A tibble with 10,000 rows and 7 variables:
USUBJID: subject ID.
VISITN: visit number (numeric).
AVISIT: visit number (factor).
ARMCD: treatment, TRT or CTL.
RACE: 3-category race.
BCVA_BL: BCVA at baseline.
BCVA_CHG: Change in BCVA at study visits.