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Interventions for the Management of Computer Vision Syndrome: A Systematic Review and Meta-analysis.Ophthalmology Oct 2022To evaluate the efficacy and safety of interventions for treating eye strain related to computer use relative to placebo or no treatment. (Meta-Analysis)
Meta-Analysis Review
TOPIC
To evaluate the efficacy and safety of interventions for treating eye strain related to computer use relative to placebo or no treatment.
CLINICAL RELEVANCE
Computer use is pervasive and often associated with eye strain, referred to as computer vision syndrome (CVS). Currently, no clinical guidelines exist to help practitioners provide evidence-based advice about CVS treatments, many of which are marketed directly to patients. This systematic review and meta-analysis was designed to help inform best practice for eye care providers.
METHODS
Eligible randomized controlled trials (RCTs) were identified in Ovid MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and trial registries, searched from inception through November 23, 2021. Eligible studies were appraised for risk of bias and were synthesized. The certainty of the body of evidence was judged using the Grading of Recommendations, Assessment, Development, and Evaluation system. Standardized mean differences (SMDs) were used when differently scaled measures were combined.
RESULTS
Forty-five RCTs, involving 4497 participants, were included. Multifocal lenses did not improve visual fatigue scores compared with single-vision lenses (3 RCTs; SMD, 0.11; 95% confidence interval [CI], -0.14 to 0.37; P = 0.38). Visual fatigue symptoms were not reduced by blue-blocking spectacles (3 RCTs), with evidence judged of low certainty. Relative to placebo, oral berry extract supplementation did not improve visual fatigue (7 RCTs; SMD, -0.27; 95% CI, -0.70 to 0.16; P = 0.22) or dry eye symptoms (4 RCTs; SMD, -0.10; 95% CI, -0.54 to 0.33; P = 0.65). Likewise, berry extract supplementation had no significant effects on critical flicker-fusion frequency (CFF) or accommodative amplitude. Oral omega-3 supplementation for 45 days to 3 months improved dry eye symptoms (2 RCTs; mean difference [MD], -3.36; 95% CI, -3.63 to -3.10 on an 18 unit scale; P < 0.00001) relative to placebo. Oral carotenoid supplementation improved CFF (2 RCTs; MD, 1.55 Hz; 95% CI, 0.42 to 2.67 Hz; P = 0.007) relative to placebo, although the clinical significance of this finding is unclear.
DISCUSSION
We did not identify high-certainty evidence supporting the use of any of the therapies analyzed. Low-certainty evidence suggested that oral omega-3 supplementation reduces dry eye symptoms in symptomatic computer users.
Topics: Asthenopia; Carotenoids; Computers; Dry Eye Syndromes; Eyeglasses; Humans
PubMed: 35597519
DOI: 10.1016/j.ophtha.2022.05.009 -
Nutrients Apr 2023According to reports, supplementation with appropriate doses of taurine may help to reduce visual fatigue. Presently, some progress has been made in research related to... (Review)
Review
According to reports, supplementation with appropriate doses of taurine may help to reduce visual fatigue. Presently, some progress has been made in research related to taurine in eye health, but the lack of systematic summaries has led to the neglect of its application in the relief of visual fatigue. This paper, therefore, provides a systematic review of the sources of taurine, including the endogenous metabolic and exogenous dietary pathways, as well as a detailed review of the distribution and production of exogenous taurine. The physiological mechanisms underlying the production of visual fatigue are summarized and the research progress of taurine in relieving visual fatigue is reviewed, including the safety of consumption and the mechanism of action in relieving visual fatigue, in order to provide some reference basis and inspiration for the development and application of taurine in functional foods for relieving visual fatigue.
Topics: Humans; Taurine; Asthenopia; Diet; Functional Food; Dietary Supplements
PubMed: 37111062
DOI: 10.3390/nu15081843 -
Journal of Medical Internet Research Dec 2020Smartphone overuse has been cited as a potentially modifiable risk factor that can result in visual impairment. However, reported associations between smartphone overuse... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Smartphone overuse has been cited as a potentially modifiable risk factor that can result in visual impairment. However, reported associations between smartphone overuse and visual impairment have been inconsistent.
