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Review Article

The Impact of Hyperopia on Academic Performance Among Children: A Systematic Review

Mavi, Sonia BSc (Hons); Chan, Ving Fai MSc, PhD; Virgili, Gianni MD, MSc∗,†; Biagini, Ilaria CO, MSc; Congdon, Nathan MD, MPH∗,‡,§; Piyasena, Prabhath MBBS, PhD; Yong, Ai Chee BOptom (Hons), MPH; Ciner, Elise B. BS, OD; Kulp, Marjean Taylor OD, MS||; Candy, T. Rowan BSc (Hons), PhD∗∗; Collins, Megan MD, MPH††; Bastawrous, Andrew MBChB, PhD‡‡,§§; Morjaria, Priya MSc, PhD‡‡,§§; Watts, Elanor BMBCh, MSc¶¶; Masiwa, Lynett Erita BSc Optom, MSc||||; Kumora, Christopher BOptom∗∗∗; Moore, Bruce OD†††; Little, Julie-Anne MOptom, PhD‡‡‡

Author Information
Asia-Pacific Journal of Ophthalmology: January-February 2022 - Volume 11 - Issue 1 - p 36-51
doi: 10.1097/APO.0000000000000492

Abstract

Education lays the foundation for sustainable economic growth and the development of a country.1 It is regarded as a fundamental human right2 and is the focus of Sustainable Development Goal 4 (SDG4) established by the United Nations, ensuring “inclusive and equitable quality education” for all.3 In 2017, it was reported that fewer than 50.0% of children and adolescents globally were achieving minimum proficiency levels4 in reading and mathematics.5 The highest regional proportion of adolescents failing to reach minimum proficiency levels worldwide were in sub-Saharan Africa (89.0%), followed by Central Asia and Southern Asia (80.0%), and Western Asia and Northern Africa (64.0%).5

Uncorrected refractive error is the leading cause of vision impairment in children globally.6 An estimated 12.8 million children aged 5 to 15 years are vision impaired due to this cause.7 A systematic review and meta-analysis of the regional and global prevalence of refractive errors across childhood found the pooled prevalence estimates of myopia, hyperopia [spherical equivalent (SE) ≥+2.00 diopters (D)], and astigmatism to be 11.7% [95% confidence interval (CI), 10.5–13.0], 4.6% (95% CI, 3.9–5.2), and 14.9% (95% CI, 12.7–17.1), respectively.8

Vision is a crucial component of a child's learning and education. Studies have reported that uncorrected and undercorrected refractive errors can affect a child's academic performance,9–14 social participation,15,16 and future economic productivity.17 However, a recent review identified several gaps in the evidence related to the impact of refractive errors on academic performance.18 Additionally, much of the evidence is undermined by suboptimal research methods, including small sample sizes and a lack of robust trial designs, limiting the ability to determine associations or causation. As a result, efforts have recently been undertaken to strengthen the evidence base, with trials reporting improvements in academic achievement after spectacle intervention to correct myopia.19–21 Other trials have also shown that refractive correction improves educational outcomes but have not distinguished the type of refractive error.14,22,23

Hyperopia is common in young children, with the prevalence of moderate hyperopia (≥+2.00 D) in 6- to 72-month-olds ranging between 13.0% and 29.0%.24,25 A meta-analysis reported hyperopia (≥+2.00 D) prevalence in 5-year-old children was between 2.7% and 26.3%, depending on the measurement methods and geographic location.26 Research has underscored the connection between uncorrected hyperopia, near visual function and early literacy development,27,28 reading speed,29 and academic achievement in children.12,30–33 For example, the Vision in Preschoolers–Hyperopia in Preschoolers (VIP-HIP) study concluded that 4- and 5-year-old children with uncorrected hyperopia ≥+4.00 D or uncorrected hyperopia ≥+3.00 D with reduced binocular near visual acuity/stereoacuity, performed significantly worse on early literacy tests compared to age-matched controls.28

School vision screening programs are relatively common in high-income countries, where they have been successfully incorporated into health care and educational systems.34 However, such programs predominantly rely on distance visual acuity as a measure and therefore, are biased to detect amblyopic risk factors, myopia, and astigmatism.35,36 The detection of uncorrected hyperopia could be crucial for successful reading,27,28 yet is frequently overlooked. Furthermore, modest hyperopia in children is regarded as relatively benign, as it is expected that children have sufficient accommodative (focusing) ability to overcome it.37

Besides the impact on learning, uncorrected moderate-high hyperopia in children is associated with a higher risk of strabismus38,39 and amblyopia.39–42 Amblyopia is the leading cause of unilateral vision impairment in children.43 Although treatment of amblyopia often involves correction of hyperopia to improve visual acuity, the hyperopia itself is not the impetus for clinical decision-making to prescribe spectacles.44 Current guidelines on prescribing for hyperopic correction for children under 4 years of age, in the absence of amblyopia and strabismus, are largely based on clinical experience rather than evidence derived.45,46 The absence of robust and standardized criteria makes it impossible to make unequivocal evidence-based recommendations for managing school-age children with hyperopia.

A majority of school learning activities, including reading and writing, are performed at close range over prolonged periods.47 In addition, with the advent of portable electronics, such as smartphones, tablets, and e-readers, the use of screens at close working distances over prolonged periods has become increasingly important and widely used for both educational and recreational purposes.48 Given that uncorrected hyperopia is the refractive error with the most significant impact on near vision, this increases the potential impact of uncorrected hyperopia on learning.49–51 Although uncorrected hyperopes can produce additional accommodation to overcome their refractive error temporarily. The sustained additional accommodative demand can result in asthenopia and headaches.52 This could lead to an unconscious avoidance of near tasks due to visual discomfort. In addition, children with hyperopia may not be aware that their vision is not “typical” or may not explain what they experience. A recent study reported that hyperopic correction improved accommodative performance for sustained reading tasks for the majority of participants.53

All these findings are imperative to understand the impact of hyperopia on education and learning. However, to the best of our knowledge, no systematic review or meta-analysis of the impact of hyperopia on children's academic performance has been published or registered to date. This review investigates the impact of uncorrected hyperopia and hyperopic spectacle correction on academic performance among children in the published literature and systematically synthesizes the findings.

METHODS

Data Sources and Search Methods

This systematic review and meta-analysis were conducted and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Cochrane handbook.54–56 The study protocol was registered on the International Prospective Register of Systematic Reviews database (PROSPERO reference number CRD-42021268972).

A comprehensive search strategy was applied to all electronic databases, using medical subject headings and a combination of keywords related to hyperopia, children, and academic performance. We searched the following databases: MEDLINE ALL (Ovid), EMBASE (Ovid), PsycINFO (Ovid), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Web of Science, PubMed, International Clinical Trials Registry Platform, Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials in the Cochrane Library, from database inception to July 26, 2021. One reviewer (SM) performed an additional grey literature search on Google Scholar, Open Grey, and ProQuest. No language, publication date, or geographic location restrictions were applied. Reference manager software (Endnote 20, Thomson Reuters) was used to collect references and exclude duplicates. Reference lists were also searched for all included articles and previous reviews to identify other relevant studies. The search strategy is shown in the supplementary file for the searches in the electronic databases (Supplementary Digital Content, File 1, https://links.lww.com/APJO/A125).

Eligibility Criteria

Inclusion criteria were as follows: any language, publication date, or geographic location; primary investigations and reviews; observational or interventional studies; participants were children and adolescents57 attending school between 4 and 17 years of age who had been diagnosed with uncorrected hyperopia of any degree, and with or without astigmatism, without any ocular comorbidities, including strabismus and amblyopia. Studies with mixed participant groups (eg, children and adults/cohorts including children with strabismus and/or amblyopia) that did not report data separately for the above participants were excluded. The primary outcome was academic performance assessed through standardized or nonstandardized testing or teachers’ evaluation of academic progress. Studies including only child self-reported measures of performance were excluded.

Data Extraction and Quality Appraisal

Two reviewers (IB and SM) independently checked the titles and abstracts retrieved by our searches against the review's eligibility criteria, resolving disagreements by discussion. The full texts of all potentially eligible articles were retrieved, and full-text screening was done by 2 reviewers (IB and SM) if eligibility was confirmed. Data were extracted separately from the included studies into a predesigned and piloted data spreadsheet (Excel; Microsoft Corp, Redmond, WA). For each included study, extracted data included author, year, geographic location, study setting, title, study design, sample size, participant characteristics, sampling method, reported outcome(s), and comparator groups. Two reviewers (IB and SM) checked the data for errors, and discrepancies were resolved through discussion and consensus.

