Distribution Of Refractive Errors Research Articles

Visual Status in Children with Dyslexia at the Integrated Special Education Program in Selangor, Malaysia

Objective: Dyslexia is a learning disorder, characterized by difficulties in recognizing, decoding, and spelling words. Studies on visual status of individuals with dyslexia have yielded mixed findings. This study aimed to assess visual acuity and refractive errors in dyslexic children in Selangor, Malaysia.Material and Methods: A cross-sectional study was conducted in the integrated special education program (PPKI) for secondary schools across three randomly selected districts in Selangor. Children with dyslexia from 15 schools were enrolled. Distance and near visual acuity were measured, and non-cycloplegic refraction was performed to identify refractive errors. Descriptive analysis was used to describe the distribution of visual acuity and refractive errors. The Wilcoxon Signed-Rank test was used to compare habitual and corrected visual acuity (VA).Results: 137 dyslexic children, aged 13 to 19 years, participated in the study. 60% of the participants had good habitual distance VA. Meanwhile, the percentage of good habitual near VA were higher than distance VA. The Wilcoxon Signed-Rank test showed that corrected VA was significantly better than habitual VA. The most common ametropias observed were myopia and astigmatism.Conclusion: Dyslexic children in the PPKI program generally have good visual acuity and are emmetropic. However, uncorrected refractive error and suboptimal optical refraction were the primary causes of unsatisfactory habitual vision in some children. Findings highlight the need to screen for refractive errors and provide appropriate optical correction to this population to prevent further hindrance to their reading ability.

Epidemiology of eye diseases in Bangladesh

Bangladesh is densely populated country in South Asia, faces significant challenges in eye health due to various socioeconomic, environmental, and healthcare access factors. Limited access to quality eye care services, poor hygiene practices, prevalence of infectious diseases, and a high burden of non-communicable diseases contribute to the prevalence of eye disorders in the region. This study aims to comprehensively analyze the prevalence, distribution, and risk factors associated with various eye diseases among the population of Bangladesh. A systematic review and meta-analysis were conducted to gather data on the epidemiology of eye diseases in Bangladesh. Published studies, national surveys, and reports from relevant health organizations were reviewed to compile data on the prevalence, distribution, and risk factors of common eye conditions, including cataracts, refractive errors, conjunctivitis, glaucoma, diabetic retinopathy, and age-related macular degeneration. The prevalence of eye diseases in Bangladesh is relatively high, with conditions such as refractive errors, cataracts, glaucoma, and corneal diseases being major concerns. Refractive errors, including myopia, hyperopia, and astigmatism, affect a substantial portion of the population, particularly among children and young adults. Cataracts, a leading cause of blindness worldwide, also pose a significant burden in Bangladesh, with prevalence increasing with age. While the prevalence of glaucoma in Bangladesh is lower compared to some other countries, the condition remains a cause of concern due to its impact on quality of life and the healthcare system. Diabetic retinopathy, a complication of diabetes mellitus, affects the retina and is a leading cause of vision loss and blindness globally in the elderly. In Bangladesh, the rising prevalence of diabetes, fueled by changing lifestyles and an aging population, has contributed to an increasing burden of diabetic retinopathy. Conjunctivitis is prevalent, particularly in densely populated urban areas and rural communities with limited access to clean water and sanitation facilities.Collaborative efforts involving government agencies, healthcare providers, non-governmental organizations, and the community are essential to effectively address the burden of eye diseases in Bangladesh. By implementing preventive measures and improving access to quality eye care services, it is possible to mitigate the impact of these eye diseases and improve visual health outcomes for the population.

