased, up to 2-3 times, in the younger age groups. Nationwide actions need to be taken to reduce the onset of myopia and its associated consequences.

Children in Tokyo Have a Long Sustained Axial Length from Age 3 Years: The Tokyo Myopia Study

Background: myopia prevalence is high among Japanese schoolchildren, but the underlying causes are unclear. Objective: To examine the distributions of ocular biometry and refraction and their associations with lifestyle variables among Japanese schoolchildren. Methods: This cross-sectional school-based study included 2140 children aged 3−14 years in Tokyo, Japan, and evaluated the distributions under non-cycloplegic conditions and the associated environmental factors. Results: The prevalence of spherical equivalent (SE) ≤−0.75 diopter among preschoolers (aged 3−6 years), elementary school students (aged 6−11 years), and junior high school students (aged 12−14 years) was 49.7%, 72.4%, and 87.7%, respectively. Multiple linear regression analyses showed that the time spent using digital devices was associated positively with lens thickness (β = 0.010; p < 0.050) but not SE, axial length, or vitreous chamber depth. The time spent reading was associated negatively with lens thickness (β = −0.012; p < 0.050), SE (β = −0.152; p < 0.010), axial length (β = 0.110; p < 0.001), and vitreous chamber depth (β = 0.110; p < 0.001). Conclusions: The data indicated that almost half of preschoolers may be myopic. The association with the lens thickness differed depending on the type of near work performed.

Screening for Impaired Visual Acuity in Older Adults: US Preventive Services Task Force Recommendation Statement

IMPORTANCE

Impairment of visual acuity is a serious public health problem in older adults. The number of persons 60 years or older with impaired visual acuity (defined as best corrected visual acuity worse than 20/40 but better than 20/200) was estimated at 2.91 million in 2015, and the number who are blind (defined as best corrected visual acuity of 20/200 or worse) was estimated at 760 000. Impaired visual acuity is consistently associated with decreased quality of life in older persons, including reduced ability to perform activities of daily living, work, and drive safely, as well as increased risk of falls and other unintentional injuries.

OBJECTIVE

To update its 2016 recommendation, the US Preventive Services Task Force (USPSTF) commissioned a systematic review to evaluate the benefits and harms of screening for impaired visual acuity in older adults.

POPULATION

Asymptomatic adults 65 years or older who present in primary care without known impaired visual acuity and are not seeking care for vision problems.

EVIDENCE ASSESSMENT

The USPSTF concludes that the evidence is insufficient to assess the balance of benefits and harms of screening for impaired visual acuity in asymptomatic older adults. The evidence is lacking, and the balance of benefits and harms cannot be determined. More research is needed.

RECOMMENDATION

The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for impaired visual acuity in older adults. (I statement).

Living with presbyopia: experiences from a virtual roundtable dialogue among impacted individuals and healthcare professionals

BACKGROUND

Presbyopia is a common progressive vision disorder characterised by an inability to focus on near objects. The emergence of newer treatment options in addition to spectacles or contact lenses highlights the importance of assessing patient/user preferences.

METHODS

People with presbyopia and healthcare professionals (HCPs) took part in a moderated, structured discussion of specific questions on a virtual advisory-board platform. The objective was to better understand unmet needs and the experience of living with the condition. Closed and open questions were included.

RESULTS

Nine individuals (age 40 to 70 years) with presbyopia participated, from Australia, China, France, Italy, Ireland, Japan and the US. One ophthalmologist and one optometrist represented the perspective of HCPs. Over two weeks, 621 posts were entered on the platform. There was widespread agreement that the often stated association between age and presbyopia was unfortunate. Some participants had developed presbyopia at 30-45 years of age. What is more, the association with age was seen as implying a natural process, reducing the incentive to treat. Instead there was a call for an action-oriented view of presbyopia as a condition which may be effectively treated in the future. All participants experienced dealing with presbyopia as burdensome, affecting quality of life to varying degrees. When considering new treatments, convenience was the most important factor. The option to administer drops when needed was considered favourable, but short-acting treatments may not reduce inconvenience compared with spectacles. Participants viewed a therapy that targets the underlying cause of the condition favourably compared with symptomatic treatment. Side effects would severely reduce the appeal of drops. For clinical trials in presbyopia, patient-reported outcomes should be mandatory and need adequately to capture quality of life. Studies in presbyopia must be designed to minimise the inconvenience to participants in order to counter the risk of high drop-out rates.

CONCLUSIONS

The interactive format provided insights into living with presbyopia, particularly the negative impact on quality of life, subjects' openness to new therapies, and the need to move away from considering the condition an unavoidable and intractable consequence of ageing.

Temporal trends in frequency, type and severity of myopia and associations with key environmental risk factors in the UK: Findings from the UK Biobank Study

This study investigated temporal trends in the epidemiology of primary myopia and associations with key environmental risk factors in a UK population. Data were collected at recruitment (non-cycloplegic autorefraction, year of birth, sex, ethnicity, highest educational attainment, reason and age of first wearing glasses and history of eye disease) from 107,442 UK Biobank study participants aged 40 to 69 years, born between 1939 and 1970. Myopia was defined as mean spherical equivalent (MSE) ≤-1 dioptre (D). Temporal changes in myopia frequency by birth cohort (5-year bands using date of birth) and associations with environmental factors were analysed, distinguishing both type (childhood-onset, <18 years versus adult-onset) and severity (three categories: low -1.00 to -2.99D, moderate -3.00 to -5.99D or high ≥-6.00D). Overall myopia frequency increased from 20.0% in the oldest cohort (births 1939–1944) to 29.2% in the youngest (1965–1970), reflecting a relatively higher increase in frequency of adult-onset and low myopia. Childhood-onset myopia peaked in participants born in 1950–54, adult-onset myopia peaked in the cohort born a decade later. The distribution of MSE only shifted for childhood-onset myopia (median: -3.8 [IQR -2.4, -5.4] to -4.4 [IQR -3.0, -6.2]). The magnitude of the association between higher educational attainment (proxy for educational intensity) and myopia overall increased over time (adjusted Odds Ratio (OR) 2.7 [2.5, 2.9] in the oldest versus 4.2 [3.3, 5.2] in the youngest cohort), being substantially greater for childhood-onset myopia (OR 3.3 [2.8, 4.0] to 8.0 [4.2, 13]). Without delineating childhood-onset from adult-onset myopia, important temporal trends would have been obscured. The differential impact of educational experience/intensity on both childhood-onset and high myopia, amplified over time, suggests a cohort effect in gene-environment interaction with potential for increasing myopia frequency if increasing childhood educational intensity is unchecked. However, historical plateauing of myopia frequency does suggest some potential for effective intervention.