Two reviewers (ACY and SM) independently evaluated the quality of each included study. Discrepancies were resolved through discussion and consensus. The Joanna Briggs Institute Critical Appraisal Checklist tools were used to assess the included studies’ quality and risk of bias.58

Data Synthesis and Analysis

We first described study characteristics, such as design, country, setting, refractive error, type, and category of the academic assessment tool, and then provided meta-analyses of the findings for reported outcomes. Studies were classified according to the World Bank classification of income level.59 All outcome measurement tools identified in the included studies were categorized by specific outcome measures and outcome domains: cognitive skills, educational performance, reading skills, and reading speed. This was undertaken by 4 reviewers (VFC, GV, IB, and SM) and discussed with the wider team if there were unresolved disagreements between these reviewers.

Hedges’ g effect size (ES)60 and 95% CI were calculated to characterize the association between uncorrected hyperopia and academic performance on each relevant domain for each study. Hedges’ g represents the standardized mean difference (SMD) between uncorrected hyperopic children and the 2 control groups: emmetropic and myopic children. Outcome measures from the included studies were all continuous and reported on different scales. Therefore, when studies used different outcome measurement tools in 1 academic domain, such as educational performance or reading skills, the ES was averaged to ensure that each study only added 1 ES to the final analysis. SMD and its 95% CI were used to summarize the estimated effects from individual studies reporting outcomes on the same scale. The random-effects model was used to generate a pooled ES. The magnitude of the SMDs was defined according to the guidelines laid out by Cohen: small (SMD = 0.2–0.5), medium (SMD = 0.5–0.8), and large (SMD = >0.8).61 An ES of less than zero indicates impaired academic performance. The threshold for statistical significance was set at P < 0.05, and all P values were 2-sided.

Heterogeneity between study estimates was presented visually and statistically through inspection of forest plots and the I2 statistic.62I2 values were interpreted using the threshold recommendations outlined in the Cochrane Handbook.63 Analyses were performed to assess whether academic performance differed as a function of the intended focus of the academic tool, for example, tools addressing reading skills or educational performance. All statistical analyses were performed using Stata statistical software (version 17.0, Stata Corp, College Station, TX). Sensitivity analysis was performed to evaluate each study's influence on the overall ES, using the leave-one-out method, by removing 1 study each time and repeating the analysis. We also performed a narrative synthesis of the association between uncorrected hyperopia and educational outcomes.

RESULTS

Study Selection

The electronic database search yielded 3746 titles and abstracts, 338 of which were duplicates. An additional 7 studies were identified by manually searching reference lists of the included studies. During title and abstract screening, 3302 studies were excluded as they were not relevant to the research question. One hundred thirteen studies were considered for eligibility, of which a total of 88 (77.9%) studies were excluded for the following reasons: outcome measures not reported (n = 56), simulated hyperopia was reported (n = 2), the type of refractive error could not be differentiated (n = 11), conference and meeting abstracts (n = 15), and unable to translate full text into English (n = 4, 3 in German, 1 in French). A total of 25 eligible studies were included in this review (Fig. 1). No additional studies were identified through the grey literature search.

F1
Figure 1:
Flow chart of the study selection process. Reported according to the PRISMA guidelines. Some studies contributed to both the narrative review and meta-analysis. PRISMA indicates Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Characteristics of the Eligible Studies

The 25 selected studies were comprised of 21 observational studies (16 cross-sectional studies,12,27,28,31,33,64–74 3 longitudinal studies,75–77 and 2 case-control studies78,79) and 4 interventional studies (1 cross-sectional study53 and 3 longitudinal intervention studies10,29,80). No full-scale randomized control trials were identified. A majority (n = 22, 88.0%) of included studies were conducted in high-income countries.10,12,27–29,31,33,53,66–69,71–80 One (4.0%) study was conducted in an upper middle-income country,70 and 2 (8.0%) were conducted in lower-middle-income countries (LMICs).64,65 The 25 studies included 23,883 school children [mean sample size 1038, standard deviation (SD) 2095, range 32–8245] with an age range of 3 to 17 years, across 12 countries. The sex distribution ranged from 34.3% to 63.0% males. Fourteen studies (56.0%) did not report on the sex distribution of participants.10,29,31,53,64,66–69,72,73,75,77,79 Studies were conducted in schools,10,29,31,33,64–70,74,77 community settings,12,71,72,75,78 or in health care facilities27,28,53,76,79,80 whereas 1 study did not report the setting.73

Classification of Hyperopia and Measurement Tools

The selected studies used a wide variety of definitions to classify hyperopia and utilized different refractive methods. A total of 7 studies explained the cutoff thresholds used to define hyperopia.12,27,33,53,64,69,74 Four (16.0%) studies used the plus-lens test to identify participants with hyperopia.12,29,66,71 Three out of these 4 studies, further defined hyperopia using the SE.12,29,66 One study (4.0%) used distance and near visual acuity to classify participants with refractive error.72 Seven studies (33.3%, n = 7/21) used a threshold between ≥+1.00 D and <+2.00 D on children aged between 5 and 13 years old.10,12,31,53,74,78,79 The remaining studies used a variety of threshold definitions for hyperopia from 0.00 D to ≥+4.00 D.27–29,33,64–70,75,76,80 Two studies did not provide details regarding how hyperopia was measured, for example, failure on the hyperopia test77 and “far-sighted enough to warrant use of glasses.”73

Regarding methodology to determine refractive status, 10 studies performed cycloplegic refraction,10,27,28,33,53,64,65,74,76,80 6 performed noncycloplegic refraction,31,68–70,75,78 and 4 did not clearly state whether cycloplegia was used.67,73,77,79 A variety of techniques were used to measure hyperopia. The 2 most common modalities were retinoscopy (32.0%, n = 8) and autorefraction (28.0%, n = 7) whereas 5 (20.0%) studies10,73,76,77,79 did not specify the instrument used and 4 (16.0%) studies12,29,66,80 used a combination of techniques.

Categorization of Academic Performance by Domain

All 25 included studies assessed 1 or more outcome domains: 3 (12.0%) studies in the cognitive skills domain65,67,80; 12 (48.0%) studies were in the educational performance domain12,28,31,33,64,66,68,70,71,75,77,79; 5 (20.0%) studies in the reading skills domain10,27,73,74,78; 1 (4.0%) study in the reading speed domain53; and 4 (16.0%) studies reported more than 1 domain (Table 1).29,69,72,76