OBJECTIVE
The aim of this systematic review was to determine the association between smartphone overuse and visual impairment, including myopia, blurred vision, and poor vision, in children and young adults.
METHODS
We conducted a systematic search in the Cochrane Library, PubMed, EMBASE, Web of Science Core Collection, and ScienceDirect databases since the beginning of the databases up to June 2020. Fourteen eligible studies (10 cross-sectional studies and 4 controlled trials) were identified, which included a total of 27,110 subjects with a mean age ranging from 9.5 to 26.0 years. We used a random-effects model for meta-analysis of the 10 cross-sectional studies (26,962 subjects) and a fixed-effects model for meta-analysis of the 4 controlled trials (148 subjects) to combine odds ratios (ORs) and effect sizes (ES). The I statistic was used to assess heterogeneity.
RESULTS
A pooled OR of 1.05 (95% CI 0.98-1.13, P=.16) was obtained from the cross-sectional studies, suggesting that smartphone overuse is not significantly associated with myopia, poor vision, or blurred vision; however, these visual impairments together were more apparent in children (OR 1.06, 95% CI 0.99-1.14, P=.09) than in young adults (OR 0.91, 95% CI 0.57-1.46,P=.71). For the 4 controlled trials, the smartphone overuse groups showed worse visual function scores compared with the reduced-use groups. The pooled ES was 0.76 (95% CI 0.53-0.99), which was statistically significant (P<.001).
CONCLUSIONS
Longer smartphone use may increase the likelihood of ocular symptoms, including myopia, asthenopia, and ocular surface disease, especially in children. Thus, regulating use time and restricting the prolonged use of smartphones may prevent ocular and visual symptoms. Further research on the patterns of use, with longer follow up on the longitudinal associations, will help to inform detailed guidelines and recommendations for smartphone use in children and young adults.
Topics: Adolescent; Adult; Cross-Sectional Studies; Humans; Smartphone; Young Adult
PubMed: 33289673
DOI: 10.2196/21923 -
The Ocular Surface Apr 2023Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred...
Eye strain when performing tasks reliant on a digital environment can cause discomfort, affecting productivity and quality of life. Digital eye strain (the preferred terminology) was defined as "the development or exacerbation of recurrent ocular symptoms and/or signs related specifically to digital device screen viewing". Digital eye strain prevalence of up to 97% has been reported, due to no previously agreed definition/diagnostic criteria and limitations of current questionnaires which fail to differentiate such symptoms from those arising from non-digital tasks. Objective signs such as blink rate or critical flicker frequency changes are not 'diagnostic' of digital eye strain nor validated as sensitive. The mechanisms attributed to ocular surface disease exacerbation are mainly reduced blink rate and completeness, partial/uncorrected refractive error and/or underlying binocular vision anomalies, together with the cognitive demand of the task and differences in position, size, brightness and glare compared to an equivalent non-digital task. In general, interventions are not well established; patients experiencing digital eye strain should be provided with a full refractive correction for the appropriate working distances. Improving blinking, optimizing the work environment and encouraging regular breaks may help. Based on current, best evidence, blue-light blocking interventions do not appear to be an effective management strategy. More and larger clinical trials are needed to assess artificial tear effectiveness for relieving digital eye strain, particularly comparing different constituents; a systematic review within the report identified use of secretagogues and warm compress/humidity goggles/ambient humidifiers as promising strategies, along with nutritional supplementation (such as omega-3 fatty acid supplementation and berry extracts).
Topics: Humans; Quality of Life; Eye Diseases; Asthenopia; Tears; Life Style; Dry Eye Syndromes
PubMed: 37062428
DOI: 10.1016/j.jtos.2023.04.004 -
The Cochrane Database of Systematic... Aug 2023'Blue-light filtering', or 'blue-light blocking', spectacle lenses filter ultraviolet radiation and varying portions of short-wavelength visible light from reaching the... (Review)
Review
BACKGROUND
'Blue-light filtering', or 'blue-light blocking', spectacle lenses filter ultraviolet radiation and varying portions of short-wavelength visible light from reaching the eye. Various blue-light filtering lenses are commercially available. Some claims exist that they can improve visual performance with digital device use, provide retinal protection, and promote sleep quality. We investigated clinical trial evidence for these suggested effects, and considered any potential adverse effects.