Distribution and prevalence of refractive error in Iranian adult population results of the PERSIAN eye cohort study PECS

The Persian Eye Cohort Study, a population-based cross-sectional study from 2015 to 2020, examined refractive error prevalence among 48,618 Iranian adults aged 31 to 70. The study encompassed six centers in Iran, employing random cluster sampling for demographic, medical, and socioeconomic data collection through interviews. Ophthalmic exams included visual acuity, automated and manual objective refraction, subjective refraction, slit lamp, and fundus examinations. Using the spherical equivalent definition, the sample population was categorized into groups. Results indicated a mean age of 49.52 ± 9.31 and a mean refractive error of 0.26 diopters (D) ± 1.6 SD (95% CI − 0.27 to -0.24), ranging from -26.1 to + 18.5 SD. Prevalence of myopia (< −0.5D) and hyperopia (> + 0.5D) was 22.6% (95% CI 22.2–23%) and 12.5% (95% CI 12.1–12.8%), respectively. Regarding different age groups, the prevalence of hyperopia and astigmatism exhibited a steady and significant rise with increasing age (p-value < 0.001 for both). The prevalence of Myopia, however, showed a distinctive pattern, initially increasing in adults under 45, declining in those aged 55–64, and rising again among individuals aged 60 and older. Female gender, older age, urban residency, higher education, higher income, and Fars ethnicity were significantly related to a higher prevalence of myopia (p-value < 0.001 for all). Female gender (p-value < 0.001), aging (p-value < 0.001), urban residency (p-value = 0.029), and lower-income (p-value = 0.005) were significantly related to higher prevalence of hyperopia. Astigmatism (> 1D) was prevalent in 25.5% of participants (95% CI 25.1–25.9%) and correlated with male gender, aging, urban residency, illiteracy, and higher income (p-value < 0.001, < 0.001, < 0.001, < 0.001, 0.014, respectively). The study’s comparison with regional and international surveys highlighted the increase in myopia among those over 65 due to higher nuclear cataract rates in older adults. Myopia positively related to education, income, and urban residency, while hyperopia did not exhibit such associations.

Prevalence and socio-demographic distribution of uncorrected refractive errors in school-going adolescents in Kakamega County, Kenya

Prevalence and socio-demographic distribution of uncorrected refractive errors in school-going adolescents in Kakamega County, Kenya

Does Foveal Hypoplasia Affect Emmetropization in Patients with Albinism?

(1) Background: The aim of the study was to describe refractive development from early childhood to adulthood in Danish patients with albinism and to evaluate the effect of foveal developmental stage on refractive development; (2) Methods: Patients with a clinical diagnosis of ocular or oculocutaneous albinism were invited for a refractive evaluation and comprehensive phenotyping including macular optical coherence tomography (OCT) scans. Foveal hypoplasia was graded based on OCT from 0 (normal) to 4 (absence of any signs of foveal specialization). Medical files were reviewed for historical refractive values in individual patients; (3) Results: Hyperopia (spherical equivalent refraction (SEQ) of ≥+1 Diopter (D)) was common in both children (81.3%) and adults (67.1%). The lower prevalence of hyperopia in adults was predominantly explained by increasing astigmatism with age. Emmetropization (>2D change from before 3 years to adolescence) was seen in 22.2%. There was no influence on foveal hypoplasia grade on the degree of refractive errors throughout life; (4) Conclusions: We found that emmetropization was uncommon in Danish patients with albinism and that the degree of foveal developmental stage did not influence emmetropization or the distribution of refractive errors. High degrees of hyperopia and astigmatism were common. These results indicate that fear of impeding emmetropization should not refrain the clinician from providing adequate correction for refractive errors in young children with albinism.

Prevalence and pattern of refractive errors among school-going children in district Baramulla, Kashmir: A cross sectional study.