Table 1 - Study Design Characteristics of Selected Studies Included in the Systematic Review and Meta-Analysis (N = 25)
Author (y) a) Countryb) Study Typec) Settingd) Sociodemographic Category a) Total Sample Size b) Sex (%)c) Age, yMean ±SD (Range) a) Definition of Hyperopiab) Methodc) Control Cohort a) Outcome Measure(s)b) Outcome Measurement Tool(s) Summary of Findings
Alvarez-Peregrina et al71 (2021) a) Spainb) Cross-sectionalc) Communityd) Not specified a) 6673, total hyperopic not specifiedb) 58.7% malec) Not specified (6–12) a) Failure on the plus-lens testb) Plus-lens test (+2.00 D)c) Not specified a) Educational performanceb) Parent-reported school performance The probability of poor academic performance increased with hyperopia (P = 0.001).
Atkinson et al75 (2007) a) UKb) 6-y follow-up, longitudinalc) Communityd) Broad a) 171, total hyperopic not specifiedb) Not specifiedc) 6.9 ± 0.5 (not specified) a) ≥+4.00 D in at least 1 meridianb) Noncycloplegic retinoscopyc) Emmetropia a) Educational Performanceb) British Picture Vocabulary Scale (BPVS); Phonological Abilities Test (PAT); and the Children's Test of Nonword Repetition (CN-Rep) On the BPVS test, a deficit in the hyperopic group was reported (P = 0.023). CN-Rep and PAT reported no differences between the 2 groups.
Akrami et al65 (2012) a) Iranb) Cross-sectionalc) Schoold) Not specified a) 137, total hyperopic n = 19b) 34.3% malec) 10.4 ± 0.6 (10–14) a) ≥+0.50 D SEb) Cycloplegic autorefractionc) Emmetropia; myopia; and astigmatism a) Cognitive skillsb) Teacher-based assessment Children with both myopia and astigmatism performed poorly compared to emmetropic children (P < 0.05). No significant differences were reported in the hyperopic group.
Chebil et al64 (2014) a) Tunisiab) Cross-sectionalc) Schoold) Not specified a) 162, all hyperopicb) Not specifiedc) 9.7 ± 0.4 (6–14) a) ≥+2.00 D SE in at least 1 eyeb) Cycloplegic autorefractionc) No control group a) Educational performanceb) Repeating ≥1 school year Academic delay of at least 1 y was noted in 75.9% of hyperopic children (n = 123). No significant association was reported between hyperopia and school performance (P = 0.41).
Eames73 (1955) a) USb) Cross-sectionalc) Not specifiedd) Not specified a) 171, total hyperopic n = 73b) Not specifiedc) Not specified a) Far-sighted enough to warrant use of glassesb) Not specifiedc) Grade-matched controls; emmetropia; and myopia a) Reading skillsb) The Gates Silent Reading Test The reading assessment was conducted on age-matched controls (n = 50) to establish the reading level. Grade 3 and 4 children (n = 121) received complete eye examinations. 63.0% (n = 46/73) of hyperopic children failed the reading test compared to 47.1% (n = 8/17) of myopic and 32.3% (n = 10/31) of emmetropic children. Hyperopia may contribute considerably to reading failure.
Fulk and Goss68 (2001) a) USb) Cross-sectionalc) Schoold) Not specified a) 266, total hyperopic n = 32b) Not specifiedc) Not specified (4–15) a) ≥+0.75 D SE in either eyeb) Noncycloplegic autorefractionc) Emmetropia; and myopia a) Educational performanceb) Teacher-based assessment 34.4% (n = 11/32) of hyperopic children falling into the lower one-fourth compared to 12.5% (n = 4/32) of myopic and 13.9% (n = 28/202) of emmetropic children. Uncorrected hyperopia was associated with poor academic outcomes (P = 0.015).
Harrington et al33 (2021) a) UKb) Cross-sectionalc) Schoold) Broad a) 1612, total hyperopic (6- to 7-year-old) n = 21, total hyperopic (12- to 13-year-old) not specifiedb) 54.2% malec) Not specified (6–7 and 12–13) a) ≥+3.50 Db) Cycloplegic autorefractionc) Emmetropia; existing hyperopic correction; myopia; and astigmatism a) Educational performanceb) Parent/guardian-reported school performance Uncorrected hyperopia was associated with low performance (P = 0.04); amongst the younger cohort (n = 21), low performance was reported in 23.8% (n = 5) of uncorrected hyperopic children compared to 9.5% (n = 2) of children with hyperopic correction.
Hirsch67 (1959) a) USb) Cross-sectionalc) Schoold) Not specified a) 197, total hyperopic n = 72b) Not specifiedc) Not specified(14–17) a) 0.00 D to >+2.00 D for the horizontal meridian in the right eye onlyb) Retinoscopy, not specifiedc) Myopia a) Cognitive skillsb) California Test for Mental Maturity Hyperopic children (≥+1.00 D) have intelligence test scores (range 106–109) below the mean intelligence quotient (IQ) (113 ± 17). Low IQ scores were associated with uncorrected hyperopia (P = 0.001).
Hopkins et al74 (2017) a) Australiab) Cross-sectionalc) Schoold) Disadvantaged a) 508§, total hyperopic n = 465b) 49.4% malec) Not specified (6–7 and 12–13) a) ≥+1.50 D in either eyeb) Cycloplegic retinoscopyc) Hyperopic correction ≥+1.50 D a) Reading skillsb) Neale test of reading ability assessing: reading accuracy and reading comprehension No differences were reported in reading accuracy (P = 0.77) and comprehension (P = 0.52) between children with and without uncorrected hyperopia (≥+1.50 D). Similarly, no differences were reported for varying cut-offs of hyperopia; reading accuracy (P = 0.19) and comprehension (P = 0.08) in corrected and uncorrected hyperopia (≥+2.00 D); and reading accuracy (P = 0.24) and comprehension (P = 0.28) in corrected and uncorrected hyperopia (≥+3.00 D).
Köhler and Stigmar66 (1981) a) Swedenb) Cross-sectionalc) Schoold) Advantaged a) 118, total hyperopic n = 16 (identified with the plus-lens test)b) Not specifiedc) 8.0 (Not specified) a) Failure on the plus-lens test, further defined by ≥+2.50 Db) Plus-lens test (+1.50 D and + 2.00 D)c) Emmetropia; and myopia a) Educational performanceb) Teacher-based assessment|| Hyperopic children were not representative of the poor readers group. Hyperopia was not associated with poor reading and writing skills.
Krumholtz77 (2000) a) USb) 2-y follow-up longitudinalc) Schoold) Disadvantaged a) Not specified∗∗, total hyperopic (1996–1997) n = 155, total hyperopic (1998–1999) n = 110b) Not specifiedc) Not specified (5–12) a) Failed on the hyperopia testb) Hyperopia test††c) No control group a) Educational performanceb) New York citywide test Poor academic performance was associated with hyperopia for Grade 1 (P = 0.01) and Grade 4 (P = 0.05) in the 1996–1997 cohort; and Grade 4 (P = 0.05) in the 1998–1999 cohort. Twenty-five students were given vision correction (predominantly spectacles), and of this sample, 84.0% (n = 21) gained at least a 20 percentage-point increase in their achievement test percentile rank.
Lança et al69 (2014) a) Portugalb) Cross-sectionalc) Schoold) Not specified a) 587, total hyperopic n = 16b) Not specifiedc) Not specified‡‡(6–11) a) ≥+3.75 Db) Noncycloplegic autorefractionc) Normal Visual Function (NVF); anisohyperopia; and astigmatism a) Reading skills and reading speedb) Reading errors; Reading accuracy; and Reading Speed Children with uncorrected hyperopia had poor reading performance (P = 0.003) than emmetropic controls.
Ntodie et al53 (2021) a) UKb) Cross-sectionalc) Other (school; university eye clinic; and community)d) Not specified a) 63, all hyperopicb) Not specifiedc) 7.8 ± 1.7 (5–10) a) ≥+1.00 D and <+5.00D SE in the less-hyperopic eye postrefractionb) Cycloplegic retinoscopyc) No control group a) Reading speedb) Wilkin Rate of Reading test Hyperopic spectacle correction significantly improved reading speed (P < 0.001)
Palomo-Álvarez and Puell78 (2010) a) Spainb) Case-controlc) Communityd) Broad a) 119, total hyperopic n = 30b) 63.0% malec) 9.2 (8–13) a) <+2.00 Db) Noncycloplegic retinoscopyc) Normal readers a) Reading skillsb) The Battery of Evaluation of Reading Processes (PROLEC) for Grades 3 and 4; and the Battery of Evaluation of Reading Processes for Secondary Education Students (PROLEC-SE) for Grade 5 The poor readers group§§ comprised of 25 (28.7%) hyperopic children, whereas 5 (15.6%) of the normal readers were hyperopic.
Roch-Levecq et al80 (2008) a) USb) 6-wk follow-up longitudinalc) Other (university eye clinic or mobile eye clinic)d) Disadvantaged a) 70, total hyperopic n = 35b) 40.0% malec) 4.6 (3–5) a) ≥+4.00 D bilateralb) Cycloplegic retinoscopy¶¶c) Emmetropia a) Cognitive skillsb) The Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) Children with uncorrected hyperopia scored significantly lower on the performance scale (P = 0.01) than the emmetropic controls. After wearing spectacle correction for 6 wk, the hyperopic group improved on the WPPSI-R performance scale but did not reach statistical significance (P = 0.17). Hyperopic correction was undercorrected by 1.50–2.50 D or by 3.00 D if hyperopia was ≥+7.00 D.
Rosner and Rosner79 (1987) a) USb) Case-controlc) Other (university eye clinic)d) Not specified a) 576, total hyperopic n = 140b) Not specifiedc) Not specified (6–12) a) ≥+1.00 D to >2.25 Db) Not specifiedc) Myopia; and astigmatism a) Educational performanceb) With or without learning difficulties (LD)|||| Hyperopia was more prevalent in children with LD (n = 123): 32.5% (n = 40) with moderate hyperopia (≥+1.00 D to + 2.25 D) and 21.1% (n = 26) with significant hyperopia (>+2.25 D).
Rosner and Rosner31 (1997) a) USb) Cross-sectionalc) Schoold) Advantaged a) 782, total hyperopic n = 83b) Not specifiedc) Not specified a) ≥+1.25 Db) Noncycloplegic retinoscopyc) Emmetropia; and myopia a) Educational performanceb) Iowa Test of Basic Skills 32.7% of myopic children were high scorers (>75th percentile), compared with only 13.3% of the hyperopic children. Children with hyperopia (≥+1.25 D) had significantly lower test scores (P = 0.014). Test scores were significantly lower in hyperopic children compared to myopic children (P = 0.017).
Shankar et al27 (2007) a) Canadab) Cross-sectionalc) Other (university clinic)d) Not specified a) 32, total hyperopic n = 13b) 46.9% malec) Not specified∗∗∗ (4–7) a) ≥+2.00 D along the most hyperopic meridian,bilaterallyb) Cycloplegic retinoscopy†††c) Emmetropia a) Reading skillsb) The Wide Range Achievement Test (WRAT-III); The Peabody Picture Vocabulary Test-III (PPVT); The Rosner Test of Auditory Analysis (TAAS); and the Emergent Orthography test Children with uncorrected hyperopia performed poorly compared to emmetropic children in letter and word recognition (P = 0.049), receptive vocabulary (P = 0.004) and emergent orthography (P = 0.03). There was no difference between the 2 groups in phonological awareness (P = 0.54)
Slavin et al10 (2018) a) USb) Mean 3.7 ± 1.7 mo follow-up longitudinalc) Schoold) Disadvantaged a) 262, total hyperopic n = 101b) Not specifiedc) Not specified a) ≥+1.00 Db) Cycloplegic refraction, not specifiedc) Emmetropia; and myopia a) Reading skillsb) Letter-Word Identification and Word Attack scales from the Woodcock Language Proficiency Battery Children with uncorrected refractive errors had poor reading performance, but none of these differences was statistically significant. The effect of receiving eyeglasses was only statistically significant for myopic children (P < 0.03), not hyperopic children (P < 0.10).
Stewart-Brown et al72 (1985) a) UKb) Cross-sectionalc) Communityd) Not specified a) 8245, total hyperopic n = 323b) Not specifiedc) 10.0 (Not specified) a) Hyperopia, distance vision 6/6 near vision ≤9b) Visual acuityc) Emmetropia; existing hyperopic correction; and myopia a) Cognitive skills; reading skills; and educational performanceb) British Ability Scales; Edinburgh Reading Test‡‡‡; and a mathematics test Children with uncorrected hyperopia were underachieving in reading. Reading scores were higher in children (n = 22) with existing hyperopic spectacle correction, but the difference was not statistically significant.
van Rijn et al29 (2014) a) The Netherlandsb) Four to 6-mo follow-up longitudinalc) School§§§d) Broad a) 166, total hyperopic n = 107b) Not specifiedc) Not specified (9–10) a) Failure on the plus-lens test, further defined as >0.00 D SEb) Plus-lens test (+1.50 D) and noncycloplegic autorefraction¶¶¶c) Myopia <0.00 D a) Reading skills; and reading speedb) Klepel; and One-Minute Test Children with myopia had approximately 11% higher One-minute scores (P = 0.005) than children with uncorrected hyperopia. At follow-up, the hyperopic full correction group improved its One-Minute score by about 13% more than both the no-spectacle group (P = 0.012) and +0.50DS group (P = 0.019).
VIP-HIP Study Group28 (2016) a) USb) Cross-sectionalc) Other (university eye clinic or mobile-eye clinic)d) Disadvantaged a) 492, total hyperopic n = 244b) 49.2% malec) 4.9 ± 0.5 (4–5) a) ≥+3.00 D to ≤+6.00 D in the most hyperopic meridian of at least 1 eyeb) Cycloplegic autorefractionc) Emmetropia a) Educational performanceb) Test of Preschool Early Literacy (TOPEL) The mean TOPEL score was significantly lower in children with uncorrected hyperopia than emmetropia (P = 0.004).
Williams et al76 (1988) a) New Zealandb) 4-y follow-up longitudinalc) Other (research clinic)d) Broad a) 503, total hyperopic n = 26b) 53.7% malec) Not specified (7–11) a) >+2.25 D bilaterallyb) Cycloplegic refraction, not specifiedc) Emmetropia; myopia; and premyopia a) Cognitive skills; and reading speedb) Wechsler Intelligence Scale for Children – Revised form (WISC-R) IQ test||||||; and the Burt Word Reading Test At age 11, the hyperopic group had significantly lower verbal and performance IQ scores than the emmetropic group (P < 0.05). No significant differences were reported in reading scores between the groups.
Williams et al12 (2005) a) UKb) Cross-sectionalc) Communityd) Not specified a) Not specified, total hyperopic n = 101b) 51.0% malec) 8.0 (Not specified) a) Failure on the plus-lens test, further defined hyperopia as ≤+3.00 D or >+3.00 D bilaterally; ≤+1.25 D or >+1.25 D in the better eyeb) Plus-lens test (+4.00 D)∗∗∗∗c) Nonreferred group; and nonfogging referral group a) Educational performanceb) National Foundation for Education Research (NFER); and Standardised assessment tests (SATs) attaining core subject indicator (CSI) level 2 The hyperopic (≤+3.00 D) group scored the highest on NFERs and SATs, whereas the lowest scores were seen in the more strongly hyperopic (>+3.00 D) group (NFER) and nonfogging test referrals (SATs). No significant differences were identified between the test groups.
Yang et al70 (2021) a) Chinab) Cross-sectionalc) Schoold) Not specified a) 1971, total hyperopic not specifiedb) 55.1% malec) Not specified (6–15) a) ≥+0.50 D SEb) Noncycloplegic autorefractionc) Emmetropia a) Educational Performanceb) Nationwide standard examination in the following: Chinese language; English; and mathematics Hyperopia was associated with lower academic scores in Grade 1 children (P = 0.01). Hyperopia was significantly associated with the worst academic performance in the Chinese language test (P = 0.02) and the mathematics test (P = 0.01) among Grade 1 children.
D indicates diopter; SE, spherical equivalent.
Failure of ≥1 subject at the end of the previous year.
At the first visit, noncycloplegic retinoscopy was conducted to identify participants with hyperopia who were followed up with cycloplegic retinoscopy thereafter.
Performance measured as follows: high performance (much better than classmates); average performance (about the same as classmates); and low performance (not and classmates).
§All participants (n = 508) completed the reading accuracy component of the reading test, and 465 participants completed the reading comprehension component, with the remaining 43 participants most likely experienced difficulties with the reading task. 22.8% (n = 116) of children had uncorrected hyperopia and 68.7% (n = 349) of children had hyperopic correction.
Hyperopic participants were identified by failing screening with the plus-lens test. Then cycloplegic retinoscopy was conducted.
||Assessment based on reading and writing difficulties, using a 4-graded scale: none; slight; moderate; and severe.
∗∗Reported top and bottom 25%.
††No specific detail is given on the hyperopia test, and refraction was undertaken but not reported.
‡‡Normal Visual Function cohort mean age 7.7 ± 1.2 y.
§§Poor readers identified as those who scored below the 30th percentile in the reading subtests.
¶¶Cycloplegic retinoscopy was conducted on all participants, and most had cycloplegic autorefraction conducted.
||||Learning Difficulties (LD) are defined as school achievement record not matching the predicted IQ score.
∗∗∗Mean 5.6 ± 1.1, emmetropic cohort; and mean 4.8 ± 1.0, hyperopic cohort.
†††Refractive status was categorised based on cycloplegic retinoscopy, but participants also underwent precycloplegic and cycloplegic testing with 2 autorefractors.
‡‡‡Shortened form of test.
§§§One or 2 subsequent visits to a regional optician for additional measurements.
¶¶¶Participants with visual acuity <0.8 or a difference of >2 lines; or participants who failed the plus-lens test (a decrease in visual acuity by ≤2 lines) or ≥+0.75 D in either eye measured by noncycloplegic autorefraction were then referred for cycloplegic retinoscopy. For the intervention study, only participants with uncorrected hyperopia were considered eligible.
||||||Comprehension and Picture Arrangement subtests were omitted.
∗∗∗∗Failure on the plus lens test (+4.00 D) and then referred for optometric assessment.