The utility of measures of anterior segment parameters of a Pentacam Scheimpflug tomographer in discriminating high myopic astigmatism from keratoconus

The study aimed to evaluate and compare anterior segment parameters between keratoconic eyes and eyes with high myopic astigmatism using Pentacam Scheimpflug tomography. This was a retrospective cross-sectional study that included sixty keratoconic eyes (thirty-two persons) and seventy-three eyes (forty-six persons) with high myopic astigmatism with mean ages 24.72 ± 11.65years and 26.60 ± 10.69years, respectively. Twenty-three parameters from the topographic map and fifteen parameters from the Belin-Ambrosió enhanced ectasia display map of the printouts of a Scheimpflug principle-based Pentacam tomographer were evaluated for their diagnostic accuracy using Receiver Operating Characteristic (ROC) curve. All parameters except cornea volume, anterior chamber volume, and anterior chamber angle indicated a significant difference between high myopic astigmatism and keratoconic eyes. The area under the receiver operating characteristic (AUROC) of eighteen Pentacam parameters was excellent (0.9–1.0) in discriminating keratoconus from high myopic astigmatism, out of which four {anterior minimum sagittal curvature (ant. Rmin), posterior minimum sagittal curvature (post. Rmin), maximum Ambrosió relational thickness (ART max) and total deviation value (D)} indicated excellent (>90%) sensitivity and specificity in addition to the excellent AUROC values. Topographic and Belin-Ambrosió enhanced ectasia display (BAD) maps of a Scheimpflug principle-based Pentacam tomographer are useful in enhancing the diagnosis of keratoconus and may also provide valuable information in effectively screening for keratoconus cases among refractive surgery candidates with high myopic astigmatism.

Presbyopia developed earlier during the COVID-19 pandemic

PURPOSE

The aim of this cohort study was to evaluate the development and progression of presbyopia and the status of dry eye-related symptoms from 2017 to 2020, to assess the impact of the COVID-19 pandemic.

METHODS

Near add power at 30 cm was measured in 339 participants aged between 40 and 55 from 2017 to 2021 at Japanese eye clinics. Regression analysis of near add power and age was analyzed to compare 2017 with later years up to the pandemic. The prevalence of dry eye-related signs and six common symptoms were compared.

RESULTS

The number and mean age (y) of participants were 183 (48.6±4.1) in 2017, 46 (51.3±7.5) in 2019, and 110 (49.2±3.7) in 2020-21, respectively. The mean progression rate of near add power (D/y) was 0.13 for 2017, 0.09 for 2019 (P = 0.028, vs 2017), and 0.08 for 2020-21 (P<0.001, vs 2017). The slope (rate of presbyopia progression) became flatter from 2017 to 2021 and the estimated near add power at the age of 40 increased from 2017 to 2020-2021, implicating presbyopia developed earlier and worsened during the study period. The 2017 values were comparable with previous studies described in 1922 and 2019. The standardized correlation coefficient between age and near add power was 0.816 for 2017, 0.671 for 2019 (P = 0.084, vs 2017), and 0.572 for 2020-21 (P<0.001, vs 2017). Multiple regression analysis revealed age and COVID-19 pandemic were significantly correlated with near add power. The prevalence of dryness irritation, and pain was greater in 2020-21 than in 2017 with no difference in the prevalence of eye fatigue, blurring, and photophobia. There was no difference in the prevalence of short tear break-up time and positive corneal staining among 2017, 2019 and 2020-21.

CONCLUSION

Estimated presbyopia developed earlier and progressed slower from 2017 to 2021, the COVID-19 pandemic. Stress and rapid digitalization related to strict infection control and quarantine might be contributing factors.

Hyperopia Is Not Causally Associated With a Major Deficit in Educational Attainment

Purpose

Hyperopia (farsightedness) has been associated with a deficit in children's educational attainment in some studies. We aimed to investigate the causality of the relationship between refractive error and educational attainment.

Methods

Mendelian randomization (MR) analysis in 74,463 UK Biobank participants was used to estimate the causal effect of refractive error on years spent in full-time education, which was taken as a measure of educational attainment. A polygenic score for refractive error derived from 129 genetic variants was used as the instrumental variable. Both linear and nonlinear (allowing for a nonlinear relationship between refractive error and educational attainment) MR analyses were performed.

Results

Assuming a linear relationship between refractive error and educational attainment, the causal effect of refractive error on years spent in full-time education was estimated as -0.01 yr/D (95% confidence interval, -0.04 to +0.02; P = 0.52), suggesting minimal evidence for a non-zero causal effect. Nonlinear MR supported the hypothesis of the nonlinearity of the relationship (I2 = 80.3%; Cochran's Q = 28.2; P = 8.8e-05) but did not suggest that hyperopia was associated with a major deficit in years spent in education.

Conclusions

This work suggested that the causal relationship between refractive error and educational attainment was nonlinear but found no evidence that moderate hyperopia caused a major deficit in educational attainment. Importantly, however, because statistical power was limited and some participants with moderate hyperopia would have worn spectacles as children, modest adverse effects may have gone undetected.

Translational Relevance

These findings suggest that moderate hyperopia does not cause a major deficit in educational attainment.

Presbyopia - A Review of Current Treatment Options and Emerging Therapies

Presbyopia is a common age-related vision disorder characterized by a progressive inability to focus on near objects. If uncorrected or under-corrected, presbyopia can significantly impact patients' quality of life. Presbyopia represents an area of considerable unmet need due to its rising prevalence worldwide as the population ages, the high proportion of under-treated individuals in some parts of the world, and the limitations of currently available corrective methods. Progressive or bifocal spectacles are associated with peripheral blur, a restricted visual field and impaired depth perception, which have been linked to an increased risk of falls in the elderly. Contact lens options can be difficult to maintain due to the development of age-related dry eye symptoms and reduced manual dexterity. Other corrective methods involve surgical interventions that modify the optics of the cornea, replace the crystalline lens, or attempt to restore active accommodation. While patients undergoing surgery report satisfactory outcomes post-operatively, many of them eventually require reading glasses. Non-invasive therapies with novel mechanisms of action are currently being investigated; these include miotic agents and UNR844, a lipoic acid choline ester. In this narrative review, available evidence on presbyopia prevalence, quality of life impact and risk factors are described, with a focus on observational studies in non-clinical settings. The diagnosis pathway and patient journey in presbyopia are outlined, and various treatment options are analyzed. The data reviewed herein reveals significant gaps in the provision of vision correction for this common condition, with a paucity of effective, non-invasive treatment options broadly accessible to presbyopic individuals.

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

Background

The aim of this study is to evaluate eye structures and function in patients receiving iron chelating therapy and to assess whether a correlation exists between the onset of ocular alterations and the intake of iron chelating drugs.

Methods

A prospective cohort study was performed. Eighty-eight patients, composed of children and adults with thalassemia major (TM) who are taking or had taken iron chelating drugs (deferoxamine, deferiprone or deferasirox), have been initially enrolled in the study. The final sample featured 80 patients, including 18 children and 62 adults. These subjects received an eye examination to evaluate intraocular pressure (IOP), best corrected visual acuity (BCVA), the presence of refractive defects, cornea, anterior chamber, lens, fundus oculi, visual field and mean retinal nerve fiber layer (RNFL) thickness. Logistic regression model analysis was performed in order to assess any correlation. In addition, a literature search regarding the relation between iron chelating drugs and ocular adverse events was carried out to compare the results obtained with the evidence in the literature.