Uncorrected refractive error is one of the most important causes of visual impairment worldwide. Addressing childhood vision impairment (VI) is one of the main goals of the World Health Organization (WHO) to combat blindness strategies. To ascertain the prevalence and pattern of refractive errors among children aged 10 to 16 years in Baramulla district, Kashmir. A cross-sectional study was carried out among 680 school children during an eye camp under the school health program of the national program for control of blindness. The screening was conducted in four schools in Baramulla district, Kashmir. The schools were selected using the non-probability convenient sampling technique. A total of 680 school children from classes sixth to tenth aged 10-16 years participated in the study. Out of 680 students, 545 (80%) had normal vision, 97 (14%) had impaired visual acuity ranging between 6/9 and 6/24, and 38 (6%) had severe VI ranging from 6/36 to 6/60. Among the various types of refractive errors, myopia was the most prevalent affecting 54 children. Age distribution of refractive errors showed myopia to be more prevalent in the age group 13-14 years (16, 14 cases), hypermetropia was more prevalent in the age group 14-15 years (10, 8 cases), and astigmatism 5 cases in the age group 14-15 years. The study provides useful and baseline data about the refractive error amongst the school children of the Baramulla district. A larger study needs to be conducted in all schools of the state to get a clear picture of RE and other eye-related problems to detect vision problems earlier.

Refractive Error and Axial Length and Their Related Factors in 8-Year-Old Japanese Children: The Yamanashi Adjunct Study of the Japan Environment and Children's Study (JECS).

To investigate the distribution of visual acuity, refractive error, and axial length in 8-year-old children who participated in an additional survey in Yamanashi Prefecture of the Japan Environmental Children's Study (hereafter referred to as JECS-Y) conducted from 2019 to 2021. Eight-year-old children who participated in the JECS-Y study were subjected to noncycloplegic measurements of refractive error and axial length. If the uncorrected visual acuity was less than 20/20, the best corrected visual acuity was evaluated in accordance with the autorefraction data. A questionnaire was administered regarding the parent's history of eyeglass wear or contact lens use. Among the 400 participating children, the rate of uncorrected visual acuity of 20/20 or better in both eyes was 70.4%. The mean equivalent spherical equivalent error for both eyes was -0.366 ± 1.016 D. The mean axial length was 23.08 ± 0.225 mm in all patients. The males showed significantly longer axial length than the females despite no differences in body height. There was a significant correlation between axial length, spherical refractive, and uncorrected visual acuity. The children of parents with a history of wearing eyeglasses or contact lenses showed a significantly more myopic equivalent refractive error than those without a history. This study clarified the current state of refractive error in 8-year-old children and the association of inheritance with refractive error. In addition, the axials were significantly longer in male patients.

Refractive trends in 15-year-old adolescents at optometric practices in southern Sweden between 2007 and 2020

The purpose of this study was to analyse the distribution of refractive errors in 15-year-old adolescents at optometric practices in southern Sweden between 2007 and 2020. Refractive data were collected retrospectively from clinical records in five optometric practices in southern Sweden. The inclusion criteria were individuals visiting the practice at an age of 15 years between 2007 and 2020. The refractive errors were classified by the spherical equivalent (SE) (sphere + 1⁄2 cylinder) as follows: myopia (SE ≤ -0.5 D), hyperopia (SE ≥ 0.5 D), emmetropia (-0.5 &gt; SE &lt; 0.5 D). The astigmatism axis (-1.5 DC) was analysed as with-the-rule, against-the-rule and oblique according to traditional methods. To examine trends, the average refraction and distribution of refractive errors were compared between two selected time periods, 2007–2013 and 2014–2020. During the time frame 500 adolescents aged 15 years were examined in the selected optometric practices. Myopia was found in 34%, emmetropia in 35% and hyperopia in 31%. Among 37 individuals with astigmatism, the most common axis was with- the-rule (41%), followed by oblique (32%) and against-the-rule (27%). No significant differences could be found in the distribution of different refractive errors between the periods 2007–2013 and 2014–2020. Nor could any significant difference in average refraction be found. In contrast to the expected global rise in myopia as predicted by WHO and the high prevalence of myopia reported in some parts of the world, we could not find convincing changes in distribution between myopia and hyperopia in this cohort of Swedish adolescents.

