Impact of COVID-19 on statistical analyses
death
The number and percentage of participants who died during the study due to COVID-19; who withdrew from the study due to COVID-19; whose month 12 visit was performed by an alternative data ascertainment methodology due to COVID-19 (that is, assessment at a local non-study site or extension of the protocol-defined window to include out-of-window visits); and whose month 12 visit was still missed due to COVID-19 despite the opportunity for alternative data ascertainment were summarized by treatment and by the overall cohort. Individuals who had an alternative data ascertainment or missed the month 12 visit entirely were documented as protocol deviations.For statistical analyses of all BCVA-related endpoints, available alternative data ascertainments were used as month 12 assessments unless an ad hoc visit was made by the participant to the protocol-defined study site within 30 d of the alternative assessment, in which case the data gathered from the ad hoc visit was used. Any instance in which a participant failed to complete the month 12 visit due to withdrawal or death was categorized as missing data and handled the same as other instances of missing data. The sensitivity analyses excluded participants who withdrew from the study or died due to COVID-19, used data from ad hoc visits where available and used imputed data based on alternative data ascertainment visits if the final on-site visit occurred more than 2 months before or 3 months after the planned observation window. These data imputations and/or data handling considerations superseded any subsequent data imputation described above.