OBJECTIVES
To assess the effects of blue-light filtering lenses compared with non-blue-light filtering lenses, for improving visual performance, providing macular protection, and improving sleep quality in adults.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL; containing the Cochrane Eyes and Vision Trials Register; 2022, Issue 3); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and WHO ICTRP, with no date or language restrictions. We last searched the electronic databases on 22 March 2022.
SELECTION CRITERIA
We included randomised controlled trials (RCTs), involving adult participants, where blue-light filtering spectacle lenses were compared with non-blue-light filtering spectacle lenses.
DATA COLLECTION AND ANALYSIS
Primary outcomes were the change in visual fatigue score and critical flicker-fusion frequency (CFF), as continuous outcomes, between baseline and one month of follow-up. Secondary outcomes included best-corrected visual acuity (BCVA), contrast sensitivity, discomfort glare, proportion of eyes with a pathological macular finding, colour discrimination, proportion of participants with reduced daytime alertness, serum melatonin levels, subjective sleep quality, and patient satisfaction with their visual performance. We evaluated findings related to ocular and systemic adverse effects. We followed standard Cochrane methods for data extraction and assessed risk of bias using the Cochrane Risk of Bias 1 (RoB 1) tool. We used GRADE to assess the certainty of the evidence for each outcome.
MAIN RESULTS
We included 17 RCTs, with sample sizes ranging from five to 156 participants, and intervention follow-up periods from less than one day to five weeks. About half of included trials used a parallel-arm design; the rest adopted a cross-over design. A variety of participant characteristics was represented across the studies, ranging from healthy adults to individuals with mental health and sleep disorders. None of the studies had a low risk of bias in all seven Cochrane RoB 1 domains. We judged 65% of studies to have a high risk of bias due to outcome assessors not being masked (detection bias) and 59% to be at high risk of bias of performance bias as participants and personnel were not masked. Thirty-five per cent of studies were pre-registered on a trial registry. We did not perform meta-analyses for any of the outcome measures, due to lack of available quantitative data, heterogenous study populations, and differences in intervention follow-up periods. There may be no difference in subjective visual fatigue scores with blue-light filtering lenses compared to non-blue-light filtering lenses, at less than one week of follow-up (low-certainty evidence). One RCT reported no difference between intervention arms (mean difference (MD) 9.76 units (indicating worse symptoms), 95% confidence interval (CI) -33.95 to 53.47; 120 participants). Further, two studies (46 participants, combined) that measured visual fatigue scores reported no significant difference between intervention arms. There may be little to no difference in CFF with blue-light filtering lenses compared to non-blue-light filtering lenses, measured at less than one day of follow-up (low-certainty evidence). One study reported no significant difference between intervention arms (MD - 1.13 Hz lower (indicating poorer performance), 95% CI - 3.00 to 0.74; 120 participants). Another study reported a less negative change in CFF (indicating less visual fatigue) with high- compared to low-blue-light filtering and no blue-light filtering lenses. Compared to non-blue-light filtering lenses, there is probably little or no effect with blue-light filtering lenses on visual performance (BCVA) (MD 0.00 logMAR units, 95% CI -0.02 to 0.02; 1 study, 156 participants; moderate-certainty evidence), and unknown effects on daytime alertness (2 RCTs, 42 participants; very low-certainty evidence); uncertainty in these effects was due to lack of available data and the small number of studies reporting these outcomes. We do not know if blue-light filtering spectacle lenses are equivalent or superior to non-blue-light filtering spectacle lenses with respect to sleep quality (very low-certainty evidence). Inconsistent findings were evident across six RCTs (148 participants); three studies reported a significant improvement in sleep scores with blue-light filtering lenses compared to non-blue-light filtering lenses, and the other three studies reported no significant difference between intervention arms. We noted differences in the populations across studies and a lack of quantitative data. Device-related adverse effects were not consistently reported (9 RCTs, 333 participants; low-certainty evidence). Nine studies reported on adverse events related to study interventions; three studies described the occurrence of such events. Reported adverse events related to blue-light filtering lenses were infrequent, but included increased depressive symptoms, headache, discomfort wearing the glasses, and lower mood. Adverse events associated with non-blue-light filtering lenses were occasional hyperthymia, and discomfort wearing the spectacles. We were unable to determine whether blue-light filtering lenses affect contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels or overall patient visual satisfaction, compared to non-blue-light filtering lenses, as none of the studies evaluated these outcomes.