Prevalence of refractive errors and visual impairment due to refractive errors among school children in Cairo, Egypt

Aim The aim of this research was to study the distribution and patterns of refractive errors (REs) among school children and the incidence of amblyopia in each type. Patients and methods This is an observational nonrandomized population-based cross-sectional study that included children aged 6-18 years attending the Outpatient Clinic of Al-Zahraa University Hospital, Al-Azhar University, Cairo, Egypt. All children were subjected to comprehensive eye examination including best corrected visual acuity (BCVA), expressed in LogMAR, cycloplegic REs that was documented using a NIDEK auto-refractometer-keratometer, cover-uncover testing, and fundus examination. The prevalence of REs, amblyopia, and anisometropia was estimated. Results The study included 960 children (1920 eyes), with a mean age of 13.08±3.41 years. Emmetropia was found in 834 (43.4%) eyes, while myopia was reported in 587 (30.6%) eyes, hypermetropia in 114 (5.9%) eyes, and myopic astigmatism in 385 (20%) eyes. Anisometropia was reported in 65 (6.77%) children, while amblyopia was found in 49 (5.1%) eyes. The amblyopia prevalence was statistically significantly higher among the hypermetropic group (3.9%) than the myopic astigmatism group (1.2%), (P = 0.031). Conclusion The overall prevalence of REs among the examined children was 56.6% mainly myopia followed by myopic astigmatism and lastly hypermetropia. This draws the attention to the increased incidence of myopia which needs further social studies.

Prevalence of refractive error within a Portuguese sample of optometric records

PurposeConsidering the burden of refractive error, clinical-based research methods are often used as epidemiological tools. This study aimed to generate evidence on the prevalence and distribution of refractive error in Portugal. MethodsA cross-sectional retrospective study was designed to review optometric records from Portuguese practices during July 2021. Results348 optometric records were analysed. Subjects had a mean age of 44.2 ± 19.2 years (range 6–81) and 58.4% were female. The mean spherical equivalent was myopic, −0.65 ± 2.38 Diopters (D), varying from a minimum of −13.63 to a maximum of 6.25 D. According to sex, the mean spherical equivalent was −0.76 ± 2.29 D for female and −0.49 ± 2.49 D for male, with no significant difference between them (p = .307). The distribution of the spherical equivalent mean across the age groups, linearly varies from a myopic −1.62 ± 1.74 D in the age group of [6 – 29]; −1.58 ± 2.80 D in [30 – 44]; −0.09 ± 2.40 in [45 – 59] to a hyperopic 0.67 ± 1.61 D in the group of [60 – 81]. High myopia had a prevalence of 2.7% in the sample. Myopia was the most prevalent refractive error in the sample representing 41.3%. In the age group [6–29], myopia had a prevalence of 69.3%. Hyperopia had a prevalence in the sample of 29.7%. ConclusionsMyopia represents the most prevalent refractive error within the sample and is the prevalence is higher in the younger age groups, demonstrating a shift towards an increase of myopia in the next years.

Prevalence of refractive error in Portugal estimated from ophthalmic lens manufacturing data: Ten-years analysis.

To investigate the prevalence, distribution and trends of refractive error from ophthalmic lens manufacturing data over a ten-year period. Fully anonymized data from ophthalmic lenses, for the years between 2010 and 2020, provided by the leading ophthalmic lens manufacturer operating in Portugal were analysed (no human participants were involved in the research). Prescriptions delivered were divided in single vision prescriptions and progressive/multifocal prescriptions and categorized into 14 spherical equivalent ranges. Given the lack of absolute values, indirect estimates and a qualitative analysis of the current situation and trends on refractive error epidemiology was carried out. Dataset from manufacturer comprises percentage values of ophthalmic lenses dispensed in Portugal. The distribution of ophthalmic prescriptions for single vision prescriptions presents most of the observations in the range [-1.49, -0.50] diopters, in every year from 2010 to 2020. For the progressive prescription's lenses, most of the observations is in an interval of two ranges, [0.50, 1.49] and [1.50, 2.99] diopters. From 2010 to 2020 the proportion of single vision ophthalmic lens prescriptions for myopia increased from 38.13% to 46.21%; the proportion for high myopia increased from 2.76% to 4.45%; and the proportion for hyperopia decreased from 40.85% to 31.36%. Ophthalmic lens manufacturing data can be a valuable source for long-term analysis of refractive error prescription and trends over time. It was possible to observe a trend of increasing prevalence of myopia and high myopia from 40.89% in 2010 to 50.66% in 2020. That increase trend has important implications for public health and in the planning of services.

