Potential biases in the review process
Some trials, only reported the median, minimum, and maximum values, and/or the first and third quartiles (when data do not follow a normal distribution), instead of reporting the sample mean and the standard deviation (SD). Being these measures necessary to pool results in a consistent format, a statistical method was used for its estimation (45). We note that even if the means and SD can be satisfactorily estimated from the proposed formulas, it’s still a question of to what extent it makes sense to use them if they do not represent the true distribution and dispersion of the data.
Information on the safety of oil-based GL comes exclusively from the RCT. Studies with other designs, which could be valuable in providing pharmacovigilance information on adverse effects, were not included.
Also, we were unable to perform a funnel plot to detectpublication bias .