Results

Logistic regression did not report a significant correlation between the intake of iron chelating drugs and the onset of anterior ocular segment alterations, lens opacities, retinal diseases, optical neuropathies, astigmatism, visual field and RNFL thickness defects. Logistic regression returned a statistically significant correlation between myopia and iron chelation therapy (p-value 0.04; OR 1.05) and also between presbyopia and total duration of therapy with deferoxamine (p-value 0.03; OR 1.21). Although intraocular pressure levels remained within the normal range, a significant correlation with the length of deferoxamine therapy has been found (p-value 0.002; association coefficient -0.12). A negative correlation between deferiprone and presbyopia has also been observed.

Conclusion

Iron chelation therapy is not associated with severe visual function alterations. Limitation of deferoxamine treatment can help prevent ocular complications. Deferiprone and/or deferasirox may be preferable, especially in patients over age 40 years.

The influence of axial myopia on optic disc characteristics of glaucoma eyes

This study characterizes differences in glaucomatous eyes with and without high axial myopia using custom automated analysis of OCT images. 452 eyes of 277 glaucoma patients were stratified into non (n = 145 eyes), mild (n = 214 eyes), and high axial myopia (axial length (AL) > 26 mm, n = 93 eyes). Optic disc ovality index, tilt and rotation angle of Bruch´s membrane opening (BMO) and peripapillary choroidal thickness (PCT) were calculated using automated and deep learning strategies. High myopic optic discs were more oval and had larger BMO tilt than mild and non-myopic discs (both p < 0.001). Mean PCT was thinnest in high myopic eyes followed by mild and non-myopic eyes (p < 0.001). BMO rotation angle, global retinal nerve fiber layer (RNFL) thickness and BMO-minimum rim width (MRW) were similar among groups. Temporal RNFL was thicker and supranasal BMO-MRW was thinner in high myopic eyes. BMO tilt and PCT showed moderate and temporal RNFL and nasal BMO-MRW showed weak but significant associations with AL in multivariable analyses (all p < 0.05). Large BMO tilt angle and thin PCT are characteristics of highly myopic discs and were not associated with severity of glaucoma. Caution should be exercised when using sectoral BMO-MRW and RNFL thickness for glaucoma management decisions in myopic eyes.

Near-vision impairment and effective near-vision spectacle coverage in two districts in Telangana, India: a population-based cross-sectional study

OBJECTIVES

To investigate the prevalence of near-vision impairment (NVI) and effective spectacle coverage for near vision in those aged ≥40 years in Khammam and Warangal district in Telangana, India.

DESIGN

A population-based cross-sectional study.

SETTING

Khammam and Warangal district in Telangana, India.

PARTICIPANTS

Of 6000 people enumerated, 5357 were examined (89%). 4526 participants without distance vision impairment were included in the analysis.

MAIN OUTCOME MEASURES

The study teams visited selected households and conducted eye examinations. NVI was defined as binocular presenting near vision worse than N6. 'Unmet need' was deemed to be present if the unaided near vision was worse than N6 and improved to N6 with near correction among the participants who did not have spectacles for near vision. 'Met need' was deemed to be present when unaided near vision was worse than N6 but improving to N6 with their spectacles. The 'undermet need' was deemed to be present when aided near vision was worse than N6 but improved to N6 with correction. Based on these definitions, e-near-vision coverage (%) is calculated as follows: e-NVC (%)=met need/(met need+undermet need+unmet need) × 100.

RESULTS

The mean age was 53.5 years (SD: 10.8 years), 2534/4526 (55.8%) were women, 1819/4526 (41.8%) had at least primary school education and 2368/4526 (52.3%) were from the Khammam district. The prevalence of NVI was 55.8% (95% CI 72.5 to 75.1; n=3343). Overall, the e-NVC (%) was 31.8%. It was 40.0% in Khammam and 23.2% in Warangal.

CONCLUSION

NVI is common in Khammam and Warangal districts in Telangana with inadequate effective near-vision coverage. Effective service delivery models are needed to reach out and provide services to address NVI to achieve universal eye health coverage in the region.

Patients' attitudes and beliefs to presbyopia and its correction

OBJECTIVE

Presbyopia is the gradual inability to focus near objects with age. This study explores patients' attitudes and beliefs towards presbyopia including preferred modes of near refractive correction.

METHODS

In the United Kingdom, twenty-four volunteers completed an online questionnaire and attended a structured, recorded focus group. Participants' age ranged between 36 and 48 years, representing a pre-presbyopic and a presbyopic population. Attitudes and beliefs about presbyopia, its significance, and opinions about current refractive correction including multifocal contact lenses were transcribed and coded using content analysis for overarching themes and patterns.

RESULTS

Six participants (25%) were already wearing a near visual correction while 18 (75%) were not. Five key primary themes with clear inter-participant similarities were identified as 'age-related' (75%), 'acceptance' (50%), clear lack of 'familiarity with the word presbyopia' (65%), a mixed/ reluctant attitude 'towards (multifocal) contact lenses' (62.5%), and 'comfort and convenience' of a presbyopic correction (79%) whereby cost is of less importance.

CONCLUSION

The need for a reading correction was perceived as a sign of age. Spectacles were the most preferred mode of near vision correction, while comfort and convenience were seen as more important than cost. Patient education about presbyopia is lacking. Multifocal contact lenses are not necessarily the preferred visual correction even if the patient already wears contact lenses for distance.

Difference in Pupillary Diameter as an Important Factor for Evaluating Amplitude of Accommodation: A Prospective Observational Study

Presbyopia is increasing globally due to aging and the widespread use of visual display terminals. Presbyopia is a decrease in the eye's amplitude of accommodation (AA) due to loss of crystalline lens elasticity. AA differs widely among individuals. We aimed to determine the factors that cause presbyopia, other than advanced age, for early medical intervention. We examined 95 eyes of 95 healthy volunteers (33 men, 62 women) aged 22-62 years (mean: 37.22 ± 9.77 years) with a corrected visual acuity of ≥1.0 and without other eye afflictions except ametropia. Subjective refraction, AA, maximum and minimum pupillary diameters during accommodation, axial length of the eye, and crystalline lens thickness were measured. AA was measured using an auto refractometer/keratometer/tonometer/pachymeter. The difference between maximum and minimum pupillary diameters was calculated. On multiple regression analysis, age and difference in pupillary diameter were both significantly and independently associated with AA in participants aged <44 years, but not in those aged ≥45 years. Our results suggest that the difference in pupillary diameter could be an important age-independent factor for evaluating AA in healthy individuals without cataract. Thus, improving the difference in pupillary diameter values could be an early treatment target for presbyopia.

Willingness to Pay for Spectacle: An Outreach-Based Cross-sectional Study

AIM

The ophthalmic service lacks to supply spectacles following standard refraction, because of the absence of the optical dispensing unit. The aim was to determine willingness to pay for a pair of spectacles among presbyopic people if the service begins.