AUTHORS' CONCLUSIONS
This systematic review found that blue-light filtering spectacle lenses may not attenuate symptoms of eye strain with computer use, over a short-term follow-up period, compared to non-blue-light filtering lenses. Further, this review found no clinically meaningful difference in changes to CFF with blue-light filtering lenses compared to non-blue-light filtering lenses. Based on the current best available evidence, there is probably little or no effect of blue-light filtering lenses on BCVA compared with non-blue-light filtering lenses. Potential effects on sleep quality were also indeterminate, with included trials reporting mixed outcomes among heterogeneous study populations. There was no evidence from RCT publications relating to the outcomes of contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels, or overall patient visual satisfaction. Future high-quality randomised trials are required to define more clearly the effects of blue-light filtering lenses on visual performance, macular health and sleep, in adult populations.
Topics: Adult; Humans; Eyeglasses; Asthenopia; Melatonin; Sleep; Light; Drug-Related Side Effects and Adverse Reactions
PubMed: 37593770
DOI: 10.1002/14651858.CD013244.pub2 -
Jornal de Pediatria 2015To estimate the prevalence of asthenopia in 0-18 year-old children through a systematic review and meta-analysis of prevalence studies. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To estimate the prevalence of asthenopia in 0-18 year-old children through a systematic review and meta-analysis of prevalence studies.
SOURCES
Inclusion criteria were population-based studies from 1960 to May of 2014 reporting the prevalence of asthenopia in children. The search was performed independently by two reviewers in the PubMed, EMBASE, and LILACS databases, with no language restriction. This systematic review was performed in accordance with the Cochrane Collaboration guidelines and the PRISMA Statement. Downs and Black score was used for quality assessment.
SUMMARY OF FINDINGS
Out of 1692 potentially relevant citations retrieved from electronic databases and searches of reference lists, 26 were identified as potentially eligible. Five of these studies met the inclusion criteria, comprising a total of 2465 subjects. Pooled prevalence of asthenopia was 19.7% (12.4-26.4%). The majority of children with asthenopia did not present visual acuity or refraction abnormalities. The largest study evaluated 1448 children aged 6 years and estimated a prevalence of 12.6%. Associated risk factors were not clearly established.
CONCLUSION
Although asthenopia is a frequent and relevant clinical problem in childhood, with potential consequences for learning, the scarcity of studies about the prevalence and clinical impact of asthenopia hinders the effective planning of public health measures.
Topics: Adolescent; Asthenopia; Child; Child, Preschool; Early Diagnosis; Humans; Infant; Observational Studies as Topic; Prevalence; Selection Bias
PubMed: 25986614
DOI: 10.1016/j.jped.2014.10.008 -
Journal of Optometry 2024This review aimed to estimate the prevalence of computer vision syndrome (CVS) in the general population and subgroups. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
This review aimed to estimate the prevalence of computer vision syndrome (CVS) in the general population and subgroups.
METHODS
A search was conducted in the following the databases: PubMed, SCOPUS, EMBASE, and Web of Science until February 13, 2023. We included studies that assessed the prevalence of CVS in any population. The Joanna Briggs Institute's critical appraisal tool was used to evaluate the methodological quality. A meta-analysis of the prevalence of CVS was done using a random-effects model, assessing the sources of heterogeneity using subgroup and meta-regression analyses.
