Summary of findings 4. Progressive computer glasses with far distance focus compared to bifocal computer lenses.
| Progressive computer glasses with far distance focus compared to bifocal computer glassesfor preventing and treating asthenopia | ||||||
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Patient or population: computer workers Setting: workplace Intervention: progressive computer glasses with far distance focus Comparison: bifocal computer glasses | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | № of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with Bifocal computer glasses | Risk with Progressive computer glasses | |||||
| Asthenopia (improvement of symptoms after 4 weeks) | Study population | RR 1.00 (0.80 to 1.24) | 38 (1 RCT) | ⊕⊝⊝⊝ very low 1 2 | Cross‐over trial, events during intervention and during control per total group at risk | |
| 895 per 1000 | 895 per 1000 (716 to 1000) | |||||
| Headache (improvement of symptoms after 4 weeks) | Study population | OR 1.43 (0.27 to 7.55) | 36 (1 RCT) | ⊕⊝⊝⊝ very low 1 2 | ||
| 778 per 1000 | 833 per 1000 (486 to 964) | |||||
| Nausea (improvement of symptoms after 4 weeks) | Study population | RR 1.29 (0.68 to 2.45) | 8 (1 RCT) | ⊕⊝⊝⊝ very low 1 2 | ||
| 750 per 1000 | 968 per 1000 (510 to 1000) | |||||
| Dizziness (improvement of symptoms after 4 weeks) | Study population | RR 1.00 (0.25 to 4.00) | 8 (1 RCT) | ⊕⊝⊝⊝ very low 1 2 | ||
| 500 per 1000 | 500 per 1000 (125 to 1000) | |||||
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio; OR: Odds ratio; | ||||||
| GRADE Working Group grades of evidence High quality: we are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect Very low quality: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect | ||||||
1 We downgraded the quality of evidence with two levels because of unclear risk of selection bias, high risk of performance bias and detection bias.
2 We downgraded the quality of evidence with one level because of very small sample size, i.e. the optimal information size not reached.