Cognitive skills encompassed a variety of labels, for example, general intelligence in children such as full-scale intelligence quotient (IQ), verbal IQ, performance IQ, working memory, and processing speed. Standardized intelligence tests including the Wechsler Preschool and Primary Scale of Intelligence-Revised, Wechsler Intelligence Scale for Children-Revised, and the California Test for Mental Maturity and British Ability Scales were used to assess cognitive function. Four of the 5 studies assessing cognitive skills used standardized tests67,72,76,80 and 1 study utilized teacher-based assessments to determine cognitive functioning.65

The domain of educational performance was comprised of many measures of academic performance such as mathematics, language, early literacy skills, and the number of schooling years that were repeated. Early literacy skills are reading and writing skills developed from birth to approximately 5 years old that strongly predict later conventional literacy skills.81,82 Seven (53.8%) of the 13 studies used nonstandardized tests to assess educational performance.33,64,66,68,71,72,79 Reading skills were categorized into constructs of overall reading or clusters/subtests to assess a range of tasks, for example, reading comprehension, letter-word identification, picture vocabulary, reading accuracy, and errors. Seven (87.5%) out of 8 studies used standardized testing to assess reading levels in children.10,27,29,72–74,78 All 4 studies assessing reading speed have reported outcome measures separately; therefore, reading speed was evaluated as a separate domain.29,53,69,76 Three studies used standardized tests to measure and report reading speed.29,53,76 Lança et al69 reported the validity of the tool used to assess reading skills and speed.