RESULTS
A total of 103 cross-sectional studies with 66 577 participants were included. The prevalence of CVS was 69.0% (95% CI: 62.3 to 75.3; I: 99.7%), ranging from 12.1 to 97.3% across studies. Point prevalence was higher in women than in men (71.4 vs. 61.8%), university students (76.1%), Africa (71.2%), Asia (69.9%), contact lens wearers (73.1% vs. 63.8%) in studies conducted before the COVID-19 pandemic (72.8%), and in those that did not use the CVS-Q questionnaire (75.4%). In meta-regression, using the CVS-Q scale was associated with a lower prevalence of CVS.
CONCLUSION
Seven out of ten people suffer from CVS. Preventive strategies and interventions are needed to decrease the prevalence of this condition which can affect productivity and quality of life. Future studies should standardize a definition of CVS.
Topics: Female; Humans; Male; Computers; Cross-Sectional Studies; Pandemics; Prevalence; Quality of Life; Syndrome; Asthenopia
PubMed: 37866176
DOI: 10.1016/j.optom.2023.100482 -
Preventive Medicine May 2023Digital eye strain (DES) or computer vision syndrome (CVS) is a phenomenon linked to ever increasing digital screen use globally, affecting a large number of... (Review)
Review
Digital eye strain (DES) or computer vision syndrome (CVS) is a phenomenon linked to ever increasing digital screen use globally, affecting a large number of individuals. Recognizing causative and alleviating factors of DES may help establish appropriate policies. We aimed to review factors that aggravate or alleviate DES symptoms in young, i.e. pre-presbyopic (< 40 years old), digital device users. We searched PubMed, Scopus, EMBASE, Cochrane, Trip Database, and grey literature up to 1st July 2021. Among a plethora of studies with heterogeneous diagnostic criteria for DES, we only included those using a validated questionnaire for the diagnosis and evaluating associated factors in young subjects. Relevant data were extracted, risk of bias assessment of the included studies and GRADE evaluation of each outcome were performed. Ten studies were included (five interventional, five observational) involving 2365 participants. Evidence coming from studies with moderate risk of bias suggested that blue-blocking filters do not appear to prevent DES (2 studies, 130 participants), while use of screens for > 4-5 h/day (2 studies, 461 participants) and poor ergonomic parameters during screen use (1 study, 200 participants) are associated with higher DES symptoms' score. GRADE evaluation for the outcomes of blue-blocking filters and duration of screen use showed low to moderate quality of evidence. It appears advisable to optimize ergonomic parameters and restrict screen use duration, for minimizing DES symptoms. Health professionals and policy makers may consider recommending such practices for digital screen users at work or leisure. There is no evidence for use of blue-blocking filters.
Topics: Adult; Humans; Ergonomics; Computers; Asthenopia
PubMed: 36977430
DOI: 10.1016/j.ypmed.2023.107493 -
The Cochrane Database of Systematic... Apr 2018Computer users frequently complain about problems with seeing and functioning of the eyes. Asthenopia is a term generally used to describe symptoms related to... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Computer users frequently complain about problems with seeing and functioning of the eyes. Asthenopia is a term generally used to describe symptoms related to (prolonged) use of the eyes like ocular fatigue, headache, pain or aching around the eyes, and burning and itchiness of the eyelids. The prevalence of asthenopia during or after work on a computer ranges from 46.3% to 68.5%. Uncorrected or under-corrected refractive error can contribute to the development of asthenopia. A refractive error is an error in the focusing of light by the eye and can lead to reduced visual acuity. There are various possibilities for optical correction of refractive errors including eyeglasses, contact lenses and refractive surgery.
OBJECTIVES
To examine the evidence on the effectiveness, safety and applicability of optical correction of refractive error for reducing and preventing eye symptoms in computer users.
SEARCH METHODS
We searched the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; Embase; Web of Science; and OSH update, all to 20 December 2017. Additionally, we searched trial registries and checked references of included studies.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) and quasi-randomised trials of interventions evaluating optical correction for computer workers with refractive error for preventing or treating asthenopia and their effect on health related quality of life.