Improving population-level refractive error monitoring via mixture distributions.

Sampling and describing the distribution of refractive error in populations is critical to understanding eye care needs, refractive differences between groups and factors affecting refractive development. We investigated the ability of mixture models to describe refractive error distributions. We used key informants to identify raw refractive error datasets and a systematic search strategy to identify published binned datasets of community-representative refractive error. Mixture models combine various component distributions via weighting to describe an observed distribution. We modelled raw refractive error data with a single-Gaussian (normal) distribution, mixtures of two to six Gaussian distributions and an additive model of an exponential and Gaussian (ex-Gaussian) distribution. We tested the relative fitting accuracy of each method via Bayesian Information Criterion (BIC) and then compared the ability of selected models to predict the observed prevalence of refractive error across a range of cut-points for both the raw and binned refractive data. We obtained large raw refractive error datasets from the United States and Korea. The ability of our models to fit the data improved significantly from a single-Gaussian to a two-Gaussian-component additive model and then remained stable with ≥3-Gaussian-component mixture models. Means and standard deviations for BIC relative to 1 for the single-Gaussian model, where lower is better, were 0.89 ± 0.05, 0.88 ± 0.06, 0.89 ± 0.06, 0.89 ± 0.06 and 0.90 ± 0.06 for two-, three-, four-, five- and six-Gaussian-component models, respectively, tested across US and Korean raw data grouped by age decade. Means and standard deviations for the difference between observed and model-based estimates of refractive error prevalence across a range of cut-points for the raw data were -3.0% ± 6.3, 0.5% ± 1.9, 0.6% ± 1.5 and -1.8% ± 4.0 for one-, two- and three-Gaussian-component and ex-Gaussian models, respectively. Mixture models appear able to describe the population distribution of refractive error accurately, offering significant advantages over commonly quoted simple summary statistics such as mean, standard deviation and prevalence.

Refractive Error and Ocular Biometry among Young Adults from Cuiabá, Brazil

Objective To investigate the distribution of refractive errors and their association with ocular biometric data, family history and environment variables in medical university students of first to six semesters of UNIVAG - MT. Methods A general ophthalmological exam was performed including, corneal topography, and ocular optical biometry. Lens power has calculated by Bennett and Rozema’s formula. A questionnaire regarding family history of myopia and lifestyle visual activities was applied. Only university students with normal ophthalmological exams were included. Statistical significance was considered at the level of p&lt;0.05. Results One hundred twenty-eight students were selected, whereas other 13 were excluded. The mean age was 21.28 ± 2.18 years. Forty-four (34.4%) participants were males. Regarding refractive errors, 18 (14.1%) were hyperopic, 41 (32%) were emmetropic, 61 (47.7%) were myopic, and 8 (6.3%) were high myopic. The mean and standard deviations of spherical equivalents, axial lengths, keratometries (K1 and K2), and lens powers were -1.27 ± 2.21 D, 24.17 ± 1.07 mm, 42.90 ± 1.25 D, 43.94 ± 1.37 D, and 22.62 ± 1.73 D, respectively. In relation to the family history of myopia, one parent was myopic in 28 (50%) of subjects, and both parents were myopic in 7 (12.5%) subjects. The average of hours per week spent outdoors were 5.82 +/- 7.38 hs. and spent 6.85 +/- 6.26 hs. at sports activities at night. Conclusion Myopia was the most frequent refractive error among the medical university students subject of this study, and was approximately three times higher than those reported for other samples of Brazilian population. There was a positive correlation between refraction errors and axial length.

