Cagnie 2017.

Methods	Randomised controlled trial, 2 groups, parallel
Participants	35 computer workers who are between 45 and 65 years of age, recruited from the employee population of a financial holding in Ghent (Belgium), performing computer work for at least 4 h a day and 20 h a week, experiencing work‐related neck/shoulder pain or discomfort of more than 30 days during the last year and having a difference in spectacle correction for presbyopia and myopia of minimum 1.5 dioptres. Mean age ± SD (intervention vs. control group): 51.09 ± 4.19 years vs. 53.67 ± 3.97 years Male/Female: 21/14 Country: Belgium
Interventions	Eyeglasses: progressive computer glasses (n=17 randomised, n=15 analyzed) vs. general purpose progressive glasses (n=18 randomised, n=13 analyzed).
Outcomes	Visual fatigue (visual fatigue questionnaire‐ VFQ), self‐perceived pain (numeric rating scale ‐ NRS) and disability (neck disability index ‐ NDI) at baseline (with old glasses), and 1 week, 3 months and 6 months after wearing new glasses. In addition, Forward Head Angle and Pressure Pain Thresholds were assessed during and after a VDU task before and 6 months after wearing the new lenses. A short questionnaire concerning the satisfaction about the study lenses was completed at the end of the study.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Block randomization, yet method not described.Authors responded: "We had an envelope for males and an envelope for females with each 6 sheets. In the envelope for males, there were 6 sheets, 3 with the letter A (was similar to VDU glasses) and 3 with the letter B (was similar to normal glasses). All 6 consecutive male participants took one sheet and pending of the letter they took, they were assigned to the VDU or normal glasses group. The same procedure was performed for the females."
Allocation concealment (selection bias)	Unclear risk	No information on concealment of allocation.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	The authors communicated that: "Patients were not informed by the type of glasses. All glasses looked similar and had similar frames (typical silhouette glasses have no ‘frame’). Although the participants were not informed, they easily knew afterwards to which group they were allocated, as VDU lenses can only be used during VDU work, whereas progressive lenses can be used all day long (this was also mentioned in the discussion section). Subjects didn't know which type of glasses were intended to have a more beneficial effect."
Blinding of outcome assessment (detection bias) Primary outcomes	Low risk	See blinding of participants performance bias.
Incomplete outcome data (attrition bias) All outcomes	High risk	5/18 dropouts in control group; 2/17 dropouts in intervention group. In both groups are reasons related to type of intervention.
Selective reporting (reporting bias)	Unclear risk	No trial register record or study protocol available. Outcomes listed in methods were reported results for.
Other bias	Low risk	No indication of other bias.