DATA COLLECTION AND ANALYSIS
Two authors independently assessed study eligibility and risk of bias, and extracted data. Where appropriate, we combined studies in a meta-analysis.
MAIN RESULTS
We included eight studies with 381 participants. Three were parallel group RCTs, three were cross-over RCTs and two were quasi-randomised cross-over trials. All studies evaluated eyeglasses, there were no studies that evaluated contact lenses or surgery. Seven studies evaluated computer glasses with at least one focal area for the distance of the computer screen with or without additional focal areas in presbyopic persons. Six studies compared computer glasses to other types of glasses; and one study compared them to an ergonomic workplace assessment. The eighth study compared optimal correction of refractive error with the actual spectacle correction in use. Two studies evaluated computer glasses in persons with asthenopia but for the others the glasses were offered to all workers regardless of symptoms. The risk of bias was unclear in five, high in two and low in one study. Asthenopia was measured as eyestrain or a summary score of symptoms but there were no studies on health-related quality of life. Adverse events were measured as headache, nausea or dizziness. Median asthenopia scores at baseline were about 30% of the maximum possible score.Progressive computer glasses versus monofocal glassesOne study found no considerable difference in asthenopia between various progressive computer glasses and monofocal computer glasses after one-year follow-up (mean difference (MD) change scores 0.23, 95% confidence interval (CI) -5.0 to 5.4 on a 100 mm VAS scale, low quality evidence). For headache the results were in favour of progressive glasses.Progressive computer glasses with an intermediate focus in the upper part of the glasses versus other glassesIn two studies progressive computer glasses with intermediate focus led to a small decrease in asthenopia symptoms (SMD -0.49, 95% CI -0.75 to -0.23, low-quality evidence) but not in headache score in the short-term compared to general purpose progressive glasses. There were similar small decreases in dizziness. At medium term follow-up, in one study the effect size was not statistically significant (SMD -0.64, 95% CI -1.40 to 0.12). The study did not assess adverse events.Another study found no considerable difference in asthenopia between progressive computer glasses and monofocal computer glasses after one-year follow-up (MD change scores 1.44, 95% CI -6.95 to 9.83 on a 100 mm VAS scale, very low quality evidence). For headache the results were inconsistent.Progressive computer glasses with far-distance focus in the upper part of the glasses versus other glassesOne study found no considerable difference in number of persons with asthenopia between progressive computer glasses with far-distance focus and bifocal computer glasses after four weeks' follow-up (OR 1.00, 95% CI 0.40 to 2.50, very low quality evidence). The number of persons with headache, nausea and dizziness was also not different between groups.Another study found no considerable difference in asthenopia between progressive computer glasses with far-distance focus and monofocal computer glasses after one-year follow-up (MD change scores -1.79, 95% CI -11.60 to 8.02 on a 100 mm VAS scale, very low quality evidence). The effects on headaches were inconsistent.One study found no difference between progressive far-distance focus computer glasses and trifocal glasses in effect on eyestrain severity (MD -0.50, 95% CI -1.07 to 0.07, very low quality evidence) or on eyestrain frequency (MD -0.75, 95% CI -1.61 to 0.11, very low quality evidence).Progressive computer glasses versus ergonomic assessment with habitual (computer) glassesOne study found that computer glasses optimised for individual needs reduced asthenopia sum score more than an ergonomic assessment and habitual (computer) glasses (MD -8.9, 95% CI -16.47 to -1.33, scale 0 to 140, very low quality evidence) but there was no effect on the frequency of eyestrain (OR 1.08, 95% CI 0.38 to 3.11, very low quality evidence).We rated the quality of the evidence as low or very low due to risk of bias in the included studies, inconsistency in the results and imprecision.