METHODS

An interview-based questionnaire was employed among presbyopic people, who were refracted during a community-based outreach service conducted at Debre-Tabor town, South Gondar.

RESULTS

A total of 322 study subjects have completed the questionnaire. The median value of gross monthly income was US $75.0 (Range from US $7.1-321.4). The mean amount of willing to pay for a pair of spectacles was US $17.9 (Range from US $1.1-107.1). Participants who were willing to pay at least US $12.5 (minimum cost at the public optical dispensing unit) for a pair of spectacles accounted 63.0% (95% CI: 57.8-68.3). Based on multivariable logistics regression output analysis age (P = .049), occupation (P = .001), monthly income (p = .001), and positive history of previous spectacles wear (P = .005) show statistically significant association with willingness to pay for a pair of spectacles.

CONCLUSION

In the study area, the mean amount willing to pay for a pair of spectacles was higher than the average set of the price at the public optical dispensing units in Gondar. Public willingness to pay for a pair of spectacles could be considered as an assurance to set up an affordable and financially sustainable spectacle supply service. Conducted on a community-based outreach service may likely pool keen population segments to overestimate the result. Abbreviations: ANOVA: Analysis of Variance; CI: Confidence Interval; SPSS: Statistical Package for Social Science; USA: United States of America; US$: United States dollar.

Association Between Type of Educational System and Prevalence and Severity of Myopia Among Male Adolescents in Israel

Importance

A substantial portion of the public is diagnosed with myopia, which increases the risk of potential sight-threatening complications. The association between study style and the development of myopia is unclear.

Objective

To analyze the association between studying in different educational systems and the prevalence and severity of myopia among Jewish male adolescents in Israel.

Design, Setting, and Participants

A nationwide, population-based study was conducted of 22 823 male candidates for military service in Israel aged 17 to 18 years attending the military draft board in 2013 who underwent a medical examination and a visual acuity assessment. Statistical analysis was performed from January 1 to March 31, 2018.

Exposures

The participants studied in 1 of 3 Israeli educational systems: secular, Orthodox, or ultra-Orthodox. The ultra-Orthodox system and, to a lesser extent, the Orthodox system involve intensive reading starting in early childhood compared with the secular system.

Main Outcomes and Measures

The odds ratio (OR) for the association between educational system and the prevalence and severity of myopia.

Results

Among the 22 823 participants (mean [SD] age, 17.7 [0.6] years), there was a higher proportion of adolescents in the ultra-Orthodox educational system with myopia (1871 of 2276 [82.2%]) compared with adolescents in the Orthodox educational system (1604 of 3189 [50.3%]) and those in the secular educational system (5155 of 17 358 [29.7%]). Compared with adolescents in the secular educational system, those in the Orthodox educational system were more likely to have myopia (OR, 2.3; 95% CI, 2.1-2.5; P < .001), as were those in the ultra-Orthodox educational system (OR, 9.3; 95% CI, 8.2-10.7; P < .001), after adjustment for age, country of origin, socioeconomic status, years of education, and body mass index. The multivariable adjusted OR for high myopia (refractive error of at least -6.0 diopters) was 4.6 (95% CI, 3.8-5.5; P < .001) for adolescents in the Orthodox educational system and 38.5 (95% CI, 30.7-48.2; P < .001) for adolescents in the ultra-Orthodox educational system compared with adolescents in the secular educational system.

Conclusions and Relevance

This study provides evidence of the independent association between educational systems and the prevalence and severity of myopia. Male adolescents in the ultra-Orthodox educational system have higher odds of having myopia and high myopia. These findings suggest that study styles that involve intensive reading and other near-work activities (those done at a short working distance) play a role in the development of myopia and warrant consideration of prevention strategies.

Novel Technique for Rapid and Accurate Insertion of a Microguidewire Tail Into Low-Profile Devices During Endovascular Procedures: The Paper Rail Method

PURPOSE

To report a novel technique ("paper rail") to facilitate inserting the tail of a microguidewire into the tip of a low-profile device during endovascular procedures.

TECHNIQUE

A sterilized nonwoven fabric tape with a smooth glossy paper backing is used. The tape has several linear folds ideal for a paper rail. Holding each piece of equipment about 5 cm from its respective tip, both the tail of the guidewire and the tip of the catheter are navigated at a 30° angle toward each other in the crease until the guidewire enters the catheter. The paper rail technique was compared with the conventional freehand method under varying luminosities found in an operating room. The paper rail technique was most effective in suboptimal lighting, where the mean time was reduced from 83 seconds with the conventional method to 20 seconds with the paper rail maneuver. The times required to insert the wire with the paper rail method were comparable (~22 seconds) at all light levels.

CONCLUSION

The paper rail method may help improve the speed and accurate insertion of the tail of a microguidewire into the tip of low-profile devices during endovascular procedures. It may be particularly useful for physicians in a low-light environment or trainees.

Education and myopia: assessing the direction of causality by mendelian randomisation

OBJECTIVES

To determine whether more years spent in education is a causal risk factor for myopia, or whether myopia is a causal risk factor for more years in education.

DESIGN

Bidirectional, two sample mendelian randomisation study.

SETTING

Publically available genetic data from two consortiums applied to a large, independent population cohort. Genetic variants used as proxies for myopia and years of education were derived from two large genome wide association studies: 23andMe and Social Science Genetic Association Consortium (SSGAC), respectively.

PARTICIPANTS

67 798 men and women from England, Scotland, and Wales in the UK Biobank cohort with available information for years of completed education and refractive error.

MAIN OUTCOME MEASURES

Mendelian randomisation analyses were performed in two directions: the first exposure was the genetic predisposition to myopia, measured with 44 genetic variants strongly associated with myopia in 23andMe, and the outcome was years in education; and the second exposure was the genetic predisposition to higher levels of education, measured with 69 genetic variants from SSGAC, and the outcome was refractive error.

RESULTS

Conventional regression analyses of the observational data suggested that every additional year of education was associated with a more myopic refractive error of -0.18 dioptres/y (95% confidence interval -0.19 to -0.17; P<2e-16). Mendelian randomisation analyses suggested the true causal effect was even stronger: -0.27 dioptres/y (-0.37 to -0.17; P=4e-8). By contrast, there was little evidence to suggest myopia affected education (years in education per dioptre of refractive error -0.008 y/dioptre, 95% confidence interval -0.041 to 0.025, P=0.6). Thus, the cumulative effect of more years in education on refractive error means that a university graduate from the United Kingdom with 17 years of education would, on average, be at least -1 dioptre more myopic than someone who left school at age 16 (with 12 years of education). Myopia of this magnitude would be sufficient to necessitate the use of glasses for driving. Sensitivity analyses showed minimal evidence for genetic confounding that could have biased the causal effect estimates.

CONCLUSIONS

This study shows that exposure to more years in education contributes to the rising prevalence of myopia. Increasing the length of time spent in education may inadvertently increase the prevalence of myopia and potential future visual disability.