Assessment of Quality and Risk of Bias

The studies were assessed for their methodological quality using the Joanna Briggs Institute Critical Appraisal Checklist tools.58 In brief, the quality of the studies was assessed by determining whether the studies have (1) included a rigorous selection of representative participants, (2) the undertaking of cycloplegic refraction to define refractive error, (3) identified confounding factors, and (4) used valid and reliable outcome measurements with robust statistical analyses, underpinned by a detailed methodological description of the study. By applying these criteria, the quality of a majority (88.0%) of the included studies was moderate-low.10,12,29,31,33,64–80 Three studies were considered high quality.27,28,53 Notably, out of these 3 studies, the VIP-HIP study28 used a large sample size of hyperopic children. The most common issues included: (1) small sample size of exposure group27,31,53,65,68,69,72,74,79,80; (2) failure to measure hyperopia using a valid, clearly-defined, reliable method across all study participants12,33,64,65,67–73,75–79; (3) failure to measure academic performance using a clearly-defined, valid, and reliable tool across all study participants31,33,64–66,68,71,73,76,77,79; and (4) limitations inherent in the cross-sectional design. A summary of the methodological quality is shown in Table 2.

T2
Table 2:
The Checklist Results for Assessing the Methodological Quality of the Selected Studies (N = 25)

Meta-Analyses Findings

Separate meta-analyses were conducted to assess 2 indicators of the association between uncorrected hyperopia and academic performance: (1) educational performance and (2) reading skills. Among the 25 included studies, 5 (20.0%) could be included in our meta-analysis.27,28,31,69,72 All included studies are presented narratively. The 16 (64.0%) studies that could not be included in the meta-analysis did not provide the SD,12,67,74,76 reported median values but not the means and SDs,73 failed to investigate a sufficient number of hyperopic participants,70,75,77,78 or did not measure academic performance objectively.33,64–66,68,71,79 Four studies that reported on the impact of hyperopic spectacle correction on academic performance were excluded from the meta-analysis for the following reasons: 1 study did not provide the SD,29 and the remaining 3 studies could not be pooled to estimate the effect of hyperopic spectacle correction.10,53,80

Pooled estimates of educational performance from 4 studies with 9551 total participants, ranging in age from 4 to 10 years, showed children with uncorrected hyperopia had worse educational performance than emmetropic children, with a pooled SMD of −0.18 (95% CI, −0.27 to −0.09; P < 0.001) (Fig. 2). There was no evidence of a difference between hyperopic and myopic children, but the estimate was imprecise [SMD −0.08 (95% CI, −0.29 to 0.13; P = 0.474)] (Fig. 3). Low statistical heterogeneity was observed between studies using an emmetropic control group (I2 = 0.0%), suggesting a consistent effect across studies. Moderate statistical heterogeneity was observed between studies using a myopic control group (I2 = 47.5%). Regarding study design features, we found 1 study27 with a small sample size that showed a greater ES, but this had little effect on overall heterogeneity (Fig. 2).

F2
Figure 2:
Results of random-effects meta-analysis for educational performance between hyperopic children and emmetropic control group. The number of hyperopic children and the emmetropic control group is shown for each study. Forest plots show effect sizes on educational performance using standard deviation scores (Hedges’ g).
F3
Figure 3:
Results of random-effects meta-analysis for educational performance between hyperopic children and myopic control group. The number of hyperopic children and the myopic control group is shown for each study. Forest plots show effect sizes on educational performance using standard deviation scores (Hedges’ g).

Pooled estimates of reading skills from 3 studies including 8855 participants, ranging in age from 4 to 11 years, showed children with uncorrected hyperopia had worse reading skills than emmetropic children, with a pooled SMD of −0.46 (95% CI, −0.90 to −0.03; P = 0.036) (Fig. 4). One study found that participants with uncorrected hyperopia had significantly worse reading skills than those with myopia [SMD −0.29 (95% CI, −0.43 to −0.1; P < 0.001)] (Fig. 5). Substantial statistical heterogeneity was observed between studies using an emmetropic control group (I2 = 68.0%) (Fig. 4).

F4
Figure 4:
Results of random-effects meta-analysis for reading skills between hyperopic children and emmetropic control group. The number of hyperopic children and the emmetropic control group is shown for each study. Forest plots show effect sizes on reading skills using standard deviation scores (Hedges’ g).
F5
Figure 5:
Results of random-effects meta-analysis for reading skills between hyperopic children and myopic control group. The number of hyperopic children and the myopic control group is shown for each study. Forest plots show effect sizes on reading skills using standard deviation scores (Hedges’ g).

Sensitivity Analysis

In the leave-one-out sensitivity analyses conducted, the removal of most studies unsurprisingly rendered the nonsignificant pooled ES estimate due to loss of precision, considering the small number of studies in each meta-analysis (Figs. 6, 7).

F6
Figure 6:
Results of leave-one-out sensitivity analysis for educational performance with the emmetropic control group.
F7
Figure 7:
Results of leave-one-out sensitivity analysis for reading skills with the emmetropic control group.

Narrative Findings From Studies Not Included in the Meta-Analysis

The 20 eligible studies excluded from the meta-analysis included 16 observational (11 cross-sectional studies,12,33,64–68,70,71,73,74 3 longitudinal studies,75–77 2 case-control78,79) and 4 interventional studies (1 cross-sectional study53 and 3 longitudinal studies10,29,80). The findings of all the studies are described in Table 1. Of the 19 studies that assessed the association between uncorrected hyperopia and academic performance, ten29,33,67,68,70,71,75–77,80 found a significant (P < 0.05) detrimental impact on academic performance. Of these studies, 2 reported that uncorrected hyperopia was associated with poor academic performance compared to both emmetropic and myopic comparator groups33,68; 4 found a significant association between uncorrected hyperopia and poorer academic outcomes compared to emmetropia70,75,76,80; 2 reported poorer academic outcomes in children with uncorrected hyperopia compared to myopia29,67; and 2 reported impaired academic outcomes in children with uncorrected hyperopia but did not include a comparator group.71,77 For those studies that did not find a significant association between uncorrected hyperopia and poor academic performance, some reported a significant difference (although P values were not reported) between uncorrected hyperopia and educational performance.73,79 Two of the 4 interventional studies found a significant improvement in reading speed29,53 with hyperopic spectacle correction, whereas the remaining 2 did not.10,80 One study failed to report measured outcomes on a sufficient number of hyperopic participants.78

DISCUSSION

This systematic review summarizes the existing evidence from 25 eligible studies across 12 countries investigating the relationship between hyperopia and academic performance. The meta-analyses from 5 studies found a statistically significant association between uncorrected hyperopia and poor academic performance, whereas the narrative synthesis including all 20 studies found mixed results.

Our findings from the meta-analyses of 5 studies showed that children with uncorrected hyperopia had worse educational performance than the emmetropic children [SMD −0.18 (95% CI, −0.27 to −0.09)]. However, a significant difference was found when compared with myopic children [SMD −0.08 (95% CI, −0.29 to 0.13)]. A statistically significant difference was seen in the reading skills of uncorrected hyperopic children when compared with both emmetropic children [SMD −0.46 (95% CI, −0.90 to −0.03)] and myopic children [SMD −0.29 (95% CI, −0.43 to −0.15)]. Over half (52.6%, n = 10/19) of the studies included in the narrative synthesis reported a statistically significant association between uncorrected hyperopia and impaired academic performance.29,33,67,68,70,71,75–77,80 Additionally, 2 interventional studies reported improvement in reading speed29,53 when hyperopic spectacle correction was provided.

Based on the 2 meta-analyses, greater ESs were seen in smaller studies, which could be confounded by methodological quality. The VIP-HIP study28 was designed with sufficient statistical power to make comparisons between children with moderate hyperopia and emmetropia who underwent early literacy testing; this study found significant deficits in early literacy in children with uncorrected moderate hyperopia (+3.00 to +6.00 D) as compared to children with emmetropia, with the greatest deficits in hyperopic children with reduced near visual function (near stereoacuity, binocular near visual acuity, accommodative response). Further analysis of children participating in VIP-HIP also showed a significant association between reduced near visual function and moderate hyperopia (P < 0.001).51 Children with low to moderate hyperopia also demonstrated worse near visual acuity, stereopsis, and accommodative responses (larger lags of accommodation).83

The majority of these studies indicate that uncorrected hyperopia is associated with impaired academic performance. However, the quality appraisal indicates that many of these studies provide only moderate to low evidence. A full-scale randomized clinical trial is needed to determine the causal association between hyperopic correction and academic performance. A further issue that remains unresolved is whether correction of hyperopia restores academic performance. Although the majority of studies have used different refractive groups as comparators, comparison between uncorrected and corrected hyperopic groups would provide valuable insights as to whether the correction of hyperopia contributes to improved academic performance in children.

