Wertheimer 1997.
| Methods | Parallel‐group RCT | |
| Participants | 69 participants with acute allergic conjunctivitis | |
| Interventions | Two treatment arms: antazoline 0.05% and tetryzoline 0.04%; levocabastine 0.05%. Duration of treatment 2 weeks | |
| Outcomes | The total symptom score (Figure 1 of the trial report) of eight symptoms (each scored 0 = none; 3 = worst symptom). Four subjective and four objective symptoms; unclear which symptoms were assessed by participants or clinicians | |
| Country | Germany | |
| Number randomised, gender (male:female) | 69 participants randomised. M:F 35:34 | |
| Age mean (SD), median, range | Mean (SD): antazoline and tetryzoline 42.4 (15.4); levocabastine 43.1 (14.9) | |
| Notes | Study conducted from March to August 1995. Source of funding not stated. Declaration of interest by the authors was not stated | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Random sequence generation (p.94): “The randomisation schedule, created at random in blocks of four, assigned patients to the medications and application instructions listed in Table 2” |
| Allocation concealment (selection bias) | Unclear risk | The method used to conceal the allocation sequence was not described |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | No dropouts were mentioned |
| Selective reporting (reporting bias) | High risk | Only P values that were statistically significant were reported (p.95, paragraph 3). No results were reported for outcomes that were not statistically significant (p.94, paragraph 8). Numerical results were not reported in the text for any outcomes except for the numbers with blurred vision (p.95, paragraph 4) |
| Other bias | Low risk | No apparent evidence of other risk of bias |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | (p. 94, paragraph 3): “After 30 minutes the eyes were studied again, without the doctor knowing which drops were administered. The medication and the double‐masked application instructions, which prevented early identification of the medication, were handed over to the patient at the end of the visit” |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Masked at 30‐minute assessment, later assessments were not masked to participants, as treatments had different dose frequencies (2 per day versus 4 per day). Assessment masked to clinicians unclear |
RCT: randomised controlled trial SD: standard deviation