Reporting of statistical sample size calculations in publications of trials on age-related macular degeneration, glaucoma and cataract.

All three treatment areas analysed lacked reporting quality regarding the justification of the number of patients included in a clinical trial based on a sample size calculation required for ethical reasons. More than half of all RCT publications reviewed did not provide all of the required information on statistical sample size calculation, and thus lacked transparency and completeness. It is therefore urgently required to involve methodologists in a study's planning and publishing processes to ensure that methodology descriptions are transparent and of high quality.