Causality in the relationship between hyperopia and educational attainment has recently been tested in a Mendelian randomization study, which used a nonlinear relationship with refractive error to simultaneously model both myopia and hyperopia on data from adults participating in the UK Biobank study.84 The study found little evidence to suggest hyperopia is a causal risk factor for lower years of educational attainment. However, there were significant methodological flaws, such as only including adult participants born in England or Wales and those of European ancestry. Some of whom were adequately corrected with spectacles for hyperopia during childhood.84 Further, educational attainment was only measured by self-reported years of education, and self-report of spectacle wear during childhood as an adult may have introduced recall bias. The paper is nonetheless relevant to any consideration of the impact of hyperopia on educational attainment and underscores the need for randomized trials in the area to provide more reliable evidence.

Accommodation is important when assessing a child's visual function because it essentially dictates the retinal image quality.85 Blur from poor accommodative response might go some way to explain the impact of uncorrected hyperopia on reading performance.49,72,86 It has been suggested that hyperopes with milder degrees of uncorrected hyperopia can readily accommodate and therefore may not require optical correction.87 However, recent studies have reported that the greater the magnitude of a child's hyperopia, the greater the variability of accommodation leading to more blur at near distances.88–90 This can impact the accommodative-convergence interaction during near work, increasing difficulty in letter and word identification and potentially hindering a child's ability to read. Interventional studies investigating the impact of correcting hyperopia on academic performance have reported a statistically significant improvement in reading speed.29,53 However, another yet unknown factor in interpreting the impact of hyperopic correction is the difference early or late intervention has in terms of academic performance. For example, if hyperopia correction occurs later in a child's educational years, does this diminish the benefit that hyperopic correction may otherwise yield?

Hyperopia prevalence is thought to be higher [by 1.82 times (95% CI, 1.03–3.23)] in children from disadvantaged compared to advantaged socioeconomic backgrounds.91 Our review found only 5 studies that reported on participants from disadvantaged socioeconomic backgrounds.10,28,74,77,80 However, the majority (n = 13, 52.0%) did not specify the sociodemographic setting.12,27,53,64,65,67–73,79 We also found only 2 studies from LMICs.64,65 Little emphasis has been placed on accurately measuring the prevalence of hyperopia and its impact on educational outcomes, especially among children in underserved settings, particularly in LMICs.

The lack of focus on hyperopia has led to methodological differences in its assessment and variation in outcome measurement tools, limiting comparisons across studies. A further difficulty in comparing studies is that the variation in the tools used to measure the magnitude of hyperopia can increase imprecision due to high inter-observer variability and measurement errors. For research studies investigating the prevalence of refractive error in children, cycloplegic refraction is the gold-standard method.92 However, clinically, dry retinoscopy and subjective refraction are also used to measure refractive error, and the use of cycloplegia may vary. Cycloplegic refraction requires the use of drugs and protocols for administration, including multiple instillations of eyedrops and additional use of topical anesthetics for some populations to ensure an appropriate effect. Such regimes are more invasive, take more time and resources, and require trained professionals. Understandably, study protocols have considered alternative routes. This review's inclusion criteria were not limited to those studies that performed cycloplegic refraction. Nevertheless, without adopting cycloplegic methods to assess refractive error in children, studies using a definition from noncycloplegic conditions would very likely be under-reporting hyperopia.

A recent study highlighted the low sensitivity of noncycloplegic approaches for detecting hyperopia, reporting sensitivity for hyperopia defined as >+0.50 D and >+1.00 D in children and young adults aged 5 to 20 years using noncycloplegic autorefraction to be 38.9% and 22.1%, respectively.93 Similar studies have also reported noncycloplegic measurement errors using autorefraction.94,95 This reinforces the importance of conducting cycloplegic refraction to determine the true power and prevalence of hyperopia.92

The United Nations Educational Scientific Cultural Organization uses indicators to monitor and report each country's progress toward achieving the SDGs.96 Despite increased participation in primary and lower secondary education globally since the World Declaration of Education for All in 1990,97 only 37.0% of lower-secondary school children achieve minimum proficiency in reading according to the (adjusted) SDG Indicator 4.1.1.96 Children in sub-Saharan Africa and Central and Southern Asia face greater challenges in education than any other regions, with only 15.0% and 21.0%, respectively, meeting minimum proficiency levels in lower-secondary education.96 This highlights the need for interventional studies in schools to determine whether the early detection and correction of refractive errors could facilitate the success of early reading and writing programs.

Strengths and Limitations

This systematic review is the first to report the impact of hyperopia on academic performance, while combining both meta-analyses and narrative synthesis. The strengths of this review include a comprehensive search of the literature and the use of 2 authors to independently screen and select studies and extract data. Nonetheless, there are several limitations. The study synthesis of the existing literature under review was limited due to methodological differences, inconsistent measurement tools, the small number of hyperopic children recruited in most cohorts, and the lack of information about the severity of hyperopia, which could have led to inaccurate findings. Furthermore, the definition of hyperopia differs considerably across studies, further limiting overall comparability. Many of the included studies are cross-sectional, which limits inference regarding causality. Our findings were limited by the variation in tests used to identify hyperopia, with 4 studies (16.0%) using the plus-lens test, which may not reliably detect low to moderate hyperopia.98 Because of the paucity of studies that have investigated visual attention53,75 and visual-motor integration,27,74,75,80 we could not explore the association between hyperopia and these domains in this review. However, 2 more recent studies83,99 have reported poorer visual attention and visual-motor integration in those with hyperopia, and these higher functions are promising areas that warrant further investigation. Because fewer than 10 studies were included in our meta-analyses, we could not test for publication and reporting biases, which are likely in observational studies that do not require prior registration. Also, most (n = 22, 88.0%) studies were conducted in high-income countries. Therefore, their data might not represent LMICs, making it difficult to inform policy in such settings, where the majority of the world's children live.

CONCLUSIONS

This is the first systematic review and meta-analysis to focus on the impact of uncorrected hyperopia and hyperopic spectacle correction on academic performance globally. We found an association between uncorrected hyperopia and children's poor educational performance and reading skills. However, firm conclusions are difficult to draw due to considerable heterogeneity in study design features and methodology, definitions of hyperopia used, assessment of academic performance, and the small number of hyperopic children recruited in some studies. Hyperopia in children, if left undetected, could have a significant negative effect on economic and academic opportunities throughout life. Standardized definitions, survey methodologies, and practical screening methodologies, together with randomized controlled trials, are required to determine the magnitude of the issue and develop evidence-based solutions to tackle it.

ACKNOWLEDGMENTS

The authors thank Richard Fallis at the Library of Queen's University, Belfast, UK, for guidance in developing search algorithms.