Awareness of Presbyopia among Rural Female Population in North Karnataka

Introduction

Presbyopia is an age related loss of lens accommodation resulting in inability to read and/write or to do near work. Though literacy level may be low in rural female population of South India, but household works like sewing, sorting grains and operating mobile phones must be difficult due to presbyopia.

Aim

To determine the awareness of presbyopia in rural females; also, to determine the knowledge levels regarding presbyopia, spectacle coverage and reasons for not wearing spectacles.

Materials and Methods

A hospital based cross-sectional study was conducted at SDM College of Medical Sciences, Dharwad, Karnataka, India, on 1000 female subjects of age group 35 years and above coming from rural area (around Dharwad). They were examined and open-ended questionnaire was used to record subject's awareness and knowledge about presbyopia and their responses were analysed.

Results

More than 2/3^rd of 1000 (66.7%) subjects were not aware about presbyopia. More than 50% subjects had difficulty in cleaning grains, threading needles and reading fine newspaper print. About 86.5% thought presbyopia is age related and 92.2% thought it could be treated with spectacles. In spite of high prevalence, almost 98% of the population were not willing to wear glasses among which majority (60.2%) felt that spectacles were difficult to be maintained while working. In the present study, no statistical significance between literacy and awareness was noted (p=0.46).

Conclusion

High prevalence of presbyopia was seen with majority of them uncorrected due to lack of awareness or unwillingness to wear glasses. We need to provide better health education regarding presbyopia among both literate and illiterate individuals. Thus, there is a need to create awareness and to provide affordable, accessible and compatible optical services to the affected population.

Adaptation to Progressive Additive Lenses: Potential Factors to Consider

People develop presbyopia as part of the normal aging process. Most presbyopes adapt to progressive additive lens (PALs), while others do not. This investigation sought to determine whether the ability to modify disparity vergence or phoria was correlated to PALs adaptation. In experiment 1, a double-step paradigm quantified the ability to modify convergence responses in sixteen presbyopes. In experiment 2, thirty-one incipient presbyopes participated in a 5-minute sustained fixation task to evoke phoria adaptation where the magnitude and rate of phoria adaptation were measured. Then, the experiment was repeated after wearing PALs for one month. Linear regression analyses were conducted between the following parameters: near point of convergence, positive fusional vergence at near, vergence facility, net change in the magnitude of phoria adaptation, and the rate of phoria adaptation. The ability to change convergence average peak velocity was significantly greater (p < 0.03) in presbyopic PALs adapters compared to presbyopic PALs non-adapters. The rate of phoria adaptation and vergence facility were significantly greater (p < 0.03) in incipient presbyopic PALs adapters compared to incipient presbyopic PALs non-adapters. Vergence facility and the rate of phoria adaptation may have potential clinical utility in differentiating which patients may adapt to PALs and which ones will have more difficulty.

Near visual impairment and spectacle coverage in Telangana, India

IMPORTANCE

The study highlights the burden of near visual impairment (NVI) in India.

BACKGROUND

NVI is a common condition that can be addressed through provision of spectacles. The study aims to assess the prevalence of NVI and spectacle coverage among those aged ≥40 years in south Indian state of Telangana.

DESIGN

Population-based cross-sectional study using a rapid assessment methodology.

PARTICIPANTS

Five thousand one hundred forty participants enumerated from 123 clusters in two districts and have presenting distance visual acuity of ≥6/18 in the better eye.

METHODS

Presenting near vision was assessed binocularly at a fixed distance of 40 cm using a log MAR chart with tumbling E optotypes in ambient lighting conditions. If the presenting near vision was worse than 6/12 (log MAR 0.3), then it was re-assessed with addition lens appropriate to the age. NVI was defined as binocular presenting near vision worse than 6/12.

MAIN OUTCOME MEASURES

Prevalence of NVI and spectacle coverage.

RESULTS

The mean age of the participants was 51.1 years (standard deviation: 9.3 years), and 46.5% (n = 2392) were women. About 80% (n = 4142) of them had no education, and 21.9% (n = 1126) were using spectacles for near vision. Nearly half of the participants were from Adilabad district (n = 2665). The prevalence of NVI was 58.3% (95% confidence interval: 56.9-59.6). NVI was associated with older age groups, male gender and no education. The spectacle coverage was 26.5%.

CONCLUSIONS AND RELEVANCE

NVI is common in rural Telangana with low spectacle coverage. Service delivery programs should use a multi-pronged approach to address the burden of NVI.

Clinical outcomes of combined versus separate carbachol and brimonidine drops in correcting presbyopia

Background

To test and compare in a masked fashion the efficacy of using a parasympathomimetic drug (3% carbachol) and an alpha-2 agonist (0.2% brimonidine) in both combined and separate forms to create optically beneficial miosis to pharmacologically improve vision in presbyopia.

Methods

A prospective, double-masked, randomized, controlled clinical trial was conducted. Ten naturally emmetropic and presbyopic subjects between 42 and 58 years old with uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. All subjects received 3% carbachol and 0.2% brimonidine in both combined and separate forms, 3% carbachol alone and 0.2% brimonidine (control) alone in their non-dominant eye in a crossover manner with one week washout between tests. The subjects’ pupil sizes and both near and distance visual acuities will be evaluated pre- and post-treatment at 1, 2, 4, and 8 h, by a masked examiner at the same room illumination.

Results

Statistically significant improvement in mean near visual acuity (NVA) was achieved in all subjects who received combined 3% carbachol and 0.2% brimonidine in the same formula compared with those who received separate forms or carbachol alone or brimonidine alone (P < 0.0001).

Conclusion

Based on the data, the combined solution demonstrated greater efficacy than the other solutions that were tested. Improving the depth of focus by making the pupil small caused statistically significant improvement in near visual acuity, with no change in binocular distance vision.

Trial registration

ACTRN12616001565437. Registered 11 November 2016.

Baseline peripheral refractive error and changes in axial refraction during one year in a young adult population

PURPOSE

To determine whether the initial characteristics of individual patterns of peripheral refraction relate to subsequent changes in refraction over a one-year period.

METHODS

54 myopic and emmetropic subjects (mean age: 24.9±5.1 years; median 24 years) with normal vision were recruited and underwent conventional non-cycloplegic subjective refraction. Peripheral refraction was also measured at 5° intervals over the central 60° of horizontal visual field, together with axial length. After one year, measurements of subjective refraction and axial length were repeated on the 43 subjects who were still available for examination.

RESULTS

In agreement with earlier studies, higher myopes tended to show greater relative peripheral hyperopia. There was, however, considerable inter-subject variation in the pattern of relative peripheral refractive error (RPRE) at any level of axial refraction. Across the group, mean one-year changes in axial refraction and axial length did not differ significantly from zero. There was no correlation between changes in these parameters for individual subjects and any characteristic of their RPRE.

CONCLUSION

No evidence was found to support the hypothesis that the pattern of RPRE is predictive of subsequent refractive change in this age group.

Visual impairment attributable to uncorrected refractive error and other causes in the Ghanaian youth: The University of Cape Coast Survey

PURPOSE

To determine the prevalence of visual impairment attributable to refractive error and other causes in a youthful Ghanaian population.