AUTHORS' CONCLUSIONS
There is low to very low quality evidence that providing computer users with progressive computer glasses does not lead to a considerable decrease in problems with the eyes or headaches compared to other computer glasses. Progressive computer glasses might be slightly better than progressive glasses for daily use in the short term but not in the intermediate term and there is no data on long-term follow-up. The quality of the evidence is low or very low and therefore we are uncertain about this conclusion. Larger studies with several hundreds of participants are needed with proper randomisation, validated outcome measurement methods, and longer follow-up of at least one year to improve the quality of the evidence.
Topics: Asthenopia; Computer Terminals; Ergonomics; Eyeglasses; Headache; Humans; Randomized Controlled Trials as Topic; Refractive Errors
PubMed: 29633784
DOI: 10.1002/14651858.CD009877.pub2 -
The Cochrane Database of Systematic... Aug 2014Hyperopia (far-sightedness) in infancy requires accommodative effort to bring images into focus. Prolonged accommodative effort has been associated with an increased... (Review)
Review
BACKGROUND
Hyperopia (far-sightedness) in infancy requires accommodative effort to bring images into focus. Prolonged accommodative effort has been associated with an increased risk of strabismus (eye misalignment). Strabismus makes it difficult for the eyes to work together and may result in symptoms of asthenopia (eye strain) and intermittent diplopia (double vision), and makes near work tasks difficult to complete. Untreated strabismus may result in the development of amblyopia (lazy eye). The prescription of spectacles to correct hyperopic refractive error is believed to prevent the development of strabismus.
OBJECTIVES
To assess the effectiveness of prescription spectacles compared with no intervention for the prevention of strabismus in infants and children with hyperopia.
SEARCH METHODS
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to April 2014), EMBASE (January 1980 to April 2014), PubMed (1966 to April 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 3 April 2014. We also searched the Science Citation Index database in September 2013.
SELECTION CRITERIA
We included randomized controlled trials and quasi-randomized trials investigating the assignment to spectacle intervention or no treatment for children with hyperopia. The definition of hyperopia remains subjective, but we required it to be at least greater than +2.00 diopters (D) of hyperopia.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted data using the standard methodologic procedures expected by The Cochrane Collaboration. One review author entered data into Review Manager and a second review author verified the data entered. The two review authors resolved discrepancies at all stages of the review process.
MAIN RESULTS
We identified three randomized controlled trials (855 children enrolled) in this review. These trials were all conducted in the UK with follow-up periods ranging from one to 3.5 years. We judged the included studies to be at high risk of bias, due to use of quasi-random methods for assigning children to treatment, no masking of outcomes assessors, and high proportions of drop-outs. None of the three trials accounted for missing data and analyses were limited to the available-case data (674 (79%) of 855 children enrolled for the primary outcome). These factors impair our ability to assess the effectiveness of treatment.Analyses incorporating the three trials we identified in this review (674 children) suggested the effect of spectacle correction initiated prior to the age of one year in hyperopic children between three and four years of age is uncertain with respect to preventing strabismus (risk ratio (RR) 0.71; 95% confidence interval (CI) 0.44 to 1.15; very low quality evidence). Based on a meta-analysis of three trials (664 children), the risk of having visual acuity worse than 20/30 at three years of age was also uncertain for children with spectacles compared with those without spectacle correction irrespective of compliance (RR 0.87; 95% CI 0.60 to 1.26; very low quality evidence).Emmetropization was reported in two trials: one trial suggested that spectacles impede emmetropization, and the second trial reported no difference in the rate of refractive error change.
AUTHORS' CONCLUSIONS
Although children who were allocated to the spectacle group were less likely to develop strabismus and less likely to have visual acuity worse than 20/30 children allocated to no spectacles, these effects may have been chance findings, or due to bias. Due to the high risk of bias and poor reporting of included trials, the true effect of spectacle correction for hyperopia on strabismus is still uncertain.
Topics: Age Factors; Child; Child, Preschool; Emmetropia; Eyeglasses; Humans; Hyperopia; Infant; Randomized Controlled Trials as Topic; Strabismus; Treatment Outcome; Vision Disorders; Visual Acuity; Watchful Waiting
PubMed: 25133974
DOI: 10.1002/14651858.CD007738.pub2