REFERENCES

1. Woessmann L. The economic case for education. Educ Econ 2015; 24:1–30.
2. United Nations General Assembly Res 217 A (III). Universal declaration of human rights. 1948. Available at: https://www.un.org/sites/un2.un.org/files/udhr.pdf. Accessed September 12, 2021.
3. United Nations General Assembly. Transforming Our World: The 2030 Agenda for Sustainable Development. 2015. Available at: https://sdgs.un.org/. Accessed September 12, 2021.
4. UNESCO Institute for Statistics. Minimum Proficiency Levels: Described, Unpacked and Illustrated Version 2. 2019. Available at: http://gaml.uis.unesco.org/wp-content/uploads/sites/2/2019/05/GAML6-REF-2-MLP-recommendations-ACER.pdf. Accessed December 6, 2021.
5. UNESCO Institute for Statistics. More than One-half of Children and Adolescents are not Learning Worldwide. Fact Sheet No. 46. 2017. Available at: http://uis.unesco.org/sites/default/files/documents/fs46-more-than-half-children-not-learning-en-2017.pdf. Accessed September 12, 2021.
6. Burton MJ, Ramke J, Marques AP, et al. The Lancet Global Health Commission on Global Eye Health: vision beyond 2020. Lancet Glob Health 2021; 9:e489–e551.
7. Resnikoff S, Pascolini D, Mariotti S, et al. Global magnitude of visual impairment caused by uncorrected refractive errors in 2004. Bull World Health Organ 2008; 86:63–70.
8. Hashemi H, Fotouhi A, Yekta A, et al. Global and regional estimates of prevalence of refractive errors: systematic review and meta-analysis. J Curr Ophthalmol 2018; 30:3–22.
9. Gogate P, Mukhopadhyaya D, Mahadik A, et al. Spectacle compliance amongst rural secondary school children in Pune district, India. Indian J Ophthalmol 2013; 61:8–12.
10. Slavin RE, Collins ME, Repka MX, et al. In plain sight: reading outcomes of providing eyeglasses to disadvantaged children. J Educ Stud Placed Risk 2018; 23:250–258.
11. Nie JC, Pang XP, Wang L, et al. Seeing is believing: experimental evidence on the impact of eyeglasses on academic performance, aspirations, and dropout among junior high school students in rural China. Econ Dev Cult Change 2020; 68:335–355.
12. Williams WR, Latif AHA, Hannington L, et al. Hyperopia and educational attainment in a primary school cohort. Arch Dis Child 2005; 90:150–153.
13. Dudovitz RN, Sim MS, Elashoff D, et al. Receipt of corrective lenses and academic performance of low-income students. Acad Pediatr 2020; 20:910–916.
14. Hark LA, Thau A, Nutaitis A, et al. Impact of eyeglasses on academic performance in primary school children. Can J Ophthalmol 2020; 55:52–57.
15. Dias L, Hyman L, Manny RE, et al. Evaluating the self-esteem of myopic children over a three-year period: the COMET experience. Optom Vis Sci 2005; 82:338–347.
16. Chan VF, Singer S, Naidoo KS. Disability-related-distress in primary school learners with vision impairment due to uncorrected refractive error in KwaZulu-Natal Province, South Africa - a qualitative study. PLoS One 2020; 15:1–16.
17. Naidoo KS, Fricke TR, Frick KD, et al. Potential lost productivity resulting from the global burden of myopia: systematic review, meta-analysis, and modeling. Ophthalmology 2019; 126:338–346.
18. Hopkins S, Narayanasamy S, Vincent SJ, et al. Do reduced visual acuity and refractive error affect classroom performance? Clin Exp Optom 2020; 103:278–289.
19. Ma Y, Congdon N, Shi Y, et al. Effect of a local vision care center on eyeglasses use and school performance in rural China: a cluster randomised clinical trial. JAMA Ophthalmol 2018; 136:731–737.
20. Hannum E, Zhang Y. Poverty and proximate barriers to learning: vision deficiencies, vision correction and educational outcomes in rural Northwest China. World Dev 2012; 40:1921–1931.
21. Ma X, Zhou Z, Yi H, et al. Effect of providing free glasses on children's educational outcomes in China: cluster randomised controlled trial. BMJ 2014; 349:g5740.
22. Glewwe P, Park A, Zhao M. A better vision for development: eyeglasses and academic performance in rural primary schools in China. J Dev Econ 2016; 122:170–182.
23. Glewwe P, West KL, Lee J. The impact of providing vision screening and free eyeglasses on academic outcomes: evidence from a randomised trial in title I elementary schools in Florida. J Policy Anal Manage 2018; 37:265–300.
24. Jiang X, Tarczy-Hornoch K, Stram D, et al. Prevalence, characteristics, and risk factors of moderate or high hyperopia among multiethnic children 6 to 72 months of age: a pooled analysis of individual participant data. Ophthalmology 2019; 126:989–999.
25. Wen G, Tarczy-Hornoch K, McKean-Cowdin R, et al. Prevalence of myopia, hyperopia, and astigmatism in non-Hispanic white and Asian children: multi-ethnic pediatric eye disease study. Ophthalmology 2013; 120:2109–2116.
26. Castagno VD, Fassa AG, Carret MLV, et al. Hyperopia: a meta-analysis of prevalence and a review of associated factors among school-aged children. BMC Ophthalmol 2014; 14:163.
27. Shankar S, Evans MA, Bobier WR. Hyperopia and emergent literacy of young children: pilot study. Optom Vis Sci 2007; 84:1031–1038.
28. Kulp MT, Ciner E, Maguire M, et al. Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study Group Writing Committee. Uncorrected hyperopia and preschool early literacy: results of the Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) study. Ophthalmology 2016; 123:681–689.
29. van Rijn LJ, Krijnen JSM, Nefkens-Molster AE, et al. Spectacles may improve reading speed in children with hyperopia. Optom Vis Sci 2014; 91:397–403.
30. Narayanasamy S, Vincent SJ, Sampson GP, et al. Impact of simulated hyperopia on academic-related performance in children. Optom Vis Sci 2015; 92:227–236.
31. Rosner J, Rosner J. The relationship between moderate hyperopia and academic achievement: how much plus is enough? J Am Optom Assoc 1997; 68:648–650.
32. Kovarski C, Portalier S, Faucher C, et al. Effects of visual disorders on the academic achievement of French secondary school students. Arch Pediatr 2020; 27:436–441.
33. Harrington S, Davison PA, O’Dwyer V. School performance and undetected and untreated visual problems in schoolchildren in Ireland; a population-based cross-sectional study. Irish Educ Stud 2021. 22https://www.tandfonline.com/doi/full/10.1080/03323315.2021.1899024
34. Evans JR, Morjaria P, Powell C. Vision screening for correctable visual acuity deficits in school-age children and adolescents. Cochrane Database Syst Rev 2018; 2:cd005023.
35. Metsing I, Hansraj R, Jacobs W, et al. Review of school vision screening guidelines. African Vis Eye Health 2018; 77:a444.
36. O’Donoghue L, Rudnicka AR, McClelland JF, et al. Visual acuity measures do not reliably detect childhood refractive error-an epidemiological study. PLoS One 2012; 7:e34441.
37. Anderson HA, Stuebing KK. Subjective versus objective accommodative amplitude: preschool to presbyopia. Optom Vis Sci 2014; 91:1290–1301.
38. Cotter SA, Varma R, Tarczy-Hornoch K, et al. Risk factors associated with childhood strabismus: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies. Ophthalmology 2011; 118:2251–2261.
39. Kulp MT, Ying GS, Huang J, et al. Associations between hyperopia and other vision and refractive error characteristics. Optom Vis Sci 2014; 91:383–389.
40. Ip JM, Robaei D, Kifley A, et al. Prevalence of hyperopia and associations with eye findings in 6- and 12-year-olds. Ophthalmology 2008; 115:678–685.e1.
41. Tarczy-Hornoch K, Varma R, Cotter SA, et al. Risk factors for decreased visual acuity in preschool children: the multi-ethnic pediatric eye disease and Baltimore pediatric eye disease studies. Ophthalmology 2011; 118:2262–2273.
42. Kulp MT, Holmes JM, Dean TW, et al. A randomised clinical trial of immediate versus delayed glasses for moderate hyperopia in 1- and 2-year-olds. Ophthalmology 2019; 126:876–887.
43. Fu Z, Hong H, Su Z, et al. Global prevalence of amblyopia and disease burden projections through 2040: a systematic review and meta-analysis. Br J Ophthalmol 2020; 104:1164–1170.
44. Babinsky E, Candy TR. Why do only some hyperopes become strabismic? Invest Ophthalmol Vis Sci 2013; 54:4941–4955.
45. Leat SJ. To prescribe or not to prescribe? Guidelines for spectacle prescribing in infants and children. Clin Exp Optom 2011; 94:514–527.
46. American Academy of Ophthalmology. Pediatric Eye Evaluations Preferred Practice Pattern. 2017. Available at: https://www.aao.org/preferred-practice-pattern/pediatric-eye-evaluations-ppp-2017. Accessed September 12, 2021.
47. Narayanasamy S, Vincent SJ, Sampson GP, et al. Visual demands in modern Australian primary school classrooms. Clin Exp Optom 2016; 99:233–240.
48. Ichhpujani P, Singh RB, Foulsham W, et al. Visual implications of digital device usage in school children: a cross-sectional study. BMC Ophthalmol 2019; 19:1–8.
49. Simons HD, Gassler PA. Vision anomalies and reading skill: a meta-analysis of the literature. Optom Vis Sci 1988; 65:893–904.
50. Roberts TL, Manny RE, Benoit JS, et al. Impact of cognitive demand during sustained near tasks in children and adults. Optom Vis Sci 2018; 95:223–233.