METHODS

A prospective survey of all consecutive visits by first-year tertiary students to the Optometry clinic between August, 2013 and April, 2014. Of the 4378 first-year students aged 16-39 years enumerated, 3437 (78.5%) underwent the eye examination. The examination protocol included presenting visual acuity (PVA), ocular motility, and slit-lamp examination of the external eye, anterior segment and media, and non-dilated fundus examination. Pinhole acuity and fundus examination were performed when the PVA≤6/12 in one or both eyes to determine the principal cause of the vision loss.

RESULTS

The mean age of participants was 21.86 years (95% CI: 21.72-21.99). The prevalence of bilateral visual impairment (BVI; PVA in the better eye ≤6/12) and unilateral visual impairment UVI; PVA in the worse eye ≤6/12) were 3.08% (95% CI: 2.56-3.72) and 0.79% (95% CI: 0.54-1.14), respectively. Among 106 participants with BVI, refractive error (96.2%) and corneal opacity (3.8%) were the causes. Of the 27 participants with UVI, refractive error (44.4%), maculopathy (18.5%) and retinal disease (14.8%) were the major causes. There was unequal distribution of BVI in the different age groups, with those above 20 years having a lesser burden.

CONCLUSION

Eye screening and provision of affordable spectacle correction to the youth could be timely to eliminate visual impairment.

Genome-wide association study for refractive astigmatism reveals genetic co-determination with spherical equivalent refractive error: the CREAM consortium

To identify genetic variants associated with refractive astigmatism in the general population, meta-analyses of genome-wide association studies were performed for: White Europeans aged at least 25 years (20 cohorts, N = 31,968); Asian subjects aged at least 25 years (7 cohorts, N = 9,295); White Europeans aged <25 years (4 cohorts, N = 5,640); and all independent individuals from the above three samples combined with a sample of Chinese subjects aged <25 years (N = 45,931). Participants were classified as cases with refractive astigmatism if the average cylinder power in their two eyes was at least 1.00 diopter and as controls otherwise. Genome-wide association analysis was carried out for each cohort separately using logistic regression. Meta-analysis was conducted using a fixed effects model. In the older European group the most strongly associated marker was downstream of the neurexin-1 (NRXN1) gene (rs1401327, P = 3.92E-8). No other region reached genome-wide significance, and association signals were lower for the younger European group and Asian group. In the meta-analysis of all cohorts, no marker reached genome-wide significance: The most strongly associated regions were, NRXN1 (rs1401327, P = 2.93E-07), TOX (rs7823467, P = 3.47E-07) and LINC00340 (rs12212674, P = 1.49E-06). For 34 markers identified in prior GWAS for spherical equivalent refractive error, the beta coefficients for genotype versus spherical equivalent, and genotype versus refractive astigmatism, were highly correlated (r = -0.59, P = 2.10E-04). This work revealed no consistent or strong genetic signals for refractive astigmatism; however, the TOX gene region previously identified in GWAS for spherical equivalent refractive error was the second most strongly associated region. Analysis of additional markers provided evidence supporting widespread genetic co-susceptibility for spherical and astigmatic refractive errors.

A retinoscopic survey of 333 horses and ponies in the UK

INTRODUCTION

Ophthalmic examination in the horse is generally limited to crude assessment of vision and screening for ocular lesions. The refractive state of equine eyes and the potential impact on vision and performance requires further investigation.

OBJECTIVE

To assess the refractive state of a large, mixed-breed sample of horses and ponies in the United Kingdom (UK).

PROCEDURE

The refractive state of both eyes of 333 horses and ponies was determined by streak retinoscopy, and the effect of age, height, gender, breed and management regime on the refractive state assessed.

RESULTS

Emmetropia was found in 557 of 666 (83.63%) of eyes; 228/333 (68.5%) of the horses/ponies were emmetropic in both eyes. Refractive errors of greater than 1.50 D (in either direction) were found in 2.7% of the eyes tested. Ametropic eyes included hyperopia (54%) and myopia (46%). Anisometropia was found in 30.3% of horses and ponies. Breed of horse/pony was the only factor that affected refractive state (in the left eye only, P < 0.05) with Thoroughbred crosses having a tendency toward myopia and Warmbloods/Shires toward hyperopia.

DISCUSSION AND CONCLUSION

The retinoscopic survey found emmetropia to be the predominant refractive state of the equine eye with no evidence of an overall trend toward myopia or hyperopia. However, individual and breed-related differences were found. Such factors should be considered in the selection of horses for sport and leisure, and when evaluating their performance potential. More comprehensive visual testing would be valuable in identifying underlying causes of behavioral problems.

Presbyopia: a pilot investigation of the barriers and benefits of near visual acuity correction among a rural Filipino population

Background

Presbyopia is the age-related decline in accommodation that diminishes the ability of the eye to focus on near objects. Presbyopia is common and easy to correct; however, many communities lack access to basic eye care. The purpose of this project was to assess the burden of uncorrected presbyopia in a rural Filipino population and to pilot an intervention aimed at increasing access to reading glasses in the community.

Methods

Individuals above the age of 40 who presented to a health outreach in the Philippines were invited to undergo a near vision exam to detect the presence of functional presbyopia and be fitted with ready-made, single-vision glasses. The change in stereoacuity was used as a surrogate measure of functional improvement after near vision correction. A questionnaire was administered to assess this population’s perceived barriers and benefits to correcting near vision.

Results

The average age of the participants was 57 ± 11 years, with 87.6% of participants having an uncorrected near visual acuity of <20/50. Reading glasses improved near vision to 20/40 or better in 77.7% of participants having near-vision impairment (uncorrected near visual acuity of <20/40). Over 75% of participants also showed improvement in stereoacuity. Cost, rather than availability, was perceived to be the greater barrier to the procurement of glasses, and 84% of participants reported that the glasses dispensed would greatly improve their ability to earn a living.

Conclusions

Dispensing ready-made, single-vision glasses is a simple and cost-effective intervention to improve near vision and enhance depth perception. A greater understanding of the barriers and benefits to correcting near vision will inform the design and execution of a sustainable program to correct presbyopia in developing countries.

Developments in the correction of presbyopia I: spectacle and contact lenses

PURPOSE

To outline the refractive problems associated with presbyopia and to review the basis and relative merits of currently-available methods for their correction, with detailed consideration of spectacle and contact lens approaches.

CONTENTS

In the developed world, most of the present population will spend roughly half their lives as presbyopes. The well-known presbyopic changes with age in amplitude of accommodation and required near addition are briefly reviewed, together with the less widely acknowledged slow drifts that occur in distance refraction. The desirability of restoring to presbyopes clear vision for objects at any distance, ideally corresponding to vergences within the range of at least 0 to -5 D, in any viewing direction, is stressed. A general outline is given of possible corrective methods. Methods which satisfy the needs of a 50 year-old may not be suitable for the 80 year-old. Corrections may involve both fixed- and variable-focus lens systems, and surgical methods which modify the optics of the cornea, replace the crystalline lens with different fixed optics, or attempt to at least partially restore active accommodation. Some more recent methods of spectacle and contact lens correction are described in more detail. Particular attention is given to recent commercially-developed spectacles in which the corrective power can be varied actively by either mechanical (liquid-filled deformable lenses or Alvarez lenses) or electrical (liquid crystal lenses) means to allow objects at different distances to be seen clearly. Contact lens corrections show less progress and are still preferred only by a minority of older patients, most of whom are early presbyopes.