Distribution Analysis of Refraction Defects in Prescriptions in Terms of Opticians: the Case of Karaman Province

The aim of this study is to analyze and evaluate refraction errors in prescriptions written in foundation and state hospitals in Karaman province. 213 people who applied to an ophthalmologist in the province of Karaman and were given prescriptions were included in the study. Of the 213 people included in the study; 126 (59.15%) are women, 87 (40.85%) are men. Near and far eyeglasses data on prescriptions were divided into 7 groups as simple myopia, simple hyperopia, simple myopic astigmatism, simple hyperopia astigmatism, composite myopic astigmatism, compound hyperopia astigmatism, and mixed astigmatism. In the near-eyeglass right glass refraction defects analysis in the research; simple hypermetropia was the most common with 22.06%, while the least common simple myopic astigmatism was detected with 0.94%. In the near eyeglass left eyeglass refraction defects analysis; while mixed astigmatism was the most common with 22.53%, it was determined that it was the least seen simple myopic astigmatism with 0.47%. In the far eyeglass right glass refraction defects analysis; compound myopic astigmatism was the most common with 30.98%, and the least common was simple hypermetropic astigmatism with 2.35%. In the far eyeglass left eyeglass refraction defects analysis; compound myopic astigmatism was the most common with 29.11%, while the least common was simple hypermetropic astigmatism with 2.35%. The research is important due to it is the first study to examine the refractive error distribution in Karaman.

Childhood Vision Impairment and Refractive Error in Zimbabwe: A Hospital-based Retrospective Study.

The objective of this study was to determine the causes and distribution of vision impairment and refractive error among children in Zimbabwe. A hospital-based retrospective cross-sectional study was conducted among children (3-16) who attended the Eye Institute, Harare, Zimbabwe, from January 2010 to December 2020. Patients' records were collated, and variables such as visual acuity, ocular morbidities, and vision impairment were analysed. During this time, 1038 children with mean age of 10.63 ± 3.54 years visited the facility. The majority of them were males (53.2%). Prior to treatment, 9.9% of the children had vision impairment which reduced to 3.5% after intervention. Uncorrected refractive error accounted for the majority of vision impairment (67.0%), followed by keratoconus (7.8%), corneal opacity/ulceration (6.8%), and amblyopia (6.8%), among other conditions. Astigmatism (60.6%) was the most prevalent type of refractive error followed by myopia (37.5%). The prevalence of childhood vision impairment is higher than that found in similar hospital-based studies conducted in Africa. The most common reason for childhood vision impairment was uncorrected refractive error.

Prevalence and Distribution of Refractive Errors among Ophthalmic Patients in Madang Province, Papua New Guinea.

Purpose:To assess the prevalence and distribution of refractive errors in Madang Province, Papua New Guinea (PNG).Methods:A retrospective hospital-based study was conducted at Madang Provincial Hospital Eye Clinic. It is a free eye clinic and spectacle costs are further subsidized by a nongovernmental organization. Nonprobability purposive sampling was used to retrieve patients' records at the eye clinic from January to December 2016. Only demographic and clinic data on the patients' first visit to the eye clinic were recorded and these included their age, gender, location, presenting visual acuity (VA), and refractive correction.Results:One thousand and one hundred eighty-four patients' records were retrieved, of which 622 (52.53%) had refractive error. The mean age of refractive error presentation was 49.68 ± 16.29 years with a range of 9–86 years. There were more males (55%) than females. About a quarter of the patients (21.2%) presented with moderate visual impairment. There was a statistically significant relationship between visual impairment and age group (P < 0.001). Myopia (53.1%) was the most common type of refractive error followed by hyperopia (32.5%) and astigmatism (14.4%). The uptake of spectacle correction was very high (95.3%) among the patients. More than one-tenth of the patients (12.5%) reported from other provinces. Almost one-third of the patients (31.4%) could not obtain a VA of 6/6 after refraction. About one-fifth (17.0%) of the patients were suspected of functional amblyopia.Conclusions:Uncorrected refractive error (URE) is a significant cause of visual impairment in PNG. There is a need for the integration of eye care services into primary health care for early detection, treatment, and prevention of visual impairment caused by UREs.