51. Ciner EB, Kulp MT, Maguire MG, et al. Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study Group Writing Committee. Visual function of moderately hyperopic 4- and 5-year-old children in the vision in preschoolers-hyperopia in preschoolers study. Am J Ophthalmol 2016; 170:143–152.
52. Junghans BM, Azizoglu S, Crewther SG. Unexpectedly high prevalence of asthenopia in Australian school children identified by the CISS survey tool. BMC Ophthalmol 2020; 20:408.
53. Ntodie M, Saunders KJ, Little J-A. Correction of low-moderate hyperopia improves accommodative function for some hyperopic children during sustained near work. Invest Ophthalmol Vis Sci 2021; 62:6.
54. Moher D, Shamseer L, Clarke M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev 2015; 4:1.
55. Moher D, Liberati A, Tetzlaff J, et al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Int J Surg 2010; 8:336–341.
56. Higgins J, Thomas J, Chandler J, et al. Cochrane Handbook for Systematic Reviews of Interventions Version 6.2 (updated February 2021). Cochrane, 2021. Available at: https://training.cochrane.org/handbook/current. Accessed September 10, 2021.
57. UNICEF UK. The United Nations Convention on the Rights of the Child. 1989. Available at: https://www.unicef.org/child-rights-convention/convention-text-childrens-version. Accessed September 12, 2021.
58. Joanna Briggs Institute. Critical Appraisal Tools. Available at: https://jbi.global/critical-appraisal-tools. Accessed September 4, 2021.
59. The World Bank Group. World Bank Country and Lending Groups. 2021. Available at: https://datahelpdesk.worldbank.org/knowledgebase/articles/906519-world-bank-country-and-lending-groups. Accessed December 6, 2021.
60. Hedges LV. Distribution theory for glass's estimator of effect size and related estimators. J Educ Stat 1981; 6:107–128.
61. Cohen J. Statistical Power Analysis for the Behavioral Sciences. 2nd ed.Hillsdale, NJ: Lawrence Erlbaum Associates; 1988.
62. Higgins JP, Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med 2002; 21:1539–1558.
63. Deeks JJ, Higgins JPT, Altman DG. Chapter 10: Analysing data and undertaking meta-analyses. In: Higgins JPT, Thomas J, Chandler J, et al, eds. Cochrane Handbook for Systematic Reviews of Interventions Version 6.2 (Updated February 2021). Cochrane; 2021. Available at: www.training.cochrane.org/handbook. Accessed September 2, 2021.
64. Chebil A, Jeddidi L, Chaker N, et al. Epidemiologic study of hyperopia in schoolchildren in Tunisia. Tunis Med 2014; 92:727–731.
65. Akrami A, Bakmohammadi N, Seyedabadi M, et al. The association between schoolchildren intelligence and refractive error. Eur Rev Med Pharmacol Sci 2012; 16:908–911.
66. Köhler L, Stigmar G. Testing for hypermetropia in the school vision screening programme. Acta Ophthalmol (Copenh) 1981; 59:369–377.
67. Hirsch MJ. The relationship between refractive state of the eye and intelligence test scores. Am J Optom Arch Am Acad Optom 1959; 36:12–21.
68. Fulk GW, Goss DA. Relationship between refractive status and teacher evaluations of school achievement. J Optom Vis Dev 2001; 32:80–82.
69. Lança C, Serra H, Prista J. Reading performance in children with visual function anomalies. Int J Ophthalmol Clin Res 2014; 1:1–5.
70. Yang Y, Li R, Ting D, et al. The associations of high academic performance with childhood ametropia prevalence and myopia development in China. Ann Transl Med 2021; 9:745.
71. Alvarez-Peregrina C, Villa-Collar C, Andreu-Vazquez C, et al. Influence of vision on educational performance: a multivariate analysis. Sustainability 2021; 13:4187.
72. Stewart-Brown S, Haslum MN, Butler N. Educational attainment of 10-year-old children with treated and untreated visual defects. Dev Med Child Neurol 1985; 27:504–513.
73. Eames TH. The influence of hypermetropia and myopia on reading achievement. Am J Ophthalmol 1955; 39:375–377.
74. Hopkins S, Sampson GP, Hendicott PL, et al. Vision problems and reduced reading outcomes in Queensland schoolchildren. Optom Vis Sci 2017; 94:345–352.
75. Atkinson J, Braddick O, Nardini M, et al. Infant hyperopia: detection, distribution, changes and correlates-outcomes from the Cambridge infant screening programs. Optom Vis Sci 2007; 84:84–96.
76. Williams SM, Sanderson GF, Share DL, et al. Refractive error, IQ and reading ability: a longitudinal study from age seven to 11. Dev Med Child Neurol 1988; 30:735–742.
77. Krumholtz I. Results from a pediatric vision screening and its ability to predict academic performance. Optometry 2000; 71:426–430.
78. Palomo-Alvarez C, Puell MC. Binocular function in school children with reading difficulties. Graefes Arch Clin Exp Ophthalmol 2010; 248:885–892.
79. Rosner J, Rosner J. Comparison of visual characteristics in children with and without learning difficulties. Am J Optom Physiol Opt 1987; 64:531–533.
80. Roch-Levecq AC, Brody BL, Thomas RG, et al. Ametropia, preschoolers’ cognitive abilities, and effects of spectacle correction. Arch Ophthalmol 2008; 126:252–258.
81. Lonigan CJ, Burgess SR, Anthony JL. Development of emergent literacy and early reading skills in preschool children: evidence from a latent-variable longitudinal study. Dev Psychol 2000; 36:596–613.
82. Storch SA, Whitehurst GJ. Oral language and code-related precursors to reading: evidence from a longitudinal structural model. Dev Psychol 2002; 38:934–947.
83. Ciner EB, Kulp MT, Pistilli M, et al. Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study Group Writing Committee. Associations between visual function and magnitude of refractive error for emmetropic to moderately hyperopic 4- and 5-year-old children in the vision in preschoolers-hyperopia in preschoolers study. Ophthalmic Physiol Opt 2021; 41:553–564.
84. Plotnikov D, Sheehan NA, Williams C, et al. Hyperopia is not causally associated with a major deficit in educational attainment. Transl Vis Sci Technol 2021; 10:34.
85. Candy TR, Wang J, Ravikumar S. Retinal image quality and postnatal visual experience during infancy. Optom Vis Sci 2009; 86:e556–e571.
86. Grisham JD, Simons HD. Refractive error and the reading process: a literature analysis. J Am Optom Assoc 1986; 57:44–55.
87. Arnold RW. Pseudo-false positive eye/vision photoscreening due to accommodative insufficiency. A serendipitous benefit for poor readers? Binocul Vis Strab Q 2004; 19:75–80.
88. Candy T, Gray K, Hohenbary C, et al. The accommodative lag of the young hyperopic patient. Invest Ophthalmol Vis Sci 2011; 53:143–149.
89. Horwood AM, Riddell PM. Hypo-accommodation responses in hypermetropic infants and children. Br J Ophthalmol 2011; 95:231–237.
90. Roberts T, Stevenson S, Benoit J, et al. Blur detection, depth of field, and accommodation in emmetropic and hyperopic children. Optom Vis Sci 2018; 95:212–222.
91. Williams C, Northstone K, Howard M, et al. Prevalence and risk factors for common vision problems in children: data from the ALSPAC study. Br J Ophthalmol 2008; 92:959–964.
92. Morgan IG, Iribarren R, Fotouhi A, et al. Cycloplegic refraction is the gold standard for epidemiological studies. Acta Ophthalmol 2015; 93:581–585.
93. Fotouhi A, Morgan IG, Iribarren R, et al. Validity of noncycloplegic refraction in the assessment of refractive errors: the Tehran eye study. Acta Ophthalmol 2012; 90:380–386.
94. Wilson LB, Melia M, Kraker RT, et al. Accuracy of autorefraction in children: a report by the American Academy of Ophthalmology. Ophthalmology 2020; 127:1259–1267.
95. Prabhakar SK, Prathibha KS, Angadhi PA, et al. Cycloplegic influence on the accuracy of autorefractometer in myopic and hyperopic children. Nepal J Ophthalmol 2015; 7:148–158.
96. UNESCO Institute for Statistics. Combining Data on Out-of-school Children, Completion and Learning to Offer a More Comprehensive View on SDG 4. Information Paper No. 61. 2019. Available at: http://uis.unesco.org/sites/default/files/documents/ip61-combining-data-out-of-school-children-completion-learning-offer-more-comprehensive-view-sdg4.pdf. Accessed September 12, 2021.
97. United Nations Development Programme, UNESCO, UNICEF, and World Bank. World Declaration on Education for All and Framework for Action to Meet Basic Learning Needs Adopted by the World Conference on Education for All: Meeting Basic Learning Needs. 1990. Available at: https://unesdoc.unesco.org/ark:/48223/pf0000127583. Accessed September 12, 2021.
98. Hopkins S, Black AA, White SL, et al. Validity of the +1.50 plus lens screening test as a predictor of uncorrected moderate hyperopia. Ophthalmic Physiol Opt 2019; 39:141–147.
99. Kulp MT, Ciner E, Maguire M, et al. Vision in Preschoolers-Hyperopia in Preschoolers (VIP-HIP) Study Group. Attention and visual motor integration in young children with uncorrected hyperopia. Optom Vis Sci 2017; 94:965–970.
Keywords:

glasses; hyperopia; learning; refractive error; school-age children

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