SUMMARY

The rising proportion of presbyopes in the population, covering an age span of around 40 years, represents both a problem for those concerned with giving their patients the best vision possible at both far and near viewing distances and a commercial opportunity. Traditional single-vision distance and near, bifocal, and progressive spectacle lens solutions, together with contact lens modalities for presbyopic correction, are being challenged by a variety of new approaches. It remains to be seen whether the latter will receive wide acceptance in practice.

A survey of ocular diseases in an isolated rural Haitian community: a retrospective evaluation

PURPOSE

To report the prevalence and incidence of ophthalmic pathology from a small, rural town in Haiti and to determine the leading causes of blindness in this population.

DESIGN

Retrospective study from 2002 to 2009. Data collected include visual acuity, intraocular pressure, and ocular and family history.

METHOD

The study was conducted in a single center--Hospital de Lascahobas, Lascahobas, Haiti. Patients were natives of Lascahobas and the surrounding areas. Treatments were dispensed as indicated or warranted.

RESULTS

A total of 3702 patients were seen and examined: 51.52% were male and 49.48% were female. Ages ranged from 6 months to 92 years (mean, 48.69 SD +/- 49.94). Uncorrected refractive error was the most common diagnosis (53.27%), followed by presbyopia (43.76%), hyperopia (34.03%), and myopia (22.21%). A total 981 patients (26.50%) were diagnosed with cataract. Three hundred twenty-three (32.93%) cataract surgeries were performed. The overall postoperative complications rate was 9.29%. A total of 706 patients (19.07%) were diagnosed with glaucoma: 23.65% were glaucoma suspect and 76.35% were diagnosed with open-angle glaucoma (POAG). Of those diagnosed with POAG, 35.06% had end-stage (absolute) glaucoma. The mean age at diagnosis was 52.56 SD +/- 8.2 years. The mean intraocular pressure was 24.07 and 25.60 mm Hg, and the mean cup to disc ratio of the right eye (OD) and the left eye (OS), respectively, was 0.67 and 0.72.

CONCLUSIONS

Glaucoma was the most common cause for blindness. The most common cause of correctable vision loss was uncorrected refractive error followed by cataract. Providing constant eye care in this region will most likely decrease the incidence of correctable and permanent vision loss.

The relationship between anisometropia and amblyopia

This review aims to disentangle cause and effect in the relationship between anisometropia and amblyopia. Specifically, we examine the literature for evidence to support different possible developmental sequences that could ultimately lead to the presentation of both conditions. The prevalence of anisometropia is around 20% for an inter-ocular difference of 0.5D or greater in spherical equivalent refraction, falling to 2-3%, for an inter-ocular difference of 3D or above. Anisometropia prevalence is relatively high in the weeks following birth, in the teenage years coinciding with the onset of myopia and, most notably, in older adults starting after the onset of presbyopia. It has about one-third the prevalence of bilateral refractive errors of the same magnitude. Importantly, the prevalence of anisometropia is higher in highly ametropic groups, suggesting that emmetropization failures underlying ametropia and anisometropia may be similar. Amblyopia is present in 1-3% of humans and around one-half to two-thirds of amblyopes have anisometropia either alone or in combination with strabismus. The frequent co-existence of amblyopia and anisometropia at a child's first clinical examination promotes the belief that the anisometropia has caused the amblyopia, as has been demonstrated in animal models of the condition. In reviewing the human and monkey literature however it is clear that there are additional paths beyond this classic hypothesis to the co-occurrence of anisometropia and amblyopia. For example, after the emergence of amblyopia secondary to either deprivation or strabismus, anisometropia often follows. In cases of anisometropia with no apparent deprivation or strabismus, questions remain about the failure of the emmetropization mechanism that routinely eliminates infantile anisometropia. Also, the chronology of amblyopia development is poorly documented in cases of 'pure' anisometropic amblyopia. Although indirect, the therapeutic impact of refractive correction on anisometropic amblyopia provides strong support for the hypothesis that the anisometropia caused the amblyopia. Direct evidence for the aetiology of anisometropic amblyopia will require longitudinal tracking of at-risk infants, which poses numerous methodological and ethical challenges. However, if we are to prevent this condition, we must understand the factors that cause it to develop.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Does ethnicity influence the short-term adaptation to first reading correction?

PURPOSE

Ethnic variations in accommodative amplitude (AA) are not uncommon. Accommodation can become reduced in response to short-term wear of first near spectacles. Whether ethnicity has an influence on the magnitude of this adaptation is not well understood. We investigated the impact of first near spectacles on changes in AA and on convergence cross-link interactions in incipient presbyopes of Chinese and Caucasian ethnicities.

METHODS

Forty-one subjects (22 Caucasians and 19 Chinese) aged 36 to 44 years completed the study. Accommodative stimulus response function, AA, and AC/A and CA/C ratios were measured before and after single vision reading spectacles were used for near tasks over a 2-month period and then again 2 months after discontinuing near spectacle wear.

RESULTS

After wearing reading spectacles for 2 months, the accommodative stimulus response slopes and AC/A and CA/C ratios remained invariant irrespective of ethnicity. The accommodative, but not vergence, bias decreased (p < 0.05). The nearpoint of accommodation shifted distally producing an average decrease in AA of 0.52 D from baseline (p < 0.05). Recovery to near baseline values occurred after discontinuing the reading glasses for 2 months. Differences based on ethnicity were not significant. The baseline AA vs. age plots showed steeper slopes for Chinese than the Caucasian subjects in the sample.

CONCLUSIONS

The pattern of adaptation by accommodation and cross-link interactions to short-term first reading spectacles is not influenced by ethnicity.

Multifocal versus single vision lenses intervention to slow progression of myopia in school-age children: a meta-analysis

Myopia in school-aged children is a major public health problem in Asians that has been extensively studied. Multifocal lenses (MLs) are advocated as a substitute for single vision lenses (SVLs) to slow myopia progression in children, but results vary greatly across studies. We systematically searched currently available randomized controlled trials that compared the effects of MLs and SVLs in children. A meta-analysis of nine of these trials showed that MLs with powers ranging from +1.50 to +2.00D were associated with a statistically significantly decrease in myopia progression in school-aged children compared with SVLs. The benefit was greater in children with a higher level of myopia at baseline and sustained for a minimum of 24 months. Asian children appeared to have greater benefit from intervention with MLs than white children.

Prevalence and risk factors for anisometropia in the Tehran eye study, Iran

PURPOSE

To determine the prevalence of anisometropia and its determinants in a population-based sample.