Distribution of refractive error among chinese primary school children in a rural area in Pahang, Malaysia.

This study aimed to determine the prevalence and status of refractive error among Chinese primary school children in a rural area in Pahang. This investigation entailed a cross-sectional retrospective study design involving case file analyses. The study site was a Chinese medium primary school in a rural locality within Bentong district. A total of 82 school children met the B40 classification and selection criteria; therefore, universal sampling was done. Analyses were done according to age group: Level 1 included ages 7 to 9 years, while Level 2 comprised 10- to 12-year-olds. The mean age of the 82 Chinese school children was 9.72±1.5 years; the percentage of refractive errors found was 80.48%. A total of 53 (64.63%) children had myopia. Two-way ANOVA showed a significant difference (P=0.038) in the refractive error between age groups Level 1 and 2, but no significant difference (P=0.947) was observed in refractive error between genders. The chi-square test and Fishers exact test showed no significant association between the type of refractive error with gender (P>0.05) and age group (P=0.319). Myopia was the most common type of refractive error among Chinese school children in a rural area in Pahang. Refractive error severity was influenced by age group but not by gender. Types of refractive error were not associated with age group and gender. Hence, it is recommended that Chinese school children in rural areas seek an annual vision screening or eye test.

Using electronic medical record data to establish and monitor the distribution of refractive errors,

ObjectiveTo establish the baseline distribution of refractive errors and associated factors amongst a population that attended primary care optometry clinics. DesignRetrospective cross sectional cohort study of electronic medical records (EMR). MethodsElectronic medical record data was extracted from forty optometry clinics, representing a mix of urban and rural areas in Ireland. The analysis was confined to demographic and clinical data gathered over a sixty-month period between 2015 and 2019. Distribution rates were calculated using the absolute and relative frequencies of refractive error in the dataset, stratified for age and gender using the following definitions: high myopia ≤ -6.00 D, myopia ≤ -0.50 D, hyperopia ≥ +0.50 D, astigmatism ≤ -0.75 DC and anisometropia ≥ 1.00 D. Visual acuity data was used to explore vision impairment rates in the population. Further analysis was carried out on a gender and age-adjusted subset of the EMR data, to match the proportion of patients in each age grouping to the population distribution in the most recent (2016) Irish census. Results153,598 clinic records were eligible for analysis. Refractive errors ranged from -26.00 to +18.50 D. Myopia was present in 32.7%, of which high myopia represented 2.4%, hyperopia in 40.1%, astigmatism in 38.3% and anisometropia in 13.4% of participants. The clinic distribution of hyperopia, astigmatism and anisometropia peaked in older age groups, whilst the myopia burden was highest amongst people in their twenties. A higher proportion of females were myopic, whilst a higher proportion of males were hyperopic and astigmatic. Vision impairment (LogMAR > 0.3) was present in 2.4% of participants. In the gender and age- adjusted distribution model, myopia was the most common refractive state, affecting 38.8% of patients. ConclusionAlthough EMR data is not representative of the population as a whole, it is likely to provide a reasonable representation of the distribution of clinically significant (symptomatic) refractive errors. In the absence of any ongoing traditional epidemiological studies of refractive error in Ireland, this study establishes, for the first time, the distribution of refractive errors observed in clinical practice settings. This will serve as a baseline for future temporal trend analysis of the changing pattern of the distribution of refractive error in EMR data. This methodology could be deployed as a useful epidemiological resource in similar settings where primary eyecare coverage for the management of refractive error is well established.

The Refractive Error and Vision Impairment Estimation with Spectacle Data Study.