METHODS

In a cross-sectional population-based study, stratified cluster sampling was carried out from the population of Tehran. Respondents were transferred to a clinic for an interview and ophthalmic examinations including tests for visual acuity with and without correction, cycloplegic refraction, the slit lamp examination, fundoscopy, and lensometry. Anisometropia was defined as unequal spherical equivalent cycloplegic refractions in the two eyes.

RESULTS

Of 4565 participants, cycloplegic refraction was performed in both eyes of 3519 people. The mean age of the examinees was 31.5 ± 18.0 (range, 5-86) years. The mean anisometropia was 0.34 diopter (D) (95% Confidence Interval (CI): 0.31-0.37). The prevalence rates of anisometropia more than 0.5, 1.0, 1.5 and 2.0 D were 18.5% (95% CI: 17.0-19.9), 6.7% (95% CI: 5.8-7.7), 3.8% (95% CI: 3.1-4.5) and 2.6% (95% CI: 2.1-3.1). The inter-gender difference in the prevalence of anisometropia ≥ 1.0D was not statistically significant (P = 0.952). The prevalence of anisometropia increased after the age of 45 years. Overall, 15.7% of the examinees had anisomyopia and 4.7% had anisohypermetropia equal to or more than 1.0D. Anisometropia was more prevalent among patients with cataracts, amblyopia, and pseudophakia. The prevalence rates of spherical and cylindrical anisometropia in the studied sample were 8.0% and 7.1%, respectively.

CONCLUSIONS

The prevalence of anisometropia in the population of Tehran is beyond negligible. It showed a significant increase with age. Results also indicate that myopic patients are more likely to have anisometropia.

Peripheral myopization using a dominant design multifocal contact lens

Purpose

The purpose of this study was to characterize the central and peripheral refraction across the horizontal meridian of the visual field without and with a multifocal dominant design soft contact lens of different add powers (+1.00 D to +4.00 D) in emmetropic eyes.

Methods

Twenty right eyes from 20 emmetropic patients (mean spherical equivalent central refraction –0.06 ± 0.54 D) with a mean age of 21.6 ± 2.3 years were fitted with Proclear Multifocal dominant design (Coopervision, Pleasanton, CA, USA). Lenses had add powers from +1.00 to +4.00 D in 1.00 D steps. The central and peripheral refraction was measured along the horizontal meridian up to 35° of eccentricity in the nasal and temporal retinal area in 5° steps using a open-field autorefractometer.

Results

Only the +3.00 and +4.00 D add powers generated a significant change in the peripheral refractive pattern compared to central refraction and compared with the no-lens wearing situation. The average myopic increase with these lenses was –3.00 D and –5.00 (p < 0.001) at the margins of inspected nasal and temporal visual field, respectively.

Conclusions

Multifocal dominant design soft contact lenses are able to change the peripheral refractive profile in emmetropic eyes increasing relative peripheral myopia. Lenses with +3.00 D add power seem to be the best option to create such effect due to significant peripheral myopization.

Ethnic differences in the prevalence of myopia and ocular biometry in 10- and 11-year-old children: the Child Heart and Health Study in England (CHASE)

PURPOSE

Ethnic differences in childhood prevalence of myopia have not been well characterized in the United Kingdom. In this study, ethnic differences in refractive status and ocular biometry were examined in a multiethnic sample of British children.

METHODS

This was a cross-sectional study of 10- and 11-year-old school children of South Asian, black African Caribbean, and white European ethnic origin. Vision, open-field autorefraction (without cycloplegia), and ocular biometry were measured in each eye. Myopia was defined as spherical equivalent refraction of -0.50 D with unaided vision of 20/30 or worse (in one or both eyes). Ethnic differences in the prevalence of myopia were examined by using logistic regression, and multiple linear regression was used for ethnic differences in ocular biometry. All models were adjusted for age, sex, and clustering within school.

RESULTS

Data were available for 1179 children. The prevalence of myopia was 25.2%, 10.0%, and 3.4%, respectively, in the South Asian, black African Caribbean, and white European children. Adjusted odds ratios (ORs) of myopia compared with the white European children were 8.9 (95% confidence interval [CI] 4.0 to 19.4) in the South Asian and 3.2 (95% CI, 1.4 to 7.2) in black African Caribbean children. Ethnic differences in the prevalence of myopia were largely accounted for by ethnic differences in axial length. The South Asian and black African Caribbean children had longer axial lengths (0.44 mm; 95% CI, 0.30 to 0.57 mm and 0.30 mm; 95% CI, 0.16 to 0.44 mm, respectively).

CONCLUSIONS

Among British children exposed to the same schooling environment, the South Asians had the highest prevalence of myopia, followed by the black African Caribbeans compared with the white Europeans. A quarter of British South Asian children were myopic, which is strongly related to increased axial length.

Tilted optic disks

Tilted optic disks are a common finding in the general population. An expression of anomalous human development, the tilted disk appears rotated and tilted along its axes. Visual sequelae described with tilted optic disks include myopia, astigmatism, visual field loss, deficient color vision, and retinal abnormalities. Although the natural course of tilted optic disks is nonprogressive, the anomaly can be mistaken for tumors of the anterior visual pathway, edema of the optic nerve head, or glaucoma. A thorough examination of patients with tilted disk includes refraction, dilated fundus examination, and visual field testing. At times, neuroimaging may be necessary to arrive at the correct diagnosis. Until normative data are validated for tilted disks, the role of new imaging technologies for the optic nerve head is limited. Familiarity with the spectrum of ophthalmoscopic appearance and the clinical manifestations of tilted disks may be the most critical factors in avoiding misdiagnosis.

Height, stunting, and refractive error among rural Chinese schoolchildren: the See Well to Learn Well project

PURPOSE

To evaluate the hypothesis that changes in nutritional status could be partly responsible for observed increases in myopia prevalence among Chinese children.

DESIGN

Cross-sectional cohort study.

METHODS

Rural Chinese secondary school children participating in a study of interventions to promote spectacle use were randomly sampled (20% of children with uncorrected vision >6/12 bilaterally, and 100% of remaining children) and underwent cycloplegic refraction with subjective refinement and measurement of height and weight. Stunting was defined according to the World Health Organization standard population.

RESULTS

Among 3226 children in the sample, 2905 (90.0%) took part. Among 1477 children undergoing refraction, 1371 (92.8%) had height and weight measurements. These children had a mean age of 14.5 +/- 1.4 years, 59.8% were girls, and mean spherical equivalent refraction was -1.93 +/- 1.82 diopters. Stunting was present in 87 children (6.4%). While height was inversely associated with refractive error (RE) (taller children were more myopic) among boys (r = -0.147, P = .001), this disappeared when adjusting for age, and no such association was observed among girls. Neither girls nor boys with stunting differed significantly in refraction from children without stunting, and neither stunting nor height was associated with RE when adjusting for age, height, and parental education. The power of this study to have detected a 0.75 diopters difference in RE between children with and without stunting was 0.96.

CONCLUSION

Results from this cross-sectional study are not consistent with the hypothesis that nutritional status is a determinant of RE in this setting.