PurposeTo investigate whether spectacle lens sales data can be used to estimate the population distribution of refractive error among patients with ametropia and hence to estimate the current and future risk of vision impairment.DesignCross-sectional study.ParticipantsA total of 141 547 436 spectacle lens sales records from an international European lens manufacturer between 1998 and 2016.MethodsAnonymized patient spectacle lens sales data, including refractive error information, was provided by a major European spectacle lens manufacturer. Data from the Gutenberg Health Survey was digitized to allow comparison of a representative, population-based sample with the spectacle lens sales data. A bootstrap analysis was completed to assess the comparability of both datasets. The expected level of vision impairment resulting from myopia at 75 years of age was calculated for both datasets using a previously published risk estimation equation combined with a saturation function.Main Outcome MeasuresComparability of spectacle lens sales data on refractive error with typical population surveys of refractive error and its potential usefulness to predict vision impairment resulting from refractive error.ResultsEquivalent estimates of the population distribution of spherical equivalent refraction can be provided from spectacle lens data within limits. For myopia, the population distribution was equivalent to the Gutenberg Health Survey (≤ 5% deviation) for levels of –2.0 diopters (D) or less, whereas for hyperopia, the distribution was equivalent (≤ 5% deviation) for levels of +3.0 D or more. The estimated rates of vision impairment resulting from myopia were not statistically significantly different (chi-square, 182; degrees of freedom, 169; P = 0.234) between the spectacle lens dataset and Gutenberg Health Survey dataset.ConclusionsThe distribution of refractive error and hence the risk of vision impairment resulting from refractive error within a population can be determined using spectacle lens sales data. Pooling this type of data from multiple industry sources could provide a cost-effective, timely, and globally representative mechanism for monitoring the evolving epidemiologic features of refractive error and associated vision impairment.

Comment on: Safety of phakic intraocular collamer lens implantation in 95 highly myopic special-needs children

We discussed the study by Reynolds et al. during the ESCRS journal club on July 7, 2021.1 In this retrospective case series, the investigators presented perioperative and longer-term adverse event data from 95 special-needs children or adults with myopia who could not comply with spectacles and/or contact lenses and underwent implantation of an intraocular collamer lens (ICL). Although this study addressed an important clinical question in a challenging patient group, we would like to highlight some points of discussion that are of relevance to the interpretation of the study. The definition of adverse events as minor or major seemed somewhat controversial. For example, in this study, wound leak requiring repair was designated as major since it necessitated a return to the theater, whereas endothelial cell loss was classed as minor. Although this nomenclature may be understandable in the context of a short-term clinical study after intervention, these definitions may not lend appropriate weight to possible serious longer-term safety concerns. The endothelial cell count was only measured in 31 of 160 eyes (ie, less than 19% of the cohort). Consequently, firm conclusions about the long-term safety of ICL implantation in this patient group cannot be made. Furthermore, these eyes are likely to be unrepresentative of the cohort since they are presumably from the most cooperative individuals. A greater yield may have been possible through specular microscopy in the lateral decubitus position undertaken under general anesthesia, although we appreciate that repeated anesthesia may have an overall detrimental effect on special-needs children. In this highly heterogeneous patient group, a more detailed presentation of the data might have allowed the reader to appreciate the relationships between clinical parameters (ie age and refraction) and adverse events. For example, the mean preoperative spherical equivalent refractive error was −11 D (range: −4 to −22) and mean age was 9.3 years (range: 1.8 to 25) with some nonpediatric patients. Illustration of distribution of refractive error and age as individual datapoints would have allowed the reader to determine, for example, whether there is a relationship between preoperative refractive error or age and postoperative endothelial cell loss? Moreover, could these parameters predict the development of postoperative pupil block? Furthermore, the details of adverse events by group (age, refraction, and underlying disorder) would have been helpful. Although the authors reported that there were 95 children and 160 implanted eyes, the article states that 35 unilateral and 60 bilateral surgeries were performed, which adds up to only 155 eyes. Previous studies on the subject have shown that ICL implantation is safe in children with a low rate of adverse events.2 Many of these studies were conducted by the same study group.3,4 Nevertheless, randomized controlled studies are needed in a larger number of pediatric patients to argue that the benefits outweigh the risks as stated by the researchers in their conclusion. Specifically, the measurement of postoperative endothelial cell counts in most individuals in such cohorts are required to make meaningful statements about long-term safety.